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Functional Knee Outcomes in Infrapatellar and Suprapatellar Tibial Nailing: Does Approach Matter?
With an incidence of 75,000 per year in the United States alone, fractures of the tibial shaft are among the most common long-bone fractures.1 Diaphyseal tibial fractures present a unique treatment challenge because of complications, including nonunion, malunion, and the potential for an open injury. Intramedullary fixation of these fractures has long been the standard of care, allowing for early mobilization, shorter time to weight-bearing, and high union rates.2-4
The classic infrapatellar approach to intramedullary nailing involves placing the knee in hyperflexion over a bump or radiolucent triangle and inserting the nail through a longitudinal incision in line with the fibers of the patellar tendon. Deforming muscle forces often cause proximal-third tibial fractures and segmental fractures to fall into valgus and procurvatum. To counter these deforming forces, orthopedic surgeons have used some novel surgical approaches, including use of blocking screws5 and a parapatellar approach that could be used with the knee in semi-extended position.6 Anterior knee pain has been reported as a common complication of tibial nailing (reported incidence, 56%).7 In a prospective randomized controlled study, Toivanen and colleagues8 found no difference in incidence of knee pain between patellar tendon splitting and parapatellar approaches.
Techniques have been developed to insert the nail through a semi-extended suprapatellar approach to facilitate intraoperative imaging, allow easier access to starting-site position, and counter deforming forces. Although outcomes of traditional infrapatellar nailing have been well documented, there is a paucity of literature on outcomes of using a suprapatellar approach. Splitting the quadriceps tendon causes scar tissue to form superior to the patella versus the anterior knee, which may reduce flexion-related pain or kneeling pain.9 The infrapatellar nerve is also well protected with this approach.
We conducted a study to determine differences in functional knee pain in patients who underwent either traditional infrapatellar nailing or suprapatellar nailing. We hypothesized that there would be no difference in functional knee scores between these approaches and that, when compared with the infrapatellar approach, the suprapatellar approach would result in improved postoperative reduction and reduced intraoperative fluoroscopy time.
Materials and Methods
This study was approved by our institutional review board. We searched our level I trauma center’s database for Current Procedural Terminology (CPT) code 27759 to identify all patients who had a tibial shaft fracture fixed with an intramedullary implant between January 2009 and February 2013. Radiographs, operative reports, and inpatient records were reviewed. Patients older than 18 years at time of injury and patients with an isolated tibial shaft fracture (Orthopaedic Trauma Association type 42 A-C) surgically fixed with an intramedullary nail through either a traditional infrapatellar approach or a suprapatellar approach were included in the study. Exclusion criteria were required fasciotomy, Gustilo type 3B or 3C open fracture, prior knee surgery, additional orthopedic injury, and preexisting radiographic evidence of degenerative joint disease.
In addition to surgical approach, demographic data, including body mass index (BMI), age, sex, and mechanism of injury, were documented from the medical record. Each patient was contacted by telephone by an investigator blinded to surgical exposure, and the 12-item Oxford Knee Score (OKS) questionnaire was administered (Figure). Operative time, quality of reduction on postoperative radiographs, and intraoperative fluoroscopy time were compared between the 2 approaches. We determined quality of reduction by measuring the angle between the line perpendicular to the tibial plateau and plafond on both the anteroposterior and lateral postoperative radiographs. Rotation was determined by measuring displacement of the fracture by cortical widths. The infrapatellar and suprapatellar groups were statistically analyzed with an unpaired, 2-tailed Student t test. Categorical variables between groups were analyzed with the χ2 test or, when expected values in a cell were less than 5, the Fisher exact test.
We then conducted an a priori power analysis to determine the appropriate sample size. To detect the reported minimally clinically important difference in the OKS of 5.2,10 estimating an approximate 20% larger patient population in the infrapatellar group, we would need to enroll 24 infrapatellar patients and 20 suprapatellar patients to achieve a power of 0.80 with a type I error rate of 0.05.11 This analysis is also based on an estimated OKS standard deviation of 6, which has been reported in several studies.12,13
Results
We identified 176 patients who had the CPT code for intramedullary fixation of a tibial shaft fracture between January 2009 and February 2013. After analysis of radiographs and medical records, 82 patients met the inclusion criteria. Thirty-six (45%) of the original 82 patients were lost to follow-up after attempts to contact them by telephone. One patient refused to participate in the study. Twenty-four patients underwent traditional infrapatellar nailing, and 21 patients had a suprapatellar nail placed with approach-specific instrumentation. Nine patients had an open fracture. There was no significant difference between the groups in terms of sex, age, BMI, mechanism of injury, or operative time (Table 1). There was also no difference (P = .210) in fracture location between groups (0 proximal-third, 14 midshaft, 10 distal-third vs 3 proximal-third, 10 midshaft, 8 distal-third). Mean age was 37.6 years (range, 20-65 years) for the infrapatellar group and 38.5 years (range, 18-68 years) for the suprapatellar group (P = .839). Mean follow-up was significantly (P < .001) shorter for the suprapatellar group (12 mo; range, 3-33 mo) than for the infrapatellar group (25 mo; range, 4-43 mo).
