David M. Levy, MD

Take-Home Points

• Fractures of the greater tuberosity are often mismanaged.
• Comprehension of greater tuberosity fractures involves classification into nonoperative and operative treatment, displacement >5mm or <5 mm, and open vs arthroscopic surgery.
• Nearly a third of patients may suffer concomitant anterior glenohumeral instability.
• Stiffness is the most common postoperative complication.
• Surgery is associated with high patient satisfaction and low rates of complications and reoperations.

Although proximal humerus fractures are common in the elderly, isolated fractures of the greater tuberosity occur less often. Management depends on several factors, including fracture pattern and displacement.^1,2 Nondisplaced fractures are often successfully managed with sling immobilization and early range of motion.^3,4 Although surgical intervention improves outcomes in displaced greater tuberosity fractures, the ideal surgical treatment is less clear.⁵

Displaced greater tuberosity fractures may require surgery for prevention of subacromial impingement and range-of-motion deficits.² Superior fracture displacement results in decreased shoulder abduction, and posterior displacement can limit external rotation.⁶ Although the greater tuberosity can displace in any direction, posterosuperior displacement has the worst outcomes.¹ The exact surgery-warranting displacement amount ranges from 3 mm to 10 mm but is yet to be clearly elucidated.^5,6 Less displacement is tolerated by young overhead athletes, and more displacement by older less active patients.^5,7,8 Surgical options for isolated greater tuberosity fractures include fragment excision, open reduction and internal fixation (ORIF), closed reduction with percutaneous fixation, and arthroscopically assisted reduction with internal fixation.^3,9,10

We conducted a study to determine the management patterns for isolated greater tuberosity fractures. We hypothesized that greater tuberosity fractures displaced <5 mm may be managed nonoperatively and that greater tuberosity fractures displaced >5 mm require surgical fixation.

Methods

Search Strategy

We performed this systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist¹¹ and registered it (CRD42014010691) with the PROSPERO international prospective register of systematic reviews. Literature searches using the PubMed/Medline database and the Cochrane Central Register of Clinical Trials were completed in August 2014. There were no date or year restrictions. Key words were used to capture all English- language studies with level I to IV evidence (Oxford Centre for Evidence-Based Medicine) and reported clinical or radiographic outcomes. Initial exclusion criteria were cadaveric, biomechanical, histologic, and kinematic results. An electronic search algorithm with key words and a series of NOT phrases was designed to match our exclusion criteria: 

((((((((((((((((((((((((((((((((((((((((((((((((((greater[Title/Abstract]) AND tuberosity [Title/Abstract] OR tubercle [Title/Abstract]) AND fracture[Title/Abstract]) AND proximal[Title/Abstract] AND (English[lang]))) NOT intramedullary[Title] AND (English[lang]))) NOT nonunion[Title] AND (English[lang]))) NOT malunion[Title] AND (English[lang]))) NOT biomechanical[Title/Abstract] AND (English[lang]))) NOT cadaveric[Title/Abstract] AND (English[lang]))) NOT cadaver[Title/Abstract] AND (English[lang]))) NOT ((basic[Title/Abstract]) AND science[Title/Abstract] AND (English[lang])) AND (English[lang]))) NOT revision[Title] AND (English[lang]))) NOT pediatric[Title] AND (English[lang]))) NOT physeal[Title] AND (English[lang]))) NOT children[Title] AND (English[lang]))) NOT instability[Title] AND (English[lang]))) NOT imaging[Title])) NOT salter[Title])) NOT physis[Title])) NOT shaft[Title])) NOT distal[Title])) NOT clavicle[Title])) NOT scapula[Title])) NOT ((diaphysis[Title]) AND diaphyseal[Title]))) NOT infection[Title])) NOT laboratory[Title/Abstract])) NOT metastatic[Title/Abstract])) NOT (((((((malignancy[Title/Abstract]) OR malignant[Title/Abstract]) OR tumor[Title/Abstract]) OR oncologic[Title/Abstract]) OR cyst[Title/Abstract]) OR aneurysmal[Title/Abstract]) OR unicameral[Title/Abstract]).

Study Selection

We obtained 135 search results and reviewed them for further differentiation. All the references in these studies were cross-referenced for inclusion (if missed by the initial search), which added another 15 studies. Technical notes, letters to the editor, and level V evidence reviews were excluded. Double-counting of patients was avoided by comparing each study’s authors, data collection period, and ethnic population with those of the other studies. In cases of overlapping authorship, period, or place, only the study with the longer follow-up, more patients, or more comprehensive data was included. For studies separating outcomes by diagnosis, only outcomes of isolated greater tuberosity fractures were included. Data on 3- or 4-part proximal humerus fractures and isolated lesser tuberosity fractures were excluded. Studies that could not be deconstructed as such or that were devoted solely to one of our exclusion criteria were excluded. Minimum follow-up was 2 years. After all inclusion and exclusion criteria were accounted for, 13 studies with 429 patients (429 shoulders) were selected for inclusion (Figure, Table 1).^2,5,12-22

 

 

Data Extraction

We extracted data from the 13 studies that met the eligibility criteria. Details of study design, sample size, and patient demographics, including age, sex, and hand dominance, were recorded, as were mechanism of injury and concomitant anterior shoulder instability. To capture the most patients, we noted radiographic fracture displacement categorically rather than continuously; patients were divided into 2 displacement groups (<5 mm, >5 mm). Most studies did not define degree of comminution or specific direction of displacement per fracture, so these variables were not included in the data analysis. Nonoperative management and operative management were studied. We abstracted surgical factors, such as approach, method, fixation type (screws or sutures), and technique (suture anchors or transosseous tunnels). Clinical outcomes included physical examination findings, functional assessment results (patient satisfaction; Constant and University of California Los Angeles [UCLA] shoulder scores), and the number of revisions. Radiologic outcomes, retrieved from radiographs or computed tomography scans, focused on loss of reduction (as determined by the respective authors), malunion, nonunion, and heterotopic ossification. Each study’s methodologic quality and bias were evaluated with the 15-item Modified Coleman Methodology Score (MCMS), which was described by Cowan and colleagues.²³ The MCMS has been used to assess randomized and nonrandomized patient trials.^24,25 Its scaled potential score ranges from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor).

Statistical Analysis

We report our data as weighted means (SDs). A mean was calculated for each study that reported a respective data point, and each mean was then weighed according to its study sample size. This calculation was performed by multiplying a study’s individual mean by the number of patients enrolled in that study and dividing the sum of these weighted data points by the number of eligible patients in all relevant studies. The result was that the nonweighted means from studies with smaller sample sizes did not carry as much weight as the nonweighted means from larger studies. We compared 3 paired groups: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic). Regarding all patient, surgery, and outcomes data, unpaired Student t tests were used for continuous variables and 2-tailed Fisher exact tests for categorical variables with α = 0.05 (SPSS Version 18; IBM).

Results

Demographic information and treatment strategies are listed in Table 2. Fifty-eight percent of patients were male, 59.0% of dominant shoulders were affected, and 59.2% of fractures were displaced <5 mm. Concomitant shoulder instability was reported in 28.1% of patients. Mechanism of injury was not reported in all studies but most commonly (n = 75; 49.3%) involved a fall on an outstretched hand; 31 patients (20.4%) had a sports-related injury, and another 37 (24.3%) were injured in a motor vehicle collision. Of the 429 patients, 217 (50.6%) were treated nonoperatively, and 212 (49.4%) underwent surgery. Open, arthroscopic, and percutaneous approaches were reported. No studies presented outcomes of fragment excision.

Postoperative physical examination findings were underreported so that surgical groups could be compared. Of all the surgical studies, 4 reported postoperative forward elevation (mean, 160°; SD, 9.8°) and external rotation (mean, 46.4°; SD 26.3°).^14,15,18,22 No malunions and only 1 nonunion were reported in all 13 studies. No deaths or other serious medical complications were reported. Patients with anterior instability more often underwent surgery than were treated nonoperatively (39.2% vs 12.0%; P < .01) and more often had fractures displaced >5 mm than <5 mm (44.3% vs 14.5%; P < .01).

 

Comparisons of treatment type are listed in Table 3. Compared with nonoperative patients, operative patients had significantly fewer radiographic losses of reduction (P < .01) and better patient satisfaction (P < .01). Operative patients had a significantly higher rate of shoulder stiffness (P < .01). Eight operative patients (3.8%) and no nonoperative patients required reoperation during clinical follow-up (P < .01). All 12 reported cases of stiffness were in the operative group, and 3 required revision surgery. One patient required revision ORIF. There were 2 cases of postoperative superficial infection (0.9%) and 4 neurologic injuries (1.9%).

Comparisons of displacement amount are listed in Table 4. Compared with fractures displaced >5 mm, those displaced <5 mm had more radiographic losses of reduction (P < .01) but fewer instances of heterotopic ossification (P < .01). Fractures displaced >5 mm were significantly more likely than not to be managed with surgery (P < .01) and significantly more likely to develop stiffness after treatment (P = .01). One patient (0.4%) with a fracture displaced <5 mm eventually underwent surgery for stiffness, and 6 patients (3.6%) with fractures displaced >5 mm required reoperation (P = .02).

Comparisons of surgery type are listed in Table 5. All open procedures were performed with a deltoid-splitting approach. Screw fixation was used in 4 cases: 2 percutaneous^5,21 and 2 open.^2,5 The other open and arthroscopic studies described suture fixation, half with anchors (77/156 patients; 49.4%) and half with transosseous tunnels (79/156; 50.6%). There were no statistically significant differences between open/percutaneous and arthroscopic techniques in terms of stiffness, superficial infection, neurologic injury, or reoperation rate.

Fisher exact tests were used to perform isolated comparisons of screws and sutures as well as suture anchors and transosseous tunnels. Patients with screw fixation were significantly (P = .051) less likely to require reoperation (0/56; 0%) than patients with suture fixation (8/100; 8.0%). Screw fixation also led to significantly less stiffness (0% vs 12.0%; P < .01) but trended toward a higher rate of superficial infection (3.6% vs 0%; P = .13). There was no statistical difference in nerve injury rates between screws and sutures (1.8% vs 3.0%; P = 1.0). There were no significant differences in reoperations, stiffness, superficial infections, or nerve injuries between suture anchor and transosseous tunnel constructs.

 

For all 13 studies, mean (SD) MCMS was 41.1 (8.6).

Discussion

Five percent of all fractures involve the proximal humerus, and 20% of proximal humerus fractures are isolated greater tuberosity fractures.^26,27 In his classic 1970 article, Neer⁶ formulated the 4-part proximal humerus fracture classification and defined greater tuberosity fracture “parts” using the same criteria as for other fracture “parts.” Neer⁶ recommended nonoperative management for isolated greater tuberosity fractures displaced <1 cm but did not present evidence corroborating his recommendation. More recent cutoffs for nonoperative management include 5 mm (general population) and 3 mm (athletes).^7,17

In the present systematic review of greater tuberosity fractures, 3 separate comparisons were made: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic).

Treatment Type. Only 4 studies reported data on nonoperative treatment outcomes.^5,12,16,17 Of these 4 studies, 2 found successful outcomes for fractures displaced <5 mm.^12,17 Platzer and colleagues¹⁷ found good or excellent results in 97% of 135 shoulders after 4 years. Good results were defined with shoulder scores of ≥80 (Constant), <8 (Vienna), and >28 (UCLA), and excellent results were defined with maximum scores on 2 of the 3 systems. Platzer and colleagues¹⁷ also found nonsignificantly worse shoulder scores with superior displacement of 3 mm to 5 mm and recommended surgery for overhead athletes in this group. Rath and colleagues¹² described a successful 3-phase rehabilitation protocol of sling immobilization for 3 weeks, pendulum exercises for 3 weeks, and active exercises thereafter. By an average of 31 months, patient satisfaction scores improved to 9.5 from 4.2 (10-point scale), though the authors cautioned that pain and decreased motion lasted 8 months on average. Conservative treatment was far less successful in the 2 studies of fractures displaced >5 mm.^5,16 Keene and colleagues¹⁶ reported unsatisfactory results in all 4 patients with fractures displaced >1.5 cm. In a study separate from their 2005 analysis,¹⁷ Platzer and colleagues⁵ in 2008 evaluated displaced fractures and found function and patient satisfaction were inferior after nonoperative treatment than after surgery. The studies by Keene and colleagues¹⁶ and Platzer and colleagues⁵ support the finding of an overall lower patient satisfaction rate in nonoperative patients.

Fracture Displacement Amount. Only 2 arthroscopic studies and no open studies addressed surgery for fractures displaced <5 mm. Fewer than 16% of these fractures were managed operatively, and <1% required reoperation. By contrast, almost all fractures displaced >5 mm were managed operatively, and 3.6% required reoperation. Radiographic loss of reduction was more common in fractures displaced <5 mm, primarily because they were managed without fixation. Radiographic loss of reduction was reported in only 9 operatively treated patients, none of whom was symptomatic enough to require another surgery.⁵ Reoperations were most commonly performed for stiffness, which itself was significantly more common in fractures displaced >5 mm. Bhatia and colleagues¹⁴ reported the highest reoperation rate (14.3%; 3/21), but they studied more complex, comminuted fractures of the greater tuberosity. Two of their 3 reoperations were biceps tenodeses for inflamed, stiff tenosynovitis, and the third patient had a foreign body giant cell reaction to suture material. Fewer than 1% of patients with operatively managed displaced fractures required revision ORIF, and <2% developed a superficial infection or postoperative nerve palsy.^19,22 For displaced greater tuberosity fractures, surgery is highly successful overall, complication rates are very low, and 90% of patients report being satisfied.

Surgery Type. Patients were divided into 2 groups. In the nonarthroscopic group, open and percutaneous approaches were used. All studies that described a percutaneous approach used screw fixation^5,21; in addition, 32 patients were treated with screws through an open approach.^2,5 The other open and arthroscopic studies used suture fixation. Interestingly, no studies reported on clinical outcomes of fragment excision. There were no statistically significant differences in rates of reoperation, stiffness, infection, or neurologic injury between the arthroscopic and nonarthroscopic groups. Patient satisfaction scores were slightly higher in the nonarthroscopic group (91.0% vs 87.8%), but the difference was not statistically significant.

 

With surgical techniques isolated, there were no significant differences between suture anchors and transosseous tunnel constructs, but screws performed significantly better than suture techniques. Compared with suture fixation, screw fixation led to significantly fewer cases of stiffness and reoperation, which suggests surgeons need to give screws more consideration in the operative management of these fractures. However, the number of patients treated with screws was smaller than the number treated with suture fixation; it is possible the differences between these cohorts would be eliminated if there were more patients in the screw cohort. In addition, screw fixation was universally performed with an open or percutaneous approach and trended toward a higher infection rate. As screw and suture techniques have low rates of complications and reoperations, we recommend leaving fixation choice to the surgeon.

Anterior shoulder instability has been associated with greater tuberosity fractures.^1,8,19 The supraspinatus, infraspinatus, and teres minor muscles all insert into the greater tuberosity and resist anterior translation of the proximal humerus. Loss of this dynamic muscle stabilization is amplified by tuberosity fracture displacement: Anterior shoulder instability was significantly more common in fractures displaced >5 mm (44.3%) vs <5 mm (14.5%). In turn, glenohumeral instability was more common in patients treated with surgery, specifically open surgery, because displaced fractures may not be as easily accessed with arthroscopic techniques. No studies reported concomitant labral repair or capsular plication techniques.

This systematic review was limited by the studies analyzed. All but 1 study⁵ had level IV evidence. Mean (SD) MCMS was 41.8 (8.6). Any MCMS score <54 indicates a poor methodology level, but this scoring system is designed for randomized controlled trials,²³ and there were none in this study. Physical examination findings, such as range of motion, were underreported. In addition, radiographic parameters were not consistently described but rather were determined by the respective authors’ subjective interpretations of malunion, nonunion, and loss of reduction. Publication bias is present in that we excluded non- English language studies and medical conference abstracts and may have omitted potentially eligible studies not discoverable with our search methodology. Performance bias is a factor in any systematic review with multiple surgeons and wide variation in surgical technique.

Conclusion

Greater tuberosity fractures displaced <5 mm may be safely managed nonoperatively, as there are no reports of nonoperatively managed fractures that subsequently required surgery. Nonoperative treatment was initially associated with low patient satisfaction, but only because displaced fractures were conservatively managed in early studies.^5,16 Fractures displaced >5 mm respond well to operative fixation with screws, suture anchors, or transosseous suture tunnels. Stiffness is the most common postoperative complication (<6%), followed by heterotopic ossification, transient neurapraxias, and superficial infection. There are no discernible differences in outcome between open and arthroscopic techniques, but screw fixation may lead to significantly fewer cases of stiffness and reoperation in comparison with suture constructs.

Take-Home Points

• Fractures of the greater tuberosity are often mismanaged.
• Comprehension of greater tuberosity fractures involves classification into nonoperative and operative treatment, displacement >5mm or <5 mm, and open vs arthroscopic surgery.
• Nearly a third of patients may suffer concomitant anterior glenohumeral instability.
• Stiffness is the most common postoperative complication.
• Surgery is associated with high patient satisfaction and low rates of complications and reoperations.

Although proximal humerus fractures are common in the elderly, isolated fractures of the greater tuberosity occur less often. Management depends on several factors, including fracture pattern and displacement.^1,2 Nondisplaced fractures are often successfully managed with sling immobilization and early range of motion.^3,4 Although surgical intervention improves outcomes in displaced greater tuberosity fractures, the ideal surgical treatment is less clear.⁵

Displaced greater tuberosity fractures may require surgery for prevention of subacromial impingement and range-of-motion deficits.² Superior fracture displacement results in decreased shoulder abduction, and posterior displacement can limit external rotation.⁶ Although the greater tuberosity can displace in any direction, posterosuperior displacement has the worst outcomes.¹ The exact surgery-warranting displacement amount ranges from 3 mm to 10 mm but is yet to be clearly elucidated.^5,6 Less displacement is tolerated by young overhead athletes, and more displacement by older less active patients.^5,7,8 Surgical options for isolated greater tuberosity fractures include fragment excision, open reduction and internal fixation (ORIF), closed reduction with percutaneous fixation, and arthroscopically assisted reduction with internal fixation.^3,9,10

We conducted a study to determine the management patterns for isolated greater tuberosity fractures. We hypothesized that greater tuberosity fractures displaced <5 mm may be managed nonoperatively and that greater tuberosity fractures displaced >5 mm require surgical fixation.

Methods

Search Strategy

We performed this systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist¹¹ and registered it (CRD42014010691) with the PROSPERO international prospective register of systematic reviews. Literature searches using the PubMed/Medline database and the Cochrane Central Register of Clinical Trials were completed in August 2014. There were no date or year restrictions. Key words were used to capture all English- language studies with level I to IV evidence (Oxford Centre for Evidence-Based Medicine) and reported clinical or radiographic outcomes. Initial exclusion criteria were cadaveric, biomechanical, histologic, and kinematic results. An electronic search algorithm with key words and a series of NOT phrases was designed to match our exclusion criteria: 

((((((((((((((((((((((((((((((((((((((((((((((((((greater[Title/Abstract]) AND tuberosity [Title/Abstract] OR tubercle [Title/Abstract]) AND fracture[Title/Abstract]) AND proximal[Title/Abstract] AND (English[lang]))) NOT intramedullary[Title] AND (English[lang]))) NOT nonunion[Title] AND (English[lang]))) NOT malunion[Title] AND (English[lang]))) NOT biomechanical[Title/Abstract] AND (English[lang]))) NOT cadaveric[Title/Abstract] AND (English[lang]))) NOT cadaver[Title/Abstract] AND (English[lang]))) NOT ((basic[Title/Abstract]) AND science[Title/Abstract] AND (English[lang])) AND (English[lang]))) NOT revision[Title] AND (English[lang]))) NOT pediatric[Title] AND (English[lang]))) NOT physeal[Title] AND (English[lang]))) NOT children[Title] AND (English[lang]))) NOT instability[Title] AND (English[lang]))) NOT imaging[Title])) NOT salter[Title])) NOT physis[Title])) NOT shaft[Title])) NOT distal[Title])) NOT clavicle[Title])) NOT scapula[Title])) NOT ((diaphysis[Title]) AND diaphyseal[Title]))) NOT infection[Title])) NOT laboratory[Title/Abstract])) NOT metastatic[Title/Abstract])) NOT (((((((malignancy[Title/Abstract]) OR malignant[Title/Abstract]) OR tumor[Title/Abstract]) OR oncologic[Title/Abstract]) OR cyst[Title/Abstract]) OR aneurysmal[Title/Abstract]) OR unicameral[Title/Abstract]).

Study Selection

We obtained 135 search results and reviewed them for further differentiation. All the references in these studies were cross-referenced for inclusion (if missed by the initial search), which added another 15 studies. Technical notes, letters to the editor, and level V evidence reviews were excluded. Double-counting of patients was avoided by comparing each study’s authors, data collection period, and ethnic population with those of the other studies. In cases of overlapping authorship, period, or place, only the study with the longer follow-up, more patients, or more comprehensive data was included. For studies separating outcomes by diagnosis, only outcomes of isolated greater tuberosity fractures were included. Data on 3- or 4-part proximal humerus fractures and isolated lesser tuberosity fractures were excluded. Studies that could not be deconstructed as such or that were devoted solely to one of our exclusion criteria were excluded. Minimum follow-up was 2 years. After all inclusion and exclusion criteria were accounted for, 13 studies with 429 patients (429 shoulders) were selected for inclusion (Figure, Table 1).^2,5,12-22

 

 

Data Extraction

We extracted data from the 13 studies that met the eligibility criteria. Details of study design, sample size, and patient demographics, including age, sex, and hand dominance, were recorded, as were mechanism of injury and concomitant anterior shoulder instability. To capture the most patients, we noted radiographic fracture displacement categorically rather than continuously; patients were divided into 2 displacement groups (<5 mm, >5 mm). Most studies did not define degree of comminution or specific direction of displacement per fracture, so these variables were not included in the data analysis. Nonoperative management and operative management were studied. We abstracted surgical factors, such as approach, method, fixation type (screws or sutures), and technique (suture anchors or transosseous tunnels). Clinical outcomes included physical examination findings, functional assessment results (patient satisfaction; Constant and University of California Los Angeles [UCLA] shoulder scores), and the number of revisions. Radiologic outcomes, retrieved from radiographs or computed tomography scans, focused on loss of reduction (as determined by the respective authors), malunion, nonunion, and heterotopic ossification. Each study’s methodologic quality and bias were evaluated with the 15-item Modified Coleman Methodology Score (MCMS), which was described by Cowan and colleagues.²³ The MCMS has been used to assess randomized and nonrandomized patient trials.^24,25 Its scaled potential score ranges from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor).

Statistical Analysis

We report our data as weighted means (SDs). A mean was calculated for each study that reported a respective data point, and each mean was then weighed according to its study sample size. This calculation was performed by multiplying a study’s individual mean by the number of patients enrolled in that study and dividing the sum of these weighted data points by the number of eligible patients in all relevant studies. The result was that the nonweighted means from studies with smaller sample sizes did not carry as much weight as the nonweighted means from larger studies. We compared 3 paired groups: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic). Regarding all patient, surgery, and outcomes data, unpaired Student t tests were used for continuous variables and 2-tailed Fisher exact tests for categorical variables with α = 0.05 (SPSS Version 18; IBM).

Results

Demographic information and treatment strategies are listed in Table 2. Fifty-eight percent of patients were male, 59.0% of dominant shoulders were affected, and 59.2% of fractures were displaced <5 mm. Concomitant shoulder instability was reported in 28.1% of patients. Mechanism of injury was not reported in all studies but most commonly (n = 75; 49.3%) involved a fall on an outstretched hand; 31 patients (20.4%) had a sports-related injury, and another 37 (24.3%) were injured in a motor vehicle collision. Of the 429 patients, 217 (50.6%) were treated nonoperatively, and 212 (49.4%) underwent surgery. Open, arthroscopic, and percutaneous approaches were reported. No studies presented outcomes of fragment excision.

