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Use of a Turndown Quadriceps Tendon Flap for Rupture of the Patellar Tendon After Total Knee Arthroplasty
The Journal of Arthroplasty, Vol 22 No 6 2007
Case Report
Use of a Turndown Quadriceps Tendon Flap for Rupture of the Patellar Tendon After Total Knee Arthroplasty Po-Chun Lin, MD, and Jun-Wen Wang, MD Abstract: Patellar tendon rupture is a devastating complication after total knee arthroplasty. The results of surgical treatment of this complication were discouraging in most of the reports. We describe a case of rupture of patellar tendon 7 weeks after total knee arthroplasty treated with a turndown quadriceps flap and circumferential wiring. Two years and 6 months after operation, the patient had no extension lag of the knee and knee flexion to 1108. Key words: total knee arthroplasty, turndown quadriceps flap. n 2007 Elsevier Inc. All rights reserved.
unsuccessful [1,2,5]. Direct repair with augmentation with an autogenous semitendinosus tendon grafts has gained a higher successful result but with poor knee flexion because of prolonged immobilization [3]. The use of gastrocnemius flap and different types of allograft reconstruction has provided a better clinical result; however, certain degrees of extension lag of the knee have been reported [6-10]. We present a case with patellar tendon rupture after TKA treated with a turndown quadriceps tendon flap.
Patellar tendon rupture is a rare but disturbing complication after total knee arthroplasty (TKA). The reported incidence ranged from 0.17% to 2.5% [1,2]. The etiology of patellar tendon rupture after TKA is classified as traumatic [2,3] and nontraumatic origin. Nontraumatic factors included longterm local steroid injection, diabetes mellitus, rheumatoid arthritis, lupus erythematous [2], devascularization after extensive lateral retinacular release or multiple operations [1], and inadvertent detachment during exposure of a stiff knee [4]. There were various operative methods treating this complication, but the results were not consistent. Direct repair with suture or staples was often
Case Report A 77-year-old male patient received right TKA using a Whiteside posterior-stabilized implant (Dow Corning Wright, Arlington, Tenn) because of advanced osteoarthritis on October 28, 2003. More than 50 years ago, he had a below-knee amputation of his left leg because of severe trauma in a traffic accident. At the time of TKA, there was no iatrogenic partial avulsion of the patellar tendon, overcutting of the patellar bone, or lateral retinacular release. He had an uneventful postoperative course.
From the Department of Orthopaedic Surgery, Chang Gung Memorial Hospital-Kaohsiung, Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan, Republic of China. Submitted August 3, 2006; accepted December 24, 2006. No benefits or funds were received in support of the study. Reprint requests: Jun-Wen Wang, MD, Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Kaohsiung, 123, Ta Pei Rd, Niao Sung Hsiang, Kaohsiung, Taiwan, Republic of China. n 2007 Elsevier Inc. All rights reserved. 0883-5403/07/1906-0004$32.00/0 doi:10.1016/j.arth.2006.12.105
934
Rupture of the Patellar Tendon after Total Knee Arthroplasty ! Lin and Wang 935
Fig. 1. Preoperative anteroposterior (A) and lateral (B) radiographs of the right knee demonstrating a patellar alta after TKA indicating rupture of the patellar tendon.
About 4 weeks after TKA, he had a fall accident when he tried to move from one chair to another. At that time, he was not wearing his prosthetic leg on his left amputee. On January 7, 2004, he visited the orthopedic clinic for routine checkup. Physical examination revealed a palpable tendon gap in the infrapatellar region of the right knee. He could bend his right knee to 1008 but could not extend the knee actively. The extension lag of the knee was 608. The radiograph of the right knee showed a well-fixed total knee prosthesis; however, an obvious patellar alta was noted (Fig. 1A and B).
Fig. 2. Intraoperative photograph (A) and sketch (B) showing rupture of the patellar tendon at the midsubstance with a 3-cm gap caused by tendon retraction. A strip of quadriceps tendon was harvested and readied for reconstruction.