Mean OKS (maximum, 48 points) was 40.1 (range, 11-48) for the infrapatellar group and 36.7 (range, 2-48) for the suprapatellar group (P = .293). Table 2 summarizes the data. Radiographic reduction in the sagittal plane was improved (P = .044) in the suprapatellar group (2.90°) compared with the infrapatellar group (4.58°). There was no difference in rotational malreduction (0.31 vs 0.25 cortical width; P = .599) or in reduction in the coronal plane (2.52° vs 3.17°; P = .280). All patients in both groups maintained radiographic reduction within 5° in any plane throughout follow-up. There was no difference (P = .654) in radiographic follow-up between the infrapatellar group (11 mo) and the suprapatellar group (12 mo). The 1 nonunion in the suprapatellar group required return to the operating room for exchange intramedullary nailing. The suprapatellar approach required less (P = .003) operative fluoroscopy time (80.8 s; range, 46-180 s) than the standard infrapatellar approach (122.1 s; range, 71-240 s). Two patients in the suprapatellar group and 8 in the infrapatellar group did not have their fluoroscopy time recorded in the operative report.
Discussion
We have described the first retrospective cohort-comparison study of functional knee scores associated with traditional infrapatellar nailing and suprapatellar nailing. Although much has been written about the incidence of anterior knee pain with use of a patellar splitting or parapatellar approach, the clinical effects of knee pain after use of suprapatellar nails are yet to be addressed. In a cadaveric study, Gelbke and colleagues14 found higher mean patellofemoral pressures and higher peak contact pressures with a suprapatellar approach. These numbers, however, were still far below the threshold for chondrocyte damage, and that study is yet to be clinically validated. Our data showed no difference in OKS between the 2 groups. Despite being intra-articular, approach-specific instrumentation may protect the trochlea and patellar cartilage.
Although the OKS questionnaire was originally developed and widely validated to describe clinical outcomes of total knee arthroplasty,15,16 it has also been evaluated for other interventions, including viscosupplementation injections17 and high tibial osteotomy.18 We used the OKS questionnaire in our study because it is simple to administer by telephone and is not as cumbersome as the Knee Society Score or the Western Ontario and McMaster Universities Osteoarthritis Index. It is also more specific to the knee than generalized outcome measures used in trauma, such as the Short Form 36 (SF-36). Sanders and colleagues19 reported excellent tibial alignment, radiographic union, and knee range of motion using semi-extended tibial nailing with a suprapatellar approach. For outcome measures, they used the Lysholm Knee Score and the SF-36. Our clinical and radiographic results confirmed their finding—that the semi-extended suprapatellar approach is an option for tibial nailing.
OKS results by question (Table 3) showed that the infrapatellar group had less pain walking down stairs. This result approached statistical significance (P = .063). As surgeons at our institution began using the suprapatellar approach only during the final 2 years of the study period, mean follow-up was significantly (P < .001) less than for the infrapatellar group (12 vs 25 mo). Although there was no statistically significant difference in reduction quality on anteroposterior radiographs, the suprapatellar approach had improved (P = .044) reduction on lateral radiographs (2.90° vs 4.58°).
Although operative time did not differ between our 2 groups, significantly (P = .003) less fluoroscopy time was required for suprapatellar nails (80.8 s) than for infrapatellar nails (122.1 s). Positioning the knee in the semi-extended position offers easier access for fluoroscopy and less radiation exposure for the patient. Placing the nail in extension also helps eliminate the deforming forces that cause malreduction of proximal tibial shaft or segmental fractures. However, our study was limited in that only 2 surgeons at our institution used the suprapatellar approach, and both were fellowship-trained in orthopedic traumatology. This situation could have introduced bias into the interpretation of fluoroscopy data, as these surgeons may have been more comfortable with the procedure and less likely to use fluoroscopy. Both surgeons also performed infrapatellar nailing during the study period, and there was no statistical difference in fracture patterns between the groups, thus minimizing bias.
This study was retrospective but had several strengths. Sample size met the prestudy power analysis to determine a minimally clinically important difference in OKS results. The investigator who administered the telephone survey was blinded to surgical approach. This study was also the first clinical study to compare outcomes of infrapatellar and suprapatellar nailing. However, the study’s follow-up rate was a weakness. The patient population at our academic, urban, level I trauma center is transient. We lost 36 patients (45%) to follow-up; their telephone numbers in the hospital records likely changed since surgery, and we could not contact these patients.
Conclusion
Our retrospective cohort study found no difference in OKS between traditional infrapatellar nailing and suprapatellar nailing for diaphyseal tibia fractures. Suprapatellar nails require less fluoroscopy time and may show improved radiographic reduction in the sagittal plane. Although further study is needed, the suprapatellar entry portal appears to be a safe alternative for tibial nailing with use of appropriate instrumentation.
1. Praemer A, Furner S, Rice DP. Musculoskeletal Conditions in the United States. Park Ridge, IL: American Academy of Orthopaedic Surgeons; 1992.
2. Bone LB, Sucato D, Stegemann PM, Rohrbacher BJ. Displaced isolated fractures of the tibial shaft treated with either a cast or intramedullary nailing. An outcome analysis of matched pairs of patients. J Bone Joint Surg Am. 1997;79(9):1336-1341.
3. Hooper GJ, Keddell RG, Penny ID. Conservative management or closed nailing for tibial shaft fractures. A randomised prospective trial. J Bone Joint Surg Br. 1991;73(1):83-85.