Postoperative physical examination findings were underreported so that surgical groups could be compared. Of all the surgical studies, 4 reported postoperative forward elevation (mean, 160°; SD, 9.8°) and external rotation (mean, 46.4°; SD 26.3°).^14,15,18,22 No malunions and only 1 nonunion were reported in all 13 studies. No deaths or other serious medical complications were reported. Patients with anterior instability more often underwent surgery than were treated nonoperatively (39.2% vs 12.0%; P < .01) and more often had fractures displaced >5 mm than <5 mm (44.3% vs 14.5%; P < .01).

 

Comparisons of treatment type are listed in Table 3. Compared with nonoperative patients, operative patients had significantly fewer radiographic losses of reduction (P < .01) and better patient satisfaction (P < .01). Operative patients had a significantly higher rate of shoulder stiffness (P < .01). Eight operative patients (3.8%) and no nonoperative patients required reoperation during clinical follow-up (P < .01). All 12 reported cases of stiffness were in the operative group, and 3 required revision surgery. One patient required revision ORIF. There were 2 cases of postoperative superficial infection (0.9%) and 4 neurologic injuries (1.9%).

Comparisons of displacement amount are listed in Table 4. Compared with fractures displaced >5 mm, those displaced <5 mm had more radiographic losses of reduction (P < .01) but fewer instances of heterotopic ossification (P < .01). Fractures displaced >5 mm were significantly more likely than not to be managed with surgery (P < .01) and significantly more likely to develop stiffness after treatment (P = .01). One patient (0.4%) with a fracture displaced <5 mm eventually underwent surgery for stiffness, and 6 patients (3.6%) with fractures displaced >5 mm required reoperation (P = .02).

Comparisons of surgery type are listed in Table 5. All open procedures were performed with a deltoid-splitting approach. Screw fixation was used in 4 cases: 2 percutaneous^5,21 and 2 open.^2,5 The other open and arthroscopic studies described suture fixation, half with anchors (77/156 patients; 49.4%) and half with transosseous tunnels (79/156; 50.6%). There were no statistically significant differences between open/percutaneous and arthroscopic techniques in terms of stiffness, superficial infection, neurologic injury, or reoperation rate.

Fisher exact tests were used to perform isolated comparisons of screws and sutures as well as suture anchors and transosseous tunnels. Patients with screw fixation were significantly (P = .051) less likely to require reoperation (0/56; 0%) than patients with suture fixation (8/100; 8.0%). Screw fixation also led to significantly less stiffness (0% vs 12.0%; P < .01) but trended toward a higher rate of superficial infection (3.6% vs 0%; P = .13). There was no statistical difference in nerve injury rates between screws and sutures (1.8% vs 3.0%; P = 1.0). There were no significant differences in reoperations, stiffness, superficial infections, or nerve injuries between suture anchor and transosseous tunnel constructs.

 

For all 13 studies, mean (SD) MCMS was 41.1 (8.6).

Discussion

Five percent of all fractures involve the proximal humerus, and 20% of proximal humerus fractures are isolated greater tuberosity fractures.^26,27 In his classic 1970 article, Neer⁶ formulated the 4-part proximal humerus fracture classification and defined greater tuberosity fracture “parts” using the same criteria as for other fracture “parts.” Neer⁶ recommended nonoperative management for isolated greater tuberosity fractures displaced <1 cm but did not present evidence corroborating his recommendation. More recent cutoffs for nonoperative management include 5 mm (general population) and 3 mm (athletes).^7,17

In the present systematic review of greater tuberosity fractures, 3 separate comparisons were made: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic).

Treatment Type. Only 4 studies reported data on nonoperative treatment outcomes.^5,12,16,17 Of these 4 studies, 2 found successful outcomes for fractures displaced <5 mm.^12,17 Platzer and colleagues¹⁷ found good or excellent results in 97% of 135 shoulders after 4 years. Good results were defined with shoulder scores of ≥80 (Constant), <8 (Vienna), and >28 (UCLA), and excellent results were defined with maximum scores on 2 of the 3 systems. Platzer and colleagues¹⁷ also found nonsignificantly worse shoulder scores with superior displacement of 3 mm to 5 mm and recommended surgery for overhead athletes in this group. Rath and colleagues¹² described a successful 3-phase rehabilitation protocol of sling immobilization for 3 weeks, pendulum exercises for 3 weeks, and active exercises thereafter. By an average of 31 months, patient satisfaction scores improved to 9.5 from 4.2 (10-point scale), though the authors cautioned that pain and decreased motion lasted 8 months on average. Conservative treatment was far less successful in the 2 studies of fractures displaced >5 mm.^5,16 Keene and colleagues¹⁶ reported unsatisfactory results in all 4 patients with fractures displaced >1.5 cm. In a study separate from their 2005 analysis,¹⁷ Platzer and colleagues⁵ in 2008 evaluated displaced fractures and found function and patient satisfaction were inferior after nonoperative treatment than after surgery. The studies by Keene and colleagues¹⁶ and Platzer and colleagues⁵ support the finding of an overall lower patient satisfaction rate in nonoperative patients.

Fracture Displacement Amount. Only 2 arthroscopic studies and no open studies addressed surgery for fractures displaced <5 mm. Fewer than 16% of these fractures were managed operatively, and <1% required reoperation. By contrast, almost all fractures displaced >5 mm were managed operatively, and 3.6% required reoperation. Radiographic loss of reduction was more common in fractures displaced <5 mm, primarily because they were managed without fixation. Radiographic loss of reduction was reported in only 9 operatively treated patients, none of whom was symptomatic enough to require another surgery.⁵ Reoperations were most commonly performed for stiffness, which itself was significantly more common in fractures displaced >5 mm. Bhatia and colleagues¹⁴ reported the highest reoperation rate (14.3%; 3/21), but they studied more complex, comminuted fractures of the greater tuberosity. Two of their 3 reoperations were biceps tenodeses for inflamed, stiff tenosynovitis, and the third patient had a foreign body giant cell reaction to suture material. Fewer than 1% of patients with operatively managed displaced fractures required revision ORIF, and <2% developed a superficial infection or postoperative nerve palsy.^19,22 For displaced greater tuberosity fractures, surgery is highly successful overall, complication rates are very low, and 90% of patients report being satisfied.

Surgery Type. Patients were divided into 2 groups. In the nonarthroscopic group, open and percutaneous approaches were used. All studies that described a percutaneous approach used screw fixation^5,21; in addition, 32 patients were treated with screws through an open approach.^2,5 The other open and arthroscopic studies used suture fixation. Interestingly, no studies reported on clinical outcomes of fragment excision. There were no statistically significant differences in rates of reoperation, stiffness, infection, or neurologic injury between the arthroscopic and nonarthroscopic groups. Patient satisfaction scores were slightly higher in the nonarthroscopic group (91.0% vs 87.8%), but the difference was not statistically significant.

 

With surgical techniques isolated, there were no significant differences between suture anchors and transosseous tunnel constructs, but screws performed significantly better than suture techniques. Compared with suture fixation, screw fixation led to significantly fewer cases of stiffness and reoperation, which suggests surgeons need to give screws more consideration in the operative management of these fractures. However, the number of patients treated with screws was smaller than the number treated with suture fixation; it is possible the differences between these cohorts would be eliminated if there were more patients in the screw cohort. In addition, screw fixation was universally performed with an open or percutaneous approach and trended toward a higher infection rate. As screw and suture techniques have low rates of complications and reoperations, we recommend leaving fixation choice to the surgeon.

Anterior shoulder instability has been associated with greater tuberosity fractures.^1,8,19 The supraspinatus, infraspinatus, and teres minor muscles all insert into the greater tuberosity and resist anterior translation of the proximal humerus. Loss of this dynamic muscle stabilization is amplified by tuberosity fracture displacement: Anterior shoulder instability was significantly more common in fractures displaced >5 mm (44.3%) vs <5 mm (14.5%). In turn, glenohumeral instability was more common in patients treated with surgery, specifically open surgery, because displaced fractures may not be as easily accessed with arthroscopic techniques. No studies reported concomitant labral repair or capsular plication techniques.

This systematic review was limited by the studies analyzed. All but 1 study⁵ had level IV evidence. Mean (SD) MCMS was 41.8 (8.6). Any MCMS score <54 indicates a poor methodology level, but this scoring system is designed for randomized controlled trials,²³ and there were none in this study. Physical examination findings, such as range of motion, were underreported. In addition, radiographic parameters were not consistently described but rather were determined by the respective authors’ subjective interpretations of malunion, nonunion, and loss of reduction. Publication bias is present in that we excluded non- English language studies and medical conference abstracts and may have omitted potentially eligible studies not discoverable with our search methodology. Performance bias is a factor in any systematic review with multiple surgeons and wide variation in surgical technique.

Conclusion

Greater tuberosity fractures displaced <5 mm may be safely managed nonoperatively, as there are no reports of nonoperatively managed fractures that subsequently required surgery. Nonoperative treatment was initially associated with low patient satisfaction, but only because displaced fractures were conservatively managed in early studies.^5,16 Fractures displaced >5 mm respond well to operative fixation with screws, suture anchors, or transosseous suture tunnels. Stiffness is the most common postoperative complication (<6%), followed by heterotopic ossification, transient neurapraxias, and superficial infection. There are no discernible differences in outcome between open and arthroscopic techniques, but screw fixation may lead to significantly fewer cases of stiffness and reoperation in comparison with suture constructs.

Take-Home Points

• Fractures of the greater tuberosity are often mismanaged.
• Comprehension of greater tuberosity fractures involves classification into nonoperative and operative treatment, displacement >5mm or <5 mm, and open vs arthroscopic surgery.
• Nearly a third of patients may suffer concomitant anterior glenohumeral instability.
• Stiffness is the most common postoperative complication.
• Surgery is associated with high patient satisfaction and low rates of complications and reoperations.

Although proximal humerus fractures are common in the elderly, isolated fractures of the greater tuberosity occur less often. Management depends on several factors, including fracture pattern and displacement.^1,2 Nondisplaced fractures are often successfully managed with sling immobilization and early range of motion.^3,4 Although surgical intervention improves outcomes in displaced greater tuberosity fractures, the ideal surgical treatment is less clear.⁵

Displaced greater tuberosity fractures may require surgery for prevention of subacromial impingement and range-of-motion deficits.² Superior fracture displacement results in decreased shoulder abduction, and posterior displacement can limit external rotation.⁶ Although the greater tuberosity can displace in any direction, posterosuperior displacement has the worst outcomes.¹ The exact surgery-warranting displacement amount ranges from 3 mm to 10 mm but is yet to be clearly elucidated.^5,6 Less displacement is tolerated by young overhead athletes, and more displacement by older less active patients.^5,7,8 Surgical options for isolated greater tuberosity fractures include fragment excision, open reduction and internal fixation (ORIF), closed reduction with percutaneous fixation, and arthroscopically assisted reduction with internal fixation.^3,9,10

We conducted a study to determine the management patterns for isolated greater tuberosity fractures. We hypothesized that greater tuberosity fractures displaced <5 mm may be managed nonoperatively and that greater tuberosity fractures displaced >5 mm require surgical fixation.

Methods

Search Strategy

We performed this systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist¹¹ and registered it (CRD42014010691) with the PROSPERO international prospective register of systematic reviews. Literature searches using the PubMed/Medline database and the Cochrane Central Register of Clinical Trials were completed in August 2014. There were no date or year restrictions. Key words were used to capture all English- language studies with level I to IV evidence (Oxford Centre for Evidence-Based Medicine) and reported clinical or radiographic outcomes. Initial exclusion criteria were cadaveric, biomechanical, histologic, and kinematic results. An electronic search algorithm with key words and a series of NOT phrases was designed to match our exclusion criteria: 

((((((((((((((((((((((((((((((((((((((((((((((((((greater[Title/Abstract]) AND tuberosity [Title/Abstract] OR tubercle [Title/Abstract]) AND fracture[Title/Abstract]) AND proximal[Title/Abstract] AND (English[lang]))) NOT intramedullary[Title] AND (English[lang]))) NOT nonunion[Title] AND (English[lang]))) NOT malunion[Title] AND (English[lang]))) NOT biomechanical[Title/Abstract] AND (English[lang]))) NOT cadaveric[Title/Abstract] AND (English[lang]))) NOT cadaver[Title/Abstract] AND (English[lang]))) NOT ((basic[Title/Abstract]) AND science[Title/Abstract] AND (English[lang])) AND (English[lang]))) NOT revision[Title] AND (English[lang]))) NOT pediatric[Title] AND (English[lang]))) NOT physeal[Title] AND (English[lang]))) NOT children[Title] AND (English[lang]))) NOT instability[Title] AND (English[lang]))) NOT imaging[Title])) NOT salter[Title])) NOT physis[Title])) NOT shaft[Title])) NOT distal[Title])) NOT clavicle[Title])) NOT scapula[Title])) NOT ((diaphysis[Title]) AND diaphyseal[Title]))) NOT infection[Title])) NOT laboratory[Title/Abstract])) NOT metastatic[Title/Abstract])) NOT (((((((malignancy[Title/Abstract]) OR malignant[Title/Abstract]) OR tumor[Title/Abstract]) OR oncologic[Title/Abstract]) OR cyst[Title/Abstract]) OR aneurysmal[Title/Abstract]) OR unicameral[Title/Abstract]).

Study Selection

We obtained 135 search results and reviewed them for further differentiation. All the references in these studies were cross-referenced for inclusion (if missed by the initial search), which added another 15 studies. Technical notes, letters to the editor, and level V evidence reviews were excluded. Double-counting of patients was avoided by comparing each study’s authors, data collection period, and ethnic population with those of the other studies. In cases of overlapping authorship, period, or place, only the study with the longer follow-up, more patients, or more comprehensive data was included. For studies separating outcomes by diagnosis, only outcomes of isolated greater tuberosity fractures were included. Data on 3- or 4-part proximal humerus fractures and isolated lesser tuberosity fractures were excluded. Studies that could not be deconstructed as such or that were devoted solely to one of our exclusion criteria were excluded. Minimum follow-up was 2 years. After all inclusion and exclusion criteria were accounted for, 13 studies with 429 patients (429 shoulders) were selected for inclusion (Figure, Table 1).^2,5,12-22

 

 

Data Extraction

We extracted data from the 13 studies that met the eligibility criteria. Details of study design, sample size, and patient demographics, including age, sex, and hand dominance, were recorded, as were mechanism of injury and concomitant anterior shoulder instability. To capture the most patients, we noted radiographic fracture displacement categorically rather than continuously; patients were divided into 2 displacement groups (<5 mm, >5 mm). Most studies did not define degree of comminution or specific direction of displacement per fracture, so these variables were not included in the data analysis. Nonoperative management and operative management were studied. We abstracted surgical factors, such as approach, method, fixation type (screws or sutures), and technique (suture anchors or transosseous tunnels). Clinical outcomes included physical examination findings, functional assessment results (patient satisfaction; Constant and University of California Los Angeles [UCLA] shoulder scores), and the number of revisions. Radiologic outcomes, retrieved from radiographs or computed tomography scans, focused on loss of reduction (as determined by the respective authors), malunion, nonunion, and heterotopic ossification. Each study’s methodologic quality and bias were evaluated with the 15-item Modified Coleman Methodology Score (MCMS), which was described by Cowan and colleagues.²³ The MCMS has been used to assess randomized and nonrandomized patient trials.^24,25 Its scaled potential score ranges from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor).

Statistical Analysis

We report our data as weighted means (SDs). A mean was calculated for each study that reported a respective data point, and each mean was then weighed according to its study sample size. This calculation was performed by multiplying a study’s individual mean by the number of patients enrolled in that study and dividing the sum of these weighted data points by the number of eligible patients in all relevant studies. The result was that the nonweighted means from studies with smaller sample sizes did not carry as much weight as the nonweighted means from larger studies. We compared 3 paired groups: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic). Regarding all patient, surgery, and outcomes data, unpaired Student t tests were used for continuous variables and 2-tailed Fisher exact tests for categorical variables with α = 0.05 (SPSS Version 18; IBM).

Results

Demographic information and treatment strategies are listed in Table 2. Fifty-eight percent of patients were male, 59.0% of dominant shoulders were affected, and 59.2% of fractures were displaced <5 mm. Concomitant shoulder instability was reported in 28.1% of patients. Mechanism of injury was not reported in all studies but most commonly (n = 75; 49.3%) involved a fall on an outstretched hand; 31 patients (20.4%) had a sports-related injury, and another 37 (24.3%) were injured in a motor vehicle collision. Of the 429 patients, 217 (50.6%) were treated nonoperatively, and 212 (49.4%) underwent surgery. Open, arthroscopic, and percutaneous approaches were reported. No studies presented outcomes of fragment excision.

Postoperative physical examination findings were underreported so that surgical groups could be compared. Of all the surgical studies, 4 reported postoperative forward elevation (mean, 160°; SD, 9.8°) and external rotation (mean, 46.4°; SD 26.3°).^14,15,18,22 No malunions and only 1 nonunion were reported in all 13 studies. No deaths or other serious medical complications were reported. Patients with anterior instability more often underwent surgery than were treated nonoperatively (39.2% vs 12.0%; P < .01) and more often had fractures displaced >5 mm than <5 mm (44.3% vs 14.5%; P < .01).

 

Comparisons of treatment type are listed in Table 3. Compared with nonoperative patients, operative patients had significantly fewer radiographic losses of reduction (P < .01) and better patient satisfaction (P < .01). Operative patients had a significantly higher rate of shoulder stiffness (P < .01). Eight operative patients (3.8%) and no nonoperative patients required reoperation during clinical follow-up (P < .01). All 12 reported cases of stiffness were in the operative group, and 3 required revision surgery. One patient required revision ORIF. There were 2 cases of postoperative superficial infection (0.9%) and 4 neurologic injuries (1.9%).

Comparisons of displacement amount are listed in Table 4. Compared with fractures displaced >5 mm, those displaced <5 mm had more radiographic losses of reduction (P < .01) but fewer instances of heterotopic ossification (P < .01). Fractures displaced >5 mm were significantly more likely than not to be managed with surgery (P < .01) and significantly more likely to develop stiffness after treatment (P = .01). One patient (0.4%) with a fracture displaced <5 mm eventually underwent surgery for stiffness, and 6 patients (3.6%) with fractures displaced >5 mm required reoperation (P = .02).

Comparisons of surgery type are listed in Table 5. All open procedures were performed with a deltoid-splitting approach. Screw fixation was used in 4 cases: 2 percutaneous^5,21 and 2 open.^2,5 The other open and arthroscopic studies described suture fixation, half with anchors (77/156 patients; 49.4%) and half with transosseous tunnels (79/156; 50.6%). There were no statistically significant differences between open/percutaneous and arthroscopic techniques in terms of stiffness, superficial infection, neurologic injury, or reoperation rate.

Fisher exact tests were used to perform isolated comparisons of screws and sutures as well as suture anchors and transosseous tunnels. Patients with screw fixation were significantly (P = .051) less likely to require reoperation (0/56; 0%) than patients with suture fixation (8/100; 8.0%). Screw fixation also led to significantly less stiffness (0% vs 12.0%; P < .01) but trended toward a higher rate of superficial infection (3.6% vs 0%; P = .13). There was no statistical difference in nerve injury rates between screws and sutures (1.8% vs 3.0%; P = 1.0). There were no significant differences in reoperations, stiffness, superficial infections, or nerve injuries between suture anchor and transosseous tunnel constructs.

 

For all 13 studies, mean (SD) MCMS was 41.1 (8.6).

Discussion

Five percent of all fractures involve the proximal humerus, and 20% of proximal humerus fractures are isolated greater tuberosity fractures.^26,27 In his classic 1970 article, Neer⁶ formulated the 4-part proximal humerus fracture classification and defined greater tuberosity fracture “parts” using the same criteria as for other fracture “parts.” Neer⁶ recommended nonoperative management for isolated greater tuberosity fractures displaced <1 cm but did not present evidence corroborating his recommendation. More recent cutoffs for nonoperative management include 5 mm (general population) and 3 mm (athletes).^7,17

In the present systematic review of greater tuberosity fractures, 3 separate comparisons were made: treatment type (nonoperative vs operative), fracture displacement amount (<5 mm vs >5 mm), and surgery type (open vs arthroscopic).

Treatment Type. Only 4 studies reported data on nonoperative treatment outcomes.^5,12,16,17 Of these 4 studies, 2 found successful outcomes for fractures displaced <5 mm.^12,17 Platzer and colleagues¹⁷ found good or excellent results in 97% of 135 shoulders after 4 years. Good results were defined with shoulder scores of ≥80 (Constant), <8 (Vienna), and >28 (UCLA), and excellent results were defined with maximum scores on 2 of the 3 systems. Platzer and colleagues¹⁷ also found nonsignificantly worse shoulder scores with superior displacement of 3 mm to 5 mm and recommended surgery for overhead athletes in this group. Rath and colleagues¹² described a successful 3-phase rehabilitation protocol of sling immobilization for 3 weeks, pendulum exercises for 3 weeks, and active exercises thereafter. By an average of 31 months, patient satisfaction scores improved to 9.5 from 4.2 (10-point scale), though the authors cautioned that pain and decreased motion lasted 8 months on average. Conservative treatment was far less successful in the 2 studies of fractures displaced >5 mm.^5,16 Keene and colleagues¹⁶ reported unsatisfactory results in all 4 patients with fractures displaced >1.5 cm. In a study separate from their 2005 analysis,¹⁷ Platzer and colleagues⁵ in 2008 evaluated displaced fractures and found function and patient satisfaction were inferior after nonoperative treatment than after surgery. The studies by Keene and colleagues¹⁶ and Platzer and colleagues⁵ support the finding of an overall lower patient satisfaction rate in nonoperative patients.

Fracture Displacement Amount. Only 2 arthroscopic studies and no open studies addressed surgery for fractures displaced <5 mm. Fewer than 16% of these fractures were managed operatively, and <1% required reoperation. By contrast, almost all fractures displaced >5 mm were managed operatively, and 3.6% required reoperation. Radiographic loss of reduction was more common in fractures displaced <5 mm, primarily because they were managed without fixation. Radiographic loss of reduction was reported in only 9 operatively treated patients, none of whom was symptomatic enough to require another surgery.⁵ Reoperations were most commonly performed for stiffness, which itself was significantly more common in fractures displaced >5 mm. Bhatia and colleagues¹⁴ reported the highest reoperation rate (14.3%; 3/21), but they studied more complex, comminuted fractures of the greater tuberosity. Two of their 3 reoperations were biceps tenodeses for inflamed, stiff tenosynovitis, and the third patient had a foreign body giant cell reaction to suture material. Fewer than 1% of patients with operatively managed displaced fractures required revision ORIF, and <2% developed a superficial infection or postoperative nerve palsy.^19,22 For displaced greater tuberosity fractures, surgery is highly successful overall, complication rates are very low, and 90% of patients report being satisfied.

Surgery Type. Patients were divided into 2 groups. In the nonarthroscopic group, open and percutaneous approaches were used. All studies that described a percutaneous approach used screw fixation^5,21; in addition, 32 patients were treated with screws through an open approach.^2,5 The other open and arthroscopic studies used suture fixation. Interestingly, no studies reported on clinical outcomes of fragment excision. There were no statistically significant differences in rates of reoperation, stiffness, infection, or neurologic injury between the arthroscopic and nonarthroscopic groups. Patient satisfaction scores were slightly higher in the nonarthroscopic group (91.0% vs 87.8%), but the difference was not statistically significant.

 

With surgical techniques isolated, there were no significant differences between suture anchors and transosseous tunnel constructs, but screws performed significantly better than suture techniques. Compared with suture fixation, screw fixation led to significantly fewer cases of stiffness and reoperation, which suggests surgeons need to give screws more consideration in the operative management of these fractures. However, the number of patients treated with screws was smaller than the number treated with suture fixation; it is possible the differences between these cohorts would be eliminated if there were more patients in the screw cohort. In addition, screw fixation was universally performed with an open or percutaneous approach and trended toward a higher infection rate. As screw and suture techniques have low rates of complications and reoperations, we recommend leaving fixation choice to the surgeon.