Fig. 3. Intraoperative photograph (A) and sketch (B) after repair of the patellar tendon and augmentation with a turndown quadriceps flap and a circumferential wire.
The preoperative diagnosis was rupture of the patellar tendon after TKA. On January 13, 2004, which was about 7 weeks after the injury, he underwent repair of the patellar tendon with augmentation. At operation, rupture
Fig. 4. Postoperative anteroposterior (A) and lateral (B) radiographs of the right knee 6 weeks after repair of patellar tendon with augmentation showing good restoration of the patellar position with a circumferential wire.
936 The Journal of Arthroplasty Vol. 22 No. 6 September 2007 tuberosity with interrupted sutures. The edges of the turndown quadriceps tendon were fixed to the underlying patellar tendon using slowly absorbable sutures (Vicryl; Ethicon, Somerville, NJ) interruptedly (Fig. 3). The reconstruction was further protected by a circumferential wire (stainless steel, 1.22 mm) passing through the upper pole of the patellar bone superiorly and the tibial tuberosity inferiorly (Figs. 3 and 4). Postoperatively, a long leg cast was applied for 3 weeks. After that, he was allowed to start range of motion exercise of the knee. However, because of below-knee amputation of the contralateral leg, he was commenced to use wheelchair for ambulation to avoid re-rupture of the tendon. Six weeks postoperatively, he had almost full extension of the knee and flexion of the knee up to 908. At 3 months, the augmented circumferential wire was removed. After that, he was allowed to walk with a walker support. At 6 months, he had a full extension of the knee with 1108 of knee flexion. Two years and 6 months postoperatively, the patient had good recovery of the quadriceps power, with range of motion of the knee from 08 to 1108 (Fig. 5A and B). The standing radiographs of the knee showed a well-fixed and aligned total knee prosthesis and good restoration of the patellar position. He could ambulate without support. According to the evaluation system of the Knee Society [11], his Knee Score was 93 points and his Function Score was 95 points.
Discussion
Fig. 5. Clinical photographs of the patient at 2.5 years after operation showing full extension (A) and 1108 flexion (B) of the knee.
of patellar tendon at the midsubstance with a 3-cm gap caused by retraction of the proximal part of the patellar tendon was found (Fig. 2A and B). Primary repair of the ruptured patellar tendon was performed, but there was tension even after bringing down the retracted patellar tendon by soft tissue release. A strip of quadriceps tendon measuring 8 1.5 cm was harvested and turned down to reconstruct the repaired tendon (Fig. 2). The harvested quadriceps tendon was long enough to cover the repaired patellar tendon and was anchored into the distal portion of the patellar tendon at the tibial
Rupture of the patellar tendon after TKA is a rare but catastrophic complication. The possible causes are prosthetic impingement, resection of excessive amounts of the bone of the patella, devascularization of the patellar tendon, and excessive tension on the patellar tendon during exposure of the stiff knee [2,12]. However, because there is no reconstructive approach that provides consistent results, the best way to solve this problem is to avoid this complication. Some authors suggested preservation of the blood supply to the patellar tendon during TKA [3]; others emphasized meticulous surgical approach during TKA if patient has limited preoperative motion of the knee [2,4]. In the current report, the patient had a trauma event 4 weeks after TKA, which resulted in rupture of the patellar tendon. The results of the treatment of patellar tendon rupture after TKA varied. Rand et al reported 18 ruptures of patellar ligament after TKA, 16 of whom had operative procedures that included
Rupture of the Patellar Tendon after Total Knee Arthroplasty ! Lin and Wang 937
direct repair in nine, staple fixation in four, xenograft reconstruction in two, and semitendinosus reconstruction in one. Only two with a staple repair and two having a reconstruction with a xenograft succeeded [2]. The results of direct suture repair of the ruptured tendon were discouraging. In a series of complications of the extensor mechanism after TKA reported by Lynch et al, results in 4 cases of direct suture repair were reruptured tendon in one, deep infection in one, and extension lags of 188 and 228 in two [1]. Oglesby and Wilson reported direct repairs in 5 patients; only one of them had full active extension [13]. The use of composite allografts that included a quadriceps tendon, a patella with a cemented patellar component, the patellar tendon, and the tibial tubercle reported by Emerson et al had