4. Alho A, Benterud JG, Høgevold HE, Ekeland A, Strømsøe K. Comparison of functional bracing and locked intramedullary nailing in the treatment of displaced tibial shaft fractures. Clin Orthop Relat Res. 1992;(277):243-250.
5. Ricci WM, O’Boyle M, Borrelli J, Bellabarba C, Sanders R. Fractures of the proximal third of the tibial shaft treated with intramedullary nails and blocking screws. J Orthop Trauma. 2001;15(4):264-270.
6. Tornetta P 3rd, Collins E. Semiextended position of intramedullary nailing of the proximal tibia. Clin Orthop Relat Res. 1996;(328):185-189.
7. Court-Brown CM, Gustilo T, Shaw AD. Knee pain after intramedullary tibial nailing: its incidence, etiology, and outcome. J Orthop Trauma. 1997;11(2):103-105.
8. Toivanen JA, Väistö O, Kannus P, Latvala K, Honkonen SE, Järvinen MJ. Anterior knee pain after intramedullary nailing of fractures of the tibial shaft. A prospective, randomized study comparing two different nail-insertion techniques. J Bone Joint Surg Am. 2002;84(4):580-585.
9. Morandi M, Banka T, Gairarsa GP, et al. Intramedullary nailing of tibial fractures: review of surgical techniques and description of a percutaneous lateral suprapatellar approach. Orthopaedics. 2010;33(3):172-179.
10. Bohm ER, Loucks L, Tan QE, et al. Determining minimum clinically important difference and targeted clinical improvement values for the Oxford 12. Presented at: Annual Meeting of the American Academy of Orthopaedic Surgeons; 2012; San Francisco, CA.
11. Dupont WD, Plummer WD Jr. Power and sample size calculations. A review and computer program. Control Clin Trials. 1990;11(2):116-128.
12. Streit MR, Walker T, Bruckner T, et al. Mobile-bearing lateral unicompartmental knee replacement with the Oxford domed tibial component: an independent series. J Bone Joint Surg Br. 2012;94(10):1356-1361.
13. Jenny JY, Diesinger Y. The Oxford Knee Score: compared performance before and after knee replacement. Orthop Traumatol Surg Res. 2012;98(4):409-412.
14. Gelbke MK, Coombs D, Powell S, et al. Suprapatellar versus infra-patellar intramedullary nail insertion of the tibia: a cadaveric model for comparison of patellofemoral contact pressures and forces. J Orthop Trauma. 2010;24(11):665-671.
15. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br. 1998;80(1):63-69.
16. Dunbar MJ, Robertsson O, Ryd L, Lidgren L. Translation and validation of the Oxford-12 item knee score for use in Sweden. Acta Orthop Scand. 2000;71(3):268-274.
17. Clarke S, Lock V, Duddy J, Sharif M, Newman JH, Kirwan JR. Intra-articular hylan G-F 20 (Synvisc) in the management of patellofemoral osteoarthritis of the knee (POAK). Knee. 2005;12(1):57-62.
18. Weale AE, Lee AS, MacEachern AG. High tibial osteotomy using a dynamic axial external fixator. Clin Orthop Relat Res. 2001;(382):154-167.
19. Sanders RW, DiPasquale TG, Jordan CJ, Arrington JA, Sagi HC. Semiextended intramedullary nailing of the tibia using a suprapatellar approach: radiographic results and clinical outcomes at a minimum of 12 months follow-up. J Orthop Trauma. 2014;28(suppl 8):S29-S39.
With an incidence of 75,000 per year in the United States alone, fractures of the tibial shaft are among the most common long-bone fractures.1 Diaphyseal tibial fractures present a unique treatment challenge because of complications, including nonunion, malunion, and the potential for an open injury. Intramedullary fixation of these fractures has long been the standard of care, allowing for early mobilization, shorter time to weight-bearing, and high union rates.2-4
The classic infrapatellar approach to intramedullary nailing involves placing the knee in hyperflexion over a bump or radiolucent triangle and inserting the nail through a longitudinal incision in line with the fibers of the patellar tendon. Deforming muscle forces often cause proximal-third tibial fractures and segmental fractures to fall into valgus and procurvatum. To counter these deforming forces, orthopedic surgeons have used some novel surgical approaches, including use of blocking screws5 and a parapatellar approach that could be used with the knee in semi-extended position.6 Anterior knee pain has been reported as a common complication of tibial nailing (reported incidence, 56%).7 In a prospective randomized controlled study, Toivanen and colleagues8 found no difference in incidence of knee pain between patellar tendon splitting and parapatellar approaches.
Techniques have been developed to insert the nail through a semi-extended suprapatellar approach to facilitate intraoperative imaging, allow easier access to starting-site position, and counter deforming forces. Although outcomes of traditional infrapatellar nailing have been well documented, there is a paucity of literature on outcomes of using a suprapatellar approach. Splitting the quadriceps tendon causes scar tissue to form superior to the patella versus the anterior knee, which may reduce flexion-related pain or kneeling pain.9 The infrapatellar nerve is also well protected with this approach.