Anterior shoulder instability has been associated with greater tuberosity fractures.^1,8,19 The supraspinatus, infraspinatus, and teres minor muscles all insert into the greater tuberosity and resist anterior translation of the proximal humerus. Loss of this dynamic muscle stabilization is amplified by tuberosity fracture displacement: Anterior shoulder instability was significantly more common in fractures displaced >5 mm (44.3%) vs <5 mm (14.5%). In turn, glenohumeral instability was more common in patients treated with surgery, specifically open surgery, because displaced fractures may not be as easily accessed with arthroscopic techniques. No studies reported concomitant labral repair or capsular plication techniques.

This systematic review was limited by the studies analyzed. All but 1 study⁵ had level IV evidence. Mean (SD) MCMS was 41.8 (8.6). Any MCMS score <54 indicates a poor methodology level, but this scoring system is designed for randomized controlled trials,²³ and there were none in this study. Physical examination findings, such as range of motion, were underreported. In addition, radiographic parameters were not consistently described but rather were determined by the respective authors’ subjective interpretations of malunion, nonunion, and loss of reduction. Publication bias is present in that we excluded non- English language studies and medical conference abstracts and may have omitted potentially eligible studies not discoverable with our search methodology. Performance bias is a factor in any systematic review with multiple surgeons and wide variation in surgical technique.

Conclusion

Greater tuberosity fractures displaced <5 mm may be safely managed nonoperatively, as there are no reports of nonoperatively managed fractures that subsequently required surgery. Nonoperative treatment was initially associated with low patient satisfaction, but only because displaced fractures were conservatively managed in early studies.^5,16 Fractures displaced >5 mm respond well to operative fixation with screws, suture anchors, or transosseous suture tunnels. Stiffness is the most common postoperative complication (<6%), followed by heterotopic ossification, transient neurapraxias, and superficial infection. There are no discernible differences in outcome between open and arthroscopic techniques, but screw fixation may lead to significantly fewer cases of stiffness and reoperation in comparison with suture constructs.

Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

A desire to integrate the advantages of the 2 designs led to a novel glenoid implant design with variable conformity. This innovative component has a central conforming region and a peripheral nonconforming region or “translation zone” (Figure 1). 

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Acromioplasty, performed in TSA patients who had subacromial impingement stemming from improved ROM, represented a second operation, and therefore the need for this surgery was deemed a complication as well. Figure 2 breaks down the 4 major study cohorts.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

All radiographs were independently assessed by 2 blinded physicians who were not involved in the index procedure. Any disputed radiographs were reassessed by these physicians together, until consensus was reached. Radiographs were reviewed for the presence of glenoid lucencies around the pegs or keel and were scored using the system of Lazarus and colleagues²³ (Table 1). The humerus was assessed for total number of lucent lines in any of 8 periprosthetic zones, as described by Sperling and colleagues.²⁴

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Of the 148 patients with office follow-up, only 8 had a positive belly-press or lift-off test. Of all 178 clinical study shoulders, 10 (5.6%) had a subscapularis tear confirmed by magnetic resonance imaging or a physician. Of these 10 tears, 3 resulted from traumatic falls. Four of the 10 tears were managed nonoperatively, and the other 6 underwent surgical repair at a mean of 2.9 years (range, 0.3-7.8 years) after index TSA. In 2 of the 6 repair cases, a 46-mm humeral head had been used, and, in the other 4 cases, a 52-mm humeral head. Of the 6 repaired tears, 2 were massive, and 4 were isolated to the subscapularis. None of these 6 tears required a second repair. Seven (4%) of the 178 shoulders experienced a clinically significant posterosuperior subluxation or dislocation; 5 of the 7 were managed nonoperatively, and the other 2 underwent open capsular shift, at 0.5 year and 3.0 years, respectively. Table 3 lists the other postoperative complications that required surgery.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

A desire to integrate the advantages of the 2 designs led to a novel glenoid implant design with variable conformity. This innovative component has a central conforming region and a peripheral nonconforming region or “translation zone” (Figure 1). 

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Acromioplasty, performed in TSA patients who had subacromial impingement stemming from improved ROM, represented a second operation, and therefore the need for this surgery was deemed a complication as well. Figure 2 breaks down the 4 major study cohorts.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

All radiographs were independently assessed by 2 blinded physicians who were not involved in the index procedure. Any disputed radiographs were reassessed by these physicians together, until consensus was reached. Radiographs were reviewed for the presence of glenoid lucencies around the pegs or keel and were scored using the system of Lazarus and colleagues²³ (Table 1). The humerus was assessed for total number of lucent lines in any of 8 periprosthetic zones, as described by Sperling and colleagues.²⁴

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Of the 148 patients with office follow-up, only 8 had a positive belly-press or lift-off test. Of all 178 clinical study shoulders, 10 (5.6%) had a subscapularis tear confirmed by magnetic resonance imaging or a physician. Of these 10 tears, 3 resulted from traumatic falls. Four of the 10 tears were managed nonoperatively, and the other 6 underwent surgical repair at a mean of 2.9 years (range, 0.3-7.8 years) after index TSA. In 2 of the 6 repair cases, a 46-mm humeral head had been used, and, in the other 4 cases, a 52-mm humeral head. Of the 6 repaired tears, 2 were massive, and 4 were isolated to the subscapularis. None of these 6 tears required a second repair. Seven (4%) of the 178 shoulders experienced a clinically significant posterosuperior subluxation or dislocation; 5 of the 7 were managed nonoperatively, and the other 2 underwent open capsular shift, at 0.5 year and 3.0 years, respectively. Table 3 lists the other postoperative complications that required surgery.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

A desire to integrate the advantages of the 2 designs led to a novel glenoid implant design with variable conformity. This innovative component has a central conforming region and a peripheral nonconforming region or “translation zone” (Figure 1). 

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Acromioplasty, performed in TSA patients who had subacromial impingement stemming from improved ROM, represented a second operation, and therefore the need for this surgery was deemed a complication as well. Figure 2 breaks down the 4 major study cohorts.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

All radiographs were independently assessed by 2 blinded physicians who were not involved in the index procedure. Any disputed radiographs were reassessed by these physicians together, until consensus was reached. Radiographs were reviewed for the presence of glenoid lucencies around the pegs or keel and were scored using the system of Lazarus and colleagues²³ (Table 1). The humerus was assessed for total number of lucent lines in any of 8 periprosthetic zones, as described by Sperling and colleagues.²⁴

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Of the 148 patients with office follow-up, only 8 had a positive belly-press or lift-off test. Of all 178 clinical study shoulders, 10 (5.6%) had a subscapularis tear confirmed by magnetic resonance imaging or a physician. Of these 10 tears, 3 resulted from traumatic falls. Four of the 10 tears were managed nonoperatively, and the other 6 underwent surgical repair at a mean of 2.9 years (range, 0.3-7.8 years) after index TSA. In 2 of the 6 repair cases, a 46-mm humeral head had been used, and, in the other 4 cases, a 52-mm humeral head. Of the 6 repaired tears, 2 were massive, and 4 were isolated to the subscapularis. None of these 6 tears required a second repair. Seven (4%) of the 178 shoulders experienced a clinically significant posterosuperior subluxation or dislocation; 5 of the 7 were managed nonoperatively, and the other 2 underwent open capsular shift, at 0.5 year and 3.0 years, respectively. Table 3 lists the other postoperative complications that required surgery.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

Take-Home Points

• The optimal centrifugation protocol for production of rat PRP is 1300 rpm for 5 minutes.
• PRP administration in RCR improves tendon biomechanics in a rat model.
• Administration of NSAIDs following RCR has no significant effect on tendon biomechanical properties.
• NSAIDs may be co-administered with PRP without reducing efficacy of PRP.
• The role of PRP and NSAIDs in human RCR remains unclear.

Rotator cuff tears are a common source of shoulder pain and disability among older adults and athletes. Full-thickness tears alone occur in up to 30% of adults older than 60 years.¹ Surgical repair is plagued by an unpredictable rate of recurrence (range, 11%-94%).^1-10 As a result of improved suture materials, knotting patterns, and anchor designs, hardware issues are no longer the primary cause of rotator cuff repair (RCR) failures; now the principal mode of failure is biologic.² Animal model studies have found that, after injury and subsequent healing, the tendon–bone interface remains abnormal.¹¹ Rotator cuff research therefore has focused largely on biological enhancement of tendon-to-bone healing.

One means of biological augmentation is autologous platelet-rich plasma (PRP), which has supraphysiologic concentrations of platelets and their secreted growth factors. Although there is no consensus on the long-term efficacy of PRP, some studies suggest PRP accelerates healing over short and intermediate terms, which may contribute to a more rapid decrease in pain and more rapid return to normal activities.^12-18 Similarly, systemic nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat musculoskeletal injuries, including rotator cuff pathology. However, NSAIDs inhibit cyclooxygenase activity, and clinical and experimental data have shown that cyclooxygenase 2 function is crucial in normal tendon-to-bone healing.^19-21

Comprehensive studies have been conducted on the efficacy of both PRP and NSAIDs, but the interaction of concurrently used PRP and NSAIDs has not been determined. As many physicians use both modalities in the treatment of soft-tissue injuries, it is important to study the potential interactions when coadministered. Prior studies in small animal models suggest NSAIDs may impair tendon-to-bone healing in RCR, but there is no evidence regarding the effect of NSAIDs on the efficacy of PRP treatment.²¹

We conducted a study to determine the interaction of PRP and NSAIDs when used as adjuncts to RCR in a rat model. We hypothesized that PRP would increase the strength of RCR and that NSAIDs would interfere with the effects of PRP. A preliminary study objective was to determine an appropriate centrifugation protocol for producing PRP from rat blood, for use in this study and in future rat-based studies of PRP.

Materials and Methods

Part A: Pretesting Determination of PRP Centrifugation Protocol

Fourteen adult male Fischer rats were used in part A of this study, which was conducted to determine an appropriate PRP centrifugation protocol. Traditional PRP centrifugation protocols are established for human blood, but rat red blood cells (RBCs) and human RBCs differ in size.²² In our preliminary study, we wanted to determine the adjusted centrifuge speed and duration for producing clinically optimal PRP from rats. Clinically optimal PRP has reduced levels of RBCs, which decrease platelet affinity. Although the role of leukocytes in PRP preparations is debated, reducing the number of white blood cells (WBCs) decreases the number of matrix metalloproteinases and reactive oxygen species that may lead to inflammation. We used the platelet index (ratio of platelets to WBCs) and the RBC count to quantify the quality of our PRP sample.

Each rat in part A was anesthetized while supine. We used the Autologous Conditioned Plasma (ACP) system (Arthrex), which requires only 1 centrifugation cycle to create PRP. About 9 mL or 10 mL of blood was obtained by cardiac aspiration using an ACP Double Syringe (Arthrex). After blood retrieval, a thoracotomy was performed to confirm each rat’s death.

Each blood sample was centrifuged once under 1 of 6 different centrifugation protocols, varying in duration (minutes) and speed (revolutions per minute [rpm]) (Figure 1). Initially, 12 rats were evenly divided among the 6 protocols, 2 rats per group. The spun PRP product from each rat was evaluated for RBC count, platelet count, and WBC count, and a platelet index was calculated. The 2 centrifugation protocols with the highest mean platelet index, 5 minutes × 1300 rpm and 3 minutes × 1800 rpm, were then increased in size by 1 rat each (new sample size, 3). With these 2 rats added, the highest overall platelet index and lowest RBC and WBC counts were found in the 5 minutes × 1300 rpm protocol (Table 1). We concluded that this protocol produces optimal PRP from rats, and it was implemented for use in part B of the study.

Part B: Determining the Effects of PRP and NSAIDs on RCR in a Rat Model 

Operative Cohort. Of the 34 Fischer rats used in part B of this study, 6 were used as blood donors for PRP production, and the other 28 underwent bilateral rotator cuff surgeries. We used donor rats to maximize the amount of PRP retrieval, allocating about 1 donor rat per 5 operative rats. Fischer rats are an inbred strain, so the PRP from a donor Fischer rat simulates autologous blood in other Fischer rats. Use of allogenic blood is consistent with prior rat PRP studies.^23,24

Operative Technique. Each bilateral surgery was performed by a single board-certified shoulder surgeon, and the anesthetic and surgical protocols were followed as approved by the home institution’s Institutional Animal Care and Use Committee. Before surgery, blood was harvested for PRP production from donor rats, as described earlier, and centrifuged for 5 minutes × 1300 rpm. After anesthetic induction and skin incision, the deltoid muscle was cut to expose the acromion and underlying rotator cuff. The distal supraspinatus tendon was sharply detached from the greater tuberosity. A bone-tunnel RCR was performed by drilling a transverse tunnel across the greater tuberosity and affixing the tendon to its footprint with a 5-0 polypropylene suture (Prolene; Ethicon). Each rat was then randomly assigned to receive 50 µL of donor PRP injected in 1 operative shoulder and saline in the contralateral shoulder. Injections were made in the supraspinatus tendon at its attachment to the humerus. Deltoid and skin were closed with 4-0 polyglactin (Vicryl) suture (Ethicon) and staples, respectively.

Postoperative Protocol. After surgery, the rats were allowed regular ambulation and feeding. The first 2 weeks after surgery, 14 rats were fed a regular diet, and the other 14 an indomethacin-based diet. Other studies have found that rats do not prefer one diet over the other.²⁰ The 56 shoulders were divided into 4 treatment-diet cohorts (PRP-NSAIDs, saline-NSAIDs, PRP-regular, saline-regular) (Figure 2). Rat weights were monitored daily for the first 5 days and twice weekly thereafter. Indomethacin was administered at a dose of 3 mg/kg/d by infusion in a dry food pellet, and excess food was weighed before the next feeding to quantify drug intake.²¹ After 14 days, the indomethacin-based diet was changed to a control diet for another 7 days. The rats in the regular-diet group received a control diet all 21 days. All rats were euthanized 3 weeks after surgery, a time point used in previous studies.^24,25

Tendon Preparation. Immediately post mortem, each shoulder was grossly dissected to isolate the supraspinatus muscle attached to the humerus. Shoulders were then frozen in 0.15-M saline solution until specified biomechanical testing dates.

On day of dimensional/biomechanical testing, each specimen was thawed at room temperature and finely dissected under a microscope (Stemi 200-C; Car Zeiss). After dissection, the humeral shaft was embedded in polymethylmethacrylate within a test tube. The free end of the supraspinatus tendon was glued within a “tab” of waterproofed emery cloth, leaving about 2 mm of tendon between the tab and the greater tuberosity. 

Dimensional Analysis. Photographs were taken of each tendon under 0.2 N of tension to simulate the biomechanical preload (to be described). A Canon G9 digital camera attached to a microscope was used to photograph 2 dimensions: thickness (superoinferior) and width (anteroposterior). A 3-mm gauge block (Mitutoyo America) (Figures 3A-3C) was placed on all images, and ImageJ photoanalysis software (National Institutes of Health) was used to measure each dimension at 5 different points along the tendon. The mean of these 5 measurements represented the respective thickness or width, and the SD represented the measurement error. Statistical differences between treatments (PRP, saline) and diet (NSAIDs, regular) were assessed with 2-way analysis of variance (ANOVA). Significance was set to an α level of P < .05.

Biomechanical Analysis. A 5848 MicroTester (Instron) was used for biomechanical testing. Each tabbed tendon, held by a pneumatic clamp attached to the MicroTester, was tested in a preconditioning phase and then a ramp-to-failure phase. A constant drip of 0.15-M saline was run through the apparatus to simulate physiologic hydration of tissue. After the embedded specimen was secure within the loading apparatus, an initial tensile preload of 0.2 N was applied. After preloading, the tendon was run through a preconditioning phase to account for viscoelastic relaxation. Immediately after preconditioning, each tendon was subjected to failure testing at a ramp rate of 0.1 mm/s. Force data were collected as a function of displacement, allowing for the calculation of 4 biomechanical parameters: failure force, tendon stiffness and normalized stiffness, energy to failure, and total energy. Tendon stiffness is the slope of a curve-fit line of the initial peak; failure force is the force of the highest peak; energy to failure is the area under the curve (AUC) to the highest peak; and total energy is the AUC from the start of failure ramping to the point at which the tendon is torn off completely. Two-way ANOVA was used to assess the differences between treatment groups and diet groups for all parameters. Statistical significance was set at P < .05.

A power analysis was performed to determine ability to detect differences between cohorts. For power of 80% and P = .05, a difference of 16% of the mean could be detected for failure force, 30% for energy to failure, 14% for total energy to failure, and 24% for stiffness. In addition, a difference of 4% of the mean could be detected for tendon length, 6% for width, and 10% for thickness.

Results

There were no significant differences in supraspinatus width, thickness, or length between treatments or diet types (Table 2).

Tendon mode of failure was consistent throughout testing. All 56 shoulders failed at the humeral attachment/tendon insertion. Nine of the 56 experienced partial failure at the attachment combined with partial failure in the midsubstance region.

Across all collective treatment-diet groups and biomechanical parameters, there was only 1 statistically significant difference. Mean (SD) energy to failure was significantly higher (P = .03) in shoulders treated with PRP, 11.7 (7.3) N-mm, than in those treated without PRP, 8.7 (4.6) N-mm (Figure 4). There were no statistically significant differences between shoulders treated with indomethacin and those treated without indomethacin (Table 3), and no statistically significant relationships between treatment and drug for any other biomechanical parameter (Figures 5-7).

Discussion

Our preliminary objective in this study was to determine the optimal centrifugation protocol for producing rat-based PRP. Optimal PRP requires a dense concentration of platelets as well as reduced levels of RBCs and WBCs.²⁵ We used the platelet index to quantify the quality of our PRP samples, and we obtained the highest platelet index for the protocol of 5 minutes × 1300 rpm. This finding may be useful in later rat studies involving PRP.

The primary objective of this study was to assess the effect of the interaction of PRP and NSAIDs on RCR. PRP has been found to augment RCR,^12,26,27 but indomethacin may impair healing.^21,25 We hypothesized that shoulders treated with PRP would have more biomechanical strength than control shoulders and that indomethacin would decrease biomechanical strength. 

Our data showed increased energy to failure of the rotator cuff with PRP injections (P = .03). All other biomechanical parameters showed no significant differences with PRP treatment, though there were statistically insignificant trends of increased total energy, failure force, and stiffness in the PRP cohorts. There were no statistically significant differences between the indomethacin and no-indomethacin groups, and indomethacin had no effect on the efficacy of PRP treatment. It should be noted that the measurements of total energy, energy to failure, and failure force best reflect the strength of the tendon–bone interface. Other biomechanical measures, such as stiffness and normalized stiffness, are physical properties of the tendon itself and apply less to enthesis strength, which was the primary focus of this study.

Beck and colleagues²³ studied the effect of allogeneic PRP on RCR in a rat model. They tested biomechanical and histologic outcomes 7, 14, and 21 days after surgery. There was no significant difference in failure load between the 2 groups at any time point. Compared with failure strain in the control group, failure strain in the PRP group was decreased at 7 days, normalized at 14 days, and increased at 21 days. The authors hypothesized that increased tendon failure strain at 21 days may have reduced forces being transmitted to the suture fixation site, which may be clinically significant and warrants further investigation. In a similar study, by Dolkart and colleagues,²⁸ intraoperative PRP administration enhanced the maximal load-to-failure and stiffness of rats’ repaired rotator cuffs. On histologic examination, tendons treated with PRP (vs control tendons) had more organized collagen. Although these studies have limitations similar to our study, these results further support improved tendon-to-bone healing with PRP.

In clinical application, Barber and colleagues²⁶ found that, compared with controls, suturing PRP fibrin matrix into the rotator cuff during repair decreased the incidence of magnetic resonance imaging–detected retears. However, in 2 prospective, randomized trials, Castricini and colleagues²⁹ and Weber and colleagues³⁰ found that use of PRP in RCR did not improve outcomes. All 3 studies differ from ours in that they used fibrin matrix. However, Ersen and colleagues³¹ found no difference in the effects of PRP on rotator cuff healing between injection and fibrin matrix; PRP improved biomechanical properties of repaired rotator cuff independent of administration method. In a meta-analysis of PRP supplementation in RCR, Warth and colleagues³² found a statistically significant improvement in retear rates for tears >3 cm repaired with a double-row technique, but otherwise no overall improvement in retear rates or outcome scores with PRP. The authors acknowledged that the significant heterogeneity of the studies in their meta-analysis may have affected the quality of their data.

Although our study provides some insight into the effectiveness of PRP in tendon repair, the lack of standardization in PRP preparation and time points tested makes comparisons with similar studies difficult.³³ Recent reports have emphasized that not all PRP separation systems yield similar products.³³ Platelet concentrations, and therefore platelet-derived growth factor concentrations, differ between systems and may yield different clinical outcomes. Our decision to use leukocyte-reduced PRP is supported by a meta-analysis by Riboh and colleagues,³⁴ who reviewed the literature on the effect of leukocyte concentration on the efficacy of PRP products. They found that, in the treatment of knee osteoarthritis, use of leukocyte-poor PRP resulted in improved functional outcomes scores in comparison with placebo, but this improvement did not occur with leukocyte-rich PRP. However, there is still no consensus on optimal preparation, dosing, and route of administration of PRP, and preparations described in the literature vary.

This study also assessed the interaction of PRP and NSAIDs. Although there were no statistically significant differences between treatment and diet, shoulders treated with indomethacin alone showed a trend toward weaker biomechanical parameters in comparison with shoulders treated with saline alone, with PRP alone, or with both PRP and indomethacin. A larger sample would be needed to establish statistical significance. These trends are not surprising, as Cohen and colleagues²¹ found that NSAIDs, specifically indomethacin and celecoxib, significantly inhibited rotator cuff tendon-to-bone healing. The authors also found that a 2-week course of indomethacin was sufficient to significantly inhibit tendon-to-bone healing. In fact, although the drugs were discontinued after 14 days, biomechanical properties were negatively affected up to 8 weeks after repair. Our results differ from theirs even though the 2 studies used similar doses and administration protocols.

One strength of this study was that all surgeries were performed by a single board-certified surgeon using a standardized technique. In addition, a control group was established, and personnel and techniques for all fine dissections and biomechanical tests were consistent throughout. Blinded randomization and diet normalization, as well as adequate power for detecting significant effects, strengthened the study as well.

The study had several limitations. First, whereas most human rotator cuff tears are chronic, we used a model of acute injury and repair. As acute tears that are immediately repaired are more likely to heal, detection of differences between cohorts is less likely. However, using an acute model is still the most reliable strategy for inducing a controlled injury with reproducible severity. Second, we analyzed data at only 1 time point, which may not provide an accurate representation of long-term effects. Third, systemic administration of indomethacin did not allow for intra-rat shoulder comparisons of the different drug groups. Fourth, although it is possible that the dosage of NSAID was insufficient to produce significant differences in biomechanics, our dosage was consistent with that used in a study that found a significant effect on tendon healing.²¹

Conclusion

Our study found that the strength of the supraspinatus tendon enthesis as defined by energy to failure was increased with intratendinous PRP injection. Indomethacin showed no statistical effect, but there was a trend toward reduced strength after repair. However, the extent to which coadministration of indomethacin affects PRP remains unclear, and these data cannot necessarily be extrapolated to the typical human rotator cuff tear caused by chronic repetitive stress.

Take-Home Points

• The optimal centrifugation protocol for production of rat PRP is 1300 rpm for 5 minutes.
• PRP administration in RCR improves tendon biomechanics in a rat model.
• Administration of NSAIDs following RCR has no significant effect on tendon biomechanical properties.
• NSAIDs may be co-administered with PRP without reducing efficacy of PRP.
• The role of PRP and NSAIDs in human RCR remains unclear.