gained a satisfactory result in 9 patients followed up for 4 years [10]. Three of them had an extension lag ranging from 208 to 408. The report by Leopold et al using the same technique was discouraging, however, because of the poor recovery of quadriceps power, with a mean extension lag of 598 in 7 patients followed up for 39 months [14]. Recently, with the improvement of the surgical technique by fixation of the allograft distally with multiple wires and tightening of the grafts in full extension, the clinical results of extensor tendon allografts have become much better [15]. Cadambi and Engh reported successful recovery of the extension mechanism using double semitendinosus tendon reconstruction and cast and brace protection for 18 weeks in 7 knees [3]. However, the active knee flexion was restricted, with 4 knees having less than 808 of knee flexion possibly because of prolonged immobilization. The use of a medial gastrocnemius flap provides improved soft-tissue coverage and allows the return of the extensor mechanism for a chronic disruption of the patellar tendon after TKA [6,7,16]. However, it has the disadvantages of a poor cosmesis and residual weakness of ankle plantar flexion [17]. A residual extension lag ranging from 258 to 508 in 4 of 6 treated knees has been reported [6]. Our surgical technique of reconstruction of the ruptured patellar tendon using a turndown quadriceps tendon flap was derived from Scuderi who used a triangular turndown flap of the quadriceps tendon to reinforce and lengthen the rupture of the quadriceps tendon [18]. Because our case was ruptured patellar tendon, we created a longer quadriceps flap (8 1.5 cm) rather than a triangular flap to cover the repaired tendon. In the report by Scuderi, he used Bunnell pullout wires after reconstruction to release tension on the repaired tendon.
Our technique of tension release was a circumferential wire passing through the patellar bone and the tibial tuberosity. Scuderi claimed the patients gained good extension and flexion of the knee postoperatively and that the method was better than the others that he had tried before. The increased tendon volume at the sutured line and the living tissue reinforcement are the causes of the successful results [18]. In the current report, the patient started early rehabilitation (3 weeks postoperatively) based on strong augmentation of the repaired tendon and protection of the repair by a circumferential wire, which resulted in the quick recovery of the quadriceps power (6 weeks postoperatively) because of strong reinforcement of the living tissue at the repaired tendon.
Acknowledgment The authors would like to thank Mr Jui-Hsing Chen for his excellent work of line drawings in this article.
References 1. Lynch AF, Rorabeck CH, Bourne RB. Extensor mechanism complications following total knee arthroplasty. J Arthroplasty 1987;2:135. 2. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop 1989;244:233. 3. Cadambi A, Engh GA. Use of a semitendinosus tendon autogenous graft for rupture of the patellar ligament after total knee arthroplasty. A report of seven cases. J Bone Joint Surg 1992;74A:974. 4. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture following total knee arthroplasty. Tech Orthop 1988;3:45. 5. Abril JC, Alvarez L, Vallejo JC. Patellar tendon avulsion after total knee arthroplasty. A new technique. J Arthroplasty 1995;10:275. 6. Jaureguito JW, Dubois CM, Smith SR, et al. Medial gastrocnemius transposition flap for the treatment of disruption of the extensor mechanism. J Bone Joint Surg 1997;79A:886. 7. Patel NS, Ibrahim DT, Finn HA. Knee extensor mechanism reconstruction with medial gastrocnemius flap. Clin Orthop 2002;398:176. 8. Crossett LS, Sinha RK, Sechriest VN, et al. Reconstruction of a ruptured patellar tendon with Achilles tendon allograft following total knee arthroplasty. J Bone Joint Surg 2002;84A:1354. 9. Barrack RL, Stanley T, Butler RA. Treating extensor mechanism disruption after total knee arthroplasty. Clin Orthop 2003;416:98. 10. Emerson Jr RH, Head WC, Malinin TI. Reconstruction of patellar tendon rupture after total knee
938 The Journal of Arthroplasty Vol. 22 No. 6 September 2007 arthroplasty with an extensor mechanism allograft. Clin Orthop 1990;260:154. 11. Insall JN, Dorr LD, Scott RD, et al. Rationale of the Knee Society clinical rating system. Clin Orthop 1989;248:13. 12. Gustilo RB, Thompson R. Quadriceps and patellar tendon ruptures following total knee arthroplasty. In: Rand JA, Dorr LD, editors. Total arthroplasty of the kneeProceedings of the Knee Society, 1985-1986. Rockville (Md): Aspen; 1987. p. 41. 13. Oglesby JW, Wilson FC. The evolution of knee arthroplasty: results with three generations of prosthesis. Clin orthop 1984;186:96.