We conducted a study to determine differences in functional knee pain in patients who underwent either traditional infrapatellar nailing or suprapatellar nailing. We hypothesized that there would be no difference in functional knee scores between these approaches and that, when compared with the infrapatellar approach, the suprapatellar approach would result in improved postoperative reduction and reduced intraoperative fluoroscopy time.
Materials and Methods
This study was approved by our institutional review board. We searched our level I trauma center’s database for Current Procedural Terminology (CPT) code 27759 to identify all patients who had a tibial shaft fracture fixed with an intramedullary implant between January 2009 and February 2013. Radiographs, operative reports, and inpatient records were reviewed. Patients older than 18 years at time of injury and patients with an isolated tibial shaft fracture (Orthopaedic Trauma Association type 42 A-C) surgically fixed with an intramedullary nail through either a traditional infrapatellar approach or a suprapatellar approach were included in the study. Exclusion criteria were required fasciotomy, Gustilo type 3B or 3C open fracture, prior knee surgery, additional orthopedic injury, and preexisting radiographic evidence of degenerative joint disease.
In addition to surgical approach, demographic data, including body mass index (BMI), age, sex, and mechanism of injury, were documented from the medical record. Each patient was contacted by telephone by an investigator blinded to surgical exposure, and the 12-item Oxford Knee Score (OKS) questionnaire was administered (Figure). Operative time, quality of reduction on postoperative radiographs, and intraoperative fluoroscopy time were compared between the 2 approaches. We determined quality of reduction by measuring the angle between the line perpendicular to the tibial plateau and plafond on both the anteroposterior and lateral postoperative radiographs. Rotation was determined by measuring displacement of the fracture by cortical widths. The infrapatellar and suprapatellar groups were statistically analyzed with an unpaired, 2-tailed Student t test. Categorical variables between groups were analyzed with the χ2 test or, when expected values in a cell were less than 5, the Fisher exact test.
We then conducted an a priori power analysis to determine the appropriate sample size. To detect the reported minimally clinically important difference in the OKS of 5.2,10 estimating an approximate 20% larger patient population in the infrapatellar group, we would need to enroll 24 infrapatellar patients and 20 suprapatellar patients to achieve a power of 0.80 with a type I error rate of 0.05.11 This analysis is also based on an estimated OKS standard deviation of 6, which has been reported in several studies.12,13
Results
We identified 176 patients who had the CPT code for intramedullary fixation of a tibial shaft fracture between January 2009 and February 2013. After analysis of radiographs and medical records, 82 patients met the inclusion criteria. Thirty-six (45%) of the original 82 patients were lost to follow-up after attempts to contact them by telephone. One patient refused to participate in the study. Twenty-four patients underwent traditional infrapatellar nailing, and 21 patients had a suprapatellar nail placed with approach-specific instrumentation. Nine patients had an open fracture. There was no significant difference between the groups in terms of sex, age, BMI, mechanism of injury, or operative time (Table 1). There was also no difference (P = .210) in fracture location between groups (0 proximal-third, 14 midshaft, 10 distal-third vs 3 proximal-third, 10 midshaft, 8 distal-third). Mean age was 37.6 years (range, 20-65 years) for the infrapatellar group and 38.5 years (range, 18-68 years) for the suprapatellar group (P = .839). Mean follow-up was significantly (P < .001) shorter for the suprapatellar group (12 mo; range, 3-33 mo) than for the infrapatellar group (25 mo; range, 4-43 mo).
Mean OKS (maximum, 48 points) was 40.1 (range, 11-48) for the infrapatellar group and 36.7 (range, 2-48) for the suprapatellar group (P = .293). Table 2 summarizes the data. Radiographic reduction in the sagittal plane was improved (P = .044) in the suprapatellar group (2.90°) compared with the infrapatellar group (4.58°). There was no difference in rotational malreduction (0.31 vs 0.25 cortical width; P = .599) or in reduction in the coronal plane (2.52° vs 3.17°; P = .280). All patients in both groups maintained radiographic reduction within 5° in any plane throughout follow-up. There was no difference (P = .654) in radiographic follow-up between the infrapatellar group (11 mo) and the suprapatellar group (12 mo). The 1 nonunion in the suprapatellar group required return to the operating room for exchange intramedullary nailing. The suprapatellar approach required less (P = .003) operative fluoroscopy time (80.8 s; range, 46-180 s) than the standard infrapatellar approach (122.1 s; range, 71-240 s). Two patients in the suprapatellar group and 8 in the infrapatellar group did not have their fluoroscopy time recorded in the operative report.
Discussion
We have described the first retrospective cohort-comparison study of functional knee scores associated with traditional infrapatellar nailing and suprapatellar nailing. Although much has been written about the incidence of anterior knee pain with use of a patellar splitting or parapatellar approach, the clinical effects of knee pain after use of suprapatellar nails are yet to be addressed. In a cadaveric study, Gelbke and colleagues14 found higher mean patellofemoral pressures and higher peak contact pressures with a suprapatellar approach. These numbers, however, were still far below the threshold for chondrocyte damage, and that study is yet to be clinically validated. Our data showed no difference in OKS between the 2 groups. Despite being intra-articular, approach-specific instrumentation may protect the trochlea and patellar cartilage.