Rotator cuff tears are a common source of shoulder pain and disability among older adults and athletes. Full-thickness tears alone occur in up to 30% of adults older than 60 years.¹ Surgical repair is plagued by an unpredictable rate of recurrence (range, 11%-94%).^1-10 As a result of improved suture materials, knotting patterns, and anchor designs, hardware issues are no longer the primary cause of rotator cuff repair (RCR) failures; now the principal mode of failure is biologic.² Animal model studies have found that, after injury and subsequent healing, the tendon–bone interface remains abnormal.¹¹ Rotator cuff research therefore has focused largely on biological enhancement of tendon-to-bone healing.

One means of biological augmentation is autologous platelet-rich plasma (PRP), which has supraphysiologic concentrations of platelets and their secreted growth factors. Although there is no consensus on the long-term efficacy of PRP, some studies suggest PRP accelerates healing over short and intermediate terms, which may contribute to a more rapid decrease in pain and more rapid return to normal activities.^12-18 Similarly, systemic nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat musculoskeletal injuries, including rotator cuff pathology. However, NSAIDs inhibit cyclooxygenase activity, and clinical and experimental data have shown that cyclooxygenase 2 function is crucial in normal tendon-to-bone healing.^19-21

Comprehensive studies have been conducted on the efficacy of both PRP and NSAIDs, but the interaction of concurrently used PRP and NSAIDs has not been determined. As many physicians use both modalities in the treatment of soft-tissue injuries, it is important to study the potential interactions when coadministered. Prior studies in small animal models suggest NSAIDs may impair tendon-to-bone healing in RCR, but there is no evidence regarding the effect of NSAIDs on the efficacy of PRP treatment.²¹

We conducted a study to determine the interaction of PRP and NSAIDs when used as adjuncts to RCR in a rat model. We hypothesized that PRP would increase the strength of RCR and that NSAIDs would interfere with the effects of PRP. A preliminary study objective was to determine an appropriate centrifugation protocol for producing PRP from rat blood, for use in this study and in future rat-based studies of PRP.

Materials and Methods

Part A: Pretesting Determination of PRP Centrifugation Protocol

Fourteen adult male Fischer rats were used in part A of this study, which was conducted to determine an appropriate PRP centrifugation protocol. Traditional PRP centrifugation protocols are established for human blood, but rat red blood cells (RBCs) and human RBCs differ in size.²² In our preliminary study, we wanted to determine the adjusted centrifuge speed and duration for producing clinically optimal PRP from rats. Clinically optimal PRP has reduced levels of RBCs, which decrease platelet affinity. Although the role of leukocytes in PRP preparations is debated, reducing the number of white blood cells (WBCs) decreases the number of matrix metalloproteinases and reactive oxygen species that may lead to inflammation. We used the platelet index (ratio of platelets to WBCs) and the RBC count to quantify the quality of our PRP sample.

Each rat in part A was anesthetized while supine. We used the Autologous Conditioned Plasma (ACP) system (Arthrex), which requires only 1 centrifugation cycle to create PRP. About 9 mL or 10 mL of blood was obtained by cardiac aspiration using an ACP Double Syringe (Arthrex). After blood retrieval, a thoracotomy was performed to confirm each rat’s death.

Each blood sample was centrifuged once under 1 of 6 different centrifugation protocols, varying in duration (minutes) and speed (revolutions per minute [rpm]) (Figure 1). Initially, 12 rats were evenly divided among the 6 protocols, 2 rats per group. The spun PRP product from each rat was evaluated for RBC count, platelet count, and WBC count, and a platelet index was calculated. The 2 centrifugation protocols with the highest mean platelet index, 5 minutes × 1300 rpm and 3 minutes × 1800 rpm, were then increased in size by 1 rat each (new sample size, 3). With these 2 rats added, the highest overall platelet index and lowest RBC and WBC counts were found in the 5 minutes × 1300 rpm protocol (Table 1). We concluded that this protocol produces optimal PRP from rats, and it was implemented for use in part B of the study.

Part B: Determining the Effects of PRP and NSAIDs on RCR in a Rat Model 

Operative Cohort. Of the 34 Fischer rats used in part B of this study, 6 were used as blood donors for PRP production, and the other 28 underwent bilateral rotator cuff surgeries. We used donor rats to maximize the amount of PRP retrieval, allocating about 1 donor rat per 5 operative rats. Fischer rats are an inbred strain, so the PRP from a donor Fischer rat simulates autologous blood in other Fischer rats. Use of allogenic blood is consistent with prior rat PRP studies.^23,24

Operative Technique. Each bilateral surgery was performed by a single board-certified shoulder surgeon, and the anesthetic and surgical protocols were followed as approved by the home institution’s Institutional Animal Care and Use Committee. Before surgery, blood was harvested for PRP production from donor rats, as described earlier, and centrifuged for 5 minutes × 1300 rpm. After anesthetic induction and skin incision, the deltoid muscle was cut to expose the acromion and underlying rotator cuff. The distal supraspinatus tendon was sharply detached from the greater tuberosity. A bone-tunnel RCR was performed by drilling a transverse tunnel across the greater tuberosity and affixing the tendon to its footprint with a 5-0 polypropylene suture (Prolene; Ethicon). Each rat was then randomly assigned to receive 50 µL of donor PRP injected in 1 operative shoulder and saline in the contralateral shoulder. Injections were made in the supraspinatus tendon at its attachment to the humerus. Deltoid and skin were closed with 4-0 polyglactin (Vicryl) suture (Ethicon) and staples, respectively.

Postoperative Protocol. After surgery, the rats were allowed regular ambulation and feeding. The first 2 weeks after surgery, 14 rats were fed a regular diet, and the other 14 an indomethacin-based diet. Other studies have found that rats do not prefer one diet over the other.²⁰ The 56 shoulders were divided into 4 treatment-diet cohorts (PRP-NSAIDs, saline-NSAIDs, PRP-regular, saline-regular) (Figure 2). Rat weights were monitored daily for the first 5 days and twice weekly thereafter. Indomethacin was administered at a dose of 3 mg/kg/d by infusion in a dry food pellet, and excess food was weighed before the next feeding to quantify drug intake.²¹ After 14 days, the indomethacin-based diet was changed to a control diet for another 7 days. The rats in the regular-diet group received a control diet all 21 days. All rats were euthanized 3 weeks after surgery, a time point used in previous studies.^24,25

Tendon Preparation. Immediately post mortem, each shoulder was grossly dissected to isolate the supraspinatus muscle attached to the humerus. Shoulders were then frozen in 0.15-M saline solution until specified biomechanical testing dates.

On day of dimensional/biomechanical testing, each specimen was thawed at room temperature and finely dissected under a microscope (Stemi 200-C; Car Zeiss). After dissection, the humeral shaft was embedded in polymethylmethacrylate within a test tube. The free end of the supraspinatus tendon was glued within a “tab” of waterproofed emery cloth, leaving about 2 mm of tendon between the tab and the greater tuberosity. 

Dimensional Analysis. Photographs were taken of each tendon under 0.2 N of tension to simulate the biomechanical preload (to be described). A Canon G9 digital camera attached to a microscope was used to photograph 2 dimensions: thickness (superoinferior) and width (anteroposterior). A 3-mm gauge block (Mitutoyo America) (Figures 3A-3C) was placed on all images, and ImageJ photoanalysis software (National Institutes of Health) was used to measure each dimension at 5 different points along the tendon. The mean of these 5 measurements represented the respective thickness or width, and the SD represented the measurement error. Statistical differences between treatments (PRP, saline) and diet (NSAIDs, regular) were assessed with 2-way analysis of variance (ANOVA). Significance was set to an α level of P < .05.

Biomechanical Analysis. A 5848 MicroTester (Instron) was used for biomechanical testing. Each tabbed tendon, held by a pneumatic clamp attached to the MicroTester, was tested in a preconditioning phase and then a ramp-to-failure phase. A constant drip of 0.15-M saline was run through the apparatus to simulate physiologic hydration of tissue. After the embedded specimen was secure within the loading apparatus, an initial tensile preload of 0.2 N was applied. After preloading, the tendon was run through a preconditioning phase to account for viscoelastic relaxation. Immediately after preconditioning, each tendon was subjected to failure testing at a ramp rate of 0.1 mm/s. Force data were collected as a function of displacement, allowing for the calculation of 4 biomechanical parameters: failure force, tendon stiffness and normalized stiffness, energy to failure, and total energy. Tendon stiffness is the slope of a curve-fit line of the initial peak; failure force is the force of the highest peak; energy to failure is the area under the curve (AUC) to the highest peak; and total energy is the AUC from the start of failure ramping to the point at which the tendon is torn off completely. Two-way ANOVA was used to assess the differences between treatment groups and diet groups for all parameters. Statistical significance was set at P < .05.

A power analysis was performed to determine ability to detect differences between cohorts. For power of 80% and P = .05, a difference of 16% of the mean could be detected for failure force, 30% for energy to failure, 14% for total energy to failure, and 24% for stiffness. In addition, a difference of 4% of the mean could be detected for tendon length, 6% for width, and 10% for thickness.

Results

There were no significant differences in supraspinatus width, thickness, or length between treatments or diet types (Table 2).

Tendon mode of failure was consistent throughout testing. All 56 shoulders failed at the humeral attachment/tendon insertion. Nine of the 56 experienced partial failure at the attachment combined with partial failure in the midsubstance region.

Across all collective treatment-diet groups and biomechanical parameters, there was only 1 statistically significant difference. Mean (SD) energy to failure was significantly higher (P = .03) in shoulders treated with PRP, 11.7 (7.3) N-mm, than in those treated without PRP, 8.7 (4.6) N-mm (Figure 4). There were no statistically significant differences between shoulders treated with indomethacin and those treated without indomethacin (Table 3), and no statistically significant relationships between treatment and drug for any other biomechanical parameter (Figures 5-7).

Discussion

Our preliminary objective in this study was to determine the optimal centrifugation protocol for producing rat-based PRP. Optimal PRP requires a dense concentration of platelets as well as reduced levels of RBCs and WBCs.²⁵ We used the platelet index to quantify the quality of our PRP samples, and we obtained the highest platelet index for the protocol of 5 minutes × 1300 rpm. This finding may be useful in later rat studies involving PRP.

The primary objective of this study was to assess the effect of the interaction of PRP and NSAIDs on RCR. PRP has been found to augment RCR,^12,26,27 but indomethacin may impair healing.^21,25 We hypothesized that shoulders treated with PRP would have more biomechanical strength than control shoulders and that indomethacin would decrease biomechanical strength. 

Our data showed increased energy to failure of the rotator cuff with PRP injections (P = .03). All other biomechanical parameters showed no significant differences with PRP treatment, though there were statistically insignificant trends of increased total energy, failure force, and stiffness in the PRP cohorts. There were no statistically significant differences between the indomethacin and no-indomethacin groups, and indomethacin had no effect on the efficacy of PRP treatment. It should be noted that the measurements of total energy, energy to failure, and failure force best reflect the strength of the tendon–bone interface. Other biomechanical measures, such as stiffness and normalized stiffness, are physical properties of the tendon itself and apply less to enthesis strength, which was the primary focus of this study.

Beck and colleagues²³ studied the effect of allogeneic PRP on RCR in a rat model. They tested biomechanical and histologic outcomes 7, 14, and 21 days after surgery. There was no significant difference in failure load between the 2 groups at any time point. Compared with failure strain in the control group, failure strain in the PRP group was decreased at 7 days, normalized at 14 days, and increased at 21 days. The authors hypothesized that increased tendon failure strain at 21 days may have reduced forces being transmitted to the suture fixation site, which may be clinically significant and warrants further investigation. In a similar study, by Dolkart and colleagues,²⁸ intraoperative PRP administration enhanced the maximal load-to-failure and stiffness of rats’ repaired rotator cuffs. On histologic examination, tendons treated with PRP (vs control tendons) had more organized collagen. Although these studies have limitations similar to our study, these results further support improved tendon-to-bone healing with PRP.

In clinical application, Barber and colleagues²⁶ found that, compared with controls, suturing PRP fibrin matrix into the rotator cuff during repair decreased the incidence of magnetic resonance imaging–detected retears. However, in 2 prospective, randomized trials, Castricini and colleagues²⁹ and Weber and colleagues³⁰ found that use of PRP in RCR did not improve outcomes. All 3 studies differ from ours in that they used fibrin matrix. However, Ersen and colleagues³¹ found no difference in the effects of PRP on rotator cuff healing between injection and fibrin matrix; PRP improved biomechanical properties of repaired rotator cuff independent of administration method. In a meta-analysis of PRP supplementation in RCR, Warth and colleagues³² found a statistically significant improvement in retear rates for tears >3 cm repaired with a double-row technique, but otherwise no overall improvement in retear rates or outcome scores with PRP. The authors acknowledged that the significant heterogeneity of the studies in their meta-analysis may have affected the quality of their data.

Although our study provides some insight into the effectiveness of PRP in tendon repair, the lack of standardization in PRP preparation and time points tested makes comparisons with similar studies difficult.³³ Recent reports have emphasized that not all PRP separation systems yield similar products.³³ Platelet concentrations, and therefore platelet-derived growth factor concentrations, differ between systems and may yield different clinical outcomes. Our decision to use leukocyte-reduced PRP is supported by a meta-analysis by Riboh and colleagues,³⁴ who reviewed the literature on the effect of leukocyte concentration on the efficacy of PRP products. They found that, in the treatment of knee osteoarthritis, use of leukocyte-poor PRP resulted in improved functional outcomes scores in comparison with placebo, but this improvement did not occur with leukocyte-rich PRP. However, there is still no consensus on optimal preparation, dosing, and route of administration of PRP, and preparations described in the literature vary.

This study also assessed the interaction of PRP and NSAIDs. Although there were no statistically significant differences between treatment and diet, shoulders treated with indomethacin alone showed a trend toward weaker biomechanical parameters in comparison with shoulders treated with saline alone, with PRP alone, or with both PRP and indomethacin. A larger sample would be needed to establish statistical significance. These trends are not surprising, as Cohen and colleagues²¹ found that NSAIDs, specifically indomethacin and celecoxib, significantly inhibited rotator cuff tendon-to-bone healing. The authors also found that a 2-week course of indomethacin was sufficient to significantly inhibit tendon-to-bone healing. In fact, although the drugs were discontinued after 14 days, biomechanical properties were negatively affected up to 8 weeks after repair. Our results differ from theirs even though the 2 studies used similar doses and administration protocols.

One strength of this study was that all surgeries were performed by a single board-certified surgeon using a standardized technique. In addition, a control group was established, and personnel and techniques for all fine dissections and biomechanical tests were consistent throughout. Blinded randomization and diet normalization, as well as adequate power for detecting significant effects, strengthened the study as well.

The study had several limitations. First, whereas most human rotator cuff tears are chronic, we used a model of acute injury and repair. As acute tears that are immediately repaired are more likely to heal, detection of differences between cohorts is less likely. However, using an acute model is still the most reliable strategy for inducing a controlled injury with reproducible severity. Second, we analyzed data at only 1 time point, which may not provide an accurate representation of long-term effects. Third, systemic administration of indomethacin did not allow for intra-rat shoulder comparisons of the different drug groups. Fourth, although it is possible that the dosage of NSAID was insufficient to produce significant differences in biomechanics, our dosage was consistent with that used in a study that found a significant effect on tendon healing.²¹

Conclusion

Our study found that the strength of the supraspinatus tendon enthesis as defined by energy to failure was increased with intratendinous PRP injection. Indomethacin showed no statistical effect, but there was a trend toward reduced strength after repair. However, the extent to which coadministration of indomethacin affects PRP remains unclear, and these data cannot necessarily be extrapolated to the typical human rotator cuff tear caused by chronic repetitive stress.

Take-Home Points

• The optimal centrifugation protocol for production of rat PRP is 1300 rpm for 5 minutes.
• PRP administration in RCR improves tendon biomechanics in a rat model.
• Administration of NSAIDs following RCR has no significant effect on tendon biomechanical properties.
• NSAIDs may be co-administered with PRP without reducing efficacy of PRP.
• The role of PRP and NSAIDs in human RCR remains unclear.

Rotator cuff tears are a common source of shoulder pain and disability among older adults and athletes. Full-thickness tears alone occur in up to 30% of adults older than 60 years.¹ Surgical repair is plagued by an unpredictable rate of recurrence (range, 11%-94%).^1-10 As a result of improved suture materials, knotting patterns, and anchor designs, hardware issues are no longer the primary cause of rotator cuff repair (RCR) failures; now the principal mode of failure is biologic.² Animal model studies have found that, after injury and subsequent healing, the tendon–bone interface remains abnormal.¹¹ Rotator cuff research therefore has focused largely on biological enhancement of tendon-to-bone healing.

One means of biological augmentation is autologous platelet-rich plasma (PRP), which has supraphysiologic concentrations of platelets and their secreted growth factors. Although there is no consensus on the long-term efficacy of PRP, some studies suggest PRP accelerates healing over short and intermediate terms, which may contribute to a more rapid decrease in pain and more rapid return to normal activities.^12-18 Similarly, systemic nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat musculoskeletal injuries, including rotator cuff pathology. However, NSAIDs inhibit cyclooxygenase activity, and clinical and experimental data have shown that cyclooxygenase 2 function is crucial in normal tendon-to-bone healing.^19-21

Comprehensive studies have been conducted on the efficacy of both PRP and NSAIDs, but the interaction of concurrently used PRP and NSAIDs has not been determined. As many physicians use both modalities in the treatment of soft-tissue injuries, it is important to study the potential interactions when coadministered. Prior studies in small animal models suggest NSAIDs may impair tendon-to-bone healing in RCR, but there is no evidence regarding the effect of NSAIDs on the efficacy of PRP treatment.²¹

We conducted a study to determine the interaction of PRP and NSAIDs when used as adjuncts to RCR in a rat model. We hypothesized that PRP would increase the strength of RCR and that NSAIDs would interfere with the effects of PRP. A preliminary study objective was to determine an appropriate centrifugation protocol for producing PRP from rat blood, for use in this study and in future rat-based studies of PRP.

Materials and Methods

Part A: Pretesting Determination of PRP Centrifugation Protocol

Fourteen adult male Fischer rats were used in part A of this study, which was conducted to determine an appropriate PRP centrifugation protocol. Traditional PRP centrifugation protocols are established for human blood, but rat red blood cells (RBCs) and human RBCs differ in size.²² In our preliminary study, we wanted to determine the adjusted centrifuge speed and duration for producing clinically optimal PRP from rats. Clinically optimal PRP has reduced levels of RBCs, which decrease platelet affinity. Although the role of leukocytes in PRP preparations is debated, reducing the number of white blood cells (WBCs) decreases the number of matrix metalloproteinases and reactive oxygen species that may lead to inflammation. We used the platelet index (ratio of platelets to WBCs) and the RBC count to quantify the quality of our PRP sample.

Each rat in part A was anesthetized while supine. We used the Autologous Conditioned Plasma (ACP) system (Arthrex), which requires only 1 centrifugation cycle to create PRP. About 9 mL or 10 mL of blood was obtained by cardiac aspiration using an ACP Double Syringe (Arthrex). After blood retrieval, a thoracotomy was performed to confirm each rat’s death.

Each blood sample was centrifuged once under 1 of 6 different centrifugation protocols, varying in duration (minutes) and speed (revolutions per minute [rpm]) (Figure 1). Initially, 12 rats were evenly divided among the 6 protocols, 2 rats per group. The spun PRP product from each rat was evaluated for RBC count, platelet count, and WBC count, and a platelet index was calculated. The 2 centrifugation protocols with the highest mean platelet index, 5 minutes × 1300 rpm and 3 minutes × 1800 rpm, were then increased in size by 1 rat each (new sample size, 3). With these 2 rats added, the highest overall platelet index and lowest RBC and WBC counts were found in the 5 minutes × 1300 rpm protocol (Table 1). We concluded that this protocol produces optimal PRP from rats, and it was implemented for use in part B of the study.

Part B: Determining the Effects of PRP and NSAIDs on RCR in a Rat Model 

Operative Cohort. Of the 34 Fischer rats used in part B of this study, 6 were used as blood donors for PRP production, and the other 28 underwent bilateral rotator cuff surgeries. We used donor rats to maximize the amount of PRP retrieval, allocating about 1 donor rat per 5 operative rats. Fischer rats are an inbred strain, so the PRP from a donor Fischer rat simulates autologous blood in other Fischer rats. Use of allogenic blood is consistent with prior rat PRP studies.^23,24

Operative Technique. Each bilateral surgery was performed by a single board-certified shoulder surgeon, and the anesthetic and surgical protocols were followed as approved by the home institution’s Institutional Animal Care and Use Committee. Before surgery, blood was harvested for PRP production from donor rats, as described earlier, and centrifuged for 5 minutes × 1300 rpm. After anesthetic induction and skin incision, the deltoid muscle was cut to expose the acromion and underlying rotator cuff. The distal supraspinatus tendon was sharply detached from the greater tuberosity. A bone-tunnel RCR was performed by drilling a transverse tunnel across the greater tuberosity and affixing the tendon to its footprint with a 5-0 polypropylene suture (Prolene; Ethicon). Each rat was then randomly assigned to receive 50 µL of donor PRP injected in 1 operative shoulder and saline in the contralateral shoulder. Injections were made in the supraspinatus tendon at its attachment to the humerus. Deltoid and skin were closed with 4-0 polyglactin (Vicryl) suture (Ethicon) and staples, respectively.

Postoperative Protocol. After surgery, the rats were allowed regular ambulation and feeding. The first 2 weeks after surgery, 14 rats were fed a regular diet, and the other 14 an indomethacin-based diet. Other studies have found that rats do not prefer one diet over the other.²⁰ The 56 shoulders were divided into 4 treatment-diet cohorts (PRP-NSAIDs, saline-NSAIDs, PRP-regular, saline-regular) (Figure 2). Rat weights were monitored daily for the first 5 days and twice weekly thereafter. Indomethacin was administered at a dose of 3 mg/kg/d by infusion in a dry food pellet, and excess food was weighed before the next feeding to quantify drug intake.²¹ After 14 days, the indomethacin-based diet was changed to a control diet for another 7 days. The rats in the regular-diet group received a control diet all 21 days. All rats were euthanized 3 weeks after surgery, a time point used in previous studies.^24,25

Tendon Preparation. Immediately post mortem, each shoulder was grossly dissected to isolate the supraspinatus muscle attached to the humerus. Shoulders were then frozen in 0.15-M saline solution until specified biomechanical testing dates.

On day of dimensional/biomechanical testing, each specimen was thawed at room temperature and finely dissected under a microscope (Stemi 200-C; Car Zeiss). After dissection, the humeral shaft was embedded in polymethylmethacrylate within a test tube. The free end of the supraspinatus tendon was glued within a “tab” of waterproofed emery cloth, leaving about 2 mm of tendon between the tab and the greater tuberosity. 

Dimensional Analysis. Photographs were taken of each tendon under 0.2 N of tension to simulate the biomechanical preload (to be described). A Canon G9 digital camera attached to a microscope was used to photograph 2 dimensions: thickness (superoinferior) and width (anteroposterior). A 3-mm gauge block (Mitutoyo America) (Figures 3A-3C) was placed on all images, and ImageJ photoanalysis software (National Institutes of Health) was used to measure each dimension at 5 different points along the tendon. The mean of these 5 measurements represented the respective thickness or width, and the SD represented the measurement error. Statistical differences between treatments (PRP, saline) and diet (NSAIDs, regular) were assessed with 2-way analysis of variance (ANOVA). Significance was set to an α level of P < .05.

Biomechanical Analysis. A 5848 MicroTester (Instron) was used for biomechanical testing. Each tabbed tendon, held by a pneumatic clamp attached to the MicroTester, was tested in a preconditioning phase and then a ramp-to-failure phase. A constant drip of 0.15-M saline was run through the apparatus to simulate physiologic hydration of tissue. After the embedded specimen was secure within the loading apparatus, an initial tensile preload of 0.2 N was applied. After preloading, the tendon was run through a preconditioning phase to account for viscoelastic relaxation. Immediately after preconditioning, each tendon was subjected to failure testing at a ramp rate of 0.1 mm/s. Force data were collected as a function of displacement, allowing for the calculation of 4 biomechanical parameters: failure force, tendon stiffness and normalized stiffness, energy to failure, and total energy. Tendon stiffness is the slope of a curve-fit line of the initial peak; failure force is the force of the highest peak; energy to failure is the area under the curve (AUC) to the highest peak; and total energy is the AUC from the start of failure ramping to the point at which the tendon is torn off completely. Two-way ANOVA was used to assess the differences between treatment groups and diet groups for all parameters. Statistical significance was set at P < .05.