14. Leopold SS, Greidanus N, Paprosky WG, et al. High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg 1999;81A:1574. 15. Nazarian DG, Booth RE. Extensor mechanism allografts in total knee arthroplasty. Clin Orthop 1999;367:123. 16. Pagnano MW. Patellar tendon and quadriceps tendon tears after total knee arthroplasty. J Knee Surg 2003;16:242. 17. Rand JA. Extensor mechanism complications following total knee arthroplasty. J Bone Joint Surg 2004; 86A:2062. 18. Scuderi C. Ruptures of the quadriceps tendon. Am J Surg 1958;95:626.
Case Report
Use of a Turndown Quadriceps Tendon Flap for Rupture of the Patellar Tendon After Total Knee Arthroplasty Po-Chun Lin, MD, and Jun-Wen Wang, MD Abstract: Patellar tendon rupture is a devastating complication after total knee arthroplasty. The results of surgical treatment of this complication were discouraging in most of the reports. We describe a case of rupture of patellar tendon 7 weeks after total knee arthroplasty treated with a turndown quadriceps flap and circumferential wiring. Two years and 6 months after operation, the patient had no extension lag of the knee and knee flexion to 1108. Key words: total knee arthroplasty, turndown quadriceps flap. n 2007 Elsevier Inc. All rights reserved.
unsuccessful [1,2,5]. Direct repair with augmentation with an autogenous semitendinosus tendon grafts has gained a higher successful result but with poor knee flexion because of prolonged immobilization [3]. The use of gastrocnemius flap and different types of allograft reconstruction has provided a better clinical result; however, certain degrees of extension lag of the knee have been reported [6-10]. We present a case with patellar tendon rupture after TKA treated with a turndown quadriceps tendon flap.
Patellar tendon rupture is a rare but disturbing complication after total knee arthroplasty (TKA). The reported incidence ranged from 0.17% to 2.5% [1,2]. The etiology of patellar tendon rupture after TKA is classified as traumatic [2,3] and nontraumatic origin. Nontraumatic factors included longterm local steroid injection, diabetes mellitus, rheumatoid arthritis, lupus erythematous [2], devascularization after extensive lateral retinacular release or multiple operations [1], and inadvertent detachment during exposure of a stiff knee [4]. There were various operative methods treating this complication, but the results were not consistent. Direct repair with suture or staples was often
Case Report A 77-year-old male patient received right TKA using a Whiteside posterior-stabilized implant (Dow Corning Wright, Arlington, Tenn) because of advanced osteoarthritis on October 28, 2003. More than 50 years ago, he had a below-knee amputation of his left leg because of severe trauma in a traffic accident. At the time of TKA, there was no iatrogenic partial avulsion of the patellar tendon, overcutting of the patellar bone, or lateral retinacular release. He had an uneventful postoperative course.
From the Department of Orthopaedic Surgery, Chang Gung Memorial Hospital-Kaohsiung, Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan, Republic of China. Submitted August 3, 2006; accepted December 24, 2006. No benefits or funds were received in support of the study. Reprint requests: Jun-Wen Wang, MD, Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Kaohsiung, 123, Ta Pei Rd, Niao Sung Hsiang, Kaohsiung, Taiwan, Republic of China. n 2007 Elsevier Inc. All rights reserved. 0883-5403/07/1906-0004$32.00/0 doi:10.1016/j.arth.2006.12.105
934
Rupture of the Patellar Tendon after Total Knee Arthroplasty ! Lin and Wang 935
Fig. 1. Preoperative anteroposterior (A) and lateral (B) radiographs of the right knee demonstrating a patellar alta after TKA indicating rupture of the patellar tendon.