Although the OKS questionnaire was originally developed and widely validated to describe clinical outcomes of total knee arthroplasty,15,16 it has also been evaluated for other interventions, including viscosupplementation injections17 and high tibial osteotomy.18 We used the OKS questionnaire in our study because it is simple to administer by telephone and is not as cumbersome as the Knee Society Score or the Western Ontario and McMaster Universities Osteoarthritis Index. It is also more specific to the knee than generalized outcome measures used in trauma, such as the Short Form 36 (SF-36). Sanders and colleagues19 reported excellent tibial alignment, radiographic union, and knee range of motion using semi-extended tibial nailing with a suprapatellar approach. For outcome measures, they used the Lysholm Knee Score and the SF-36. Our clinical and radiographic results confirmed their finding—that the semi-extended suprapatellar approach is an option for tibial nailing.
OKS results by question (Table 3) showed that the infrapatellar group had less pain walking down stairs. This result approached statistical significance (P = .063). As surgeons at our institution began using the suprapatellar approach only during the final 2 years of the study period, mean follow-up was significantly (P < .001) less than for the infrapatellar group (12 vs 25 mo). Although there was no statistically significant difference in reduction quality on anteroposterior radiographs, the suprapatellar approach had improved (P = .044) reduction on lateral radiographs (2.90° vs 4.58°).
Although operative time did not differ between our 2 groups, significantly (P = .003) less fluoroscopy time was required for suprapatellar nails (80.8 s) than for infrapatellar nails (122.1 s). Positioning the knee in the semi-extended position offers easier access for fluoroscopy and less radiation exposure for the patient. Placing the nail in extension also helps eliminate the deforming forces that cause malreduction of proximal tibial shaft or segmental fractures. However, our study was limited in that only 2 surgeons at our institution used the suprapatellar approach, and both were fellowship-trained in orthopedic traumatology. This situation could have introduced bias into the interpretation of fluoroscopy data, as these surgeons may have been more comfortable with the procedure and less likely to use fluoroscopy. Both surgeons also performed infrapatellar nailing during the study period, and there was no statistical difference in fracture patterns between the groups, thus minimizing bias.
This study was retrospective but had several strengths. Sample size met the prestudy power analysis to determine a minimally clinically important difference in OKS results. The investigator who administered the telephone survey was blinded to surgical approach. This study was also the first clinical study to compare outcomes of infrapatellar and suprapatellar nailing. However, the study’s follow-up rate was a weakness. The patient population at our academic, urban, level I trauma center is transient. We lost 36 patients (45%) to follow-up; their telephone numbers in the hospital records likely changed since surgery, and we could not contact these patients.
Conclusion
Our retrospective cohort study found no difference in OKS between traditional infrapatellar nailing and suprapatellar nailing for diaphyseal tibia fractures. Suprapatellar nails require less fluoroscopy time and may show improved radiographic reduction in the sagittal plane. Although further study is needed, the suprapatellar entry portal appears to be a safe alternative for tibial nailing with use of appropriate instrumentation.
With an incidence of 75,000 per year in the United States alone, fractures of the tibial shaft are among the most common long-bone fractures.1 Diaphyseal tibial fractures present a unique treatment challenge because of complications, including nonunion, malunion, and the potential for an open injury. Intramedullary fixation of these fractures has long been the standard of care, allowing for early mobilization, shorter time to weight-bearing, and high union rates.2-4
The classic infrapatellar approach to intramedullary nailing involves placing the knee in hyperflexion over a bump or radiolucent triangle and inserting the nail through a longitudinal incision in line with the fibers of the patellar tendon. Deforming muscle forces often cause proximal-third tibial fractures and segmental fractures to fall into valgus and procurvatum. To counter these deforming forces, orthopedic surgeons have used some novel surgical approaches, including use of blocking screws5 and a parapatellar approach that could be used with the knee in semi-extended position.6 Anterior knee pain has been reported as a common complication of tibial nailing (reported incidence, 56%).7 In a prospective randomized controlled study, Toivanen and colleagues8 found no difference in incidence of knee pain between patellar tendon splitting and parapatellar approaches.
Techniques have been developed to insert the nail through a semi-extended suprapatellar approach to facilitate intraoperative imaging, allow easier access to starting-site position, and counter deforming forces. Although outcomes of traditional infrapatellar nailing have been well documented, there is a paucity of literature on outcomes of using a suprapatellar approach. Splitting the quadriceps tendon causes scar tissue to form superior to the patella versus the anterior knee, which may reduce flexion-related pain or kneeling pain.9 The infrapatellar nerve is also well protected with this approach.
We conducted a study to determine differences in functional knee pain in patients who underwent either traditional infrapatellar nailing or suprapatellar nailing. We hypothesized that there would be no difference in functional knee scores between these approaches and that, when compared with the infrapatellar approach, the suprapatellar approach would result in improved postoperative reduction and reduced intraoperative fluoroscopy time.
Materials and Methods
This study was approved by our institutional review board. We searched our level I trauma center’s database for Current Procedural Terminology (CPT) code 27759 to identify all patients who had a tibial shaft fracture fixed with an intramedullary implant between January 2009 and February 2013. Radiographs, operative reports, and inpatient records were reviewed. Patients older than 18 years at time of injury and patients with an isolated tibial shaft fracture (Orthopaedic Trauma Association type 42 A-C) surgically fixed with an intramedullary nail through either a traditional infrapatellar approach or a suprapatellar approach were included in the study. Exclusion criteria were required fasciotomy, Gustilo type 3B or 3C open fracture, prior knee surgery, additional orthopedic injury, and preexisting radiographic evidence of degenerative joint disease.