A power analysis was performed to determine ability to detect differences between cohorts. For power of 80% and P = .05, a difference of 16% of the mean could be detected for failure force, 30% for energy to failure, 14% for total energy to failure, and 24% for stiffness. In addition, a difference of 4% of the mean could be detected for tendon length, 6% for width, and 10% for thickness.

Results

There were no significant differences in supraspinatus width, thickness, or length between treatments or diet types (Table 2).

Tendon mode of failure was consistent throughout testing. All 56 shoulders failed at the humeral attachment/tendon insertion. Nine of the 56 experienced partial failure at the attachment combined with partial failure in the midsubstance region.

Across all collective treatment-diet groups and biomechanical parameters, there was only 1 statistically significant difference. Mean (SD) energy to failure was significantly higher (P = .03) in shoulders treated with PRP, 11.7 (7.3) N-mm, than in those treated without PRP, 8.7 (4.6) N-mm (Figure 4). There were no statistically significant differences between shoulders treated with indomethacin and those treated without indomethacin (Table 3), and no statistically significant relationships between treatment and drug for any other biomechanical parameter (Figures 5-7).

Discussion

Our preliminary objective in this study was to determine the optimal centrifugation protocol for producing rat-based PRP. Optimal PRP requires a dense concentration of platelets as well as reduced levels of RBCs and WBCs.²⁵ We used the platelet index to quantify the quality of our PRP samples, and we obtained the highest platelet index for the protocol of 5 minutes × 1300 rpm. This finding may be useful in later rat studies involving PRP.

The primary objective of this study was to assess the effect of the interaction of PRP and NSAIDs on RCR. PRP has been found to augment RCR,^12,26,27 but indomethacin may impair healing.^21,25 We hypothesized that shoulders treated with PRP would have more biomechanical strength than control shoulders and that indomethacin would decrease biomechanical strength. 

Our data showed increased energy to failure of the rotator cuff with PRP injections (P = .03). All other biomechanical parameters showed no significant differences with PRP treatment, though there were statistically insignificant trends of increased total energy, failure force, and stiffness in the PRP cohorts. There were no statistically significant differences between the indomethacin and no-indomethacin groups, and indomethacin had no effect on the efficacy of PRP treatment. It should be noted that the measurements of total energy, energy to failure, and failure force best reflect the strength of the tendon–bone interface. Other biomechanical measures, such as stiffness and normalized stiffness, are physical properties of the tendon itself and apply less to enthesis strength, which was the primary focus of this study.

Beck and colleagues²³ studied the effect of allogeneic PRP on RCR in a rat model. They tested biomechanical and histologic outcomes 7, 14, and 21 days after surgery. There was no significant difference in failure load between the 2 groups at any time point. Compared with failure strain in the control group, failure strain in the PRP group was decreased at 7 days, normalized at 14 days, and increased at 21 days. The authors hypothesized that increased tendon failure strain at 21 days may have reduced forces being transmitted to the suture fixation site, which may be clinically significant and warrants further investigation. In a similar study, by Dolkart and colleagues,²⁸ intraoperative PRP administration enhanced the maximal load-to-failure and stiffness of rats’ repaired rotator cuffs. On histologic examination, tendons treated with PRP (vs control tendons) had more organized collagen. Although these studies have limitations similar to our study, these results further support improved tendon-to-bone healing with PRP.

In clinical application, Barber and colleagues²⁶ found that, compared with controls, suturing PRP fibrin matrix into the rotator cuff during repair decreased the incidence of magnetic resonance imaging–detected retears. However, in 2 prospective, randomized trials, Castricini and colleagues²⁹ and Weber and colleagues³⁰ found that use of PRP in RCR did not improve outcomes. All 3 studies differ from ours in that they used fibrin matrix. However, Ersen and colleagues³¹ found no difference in the effects of PRP on rotator cuff healing between injection and fibrin matrix; PRP improved biomechanical properties of repaired rotator cuff independent of administration method. In a meta-analysis of PRP supplementation in RCR, Warth and colleagues³² found a statistically significant improvement in retear rates for tears >3 cm repaired with a double-row technique, but otherwise no overall improvement in retear rates or outcome scores with PRP. The authors acknowledged that the significant heterogeneity of the studies in their meta-analysis may have affected the quality of their data.

Although our study provides some insight into the effectiveness of PRP in tendon repair, the lack of standardization in PRP preparation and time points tested makes comparisons with similar studies difficult.³³ Recent reports have emphasized that not all PRP separation systems yield similar products.³³ Platelet concentrations, and therefore platelet-derived growth factor concentrations, differ between systems and may yield different clinical outcomes. Our decision to use leukocyte-reduced PRP is supported by a meta-analysis by Riboh and colleagues,³⁴ who reviewed the literature on the effect of leukocyte concentration on the efficacy of PRP products. They found that, in the treatment of knee osteoarthritis, use of leukocyte-poor PRP resulted in improved functional outcomes scores in comparison with placebo, but this improvement did not occur with leukocyte-rich PRP. However, there is still no consensus on optimal preparation, dosing, and route of administration of PRP, and preparations described in the literature vary.

This study also assessed the interaction of PRP and NSAIDs. Although there were no statistically significant differences between treatment and diet, shoulders treated with indomethacin alone showed a trend toward weaker biomechanical parameters in comparison with shoulders treated with saline alone, with PRP alone, or with both PRP and indomethacin. A larger sample would be needed to establish statistical significance. These trends are not surprising, as Cohen and colleagues²¹ found that NSAIDs, specifically indomethacin and celecoxib, significantly inhibited rotator cuff tendon-to-bone healing. The authors also found that a 2-week course of indomethacin was sufficient to significantly inhibit tendon-to-bone healing. In fact, although the drugs were discontinued after 14 days, biomechanical properties were negatively affected up to 8 weeks after repair. Our results differ from theirs even though the 2 studies used similar doses and administration protocols.

One strength of this study was that all surgeries were performed by a single board-certified surgeon using a standardized technique. In addition, a control group was established, and personnel and techniques for all fine dissections and biomechanical tests were consistent throughout. Blinded randomization and diet normalization, as well as adequate power for detecting significant effects, strengthened the study as well.

The study had several limitations. First, whereas most human rotator cuff tears are chronic, we used a model of acute injury and repair. As acute tears that are immediately repaired are more likely to heal, detection of differences between cohorts is less likely. However, using an acute model is still the most reliable strategy for inducing a controlled injury with reproducible severity. Second, we analyzed data at only 1 time point, which may not provide an accurate representation of long-term effects. Third, systemic administration of indomethacin did not allow for intra-rat shoulder comparisons of the different drug groups. Fourth, although it is possible that the dosage of NSAID was insufficient to produce significant differences in biomechanics, our dosage was consistent with that used in a study that found a significant effect on tendon healing.²¹

Conclusion

Our study found that the strength of the supraspinatus tendon enthesis as defined by energy to failure was increased with intratendinous PRP injection. Indomethacin showed no statistical effect, but there was a trend toward reduced strength after repair. However, the extent to which coadministration of indomethacin affects PRP remains unclear, and these data cannot necessarily be extrapolated to the typical human rotator cuff tear caused by chronic repetitive stress.

Take-Home Points

• Pain relief and return of strength are important satisfaction variables for patients undergoing ARCR.
• Pain relief and strength return are equally desirable in the majority (50%) of the patients before and after ARCR.
• Overall, patient preference for strength return dominates pain relief in long-term.
• Increasing age is associated with a stronger preference for pain relief.

• Improved understanding of patient expectations after ARCR will promote meaningful changes in patient satisfaction.

A rotator cuff tear (RCT) can cause significant pain, weakness, stiffness, and loss of function in the shoulder. In most patients, arthroscopic rotator cuff repair (ARCR) provides significant and reproducible pain relief and variable return of shoulder strength and function.^1-4 ARCR outcomes are well described and well represented by validated outcome measures.^5-9 However, these outcomes do not always correlate with patient satisfaction. For example, after ARCR, 2 patients with similar outcome scores may have different satisfaction levels.

Patient satisfaction involves multiple factors and varies with the patient’s preoperative expectations and the degree to which the surgery matches the patient’s desired outcomes.^10-15 In clinical studies, Tashjian and colleagues,¹⁰ Henn and colleagues,¹¹ and O’Holleran and colleagues¹² found patient satisfaction correlated most highly with postoperative shoulder pain, shoulder function, general health status, and outcome scores. However, our understanding of patients’ desired outcomes and expectations of ARCR is limited, particularly regarding the importance of pain relief and strength return relative to each other. We believe patients’ preoperative expectations are influenced by their self-assessments of symptom severity and by their understanding of the outcomes of surgical procedures and of the information they receive from their surgeons during preoperative evaluation.

We conducted an observational study to determine patients’ preoperative preferences and the importance of post-ARCR pain relief and strength return relative to each other. After surgery, preferences and ratings of pain relief and strength return were reevaluated to determine if they were altered by outcomes. We also studied the influence of multiple factors, including severity of preoperative symptoms (pain, weakness), age, sex, occupation, and active sports involvement, on patients’ preoperative ratings of the importance of post-ARCR improvements in pain relief and strength return. We hypothesized that patients would vary in how they preoperatively value and desire post-ARCR pain relief and strength return.

Materials and Methods

The simple shoulder questionnaire (Figure) designed for this study had 12 items. Patients subjectively assessed the severity of their symptoms (pain level, shoulder weakness) and rated the importance of both pain relief and strength return to their occupational and personal life.

They quantified their perceived level of pain over the preceding 7 days by rating it 0 (no pain) to 10 (worst pain imaginable). Preoperative pain level was evaluated to determine if patients with the worst pain would rate the importance of pain relief and strength return differently. Patients also rated their painful shoulder’s strength deficit as a percentage of the contralateral shoulder’s strength. In addition, patients rated the importance of pain relief and strength return from 0 (not important) to 10 (very important). Strength-to-pain difference (SPD) was calculated by subtracting the pain relief preference from the strength return preference, with positive values indicating a preference for strength return and negative values indicating a preference for pain relief.

Before patients underwent surgery for symptomatic suspected RCTs, they were approached to participate in this prospective study. Sixty-five patients provided informed consent on forms approved by an Institutional Review Board. Inclusion criteria were suspected unilateral rotator cuff pathology and willingness to participate. Of the 65 patients, 60 underwent ARCR without another procedure, such as shoulder instability repair, SLAP (superior labrum anterior-to-posterior) repair, or distal clavicle excision; the other 5 patients elected nonoperative treatment and were excluded from review. At a mean (SD) follow-up of 5.2 (0.2) years, the 60 patients who had surgery completed the questionnaire again and rated the importance of pain relief and strength return relative to each other.

Patients with RCTs were divided according to age, sex, shoulder dominance, occupation type, and active sports involvement. Standard definitions for occupation types were used: blue-collar, manual labor jobs; white-collar, salaried/educated positions; and retired.

Matched-pairs t tests were used to compare preoperative and postoperative continuous variables (strength return preference, pain relief preference, SPD). One-way analysis of variance (ANOVA) was used to compare categorical variables (sex, shoulder dominance, active sports involvement) with continuous variables (SPD), and bivariate regression was used to compare groups with continuous data (age, SPD). In cases involving more than 2 groups (occupation types), the Tukey honestly significant difference (HSD) test was used to evaluate intergroup differences. P < .05 was used for statistical significance.

 

Results

ARCR Outcomes

After ARCR, there was significant improvement in patient-reported pain and subjective strength scores. Mean (SD) pain score improved from 5.9 (2.3) to 1.3 (2.3) after ARCR (P < .001), and mean (SD) strength improved from 46% (22%) of normal to 84% (17%) of normal (P < .001).

Importance of Post-ARCR Pain Relief and Strength Return

Analysis of preoperative questionnaire responses

revealed that, of 60 patients, 29 (48.3%) considered pain relief and strength return equally important, 20 (33.3%) valued postoperative strength return was more important, and 11 patients (18.3%) rated pain relief was more important than strength return. After a mean (SD) follow-up of 5.2 (0.2) years, 33 patients (55 %) valued pain relief and strength return as equally important, 17 patients (28.3%) preferred a strength recovery, and 10 patients (16.7%) preferred pain relief.

Overall patient ratings were significantly higher for strength return compared to pain relief before surgery, mean (SD), 9.2 (2.1) and 8.6 (2.3) (P = .02), and afterward, 8.9 (1.9) and 8.2 (3.1) (P = .03) (Table 1).

Although SPD was lower after surgery (relative increase in importance of analgesia at postoperative time point), the value was not significant (P = .73). There was a weak positive correlation between patient-reported preoperative pain and importance of pain relief ratings (r = 0.05, P < .001), but there was no significant correlation between postoperative values (r = 0.01, P = .73). Also, there was no significant correlation between importance of strength return rating and strength deficits reported before surgery (r = 0.22, P = .09) or afterward (r = 0.21, P = .11).

Subgroup Analyses

Sex and Age. Of the 60 patients, 43 were male and 17 female. Mean (SD) preoperative SPD was 1.0 (2.7) for males and 0.7 (2.3) females; the difference was not significant (P = .61). After surgery, females emphasized strength return over pain relief more than males did: Mean (SD) SPD was significantly higher (P = .04) for females, 1.7 (3.0), than for males, 0.4 (2.5). There were no preoperative–postoperative differences (P = .33) for males or females (Table 2).

Before surgery, increasing age was associated with lower SPD, indicating a stronger preference for pain relief over strength return (r = 0.33, P = .01). There was no association between age and SPD after surgery (r = 0.2, P = .12).

Hand Dominance. RCT was found in the dominant shoulder of 31 patients (52%). Shoulder dominance did not affect SPD: Mean (SD) preoperative SPD was 1.3 (2.3) for dominant shoulders and 0.5 (2.7) for nondominant shoulders (P = .21), and postoperative SPD was 0.7 (2.6) for dominant and 0.9 (2.8) for nondominant (P = .79). SPD did not change from before surgery to after surgery for dominant (P = .14) or nondominant (P = .28) shoulders (Table 2).

Active Sports Participation. Thirty-two patients (53%) reported preoperative involvement in sports; 35 (58%) reported postoperative involvement (P = .37). Mean (SD) preoperative SPD was 1.4 (3.0) for involved patients and 0.3 (1.7) for uninvolved patients (P = .09), and postoperative SPD was 0.6 (2.8) for involved patients and 1.0 (2.6) for uninvolved patients (P = .53). SPD did not change from before surgery to after surgery for involved (P = .17) or uninvolved (P = .26) patients (Table 2).

Occupation Type. There were 9 blue-collar workers (15%), 32 white-collar workers (53%), and 19 retirees (32%). Mean (SD) preoperative SPD was 2.8 (4.2) for blue-collar workers, 1.2 (2.1) for white-collar workers, and –0.4 (0.4) for retirees. There were no significant differences in preoperative SPD between blue-collar and white-collar workers (P = .19) or between white-collar workers and retirees (P = .06), but there was a significant difference between blue-collar workers and retirees (P = .004). Mean (SD) postoperative SPD was 1.3 (2.7) for blue-collar workers, 1.2 (3.1) for white-collar workers, and –0.3 (1.6) for retirees. There were no significant differences between blue-collar and white-collar workers (P = .99), white-collar workers and retirees (P = .13), or blue-collar workers and retirees (P = .3).

Discussion

In this study, we wanted to determine patients’ pre- and postoperative preferences for pain relief and strength return after ARCR. Preoperative and postoperative preference analysis of the 60 patients who underwent ARCR revealed that the majority valued pain relief and strength return equally. However, overall, there was higher ratings for strength return in long term after ARCR, irrespective of age, sex, preoperative levels of shoulder pain and weakness, and preoperative and postoperative sports involvement.

Patients’ preoperative expectations are a function of their assessment of their symptoms, their perceptions of expected surgical outcomes, and their understanding of preoperative discussion with their surgeons. In this study, patients self-assessed their shoulder symptoms and their effect on their occupational and personal life. They also rated the importance of post-ARCR pain relief and strength return relative to each other. To assess whether surgical outcomes affected perceptions of pain relief and strength return, patients completed the questionnaire before and after surgery. Overall, patients rated postoperative strength return over pain relief on long-term (5 years).

Subgroup analysis revealed a weak positive correlation between patient-reported preoperative pain scores and ratings of the importance of pain relief after surgery, but there was no correlation between postoperative pain scores and ratings of the importance of pain relief after surgery. This finding was surprising because we thought pain relief would be more important than strength return for patients with higher pain scores.^1-3,16-21 We would like to clarify a point about this study: That patients preferred strength return over pain relief does not mean they did not care about pain relief. A substantial subset of patients (~50%) valued pain relief and strength return equally. In rotator cuff pathology, pain and weakness are to an extent interrelated. Shoulder pain that limits a patient’s ability to perform a strenuous task can be perceived as shoulder weakness, which may explain why, despite having higher pain scores, patients preferred strength return over pain relief. Increasing age showed a positive correlation with preference for pain relief, which explains the finding that retirees preferred pain relief over strength return. We used SPD to express the preference for strength return over pain relief before and after ARCR. Unfortunately, SPD may not be used to quantitatively define the preference for strength return over pain relief.

Patient satisfaction after RCR involves multiple factors and has been well studied. In a retrospective analysis of 112 patients, Tashjian and colleagues¹⁰ found that patient satisfaction was affected by preoperative expectations, marital status, disability status, preoperative pain function, and general health status after RCR. They also found a positive but weak correlation between patient satisfaction and functional outcome scores, including visual analog scale (VAS), Simple Shoulder Test (SST), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Henn and colleagues¹¹ evaluated 125 patients who underwent primary RCR for a chronic RCT. Higher preoperative expectations correlated with better postoperative VAS, SST, DASH, and Short Form 36 performance, irrespective of worker compensation status, symptom duration, number of patient comorbidities, tear size, repair technique, and number of previous operations. In a prospective cohort analysis of 311 RCR patients, O’Holleran and colleagues¹² found that decreased patient satisfaction was associated with postoperative pain and dysfunction. Furthermore, willingness to recommend surgery to another person was significantly related to patient satisfaction. In the present study, we did not correlate preoperative expectations with postoperative outcome scores or evaluate the effect of other known factors on RCR outcomes. Our main goal was to understand ARCR patients’ preoperative and postoperative evaluations of the importance of pain relief and strength return relative to each other. Improved understanding of patients’ expectations will allow us to identify disparities between expectations and outcomes.

Our study had several limitations. First, our questionnaire was not validated. However, we used it only as an assessment tool, to collect data, and do not propose using it to assess ARCR outcomes. Second, objective strength measurements were not performed, before or after surgery, and therefore patients’ perceptions of weakness were not tested. Third, we did not correlate preoperative or postoperative shoulder outcome scores with patients’ expectations. Our intention was to understand how ARCR patients rate the importance of pain relief and strength return relative to each other. Fourth, we did not correlate patients’ expectations of strength return and pain relief with preoperative tear size or postoperative retear status.

Our observational study results showed that, before undergoing ARCR, most patients valued postoperative pain relief and strength return equally. However, there was an overall preference for strength return over pain relief. Furthermore, this preference held up irrespective of age, sex, sports involvement, or preoperative symptom severity. These findings add to our understanding of patients’ preoperative expectations of ARCR.

Am J Orthop. 2017;46(4):E244-E250. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

 

Take-Home Points

• Pain relief and return of strength are important satisfaction variables for patients undergoing ARCR.
• Pain relief and strength return are equally desirable in the majority (50%) of the patients before and after ARCR.
• Overall, patient preference for strength return dominates pain relief in long-term.
• Increasing age is associated with a stronger preference for pain relief.

• Improved understanding of patient expectations after ARCR will promote meaningful changes in patient satisfaction.

A rotator cuff tear (RCT) can cause significant pain, weakness, stiffness, and loss of function in the shoulder. In most patients, arthroscopic rotator cuff repair (ARCR) provides significant and reproducible pain relief and variable return of shoulder strength and function.^1-4 ARCR outcomes are well described and well represented by validated outcome measures.^5-9 However, these outcomes do not always correlate with patient satisfaction. For example, after ARCR, 2 patients with similar outcome scores may have different satisfaction levels.

Patient satisfaction involves multiple factors and varies with the patient’s preoperative expectations and the degree to which the surgery matches the patient’s desired outcomes.^10-15 In clinical studies, Tashjian and colleagues,¹⁰ Henn and colleagues,¹¹ and O’Holleran and colleagues¹² found patient satisfaction correlated most highly with postoperative shoulder pain, shoulder function, general health status, and outcome scores. However, our understanding of patients’ desired outcomes and expectations of ARCR is limited, particularly regarding the importance of pain relief and strength return relative to each other. We believe patients’ preoperative expectations are influenced by their self-assessments of symptom severity and by their understanding of the outcomes of surgical procedures and of the information they receive from their surgeons during preoperative evaluation.

We conducted an observational study to determine patients’ preoperative preferences and the importance of post-ARCR pain relief and strength return relative to each other. After surgery, preferences and ratings of pain relief and strength return were reevaluated to determine if they were altered by outcomes. We also studied the influence of multiple factors, including severity of preoperative symptoms (pain, weakness), age, sex, occupation, and active sports involvement, on patients’ preoperative ratings of the importance of post-ARCR improvements in pain relief and strength return. We hypothesized that patients would vary in how they preoperatively value and desire post-ARCR pain relief and strength return.

Materials and Methods

The simple shoulder questionnaire (Figure) designed for this study had 12 items. Patients subjectively assessed the severity of their symptoms (pain level, shoulder weakness) and rated the importance of both pain relief and strength return to their occupational and personal life.

They quantified their perceived level of pain over the preceding 7 days by rating it 0 (no pain) to 10 (worst pain imaginable). Preoperative pain level was evaluated to determine if patients with the worst pain would rate the importance of pain relief and strength return differently. Patients also rated their painful shoulder’s strength deficit as a percentage of the contralateral shoulder’s strength. In addition, patients rated the importance of pain relief and strength return from 0 (not important) to 10 (very important). Strength-to-pain difference (SPD) was calculated by subtracting the pain relief preference from the strength return preference, with positive values indicating a preference for strength return and negative values indicating a preference for pain relief.

Before patients underwent surgery for symptomatic suspected RCTs, they were approached to participate in this prospective study. Sixty-five patients provided informed consent on forms approved by an Institutional Review Board. Inclusion criteria were suspected unilateral rotator cuff pathology and willingness to participate. Of the 65 patients, 60 underwent ARCR without another procedure, such as shoulder instability repair, SLAP (superior labrum anterior-to-posterior) repair, or distal clavicle excision; the other 5 patients elected nonoperative treatment and were excluded from review. At a mean (SD) follow-up of 5.2 (0.2) years, the 60 patients who had surgery completed the questionnaire again and rated the importance of pain relief and strength return relative to each other.

Patients with RCTs were divided according to age, sex, shoulder dominance, occupation type, and active sports involvement. Standard definitions for occupation types were used: blue-collar, manual labor jobs; white-collar, salaried/educated positions; and retired.

Matched-pairs t tests were used to compare preoperative and postoperative continuous variables (strength return preference, pain relief preference, SPD). One-way analysis of variance (ANOVA) was used to compare categorical variables (sex, shoulder dominance, active sports involvement) with continuous variables (SPD), and bivariate regression was used to compare groups with continuous data (age, SPD). In cases involving more than 2 groups (occupation types), the Tukey honestly significant difference (HSD) test was used to evaluate intergroup differences. P < .05 was used for statistical significance.