In addition to surgical approach, demographic data, including body mass index (BMI), age, sex, and mechanism of injury, were documented from the medical record. Each patient was contacted by telephone by an investigator blinded to surgical exposure, and the 12-item Oxford Knee Score (OKS) questionnaire was administered (Figure). Operative time, quality of reduction on postoperative radiographs, and intraoperative fluoroscopy time were compared between the 2 approaches. We determined quality of reduction by measuring the angle between the line perpendicular to the tibial plateau and plafond on both the anteroposterior and lateral postoperative radiographs. Rotation was determined by measuring displacement of the fracture by cortical widths. The infrapatellar and suprapatellar groups were statistically analyzed with an unpaired, 2-tailed Student t test. Categorical variables between groups were analyzed with the χ2 test or, when expected values in a cell were less than 5, the Fisher exact test.
We then conducted an a priori power analysis to determine the appropriate sample size. To detect the reported minimally clinically important difference in the OKS of 5.2,10 estimating an approximate 20% larger patient population in the infrapatellar group, we would need to enroll 24 infrapatellar patients and 20 suprapatellar patients to achieve a power of 0.80 with a type I error rate of 0.05.11 This analysis is also based on an estimated OKS standard deviation of 6, which has been reported in several studies.12,13
Results
We identified 176 patients who had the CPT code for intramedullary fixation of a tibial shaft fracture between January 2009 and February 2013. After analysis of radiographs and medical records, 82 patients met the inclusion criteria. Thirty-six (45%) of the original 82 patients were lost to follow-up after attempts to contact them by telephone. One patient refused to participate in the study. Twenty-four patients underwent traditional infrapatellar nailing, and 21 patients had a suprapatellar nail placed with approach-specific instrumentation. Nine patients had an open fracture. There was no significant difference between the groups in terms of sex, age, BMI, mechanism of injury, or operative time (Table 1). There was also no difference (P = .210) in fracture location between groups (0 proximal-third, 14 midshaft, 10 distal-third vs 3 proximal-third, 10 midshaft, 8 distal-third). Mean age was 37.6 years (range, 20-65 years) for the infrapatellar group and 38.5 years (range, 18-68 years) for the suprapatellar group (P = .839). Mean follow-up was significantly (P < .001) shorter for the suprapatellar group (12 mo; range, 3-33 mo) than for the infrapatellar group (25 mo; range, 4-43 mo).
Mean OKS (maximum, 48 points) was 40.1 (range, 11-48) for the infrapatellar group and 36.7 (range, 2-48) for the suprapatellar group (P = .293). Table 2 summarizes the data. Radiographic reduction in the sagittal plane was improved (P = .044) in the suprapatellar group (2.90°) compared with the infrapatellar group (4.58°). There was no difference in rotational malreduction (0.31 vs 0.25 cortical width; P = .599) or in reduction in the coronal plane (2.52° vs 3.17°; P = .280). All patients in both groups maintained radiographic reduction within 5° in any plane throughout follow-up. There was no difference (P = .654) in radiographic follow-up between the infrapatellar group (11 mo) and the suprapatellar group (12 mo). The 1 nonunion in the suprapatellar group required return to the operating room for exchange intramedullary nailing. The suprapatellar approach required less (P = .003) operative fluoroscopy time (80.8 s; range, 46-180 s) than the standard infrapatellar approach (122.1 s; range, 71-240 s). Two patients in the suprapatellar group and 8 in the infrapatellar group did not have their fluoroscopy time recorded in the operative report.
Discussion
We have described the first retrospective cohort-comparison study of functional knee scores associated with traditional infrapatellar nailing and suprapatellar nailing. Although much has been written about the incidence of anterior knee pain with use of a patellar splitting or parapatellar approach, the clinical effects of knee pain after use of suprapatellar nails are yet to be addressed. In a cadaveric study, Gelbke and colleagues14 found higher mean patellofemoral pressures and higher peak contact pressures with a suprapatellar approach. These numbers, however, were still far below the threshold for chondrocyte damage, and that study is yet to be clinically validated. Our data showed no difference in OKS between the 2 groups. Despite being intra-articular, approach-specific instrumentation may protect the trochlea and patellar cartilage.
Although the OKS questionnaire was originally developed and widely validated to describe clinical outcomes of total knee arthroplasty,15,16 it has also been evaluated for other interventions, including viscosupplementation injections17 and high tibial osteotomy.18 We used the OKS questionnaire in our study because it is simple to administer by telephone and is not as cumbersome as the Knee Society Score or the Western Ontario and McMaster Universities Osteoarthritis Index. It is also more specific to the knee than generalized outcome measures used in trauma, such as the Short Form 36 (SF-36). Sanders and colleagues19 reported excellent tibial alignment, radiographic union, and knee range of motion using semi-extended tibial nailing with a suprapatellar approach. For outcome measures, they used the Lysholm Knee Score and the SF-36. Our clinical and radiographic results confirmed their finding—that the semi-extended suprapatellar approach is an option for tibial nailing.