 

Results

ARCR Outcomes

After ARCR, there was significant improvement in patient-reported pain and subjective strength scores. Mean (SD) pain score improved from 5.9 (2.3) to 1.3 (2.3) after ARCR (P < .001), and mean (SD) strength improved from 46% (22%) of normal to 84% (17%) of normal (P < .001).

Importance of Post-ARCR Pain Relief and Strength Return

Analysis of preoperative questionnaire responses

revealed that, of 60 patients, 29 (48.3%) considered pain relief and strength return equally important, 20 (33.3%) valued postoperative strength return was more important, and 11 patients (18.3%) rated pain relief was more important than strength return. After a mean (SD) follow-up of 5.2 (0.2) years, 33 patients (55 %) valued pain relief and strength return as equally important, 17 patients (28.3%) preferred a strength recovery, and 10 patients (16.7%) preferred pain relief.

Overall patient ratings were significantly higher for strength return compared to pain relief before surgery, mean (SD), 9.2 (2.1) and 8.6 (2.3) (P = .02), and afterward, 8.9 (1.9) and 8.2 (3.1) (P = .03) (Table 1).

Although SPD was lower after surgery (relative increase in importance of analgesia at postoperative time point), the value was not significant (P = .73). There was a weak positive correlation between patient-reported preoperative pain and importance of pain relief ratings (r = 0.05, P < .001), but there was no significant correlation between postoperative values (r = 0.01, P = .73). Also, there was no significant correlation between importance of strength return rating and strength deficits reported before surgery (r = 0.22, P = .09) or afterward (r = 0.21, P = .11).

Subgroup Analyses

Sex and Age. Of the 60 patients, 43 were male and 17 female. Mean (SD) preoperative SPD was 1.0 (2.7) for males and 0.7 (2.3) females; the difference was not significant (P = .61). After surgery, females emphasized strength return over pain relief more than males did: Mean (SD) SPD was significantly higher (P = .04) for females, 1.7 (3.0), than for males, 0.4 (2.5). There were no preoperative–postoperative differences (P = .33) for males or females (Table 2).

Before surgery, increasing age was associated with lower SPD, indicating a stronger preference for pain relief over strength return (r = 0.33, P = .01). There was no association between age and SPD after surgery (r = 0.2, P = .12).

Hand Dominance. RCT was found in the dominant shoulder of 31 patients (52%). Shoulder dominance did not affect SPD: Mean (SD) preoperative SPD was 1.3 (2.3) for dominant shoulders and 0.5 (2.7) for nondominant shoulders (P = .21), and postoperative SPD was 0.7 (2.6) for dominant and 0.9 (2.8) for nondominant (P = .79). SPD did not change from before surgery to after surgery for dominant (P = .14) or nondominant (P = .28) shoulders (Table 2).

Active Sports Participation. Thirty-two patients (53%) reported preoperative involvement in sports; 35 (58%) reported postoperative involvement (P = .37). Mean (SD) preoperative SPD was 1.4 (3.0) for involved patients and 0.3 (1.7) for uninvolved patients (P = .09), and postoperative SPD was 0.6 (2.8) for involved patients and 1.0 (2.6) for uninvolved patients (P = .53). SPD did not change from before surgery to after surgery for involved (P = .17) or uninvolved (P = .26) patients (Table 2).

Occupation Type. There were 9 blue-collar workers (15%), 32 white-collar workers (53%), and 19 retirees (32%). Mean (SD) preoperative SPD was 2.8 (4.2) for blue-collar workers, 1.2 (2.1) for white-collar workers, and –0.4 (0.4) for retirees. There were no significant differences in preoperative SPD between blue-collar and white-collar workers (P = .19) or between white-collar workers and retirees (P = .06), but there was a significant difference between blue-collar workers and retirees (P = .004). Mean (SD) postoperative SPD was 1.3 (2.7) for blue-collar workers, 1.2 (3.1) for white-collar workers, and –0.3 (1.6) for retirees. There were no significant differences between blue-collar and white-collar workers (P = .99), white-collar workers and retirees (P = .13), or blue-collar workers and retirees (P = .3).

Discussion

In this study, we wanted to determine patients’ pre- and postoperative preferences for pain relief and strength return after ARCR. Preoperative and postoperative preference analysis of the 60 patients who underwent ARCR revealed that the majority valued pain relief and strength return equally. However, overall, there was higher ratings for strength return in long term after ARCR, irrespective of age, sex, preoperative levels of shoulder pain and weakness, and preoperative and postoperative sports involvement.

Patients’ preoperative expectations are a function of their assessment of their symptoms, their perceptions of expected surgical outcomes, and their understanding of preoperative discussion with their surgeons. In this study, patients self-assessed their shoulder symptoms and their effect on their occupational and personal life. They also rated the importance of post-ARCR pain relief and strength return relative to each other. To assess whether surgical outcomes affected perceptions of pain relief and strength return, patients completed the questionnaire before and after surgery. Overall, patients rated postoperative strength return over pain relief on long-term (5 years).

Subgroup analysis revealed a weak positive correlation between patient-reported preoperative pain scores and ratings of the importance of pain relief after surgery, but there was no correlation between postoperative pain scores and ratings of the importance of pain relief after surgery. This finding was surprising because we thought pain relief would be more important than strength return for patients with higher pain scores.^1-3,16-21 We would like to clarify a point about this study: That patients preferred strength return over pain relief does not mean they did not care about pain relief. A substantial subset of patients (~50%) valued pain relief and strength return equally. In rotator cuff pathology, pain and weakness are to an extent interrelated. Shoulder pain that limits a patient’s ability to perform a strenuous task can be perceived as shoulder weakness, which may explain why, despite having higher pain scores, patients preferred strength return over pain relief. Increasing age showed a positive correlation with preference for pain relief, which explains the finding that retirees preferred pain relief over strength return. We used SPD to express the preference for strength return over pain relief before and after ARCR. Unfortunately, SPD may not be used to quantitatively define the preference for strength return over pain relief.

Patient satisfaction after RCR involves multiple factors and has been well studied. In a retrospective analysis of 112 patients, Tashjian and colleagues¹⁰ found that patient satisfaction was affected by preoperative expectations, marital status, disability status, preoperative pain function, and general health status after RCR. They also found a positive but weak correlation between patient satisfaction and functional outcome scores, including visual analog scale (VAS), Simple Shoulder Test (SST), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Henn and colleagues¹¹ evaluated 125 patients who underwent primary RCR for a chronic RCT. Higher preoperative expectations correlated with better postoperative VAS, SST, DASH, and Short Form 36 performance, irrespective of worker compensation status, symptom duration, number of patient comorbidities, tear size, repair technique, and number of previous operations. In a prospective cohort analysis of 311 RCR patients, O’Holleran and colleagues¹² found that decreased patient satisfaction was associated with postoperative pain and dysfunction. Furthermore, willingness to recommend surgery to another person was significantly related to patient satisfaction. In the present study, we did not correlate preoperative expectations with postoperative outcome scores or evaluate the effect of other known factors on RCR outcomes. Our main goal was to understand ARCR patients’ preoperative and postoperative evaluations of the importance of pain relief and strength return relative to each other. Improved understanding of patients’ expectations will allow us to identify disparities between expectations and outcomes.

Our study had several limitations. First, our questionnaire was not validated. However, we used it only as an assessment tool, to collect data, and do not propose using it to assess ARCR outcomes. Second, objective strength measurements were not performed, before or after surgery, and therefore patients’ perceptions of weakness were not tested. Third, we did not correlate preoperative or postoperative shoulder outcome scores with patients’ expectations. Our intention was to understand how ARCR patients rate the importance of pain relief and strength return relative to each other. Fourth, we did not correlate patients’ expectations of strength return and pain relief with preoperative tear size or postoperative retear status.

Our observational study results showed that, before undergoing ARCR, most patients valued postoperative pain relief and strength return equally. However, there was an overall preference for strength return over pain relief. Furthermore, this preference held up irrespective of age, sex, sports involvement, or preoperative symptom severity. These findings add to our understanding of patients’ preoperative expectations of ARCR.

Am J Orthop. 2017;46(4):E244-E250. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

 

Take-Home Points

• Pain relief and return of strength are important satisfaction variables for patients undergoing ARCR.
• Pain relief and strength return are equally desirable in the majority (50%) of the patients before and after ARCR.
• Overall, patient preference for strength return dominates pain relief in long-term.
• Increasing age is associated with a stronger preference for pain relief.

• Improved understanding of patient expectations after ARCR will promote meaningful changes in patient satisfaction.

A rotator cuff tear (RCT) can cause significant pain, weakness, stiffness, and loss of function in the shoulder. In most patients, arthroscopic rotator cuff repair (ARCR) provides significant and reproducible pain relief and variable return of shoulder strength and function.^1-4 ARCR outcomes are well described and well represented by validated outcome measures.^5-9 However, these outcomes do not always correlate with patient satisfaction. For example, after ARCR, 2 patients with similar outcome scores may have different satisfaction levels.

Patient satisfaction involves multiple factors and varies with the patient’s preoperative expectations and the degree to which the surgery matches the patient’s desired outcomes.^10-15 In clinical studies, Tashjian and colleagues,¹⁰ Henn and colleagues,¹¹ and O’Holleran and colleagues¹² found patient satisfaction correlated most highly with postoperative shoulder pain, shoulder function, general health status, and outcome scores. However, our understanding of patients’ desired outcomes and expectations of ARCR is limited, particularly regarding the importance of pain relief and strength return relative to each other. We believe patients’ preoperative expectations are influenced by their self-assessments of symptom severity and by their understanding of the outcomes of surgical procedures and of the information they receive from their surgeons during preoperative evaluation.

We conducted an observational study to determine patients’ preoperative preferences and the importance of post-ARCR pain relief and strength return relative to each other. After surgery, preferences and ratings of pain relief and strength return were reevaluated to determine if they were altered by outcomes. We also studied the influence of multiple factors, including severity of preoperative symptoms (pain, weakness), age, sex, occupation, and active sports involvement, on patients’ preoperative ratings of the importance of post-ARCR improvements in pain relief and strength return. We hypothesized that patients would vary in how they preoperatively value and desire post-ARCR pain relief and strength return.

Materials and Methods

The simple shoulder questionnaire (Figure) designed for this study had 12 items. Patients subjectively assessed the severity of their symptoms (pain level, shoulder weakness) and rated the importance of both pain relief and strength return to their occupational and personal life.

They quantified their perceived level of pain over the preceding 7 days by rating it 0 (no pain) to 10 (worst pain imaginable). Preoperative pain level was evaluated to determine if patients with the worst pain would rate the importance of pain relief and strength return differently. Patients also rated their painful shoulder’s strength deficit as a percentage of the contralateral shoulder’s strength. In addition, patients rated the importance of pain relief and strength return from 0 (not important) to 10 (very important). Strength-to-pain difference (SPD) was calculated by subtracting the pain relief preference from the strength return preference, with positive values indicating a preference for strength return and negative values indicating a preference for pain relief.

Before patients underwent surgery for symptomatic suspected RCTs, they were approached to participate in this prospective study. Sixty-five patients provided informed consent on forms approved by an Institutional Review Board. Inclusion criteria were suspected unilateral rotator cuff pathology and willingness to participate. Of the 65 patients, 60 underwent ARCR without another procedure, such as shoulder instability repair, SLAP (superior labrum anterior-to-posterior) repair, or distal clavicle excision; the other 5 patients elected nonoperative treatment and were excluded from review. At a mean (SD) follow-up of 5.2 (0.2) years, the 60 patients who had surgery completed the questionnaire again and rated the importance of pain relief and strength return relative to each other.

Patients with RCTs were divided according to age, sex, shoulder dominance, occupation type, and active sports involvement. Standard definitions for occupation types were used: blue-collar, manual labor jobs; white-collar, salaried/educated positions; and retired.

Matched-pairs t tests were used to compare preoperative and postoperative continuous variables (strength return preference, pain relief preference, SPD). One-way analysis of variance (ANOVA) was used to compare categorical variables (sex, shoulder dominance, active sports involvement) with continuous variables (SPD), and bivariate regression was used to compare groups with continuous data (age, SPD). In cases involving more than 2 groups (occupation types), the Tukey honestly significant difference (HSD) test was used to evaluate intergroup differences. P < .05 was used for statistical significance.

 

Results

ARCR Outcomes

After ARCR, there was significant improvement in patient-reported pain and subjective strength scores. Mean (SD) pain score improved from 5.9 (2.3) to 1.3 (2.3) after ARCR (P < .001), and mean (SD) strength improved from 46% (22%) of normal to 84% (17%) of normal (P < .001).

Importance of Post-ARCR Pain Relief and Strength Return

Analysis of preoperative questionnaire responses

revealed that, of 60 patients, 29 (48.3%) considered pain relief and strength return equally important, 20 (33.3%) valued postoperative strength return was more important, and 11 patients (18.3%) rated pain relief was more important than strength return. After a mean (SD) follow-up of 5.2 (0.2) years, 33 patients (55 %) valued pain relief and strength return as equally important, 17 patients (28.3%) preferred a strength recovery, and 10 patients (16.7%) preferred pain relief.

Overall patient ratings were significantly higher for strength return compared to pain relief before surgery, mean (SD), 9.2 (2.1) and 8.6 (2.3) (P = .02), and afterward, 8.9 (1.9) and 8.2 (3.1) (P = .03) (Table 1).

Although SPD was lower after surgery (relative increase in importance of analgesia at postoperative time point), the value was not significant (P = .73). There was a weak positive correlation between patient-reported preoperative pain and importance of pain relief ratings (r = 0.05, P < .001), but there was no significant correlation between postoperative values (r = 0.01, P = .73). Also, there was no significant correlation between importance of strength return rating and strength deficits reported before surgery (r = 0.22, P = .09) or afterward (r = 0.21, P = .11).

Subgroup Analyses

Sex and Age. Of the 60 patients, 43 were male and 17 female. Mean (SD) preoperative SPD was 1.0 (2.7) for males and 0.7 (2.3) females; the difference was not significant (P = .61). After surgery, females emphasized strength return over pain relief more than males did: Mean (SD) SPD was significantly higher (P = .04) for females, 1.7 (3.0), than for males, 0.4 (2.5). There were no preoperative–postoperative differences (P = .33) for males or females (Table 2).

Before surgery, increasing age was associated with lower SPD, indicating a stronger preference for pain relief over strength return (r = 0.33, P = .01). There was no association between age and SPD after surgery (r = 0.2, P = .12).

Hand Dominance. RCT was found in the dominant shoulder of 31 patients (52%). Shoulder dominance did not affect SPD: Mean (SD) preoperative SPD was 1.3 (2.3) for dominant shoulders and 0.5 (2.7) for nondominant shoulders (P = .21), and postoperative SPD was 0.7 (2.6) for dominant and 0.9 (2.8) for nondominant (P = .79). SPD did not change from before surgery to after surgery for dominant (P = .14) or nondominant (P = .28) shoulders (Table 2).

Active Sports Participation. Thirty-two patients (53%) reported preoperative involvement in sports; 35 (58%) reported postoperative involvement (P = .37). Mean (SD) preoperative SPD was 1.4 (3.0) for involved patients and 0.3 (1.7) for uninvolved patients (P = .09), and postoperative SPD was 0.6 (2.8) for involved patients and 1.0 (2.6) for uninvolved patients (P = .53). SPD did not change from before surgery to after surgery for involved (P = .17) or uninvolved (P = .26) patients (Table 2).

Occupation Type. There were 9 blue-collar workers (15%), 32 white-collar workers (53%), and 19 retirees (32%). Mean (SD) preoperative SPD was 2.8 (4.2) for blue-collar workers, 1.2 (2.1) for white-collar workers, and –0.4 (0.4) for retirees. There were no significant differences in preoperative SPD between blue-collar and white-collar workers (P = .19) or between white-collar workers and retirees (P = .06), but there was a significant difference between blue-collar workers and retirees (P = .004). Mean (SD) postoperative SPD was 1.3 (2.7) for blue-collar workers, 1.2 (3.1) for white-collar workers, and –0.3 (1.6) for retirees. There were no significant differences between blue-collar and white-collar workers (P = .99), white-collar workers and retirees (P = .13), or blue-collar workers and retirees (P = .3).

Discussion

In this study, we wanted to determine patients’ pre- and postoperative preferences for pain relief and strength return after ARCR. Preoperative and postoperative preference analysis of the 60 patients who underwent ARCR revealed that the majority valued pain relief and strength return equally. However, overall, there was higher ratings for strength return in long term after ARCR, irrespective of age, sex, preoperative levels of shoulder pain and weakness, and preoperative and postoperative sports involvement.

Patients’ preoperative expectations are a function of their assessment of their symptoms, their perceptions of expected surgical outcomes, and their understanding of preoperative discussion with their surgeons. In this study, patients self-assessed their shoulder symptoms and their effect on their occupational and personal life. They also rated the importance of post-ARCR pain relief and strength return relative to each other. To assess whether surgical outcomes affected perceptions of pain relief and strength return, patients completed the questionnaire before and after surgery. Overall, patients rated postoperative strength return over pain relief on long-term (5 years).

Subgroup analysis revealed a weak positive correlation between patient-reported preoperative pain scores and ratings of the importance of pain relief after surgery, but there was no correlation between postoperative pain scores and ratings of the importance of pain relief after surgery. This finding was surprising because we thought pain relief would be more important than strength return for patients with higher pain scores.^1-3,16-21 We would like to clarify a point about this study: That patients preferred strength return over pain relief does not mean they did not care about pain relief. A substantial subset of patients (~50%) valued pain relief and strength return equally. In rotator cuff pathology, pain and weakness are to an extent interrelated. Shoulder pain that limits a patient’s ability to perform a strenuous task can be perceived as shoulder weakness, which may explain why, despite having higher pain scores, patients preferred strength return over pain relief. Increasing age showed a positive correlation with preference for pain relief, which explains the finding that retirees preferred pain relief over strength return. We used SPD to express the preference for strength return over pain relief before and after ARCR. Unfortunately, SPD may not be used to quantitatively define the preference for strength return over pain relief.

Patient satisfaction after RCR involves multiple factors and has been well studied. In a retrospective analysis of 112 patients, Tashjian and colleagues¹⁰ found that patient satisfaction was affected by preoperative expectations, marital status, disability status, preoperative pain function, and general health status after RCR. They also found a positive but weak correlation between patient satisfaction and functional outcome scores, including visual analog scale (VAS), Simple Shoulder Test (SST), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Henn and colleagues¹¹ evaluated 125 patients who underwent primary RCR for a chronic RCT. Higher preoperative expectations correlated with better postoperative VAS, SST, DASH, and Short Form 36 performance, irrespective of worker compensation status, symptom duration, number of patient comorbidities, tear size, repair technique, and number of previous operations. In a prospective cohort analysis of 311 RCR patients, O’Holleran and colleagues¹² found that decreased patient satisfaction was associated with postoperative pain and dysfunction. Furthermore, willingness to recommend surgery to another person was significantly related to patient satisfaction. In the present study, we did not correlate preoperative expectations with postoperative outcome scores or evaluate the effect of other known factors on RCR outcomes. Our main goal was to understand ARCR patients’ preoperative and postoperative evaluations of the importance of pain relief and strength return relative to each other. Improved understanding of patients’ expectations will allow us to identify disparities between expectations and outcomes.

Our study had several limitations. First, our questionnaire was not validated. However, we used it only as an assessment tool, to collect data, and do not propose using it to assess ARCR outcomes. Second, objective strength measurements were not performed, before or after surgery, and therefore patients’ perceptions of weakness were not tested. Third, we did not correlate preoperative or postoperative shoulder outcome scores with patients’ expectations. Our intention was to understand how ARCR patients rate the importance of pain relief and strength return relative to each other. Fourth, we did not correlate patients’ expectations of strength return and pain relief with preoperative tear size or postoperative retear status.

Our observational study results showed that, before undergoing ARCR, most patients valued postoperative pain relief and strength return equally. However, there was an overall preference for strength return over pain relief. Furthermore, this preference held up irrespective of age, sex, sports involvement, or preoperative symptom severity. These findings add to our understanding of patients’ preoperative expectations of ARCR.

Am J Orthop. 2017;46(4):E244-E250. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

 

Take-Home Points

• According to the orthopedic literature, ST and LTO for a TSA produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.
• Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions.
• ST and LTO approaches for a TSA result in similar Constant scores, pain scores, radiographic outcomes, and complication rates.

During total shoulder arthroplasty (TSA) exposure, the subscapularis muscle must be mobilized; its repair is crucial to the stability of the arthroplasty. The subscapularis is the largest rotator cuff muscle and has a contractile force equal to that of the other 3 muscles combined.^1,2 Traditionally it is mobilized with a tenotomy just medial to the tendon’s insertion onto the lesser tuberosity. Over the past 15 years, however, numerous authors have reported dysfunction after subscapularis tenotomy (ST). In 2003, Miller and colleagues³ reported that, at 2-year follow-up, almost 70% of patients had abnormal belly-press and liftoff tests, surrogate markers of subscapularis function. Other authors have found increased rates of anterior instability after subscapularis rupture.^4,5

In 2005, Gerber and colleagues⁶ introduced a technique for circumventing surgical division of the subscapularis. They described a lesser tuberosity osteotomy (LTO), in which the subscapularis tendon is detached with a bone fragment 5 mm to 10 mm in thickness and 3 cm to 4 cm in length. This approach was based on the premise that bone-to-bone healing is more reliable than tendon-to-tendon healing. Initial studies reported successful osteotomy healing, improved clinical outcome scores, and fewer abnormalities with belly-press and liftoff tests.^2,6 More recent literature, however, has questioned the necessity of LTO.^2,4,7-9We performed a systematic review to evaluate the literature, describe ST and LTO, and summarize the radiographic and clinical outcomes of both techniques. We hypothesized there would be no significant clinical differences between these approaches.

Methods

Search Strategy and Study Selection

Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we systematically reviewed the literature.¹⁰ Searches were completed in September 2014 using the PubMed Medline database and the Cochrane Central Register of Clinical Trials. Two reviewers (Dr. Louie, Dr. Levy) independently performed the search and assessed eligibility of all relevant studies based on predetermined inclusion criteria. Disagreements between reviewers were resolved by discussion. Key word selection was designed to capture all English-language studies with clinical and/or radiographic outcomes and level I to IV evidence. We used an electronic search algorithm with key words and a series of NOT phrases to match certain exclusion criteria:

(((((((((((((((((((((((((((((((((((((total[Text Word]) AND shoulder[Title]) AND arthroplasty[Title] AND (English[lang]))) NOT reverse[Title/Abstract]) NOT hemiarthroplasty[Title]) NOT nonoperative[Title]) NOT nonsurgical[Title] AND (English[lang]))) NOT rheumatoid[Title/Abstract]) NOT inflammatory[Title/Abstract]) NOT elbow[Title/Abstract]) NOT wrist[Title/Abstract]) NOT hip[Title/Abstract]) NOT knee[Title/Abstract]) NOT ankle[Title/Abstract] AND (English[lang]))) NOT biomechanic[Title/Abstract]) NOT biomechanics[Title/Abstract]) NOT biomechanical [Title/Abstract]) NOT cadaveric[Title/Abstract]) NOT revision[Title]) NOT resurfacing[Title/Abstract]) NOT surface[Title/Abstract]) NOT interphalangeal[Title/Abstract] AND (English[lang]))) NOT radiostereometric[Title/Abstract] AND (English[lang]))) NOT cmc[Title/Abstract]) NOT carpometacarpal[Title/Abstract]) NOT cervical[Title/Abstract]) NOT histology[Title/Abstract]) NOT histological[Title/Abstract]) NOT collagen[Title/Abstract] AND (English[lang]))) NOT kinematic[Title/Abstract]) NOT kinematics[Title/Abstract] AND (English[lang]))) NOT vitro[Title/Abstract] AND (English[lang]))) NOT inverted[Title/Abstract]) NOT grammont[Title/Abstract]) NOT arthrodesis[Title/Abstract]) NOT fusion[Title/Abstract]) NOT reverse[Title/Abstract] AND (English[lang]))

Study exclusion criteria consisted of cadaveric, biomechanical, histologic, and kinematic results as well as analyses of nonoperative management, hemiarthroplasty, or reverse TSA. Studies were excluded if they did not report clinical and/or radiographic data. Minimum mean follow-up was 2 years. To discount the effect of other TSA technical innovations, we evaluated the same period for the 2 surgical approaches. The first study with clinical outcomes after LTO was published in early 2005,⁶ so all studies published before 2005 were excluded.