OKS results by question (Table 3) showed that the infrapatellar group had less pain walking down stairs. This result approached statistical significance (P = .063). As surgeons at our institution began using the suprapatellar approach only during the final 2 years of the study period, mean follow-up was significantly (P < .001) less than for the infrapatellar group (12 vs 25 mo). Although there was no statistically significant difference in reduction quality on anteroposterior radiographs, the suprapatellar approach had improved (P = .044) reduction on lateral radiographs (2.90° vs 4.58°).
Although operative time did not differ between our 2 groups, significantly (P = .003) less fluoroscopy time was required for suprapatellar nails (80.8 s) than for infrapatellar nails (122.1 s). Positioning the knee in the semi-extended position offers easier access for fluoroscopy and less radiation exposure for the patient. Placing the nail in extension also helps eliminate the deforming forces that cause malreduction of proximal tibial shaft or segmental fractures. However, our study was limited in that only 2 surgeons at our institution used the suprapatellar approach, and both were fellowship-trained in orthopedic traumatology. This situation could have introduced bias into the interpretation of fluoroscopy data, as these surgeons may have been more comfortable with the procedure and less likely to use fluoroscopy. Both surgeons also performed infrapatellar nailing during the study period, and there was no statistical difference in fracture patterns between the groups, thus minimizing bias.
This study was retrospective but had several strengths. Sample size met the prestudy power analysis to determine a minimally clinically important difference in OKS results. The investigator who administered the telephone survey was blinded to surgical approach. This study was also the first clinical study to compare outcomes of infrapatellar and suprapatellar nailing. However, the study’s follow-up rate was a weakness. The patient population at our academic, urban, level I trauma center is transient. We lost 36 patients (45%) to follow-up; their telephone numbers in the hospital records likely changed since surgery, and we could not contact these patients.
Conclusion
Our retrospective cohort study found no difference in OKS between traditional infrapatellar nailing and suprapatellar nailing for diaphyseal tibia fractures. Suprapatellar nails require less fluoroscopy time and may show improved radiographic reduction in the sagittal plane. Although further study is needed, the suprapatellar entry portal appears to be a safe alternative for tibial nailing with use of appropriate instrumentation.
1. Praemer A, Furner S, Rice DP. Musculoskeletal Conditions in the United States. Park Ridge, IL: American Academy of Orthopaedic Surgeons; 1992.
2. Bone LB, Sucato D, Stegemann PM, Rohrbacher BJ. Displaced isolated fractures of the tibial shaft treated with either a cast or intramedullary nailing. An outcome analysis of matched pairs of patients. J Bone Joint Surg Am. 1997;79(9):1336-1341.
3. Hooper GJ, Keddell RG, Penny ID. Conservative management or closed nailing for tibial shaft fractures. A randomised prospective trial. J Bone Joint Surg Br. 1991;73(1):83-85.
4. Alho A, Benterud JG, Høgevold HE, Ekeland A, Strømsøe K. Comparison of functional bracing and locked intramedullary nailing in the treatment of displaced tibial shaft fractures. Clin Orthop Relat Res. 1992;(277):243-250.
5. Ricci WM, O’Boyle M, Borrelli J, Bellabarba C, Sanders R. Fractures of the proximal third of the tibial shaft treated with intramedullary nails and blocking screws. J Orthop Trauma. 2001;15(4):264-270.
6. Tornetta P 3rd, Collins E. Semiextended position of intramedullary nailing of the proximal tibia. Clin Orthop Relat Res. 1996;(328):185-189.
7. Court-Brown CM, Gustilo T, Shaw AD. Knee pain after intramedullary tibial nailing: its incidence, etiology, and outcome. J Orthop Trauma. 1997;11(2):103-105.
8. Toivanen JA, Väistö O, Kannus P, Latvala K, Honkonen SE, Järvinen MJ. Anterior knee pain after intramedullary nailing of fractures of the tibial shaft. A prospective, randomized study comparing two different nail-insertion techniques. J Bone Joint Surg Am. 2002;84(4):580-585.
9. Morandi M, Banka T, Gairarsa GP, et al. Intramedullary nailing of tibial fractures: review of surgical techniques and description of a percutaneous lateral suprapatellar approach. Orthopaedics. 2010;33(3):172-179.
10. Bohm ER, Loucks L, Tan QE, et al. Determining minimum clinically important difference and targeted clinical improvement values for the Oxford 12. Presented at: Annual Meeting of the American Academy of Orthopaedic Surgeons; 2012; San Francisco, CA.
11. Dupont WD, Plummer WD Jr. Power and sample size calculations. A review and computer program. Control Clin Trials. 1990;11(2):116-128.
12. Streit MR, Walker T, Bruckner T, et al. Mobile-bearing lateral unicompartmental knee replacement with the Oxford domed tibial component: an independent series. J Bone Joint Surg Br. 2012;94(10):1356-1361.
13. Jenny JY, Diesinger Y. The Oxford Knee Score: compared performance before and after knee replacement. Orthop Traumatol Surg Res. 2012;98(4):409-412.
14. Gelbke MK, Coombs D, Powell S, et al. Suprapatellar versus infra-patellar intramedullary nail insertion of the tibia: a cadaveric model for comparison of patellofemoral contact pressures and forces. J Orthop Trauma. 2010;24(11):665-671.
15. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br. 1998;80(1):63-69.
16. Dunbar MJ, Robertsson O, Ryd L, Lidgren L. Translation and validation of the Oxford-12 item knee score for use in Sweden. Acta Orthop Scand. 2000;71(3):268-274.
17. Clarke S, Lock V, Duddy J, Sharif M, Newman JH, Kirwan JR. Intra-articular hylan G-F 20 (Synvisc) in the management of patellofemoral osteoarthritis of the knee (POAK). Knee. 2005;12(1):57-62.
18. Weale AE, Lee AS, MacEachern AG. High tibial osteotomy using a dynamic axial external fixator. Clin Orthop Relat Res. 2001;(382):154-167.
19. Sanders RW, DiPasquale TG, Jordan CJ, Arrington JA, Sagi HC. Semiextended intramedullary nailing of the tibia using a suprapatellar approach: radiographic results and clinical outcomes at a minimum of 12 months follow-up. J Orthop Trauma. 2014;28(suppl 8):S29-S39.
1. Praemer A, Furner S, Rice DP. Musculoskeletal Conditions in the United States. Park Ridge, IL: American Academy of Orthopaedic Surgeons; 1992.
2. Bone LB, Sucato D, Stegemann PM, Rohrbacher BJ. Displaced isolated fractures of the tibial shaft treated with either a cast or intramedullary nailing. An outcome analysis of matched pairs of patients. J Bone Joint Surg Am. 1997;79(9):1336-1341.
3. Hooper GJ, Keddell RG, Penny ID. Conservative management or closed nailing for tibial shaft fractures. A randomised prospective trial. J Bone Joint Surg Br. 1991;73(1):83-85.
4. Alho A, Benterud JG, Høgevold HE, Ekeland A, Strømsøe K. Comparison of functional bracing and locked intramedullary nailing in the treatment of displaced tibial shaft fractures. Clin Orthop Relat Res. 1992;(277):243-250.
5. Ricci WM, O’Boyle M, Borrelli J, Bellabarba C, Sanders R. Fractures of the proximal third of the tibial shaft treated with intramedullary nails and blocking screws. J Orthop Trauma. 2001;15(4):264-270.
6. Tornetta P 3rd, Collins E. Semiextended position of intramedullary nailing of the proximal tibia. Clin Orthop Relat Res. 1996;(328):185-189.
7. Court-Brown CM, Gustilo T, Shaw AD. Knee pain after intramedullary tibial nailing: its incidence, etiology, and outcome. J Orthop Trauma. 1997;11(2):103-105.
8. Toivanen JA, Väistö O, Kannus P, Latvala K, Honkonen SE, Järvinen MJ. Anterior knee pain after intramedullary nailing of fractures of the tibial shaft. A prospective, randomized study comparing two different nail-insertion techniques. J Bone Joint Surg Am. 2002;84(4):580-585.
9. Morandi M, Banka T, Gairarsa GP, et al. Intramedullary nailing of tibial fractures: review of surgical techniques and description of a percutaneous lateral suprapatellar approach. Orthopaedics. 2010;33(3):172-179.
10. Bohm ER, Loucks L, Tan QE, et al. Determining minimum clinically important difference and targeted clinical improvement values for the Oxford 12. Presented at: Annual Meeting of the American Academy of Orthopaedic Surgeons; 2012; San Francisco, CA.
11. Dupont WD, Plummer WD Jr. Power and sample size calculations. A review and computer program. Control Clin Trials. 1990;11(2):116-128.
12. Streit MR, Walker T, Bruckner T, et al. Mobile-bearing lateral unicompartmental knee replacement with the Oxford domed tibial component: an independent series. J Bone Joint Surg Br. 2012;94(10):1356-1361.
13. Jenny JY, Diesinger Y. The Oxford Knee Score: compared performance before and after knee replacement. Orthop Traumatol Surg Res. 2012;98(4):409-412.
14. Gelbke MK, Coombs D, Powell S, et al. Suprapatellar versus infra-patellar intramedullary nail insertion of the tibia: a cadaveric model for comparison of patellofemoral contact pressures and forces. J Orthop Trauma. 2010;24(11):665-671.
15. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br. 1998;80(1):63-69.
16. Dunbar MJ, Robertsson O, Ryd L, Lidgren L. Translation and validation of the Oxford-12 item knee score for use in Sweden. Acta Orthop Scand. 2000;71(3):268-274.
17. Clarke S, Lock V, Duddy J, Sharif M, Newman JH, Kirwan JR. Intra-articular hylan G-F 20 (Synvisc) in the management of patellofemoral osteoarthritis of the knee (POAK). Knee. 2005;12(1):57-62.
18. Weale AE, Lee AS, MacEachern AG. High tibial osteotomy using a dynamic axial external fixator. Clin Orthop Relat Res. 2001;(382):154-167.
19. Sanders RW, DiPasquale TG, Jordan CJ, Arrington JA, Sagi HC. Semiextended intramedullary nailing of the tibia using a suprapatellar approach: radiographic results and clinical outcomes at a minimum of 12 months follow-up. J Orthop Trauma. 2014;28(suppl 8):S29-S39.