We reviewed all references within the studies included by the initial search algorithm: randomized control trials, retrospective and prospective cohort designs, case series, and treatment studies. Technical notes, review papers, letters to the editor, and level V evidence reviews were excluded. To avoid counting patients twice, we compared each study’s authors and data collection period with those of the other studies. If there was overlap in authorship, period, and place, only the study with the longer follow-up or more comprehensive data was included. All trials comparing ST and LTO were included. If the authors of a TSA study did not describe the approach used, that study was excluded from our review.

Data Extraction

We collected details of study design, sample size, and patient demographics (sex, age, hand dominance, primary diagnosis). We also abstracted surgical factors about the glenoid component (cemented vs uncemented; pegged vs keeled; all-polyethylene vs metal-backed) and the humeral component (cemented vs press-fit; stemmed vs stemless). Clinical outcomes included pain scores, functional scores, number of revisions, range of motion (ROM), and subscapularis-specific tests (eg, belly-press, liftoff). As pain scales varied between studies, all values were converted to a 10-point scoring scale (0 = no pain; 10 = maximum pain) for comparisons. Numerous functional outcome scores were reported, but the Constant score was the only one consistently used across studies, making it a good choice for comparisons. One study used Penn Shoulder Scores (PSSs) and directly compared ST and LTO groups, so its data were included. In addition, radiographic data were compiled: radiolucencies around the humeral stem and glenoid component, humeral head subluxation/migration, and osteotomy healing. The only consistent radiographic parameter available for comparisons between groups was the presence of radiolucencies.

 

The Modified Coleman Methodology Score (MCMS), described by Cowan and colleagues,¹¹ was used to evaluate the methodologic quality of each study. The MCMS is a 15-item instrument that has been used to assess both randomized and nonrandomized trials.^12,13 It has a scaled score ranging from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor). Study quality was not factored into the data synthesis analysis.

Statistical Analysis

Data are reported as weighted means and standard deviations. A mean was calculated for each study reporting on a respective data point and was then weighed according to the study sample size. The result was that the nonweighted means from studies with smaller samples did not carry as much weight as those from studies with larger samples. Student t tests and 2-way analysis of variance were used to compare the ST and LTO groups and assess differences over time (SPSS Version 18; IBM). An α of 0.05 was set as statistically significant.

Results

Twenty studies (1420 shoulders, 1392 patients) were included in the final dataset (Figure).^2,6,8,14-30 

Table 1 lists the demographic characteristics of included patients. Of the 20 studies, 12 reported level IV evidence, 6 reported level III, 1 reported level II, and 1 reported level I. Mean (SD) MCMS was 51.9 (11.2) for ST studies and 46.3 (8.1) for LTO studies.

The youngest patients in the ST and LTO groups were 22 years and 19 years of age, respectively.

The oldest patient in each group was 92 years of age. On average, the ST study populations (mean age, 66.6 years; SD, 2.0 years) were older (P = .04) than the LTO populations (mean age, 62.1 years; SD, 4.2 years). The ST group had a higher percentage of patients with osteoarthritis (P = .03) and fewer patients with posttraumatic arthritis (P = .04). There were no significant differences in sex, shoulder side, or shoulder dominance between the 2 groups.

Table 2 lists the details regarding the surgical components. For glenoid components, the ST and LTO groups’ fixation types and material used were not significantly different.

There was a significant (P < .01) difference in use of pegged (vs keeled) glenoid components (all LTO components were pegged). There was also a significant (P = .04) difference in use of cement for humeral components (the ST group had a larger percentage of cemented humeral components). There were no other significant differences in components between the groups. When subgroup analysis was applied to keeled glenoid components and uncemented humeral components in the ST study populations, there were no significant changes in the radiographic or clinical trends.

Table 3 lists the clinical and radiographic outcomes most consistently reported in the literature. Physical examination data were reported in 18 ST populations^{8,14-16,21-30} and 11 LTO populations.^2,6,14-20

Mean (SD) forward elevation improvements were significantly (P < .01) larger for the ST group, +50.9° (17.5°), than for the LTO group, +31.3° (0.9°). There were no significant differences in preoperative/postoperative shoulder external rotation or abduction. In a common method of testing internal rotation, the patient is asked to internally rotate the surgical arm as high as possible behind the back. Internal rotation improved from L4–S1 (before surgery) to T5–T12 (after surgery) in the ST group^{8,16,24,26,28,29} and from S1 to T7–T12 in the LTO group.^16,31 There were isolated improvements in other subscapularis-specific tests, such as belly-press resistance (lb),¹⁴ belly-press force (N),¹⁵ bear hug resistance (lb),^14,23 liftoff,^2,8,16 and ability to tuck in one’s shirt,^2,16,23 but data were insufficient for comparisons between the 2 groups.

Constant scores were reported in 4 ST studies^14,22,24,27 and 3 LTO studies^14,17,18 (Table 3). There was no significant difference (P = .37) in post-TSA Constant score improvement between the 2 groups. In the one study that performed direct comparisons, PSS improved on average from 29 to 81 in the ST group and from 29 to 92 in the LTO group.¹⁵ Several ST studies reported improved scores on various indices: WOOS (Western Ontario Osteoarthritis of the Shoulder), ASES (American Shoulder and Elbow Surgeons), SST (Simple Shoulder Test), DASH (Disabilities of the Arm, Shoulder, and Hand), SF-12 (Short Form 12-Item Health Survey), MACTAR (McMaster Toronto Arthritis Patient Preference Disability Questionnaire), and Neer shoulder impingement test.^{8,14,15,21,23-25,27-30} However, these outcomes were not reported in LTO cohorts for comparison. Similarly, 2 LTO cohorts reported improvements in SSV (subjective shoulder value) scores, but this measure was not used in the ST cohorts.^6,17 Five ST studies recorded patients’ subjective satisfaction: 58% of patients indicated an excellent outcome, 35% a satisfactory outcome, and 7% a less than satisfactory outcome.^{21,23,25,26,29} Only 1 LTO study reported patient satisfaction: 69% excellent, 31% satisfactory, 0% dissatisfied.¹⁷

Complications were reported in 16 ST studies^8,15,21-30 and 6 LTO studies.^15,17-19 There were 117 complications (17.8%) and 58 revisions (10.0%) in the ST group and 52 complications (17.2%) and 49 revisions (16.2%) in the LTO group. In the ST group, aseptic loosening (6.2%) was the most common complication, followed by subscapularis tear or attenuation (5.2%), dislocation (2.1%), and deep infection (0.5%). In the LTO group, aseptic loosening was again the most common (9.0%), followed by dislocation (4.0%), subscapularis tear or attenuation (2.2%), and deep infection (0.7%). There were no significant differences in the incidence of individual complications between groups. The difference in revision rates was not statistically significant (P = .31).

Radiolucency data were reported in 12 ST studies^{19,21-26,28,30} and 2 LTO studies.^17,18 There were no discussions of humeral component radiolucencies in the LTO studies. At final follow-up, radiolucencies of the glenoid component were detected in 42.3% of patients in the ST group and 40.7% of patients in the LTO group (P = .76).

 

Discussion

Our goal in this systematic review was to analyze outcomes associated with ST and LTO in a heterogenous TSA population. We hypothesized TSA with ST or LTO would produce similar clinical and radiographic outcomes. There were no significant differences in Constant scores, pain scores, radiolucencies, or complications between the 2 groups. The ST group showed trends toward wider ROM improvements and fewer revisions, but only the change in forward elevation was significant. The components used in the 2 groups were similar with the exception of a lack of keeled glenoids and cemented humeral stems in the LTO group; data stratification controlling for these differences revealed no change in outcomes.

The optimal method of subscapularis mobilization for TSA remains a source of debate. Jackson and colleagues²³ found significant improvements in Neer and DASH scores after ST. However, 7 of 15 patients ruptured the subscapularis after 6 months and had significantly lower DASH scores. In 2005, Gerber and colleagues⁶ first described the LTO technique as an alternative to ST. After a mean of 39 months, 89% of their patients had a negative belly-press test, and 75% had a normal liftoff test. Radiographic evaluation revealed that the osteotomized fragment had healed in an anatomical position in all shoulders. In a large case series, Small and colleagues²⁰ used radiographs and computed tomography to further investigate LTO healing rates and found that 89% of patients had bony union by 6 months and that smoking was a significant risk factor for nonunion.

Biomechanical studies comparing ST and LTO approaches have shown mixed results. Ponce and colleagues² found decreased cyclic displacement and increased maximum load to failure with LTO, but Giuseffi and colleagues³² showed less cyclic displacement with ST and no difference in load to failure. Others authors have found no significant differences in stiffness or maximum load to failure.³³ Van den Berghe and colleagues⁷ reported a higher failure rate in bone-to-bone repairs compared with tendon-to-tendon constructs. Moreover, they found that suture cut-out through bone tunnels is the primary mode of LTO failure, so many LTO surgeons now pass sutures around the humeral stem instead.

Three TSA studies directly compared ST and LTO approaches. Buckley and colleagues¹⁴ analyzed 60 TSAs and found no significant differences in WOOS, DASH, or Constant scores between groups. The authors described an ST subgroup with subscapularis attenuation on ultrasound but did not report the group as having any inferior functional outcome. Scalise and colleagues¹⁵ showed improved strength and PSSs in both groups after 2 years. However, the LTO group had a lower rate of subscapularis tears and significantly higher PSSs. Finally, Jandhyala and colleagues¹⁶ reported more favorable outcomes with LTO, which trended toward wider ROM and significantly higher belly-press test grades. Lapner and colleagues³⁴ conducted a randomized, controlled trial (often referenced) and found no significant differences between the 2 groups in terms of strength or functional outcome at 2-year follow-up. Their study, however, included hemiarthroplasties and did not substratify the TSA population, so we did not include it in our review.

Our systematic review found significantly more forward elevation improvement for the ST group than the LTO group, which may suggest improved ROM with a soft-tissue approach than a bony approach. At the same time, the ST group trended toward better passive external rotation relative to the LTO group. This trend indicates fewer constraints to external rotation in the ST group, possibly attributable to a more attenuated subscapularis after tenotomy. Subscapularis tear or attenuation was more commonly reported in the ST group than in the LTO group, though not significantly so. This may indicate that more ST studies than LTO studies specially emphasized postoperative subscapularis function, but these data also highlight some authors’ concerns regarding subscapularis dysfunction after tenotomy.^6,15,16The study populations’ complication rates were similar, just over 17%. The LTO group trended toward a higher revision rate, but it was not statistically significant. The LTO group also had significantly fewer patients with osteoarthritis and more patients with posttraumatic arthritis, so this group may have had more complex patients predisposed to a higher likelihood of revision surgery. Revisions were most commonly performed for aseptic loosening; theoretically, if osteotomies heal less effectively than tenotomies, the LTO approach could produce component instability and aseptic loosening. However, no prior studies or other clinical findings from this review suggest LTO predisposes to aseptic loosening. Overall, the uneven revision rates represent a clinical concern that should be monitored as larger samples of patients undergo ST and LTO procedures.

Glenoid radiolucencies were the only radiographic parameter consistently reported in the included studies. Twelve ST studies had radiolucency data—compared with only 2 LTO studies. Thus, our ability to compare radiographic outcomes was limited. Our data revealed similar rates of glenoid radiolucencies between the 2 approaches. The clinical relevance of radiolucencies is questioned by some authors, and, indeed, Razmjou and colleagues²⁵ found no correlation of radiolucencies with patient satisfaction. Nevertheless, early presence of radiolucencies may raise concerns about progressive loss of fixation,^35,36 so this should be monitored.

Limitations of this systematic review reflect the studies analyzed. We minimized selection bias by including level I to IV evidence, but most studies were level IV, and only 1 was level I. As such, there was a relative paucity of consistent clinical and radiographic data. For instance, although many ST studies reported patient satisfaction as an outcomes measure, only 1 LTO study commented on it. Perhaps the relative novelty of the LTO approach has prompted some authors to focus more on technical details and less on reporting a variety of outcome measures. As mentioned earlier, the significance of radiolucency data is controversial, and determination of their presence or absence depends on the observer. A radiolucency found in one study may not qualify as one in a study that uses different criteria. However, lucency data were the most frequently and reliably reported radiographic parameter, so we deemed it the most appropriate method for comparing radiographic outcomes. Finally, the baseline differences in diagnosis between the ST and LTO groups complicated comparisons. We stratified the groups by component design because use of keeled or pegged implants or humeral cemented or press-fit stems was usually a uniform feature of each study—enabling removal of certain studies for data stratification. However, we were unable to stratify by original diagnosis because these groups were not stratified within the individual studies.

 

Conclusion

Our systematic review found similar Constant scores, pain scores, radiographic outcomes, and complication rates for the ST and LTO approaches. Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions. Although not definitive, these data suggest the ST approach may provide more stability over the long term, but additional comprehensive studies are needed to increase the sample size and the power of the trends elucidated in this review. According to the orthopedic literature, both techniques produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.

Am J Orthop. 2017;46(2):E131-E138. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• According to the orthopedic literature, ST and LTO for a TSA produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.
• Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions.
• ST and LTO approaches for a TSA result in similar Constant scores, pain scores, radiographic outcomes, and complication rates.

During total shoulder arthroplasty (TSA) exposure, the subscapularis muscle must be mobilized; its repair is crucial to the stability of the arthroplasty. The subscapularis is the largest rotator cuff muscle and has a contractile force equal to that of the other 3 muscles combined.^1,2 Traditionally it is mobilized with a tenotomy just medial to the tendon’s insertion onto the lesser tuberosity. Over the past 15 years, however, numerous authors have reported dysfunction after subscapularis tenotomy (ST). In 2003, Miller and colleagues³ reported that, at 2-year follow-up, almost 70% of patients had abnormal belly-press and liftoff tests, surrogate markers of subscapularis function. Other authors have found increased rates of anterior instability after subscapularis rupture.^4,5

In 2005, Gerber and colleagues⁶ introduced a technique for circumventing surgical division of the subscapularis. They described a lesser tuberosity osteotomy (LTO), in which the subscapularis tendon is detached with a bone fragment 5 mm to 10 mm in thickness and 3 cm to 4 cm in length. This approach was based on the premise that bone-to-bone healing is more reliable than tendon-to-tendon healing. Initial studies reported successful osteotomy healing, improved clinical outcome scores, and fewer abnormalities with belly-press and liftoff tests.^2,6 More recent literature, however, has questioned the necessity of LTO.^2,4,7-9We performed a systematic review to evaluate the literature, describe ST and LTO, and summarize the radiographic and clinical outcomes of both techniques. We hypothesized there would be no significant clinical differences between these approaches.

Methods

Search Strategy and Study Selection

Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we systematically reviewed the literature.¹⁰ Searches were completed in September 2014 using the PubMed Medline database and the Cochrane Central Register of Clinical Trials. Two reviewers (Dr. Louie, Dr. Levy) independently performed the search and assessed eligibility of all relevant studies based on predetermined inclusion criteria. Disagreements between reviewers were resolved by discussion. Key word selection was designed to capture all English-language studies with clinical and/or radiographic outcomes and level I to IV evidence. We used an electronic search algorithm with key words and a series of NOT phrases to match certain exclusion criteria:

(((((((((((((((((((((((((((((((((((((total[Text Word]) AND shoulder[Title]) AND arthroplasty[Title] AND (English[lang]))) NOT reverse[Title/Abstract]) NOT hemiarthroplasty[Title]) NOT nonoperative[Title]) NOT nonsurgical[Title] AND (English[lang]))) NOT rheumatoid[Title/Abstract]) NOT inflammatory[Title/Abstract]) NOT elbow[Title/Abstract]) NOT wrist[Title/Abstract]) NOT hip[Title/Abstract]) NOT knee[Title/Abstract]) NOT ankle[Title/Abstract] AND (English[lang]))) NOT biomechanic[Title/Abstract]) NOT biomechanics[Title/Abstract]) NOT biomechanical [Title/Abstract]) NOT cadaveric[Title/Abstract]) NOT revision[Title]) NOT resurfacing[Title/Abstract]) NOT surface[Title/Abstract]) NOT interphalangeal[Title/Abstract] AND (English[lang]))) NOT radiostereometric[Title/Abstract] AND (English[lang]))) NOT cmc[Title/Abstract]) NOT carpometacarpal[Title/Abstract]) NOT cervical[Title/Abstract]) NOT histology[Title/Abstract]) NOT histological[Title/Abstract]) NOT collagen[Title/Abstract] AND (English[lang]))) NOT kinematic[Title/Abstract]) NOT kinematics[Title/Abstract] AND (English[lang]))) NOT vitro[Title/Abstract] AND (English[lang]))) NOT inverted[Title/Abstract]) NOT grammont[Title/Abstract]) NOT arthrodesis[Title/Abstract]) NOT fusion[Title/Abstract]) NOT reverse[Title/Abstract] AND (English[lang]))

Study exclusion criteria consisted of cadaveric, biomechanical, histologic, and kinematic results as well as analyses of nonoperative management, hemiarthroplasty, or reverse TSA. Studies were excluded if they did not report clinical and/or radiographic data. Minimum mean follow-up was 2 years. To discount the effect of other TSA technical innovations, we evaluated the same period for the 2 surgical approaches. The first study with clinical outcomes after LTO was published in early 2005,⁶ so all studies published before 2005 were excluded.

We reviewed all references within the studies included by the initial search algorithm: randomized control trials, retrospective and prospective cohort designs, case series, and treatment studies. Technical notes, review papers, letters to the editor, and level V evidence reviews were excluded. To avoid counting patients twice, we compared each study’s authors and data collection period with those of the other studies. If there was overlap in authorship, period, and place, only the study with the longer follow-up or more comprehensive data was included. All trials comparing ST and LTO were included. If the authors of a TSA study did not describe the approach used, that study was excluded from our review.

Data Extraction

We collected details of study design, sample size, and patient demographics (sex, age, hand dominance, primary diagnosis). We also abstracted surgical factors about the glenoid component (cemented vs uncemented; pegged vs keeled; all-polyethylene vs metal-backed) and the humeral component (cemented vs press-fit; stemmed vs stemless). Clinical outcomes included pain scores, functional scores, number of revisions, range of motion (ROM), and subscapularis-specific tests (eg, belly-press, liftoff). As pain scales varied between studies, all values were converted to a 10-point scoring scale (0 = no pain; 10 = maximum pain) for comparisons. Numerous functional outcome scores were reported, but the Constant score was the only one consistently used across studies, making it a good choice for comparisons. One study used Penn Shoulder Scores (PSSs) and directly compared ST and LTO groups, so its data were included. In addition, radiographic data were compiled: radiolucencies around the humeral stem and glenoid component, humeral head subluxation/migration, and osteotomy healing. The only consistent radiographic parameter available for comparisons between groups was the presence of radiolucencies.

 

The Modified Coleman Methodology Score (MCMS), described by Cowan and colleagues,¹¹ was used to evaluate the methodologic quality of each study. The MCMS is a 15-item instrument that has been used to assess both randomized and nonrandomized trials.^12,13 It has a scaled score ranging from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor). Study quality was not factored into the data synthesis analysis.

Statistical Analysis

Data are reported as weighted means and standard deviations. A mean was calculated for each study reporting on a respective data point and was then weighed according to the study sample size. The result was that the nonweighted means from studies with smaller samples did not carry as much weight as those from studies with larger samples. Student t tests and 2-way analysis of variance were used to compare the ST and LTO groups and assess differences over time (SPSS Version 18; IBM). An α of 0.05 was set as statistically significant.

Results

Twenty studies (1420 shoulders, 1392 patients) were included in the final dataset (Figure).^2,6,8,14-30 

Table 1 lists the demographic characteristics of included patients. Of the 20 studies, 12 reported level IV evidence, 6 reported level III, 1 reported level II, and 1 reported level I. Mean (SD) MCMS was 51.9 (11.2) for ST studies and 46.3 (8.1) for LTO studies.

The youngest patients in the ST and LTO groups were 22 years and 19 years of age, respectively.

The oldest patient in each group was 92 years of age. On average, the ST study populations (mean age, 66.6 years; SD, 2.0 years) were older (P = .04) than the LTO populations (mean age, 62.1 years; SD, 4.2 years). The ST group had a higher percentage of patients with osteoarthritis (P = .03) and fewer patients with posttraumatic arthritis (P = .04). There were no significant differences in sex, shoulder side, or shoulder dominance between the 2 groups.

Table 2 lists the details regarding the surgical components. For glenoid components, the ST and LTO groups’ fixation types and material used were not significantly different.

There was a significant (P < .01) difference in use of pegged (vs keeled) glenoid components (all LTO components were pegged). There was also a significant (P = .04) difference in use of cement for humeral components (the ST group had a larger percentage of cemented humeral components). There were no other significant differences in components between the groups. When subgroup analysis was applied to keeled glenoid components and uncemented humeral components in the ST study populations, there were no significant changes in the radiographic or clinical trends.

Table 3 lists the clinical and radiographic outcomes most consistently reported in the literature. Physical examination data were reported in 18 ST populations^{8,14-16,21-30} and 11 LTO populations.^2,6,14-20

Mean (SD) forward elevation improvements were significantly (P < .01) larger for the ST group, +50.9° (17.5°), than for the LTO group, +31.3° (0.9°). There were no significant differences in preoperative/postoperative shoulder external rotation or abduction. In a common method of testing internal rotation, the patient is asked to internally rotate the surgical arm as high as possible behind the back. Internal rotation improved from L4–S1 (before surgery) to T5–T12 (after surgery) in the ST group^{8,16,24,26,28,29} and from S1 to T7–T12 in the LTO group.^16,31 There were isolated improvements in other subscapularis-specific tests, such as belly-press resistance (lb),¹⁴ belly-press force (N),¹⁵ bear hug resistance (lb),^14,23 liftoff,^2,8,16 and ability to tuck in one’s shirt,^2,16,23 but data were insufficient for comparisons between the 2 groups.

Constant scores were reported in 4 ST studies^14,22,24,27 and 3 LTO studies^14,17,18 (Table 3). There was no significant difference (P = .37) in post-TSA Constant score improvement between the 2 groups. In the one study that performed direct comparisons, PSS improved on average from 29 to 81 in the ST group and from 29 to 92 in the LTO group.¹⁵ Several ST studies reported improved scores on various indices: WOOS (Western Ontario Osteoarthritis of the Shoulder), ASES (American Shoulder and Elbow Surgeons), SST (Simple Shoulder Test), DASH (Disabilities of the Arm, Shoulder, and Hand), SF-12 (Short Form 12-Item Health Survey), MACTAR (McMaster Toronto Arthritis Patient Preference Disability Questionnaire), and Neer shoulder impingement test.^{8,14,15,21,23-25,27-30} However, these outcomes were not reported in LTO cohorts for comparison. Similarly, 2 LTO cohorts reported improvements in SSV (subjective shoulder value) scores, but this measure was not used in the ST cohorts.^6,17 Five ST studies recorded patients’ subjective satisfaction: 58% of patients indicated an excellent outcome, 35% a satisfactory outcome, and 7% a less than satisfactory outcome.^{21,23,25,26,29} Only 1 LTO study reported patient satisfaction: 69% excellent, 31% satisfactory, 0% dissatisfied.¹⁷

Complications were reported in 16 ST studies^8,15,21-30 and 6 LTO studies.^15,17-19 There were 117 complications (17.8%) and 58 revisions (10.0%) in the ST group and 52 complications (17.2%) and 49 revisions (16.2%) in the LTO group. In the ST group, aseptic loosening (6.2%) was the most common complication, followed by subscapularis tear or attenuation (5.2%), dislocation (2.1%), and deep infection (0.5%). In the LTO group, aseptic loosening was again the most common (9.0%), followed by dislocation (4.0%), subscapularis tear or attenuation (2.2%), and deep infection (0.7%). There were no significant differences in the incidence of individual complications between groups. The difference in revision rates was not statistically significant (P = .31).

Radiolucency data were reported in 12 ST studies^{19,21-26,28,30} and 2 LTO studies.^17,18 There were no discussions of humeral component radiolucencies in the LTO studies. At final follow-up, radiolucencies of the glenoid component were detected in 42.3% of patients in the ST group and 40.7% of patients in the LTO group (P = .76).

 

Discussion

Our goal in this systematic review was to analyze outcomes associated with ST and LTO in a heterogenous TSA population. We hypothesized TSA with ST or LTO would produce similar clinical and radiographic outcomes. There were no significant differences in Constant scores, pain scores, radiolucencies, or complications between the 2 groups. The ST group showed trends toward wider ROM improvements and fewer revisions, but only the change in forward elevation was significant. The components used in the 2 groups were similar with the exception of a lack of keeled glenoids and cemented humeral stems in the LTO group; data stratification controlling for these differences revealed no change in outcomes.

The optimal method of subscapularis mobilization for TSA remains a source of debate. Jackson and colleagues²³ found significant improvements in Neer and DASH scores after ST. However, 7 of 15 patients ruptured the subscapularis after 6 months and had significantly lower DASH scores. In 2005, Gerber and colleagues⁶ first described the LTO technique as an alternative to ST. After a mean of 39 months, 89% of their patients had a negative belly-press test, and 75% had a normal liftoff test. Radiographic evaluation revealed that the osteotomized fragment had healed in an anatomical position in all shoulders. In a large case series, Small and colleagues²⁰ used radiographs and computed tomography to further investigate LTO healing rates and found that 89% of patients had bony union by 6 months and that smoking was a significant risk factor for nonunion.

Biomechanical studies comparing ST and LTO approaches have shown mixed results. Ponce and colleagues² found decreased cyclic displacement and increased maximum load to failure with LTO, but Giuseffi and colleagues³² showed less cyclic displacement with ST and no difference in load to failure. Others authors have found no significant differences in stiffness or maximum load to failure.³³ Van den Berghe and colleagues⁷ reported a higher failure rate in bone-to-bone repairs compared with tendon-to-tendon constructs. Moreover, they found that suture cut-out through bone tunnels is the primary mode of LTO failure, so many LTO surgeons now pass sutures around the humeral stem instead.

Three TSA studies directly compared ST and LTO approaches. Buckley and colleagues¹⁴ analyzed 60 TSAs and found no significant differences in WOOS, DASH, or Constant scores between groups. The authors described an ST subgroup with subscapularis attenuation on ultrasound but did not report the group as having any inferior functional outcome. Scalise and colleagues¹⁵ showed improved strength and PSSs in both groups after 2 years. However, the LTO group had a lower rate of subscapularis tears and significantly higher PSSs. Finally, Jandhyala and colleagues¹⁶ reported more favorable outcomes with LTO, which trended toward wider ROM and significantly higher belly-press test grades. Lapner and colleagues³⁴ conducted a randomized, controlled trial (often referenced) and found no significant differences between the 2 groups in terms of strength or functional outcome at 2-year follow-up. Their study, however, included hemiarthroplasties and did not substratify the TSA population, so we did not include it in our review.

Our systematic review found significantly more forward elevation improvement for the ST group than the LTO group, which may suggest improved ROM with a soft-tissue approach than a bony approach. At the same time, the ST group trended toward better passive external rotation relative to the LTO group. This trend indicates fewer constraints to external rotation in the ST group, possibly attributable to a more attenuated subscapularis after tenotomy. Subscapularis tear or attenuation was more commonly reported in the ST group than in the LTO group, though not significantly so. This may indicate that more ST studies than LTO studies specially emphasized postoperative subscapularis function, but these data also highlight some authors’ concerns regarding subscapularis dysfunction after tenotomy.^6,15,16The study populations’ complication rates were similar, just over 17%. The LTO group trended toward a higher revision rate, but it was not statistically significant. The LTO group also had significantly fewer patients with osteoarthritis and more patients with posttraumatic arthritis, so this group may have had more complex patients predisposed to a higher likelihood of revision surgery. Revisions were most commonly performed for aseptic loosening; theoretically, if osteotomies heal less effectively than tenotomies, the LTO approach could produce component instability and aseptic loosening. However, no prior studies or other clinical findings from this review suggest LTO predisposes to aseptic loosening. Overall, the uneven revision rates represent a clinical concern that should be monitored as larger samples of patients undergo ST and LTO procedures.

Glenoid radiolucencies were the only radiographic parameter consistently reported in the included studies. Twelve ST studies had radiolucency data—compared with only 2 LTO studies. Thus, our ability to compare radiographic outcomes was limited. Our data revealed similar rates of glenoid radiolucencies between the 2 approaches. The clinical relevance of radiolucencies is questioned by some authors, and, indeed, Razmjou and colleagues²⁵ found no correlation of radiolucencies with patient satisfaction. Nevertheless, early presence of radiolucencies may raise concerns about progressive loss of fixation,^35,36 so this should be monitored.

Limitations of this systematic review reflect the studies analyzed. We minimized selection bias by including level I to IV evidence, but most studies were level IV, and only 1 was level I. As such, there was a relative paucity of consistent clinical and radiographic data. For instance, although many ST studies reported patient satisfaction as an outcomes measure, only 1 LTO study commented on it. Perhaps the relative novelty of the LTO approach has prompted some authors to focus more on technical details and less on reporting a variety of outcome measures. As mentioned earlier, the significance of radiolucency data is controversial, and determination of their presence or absence depends on the observer. A radiolucency found in one study may not qualify as one in a study that uses different criteria. However, lucency data were the most frequently and reliably reported radiographic parameter, so we deemed it the most appropriate method for comparing radiographic outcomes. Finally, the baseline differences in diagnosis between the ST and LTO groups complicated comparisons. We stratified the groups by component design because use of keeled or pegged implants or humeral cemented or press-fit stems was usually a uniform feature of each study—enabling removal of certain studies for data stratification. However, we were unable to stratify by original diagnosis because these groups were not stratified within the individual studies.

 

Conclusion

Our systematic review found similar Constant scores, pain scores, radiographic outcomes, and complication rates for the ST and LTO approaches. Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions. Although not definitive, these data suggest the ST approach may provide more stability over the long term, but additional comprehensive studies are needed to increase the sample size and the power of the trends elucidated in this review. According to the orthopedic literature, both techniques produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.

Am J Orthop. 2017;46(2):E131-E138. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• According to the orthopedic literature, ST and LTO for a TSA produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.
• Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions.
• ST and LTO approaches for a TSA result in similar Constant scores, pain scores, radiographic outcomes, and complication rates.

During total shoulder arthroplasty (TSA) exposure, the subscapularis muscle must be mobilized; its repair is crucial to the stability of the arthroplasty. The subscapularis is the largest rotator cuff muscle and has a contractile force equal to that of the other 3 muscles combined.^1,2 Traditionally it is mobilized with a tenotomy just medial to the tendon’s insertion onto the lesser tuberosity. Over the past 15 years, however, numerous authors have reported dysfunction after subscapularis tenotomy (ST). In 2003, Miller and colleagues³ reported that, at 2-year follow-up, almost 70% of patients had abnormal belly-press and liftoff tests, surrogate markers of subscapularis function. Other authors have found increased rates of anterior instability after subscapularis rupture.^4,5

In 2005, Gerber and colleagues⁶ introduced a technique for circumventing surgical division of the subscapularis. They described a lesser tuberosity osteotomy (LTO), in which the subscapularis tendon is detached with a bone fragment 5 mm to 10 mm in thickness and 3 cm to 4 cm in length. This approach was based on the premise that bone-to-bone healing is more reliable than tendon-to-tendon healing. Initial studies reported successful osteotomy healing, improved clinical outcome scores, and fewer abnormalities with belly-press and liftoff tests.^2,6 More recent literature, however, has questioned the necessity of LTO.^2,4,7-9We performed a systematic review to evaluate the literature, describe ST and LTO, and summarize the radiographic and clinical outcomes of both techniques. We hypothesized there would be no significant clinical differences between these approaches.

Methods

Search Strategy and Study Selection

Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we systematically reviewed the literature.¹⁰ Searches were completed in September 2014 using the PubMed Medline database and the Cochrane Central Register of Clinical Trials. Two reviewers (Dr. Louie, Dr. Levy) independently performed the search and assessed eligibility of all relevant studies based on predetermined inclusion criteria. Disagreements between reviewers were resolved by discussion. Key word selection was designed to capture all English-language studies with clinical and/or radiographic outcomes and level I to IV evidence. We used an electronic search algorithm with key words and a series of NOT phrases to match certain exclusion criteria:

(((((((((((((((((((((((((((((((((((((total[Text Word]) AND shoulder[Title]) AND arthroplasty[Title] AND (English[lang]))) NOT reverse[Title/Abstract]) NOT hemiarthroplasty[Title]) NOT nonoperative[Title]) NOT nonsurgical[Title] AND (English[lang]))) NOT rheumatoid[Title/Abstract]) NOT inflammatory[Title/Abstract]) NOT elbow[Title/Abstract]) NOT wrist[Title/Abstract]) NOT hip[Title/Abstract]) NOT knee[Title/Abstract]) NOT ankle[Title/Abstract] AND (English[lang]))) NOT biomechanic[Title/Abstract]) NOT biomechanics[Title/Abstract]) NOT biomechanical [Title/Abstract]) NOT cadaveric[Title/Abstract]) NOT revision[Title]) NOT resurfacing[Title/Abstract]) NOT surface[Title/Abstract]) NOT interphalangeal[Title/Abstract] AND (English[lang]))) NOT radiostereometric[Title/Abstract] AND (English[lang]))) NOT cmc[Title/Abstract]) NOT carpometacarpal[Title/Abstract]) NOT cervical[Title/Abstract]) NOT histology[Title/Abstract]) NOT histological[Title/Abstract]) NOT collagen[Title/Abstract] AND (English[lang]))) NOT kinematic[Title/Abstract]) NOT kinematics[Title/Abstract] AND (English[lang]))) NOT vitro[Title/Abstract] AND (English[lang]))) NOT inverted[Title/Abstract]) NOT grammont[Title/Abstract]) NOT arthrodesis[Title/Abstract]) NOT fusion[Title/Abstract]) NOT reverse[Title/Abstract] AND (English[lang]))

Study exclusion criteria consisted of cadaveric, biomechanical, histologic, and kinematic results as well as analyses of nonoperative management, hemiarthroplasty, or reverse TSA. Studies were excluded if they did not report clinical and/or radiographic data. Minimum mean follow-up was 2 years. To discount the effect of other TSA technical innovations, we evaluated the same period for the 2 surgical approaches. The first study with clinical outcomes after LTO was published in early 2005,⁶ so all studies published before 2005 were excluded.

We reviewed all references within the studies included by the initial search algorithm: randomized control trials, retrospective and prospective cohort designs, case series, and treatment studies. Technical notes, review papers, letters to the editor, and level V evidence reviews were excluded. To avoid counting patients twice, we compared each study’s authors and data collection period with those of the other studies. If there was overlap in authorship, period, and place, only the study with the longer follow-up or more comprehensive data was included. All trials comparing ST and LTO were included. If the authors of a TSA study did not describe the approach used, that study was excluded from our review.

Data Extraction

We collected details of study design, sample size, and patient demographics (sex, age, hand dominance, primary diagnosis). We also abstracted surgical factors about the glenoid component (cemented vs uncemented; pegged vs keeled; all-polyethylene vs metal-backed) and the humeral component (cemented vs press-fit; stemmed vs stemless). Clinical outcomes included pain scores, functional scores, number of revisions, range of motion (ROM), and subscapularis-specific tests (eg, belly-press, liftoff). As pain scales varied between studies, all values were converted to a 10-point scoring scale (0 = no pain; 10 = maximum pain) for comparisons. Numerous functional outcome scores were reported, but the Constant score was the only one consistently used across studies, making it a good choice for comparisons. One study used Penn Shoulder Scores (PSSs) and directly compared ST and LTO groups, so its data were included. In addition, radiographic data were compiled: radiolucencies around the humeral stem and glenoid component, humeral head subluxation/migration, and osteotomy healing. The only consistent radiographic parameter available for comparisons between groups was the presence of radiolucencies.

 

The Modified Coleman Methodology Score (MCMS), described by Cowan and colleagues,¹¹ was used to evaluate the methodologic quality of each study. The MCMS is a 15-item instrument that has been used to assess both randomized and nonrandomized trials.^12,13 It has a scaled score ranging from 0 to 100 (85-100, excellent; 70-84, good; 55-69, fair; <55, poor). Study quality was not factored into the data synthesis analysis.

Statistical Analysis

Data are reported as weighted means and standard deviations. A mean was calculated for each study reporting on a respective data point and was then weighed according to the study sample size. The result was that the nonweighted means from studies with smaller samples did not carry as much weight as those from studies with larger samples. Student t tests and 2-way analysis of variance were used to compare the ST and LTO groups and assess differences over time (SPSS Version 18; IBM). An α of 0.05 was set as statistically significant.

Results

Twenty studies (1420 shoulders, 1392 patients) were included in the final dataset (Figure).^2,6,8,14-30 

Table 1 lists the demographic characteristics of included patients. Of the 20 studies, 12 reported level IV evidence, 6 reported level III, 1 reported level II, and 1 reported level I. Mean (SD) MCMS was 51.9 (11.2) for ST studies and 46.3 (8.1) for LTO studies.

The youngest patients in the ST and LTO groups were 22 years and 19 years of age, respectively.

The oldest patient in each group was 92 years of age. On average, the ST study populations (mean age, 66.6 years; SD, 2.0 years) were older (P = .04) than the LTO populations (mean age, 62.1 years; SD, 4.2 years). The ST group had a higher percentage of patients with osteoarthritis (P = .03) and fewer patients with posttraumatic arthritis (P = .04). There were no significant differences in sex, shoulder side, or shoulder dominance between the 2 groups.

Table 2 lists the details regarding the surgical components. For glenoid components, the ST and LTO groups’ fixation types and material used were not significantly different.

There was a significant (P < .01) difference in use of pegged (vs keeled) glenoid components (all LTO components were pegged). There was also a significant (P = .04) difference in use of cement for humeral components (the ST group had a larger percentage of cemented humeral components). There were no other significant differences in components between the groups. When subgroup analysis was applied to keeled glenoid components and uncemented humeral components in the ST study populations, there were no significant changes in the radiographic or clinical trends.

Table 3 lists the clinical and radiographic outcomes most consistently reported in the literature. Physical examination data were reported in 18 ST populations^{8,14-16,21-30} and 11 LTO populations.^2,6,14-20

Mean (SD) forward elevation improvements were significantly (P < .01) larger for the ST group, +50.9° (17.5°), than for the LTO group, +31.3° (0.9°). There were no significant differences in preoperative/postoperative shoulder external rotation or abduction. In a common method of testing internal rotation, the patient is asked to internally rotate the surgical arm as high as possible behind the back. Internal rotation improved from L4–S1 (before surgery) to T5–T12 (after surgery) in the ST group^{8,16,24,26,28,29} and from S1 to T7–T12 in the LTO group.^16,31 There were isolated improvements in other subscapularis-specific tests, such as belly-press resistance (lb),¹⁴ belly-press force (N),¹⁵ bear hug resistance (lb),^14,23 liftoff,^2,8,16 and ability to tuck in one’s shirt,^2,16,23 but data were insufficient for comparisons between the 2 groups.

Constant scores were reported in 4 ST studies^14,22,24,27 and 3 LTO studies^14,17,18 (Table 3). There was no significant difference (P = .37) in post-TSA Constant score improvement between the 2 groups. In the one study that performed direct comparisons, PSS improved on average from 29 to 81 in the ST group and from 29 to 92 in the LTO group.¹⁵ Several ST studies reported improved scores on various indices: WOOS (Western Ontario Osteoarthritis of the Shoulder), ASES (American Shoulder and Elbow Surgeons), SST (Simple Shoulder Test), DASH (Disabilities of the Arm, Shoulder, and Hand), SF-12 (Short Form 12-Item Health Survey), MACTAR (McMaster Toronto Arthritis Patient Preference Disability Questionnaire), and Neer shoulder impingement test.^{8,14,15,21,23-25,27-30} However, these outcomes were not reported in LTO cohorts for comparison. Similarly, 2 LTO cohorts reported improvements in SSV (subjective shoulder value) scores, but this measure was not used in the ST cohorts.^6,17 Five ST studies recorded patients’ subjective satisfaction: 58% of patients indicated an excellent outcome, 35% a satisfactory outcome, and 7% a less than satisfactory outcome.^{21,23,25,26,29} Only 1 LTO study reported patient satisfaction: 69% excellent, 31% satisfactory, 0% dissatisfied.¹⁷

Complications were reported in 16 ST studies^8,15,21-30 and 6 LTO studies.^15,17-19 There were 117 complications (17.8%) and 58 revisions (10.0%) in the ST group and 52 complications (17.2%) and 49 revisions (16.2%) in the LTO group. In the ST group, aseptic loosening (6.2%) was the most common complication, followed by subscapularis tear or attenuation (5.2%), dislocation (2.1%), and deep infection (0.5%). In the LTO group, aseptic loosening was again the most common (9.0%), followed by dislocation (4.0%), subscapularis tear or attenuation (2.2%), and deep infection (0.7%). There were no significant differences in the incidence of individual complications between groups. The difference in revision rates was not statistically significant (P = .31).

Radiolucency data were reported in 12 ST studies^{19,21-26,28,30} and 2 LTO studies.^17,18 There were no discussions of humeral component radiolucencies in the LTO studies. At final follow-up, radiolucencies of the glenoid component were detected in 42.3% of patients in the ST group and 40.7% of patients in the LTO group (P = .76).

 

Discussion

Our goal in this systematic review was to analyze outcomes associated with ST and LTO in a heterogenous TSA population. We hypothesized TSA with ST or LTO would produce similar clinical and radiographic outcomes. There were no significant differences in Constant scores, pain scores, radiolucencies, or complications between the 2 groups. The ST group showed trends toward wider ROM improvements and fewer revisions, but only the change in forward elevation was significant. The components used in the 2 groups were similar with the exception of a lack of keeled glenoids and cemented humeral stems in the LTO group; data stratification controlling for these differences revealed no change in outcomes.

The optimal method of subscapularis mobilization for TSA remains a source of debate. Jackson and colleagues²³ found significant improvements in Neer and DASH scores after ST. However, 7 of 15 patients ruptured the subscapularis after 6 months and had significantly lower DASH scores. In 2005, Gerber and colleagues⁶ first described the LTO technique as an alternative to ST. After a mean of 39 months, 89% of their patients had a negative belly-press test, and 75% had a normal liftoff test. Radiographic evaluation revealed that the osteotomized fragment had healed in an anatomical position in all shoulders. In a large case series, Small and colleagues²⁰ used radiographs and computed tomography to further investigate LTO healing rates and found that 89% of patients had bony union by 6 months and that smoking was a significant risk factor for nonunion.

Biomechanical studies comparing ST and LTO approaches have shown mixed results. Ponce and colleagues² found decreased cyclic displacement and increased maximum load to failure with LTO, but Giuseffi and colleagues³² showed less cyclic displacement with ST and no difference in load to failure. Others authors have found no significant differences in stiffness or maximum load to failure.³³ Van den Berghe and colleagues⁷ reported a higher failure rate in bone-to-bone repairs compared with tendon-to-tendon constructs. Moreover, they found that suture cut-out through bone tunnels is the primary mode of LTO failure, so many LTO surgeons now pass sutures around the humeral stem instead.

Three TSA studies directly compared ST and LTO approaches. Buckley and colleagues¹⁴ analyzed 60 TSAs and found no significant differences in WOOS, DASH, or Constant scores between groups. The authors described an ST subgroup with subscapularis attenuation on ultrasound but did not report the group as having any inferior functional outcome. Scalise and colleagues¹⁵ showed improved strength and PSSs in both groups after 2 years. However, the LTO group had a lower rate of subscapularis tears and significantly higher PSSs. Finally, Jandhyala and colleagues¹⁶ reported more favorable outcomes with LTO, which trended toward wider ROM and significantly higher belly-press test grades. Lapner and colleagues³⁴ conducted a randomized, controlled trial (often referenced) and found no significant differences between the 2 groups in terms of strength or functional outcome at 2-year follow-up. Their study, however, included hemiarthroplasties and did not substratify the TSA population, so we did not include it in our review.

Our systematic review found significantly more forward elevation improvement for the ST group than the LTO group, which may suggest improved ROM with a soft-tissue approach than a bony approach. At the same time, the ST group trended toward better passive external rotation relative to the LTO group. This trend indicates fewer constraints to external rotation in the ST group, possibly attributable to a more attenuated subscapularis after tenotomy. Subscapularis tear or attenuation was more commonly reported in the ST group than in the LTO group, though not significantly so. This may indicate that more ST studies than LTO studies specially emphasized postoperative subscapularis function, but these data also highlight some authors’ concerns regarding subscapularis dysfunction after tenotomy.^6,15,16The study populations’ complication rates were similar, just over 17%. The LTO group trended toward a higher revision rate, but it was not statistically significant. The LTO group also had significantly fewer patients with osteoarthritis and more patients with posttraumatic arthritis, so this group may have had more complex patients predisposed to a higher likelihood of revision surgery. Revisions were most commonly performed for aseptic loosening; theoretically, if osteotomies heal less effectively than tenotomies, the LTO approach could produce component instability and aseptic loosening. However, no prior studies or other clinical findings from this review suggest LTO predisposes to aseptic loosening. Overall, the uneven revision rates represent a clinical concern that should be monitored as larger samples of patients undergo ST and LTO procedures.

Glenoid radiolucencies were the only radiographic parameter consistently reported in the included studies. Twelve ST studies had radiolucency data—compared with only 2 LTO studies. Thus, our ability to compare radiographic outcomes was limited. Our data revealed similar rates of glenoid radiolucencies between the 2 approaches. The clinical relevance of radiolucencies is questioned by some authors, and, indeed, Razmjou and colleagues²⁵ found no correlation of radiolucencies with patient satisfaction. Nevertheless, early presence of radiolucencies may raise concerns about progressive loss of fixation,^35,36 so this should be monitored.

Limitations of this systematic review reflect the studies analyzed. We minimized selection bias by including level I to IV evidence, but most studies were level IV, and only 1 was level I. As such, there was a relative paucity of consistent clinical and radiographic data. For instance, although many ST studies reported patient satisfaction as an outcomes measure, only 1 LTO study commented on it. Perhaps the relative novelty of the LTO approach has prompted some authors to focus more on technical details and less on reporting a variety of outcome measures. As mentioned earlier, the significance of radiolucency data is controversial, and determination of their presence or absence depends on the observer. A radiolucency found in one study may not qualify as one in a study that uses different criteria. However, lucency data were the most frequently and reliably reported radiographic parameter, so we deemed it the most appropriate method for comparing radiographic outcomes. Finally, the baseline differences in diagnosis between the ST and LTO groups complicated comparisons. We stratified the groups by component design because use of keeled or pegged implants or humeral cemented or press-fit stems was usually a uniform feature of each study—enabling removal of certain studies for data stratification. However, we were unable to stratify by original diagnosis because these groups were not stratified within the individual studies.

 

Conclusion

Our systematic review found similar Constant scores, pain scores, radiographic outcomes, and complication rates for the ST and LTO approaches. Compared with the LTO approach, the ST approach produced significantly more forward elevation improvement and trended toward more external rotation and abduction and fewer revisions. Although not definitive, these data suggest the ST approach may provide more stability over the long term, but additional comprehensive studies are needed to increase the sample size and the power of the trends elucidated in this review. According to the orthopedic literature, both techniques produce excellent clinical outcomes, and technique selection should be based on surgeon discretion and expertise.

Am J Orthop. 2017;46(2):E131-E138. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.