About 4 weeks after TKA, he had a fall accident when he tried to move from one chair to another. At that time, he was not wearing his prosthetic leg on his left amputee. On January 7, 2004, he visited the orthopedic clinic for routine checkup. Physical examination revealed a palpable tendon gap in the infrapatellar region of the right knee. He could bend his right knee to 1008 but could not extend the knee actively. The extension lag of the knee was 608. The radiograph of the right knee showed a well-fixed total knee prosthesis; however, an obvious patellar alta was noted (Fig. 1A and B).
Fig. 2. Intraoperative photograph (A) and sketch (B) showing rupture of the patellar tendon at the midsubstance with a 3-cm gap caused by tendon retraction. A strip of quadriceps tendon was harvested and readied for reconstruction.
Fig. 3. Intraoperative photograph (A) and sketch (B) after repair of the patellar tendon and augmentation with a turndown quadriceps flap and a circumferential wire.
The preoperative diagnosis was rupture of the patellar tendon after TKA. On January 13, 2004, which was about 7 weeks after the injury, he underwent repair of the patellar tendon with augmentation. At operation, rupture
Fig. 4. Postoperative anteroposterior (A) and lateral (B) radiographs of the right knee 6 weeks after repair of patellar tendon with augmentation showing good restoration of the patellar position with a circumferential wire.
936 The Journal of Arthroplasty Vol. 22 No. 6 September 2007 tuberosity with interrupted sutures. The edges of the turndown quadriceps tendon were fixed to the underlying patellar tendon using slowly absorbable sutures (Vicryl; Ethicon, Somerville, NJ) interruptedly (Fig. 3). The reconstruction was further protected by a circumferential wire (stainless steel, 1.22 mm) passing through the upper pole of the patellar bone superiorly and the tibial tuberosity inferiorly (Figs. 3 and 4). Postoperatively, a long leg cast was applied for 3 weeks. After that, he was allowed to start range of motion exercise of the knee. However, because of below-knee amputation of the contralateral leg, he was commenced to use wheelchair for ambulation to avoid re-rupture of the tendon. Six weeks postoperatively, he had almost full extension of the knee and flexion of the knee up to 908. At 3 months, the augmented circumferential wire was removed. After that, he was allowed to walk with a walker support. At 6 months, he had a full extension of the knee with 1108 of knee flexion. Two years and 6 months postoperatively, the patient had good recovery of the quadriceps power, with range of motion of the knee from 08 to 1108 (Fig. 5A and B). The standing radiographs of the knee showed a well-fixed and aligned total knee prosthesis and good restoration of the patellar position. He could ambulate without support. According to the evaluation system of the Knee Society [11], his Knee Score was 93 points and his Function Score was 95 points.
Discussion
Fig. 5. Clinical photographs of the patient at 2.5 years after operation showing full extension (A) and 1108 flexion (B) of the knee.
of patellar tendon at the midsubstance with a 3-cm gap caused by retraction of the proximal part of the patellar tendon was found (Fig. 2A and B). Primary repair of the ruptured patellar tendon was performed, but there was tension even after bringing down the retracted patellar tendon by soft tissue release. A strip of quadriceps tendon measuring 8 1.5 cm was harvested and turned down to reconstruct the repaired tendon (Fig. 2). The harvested quadriceps tendon was long enough to cover the repaired patellar tendon and was anchored into the distal portion of the patellar tendon at the tibial
Rupture of the patellar tendon after TKA is a rare but catastrophic complication. The possible causes are prosthetic impingement, resection of excessive amounts of the bone of the patella, devascularization of the patellar tendon, and excessive tension on the patellar tendon during exposure of the stiff knee [2,12]. However, because there is no reconstructive approach that provides consistent results, the best way to solve this problem is to avoid this complication. Some authors suggested preservation of the blood supply to the patellar tendon during TKA [3]; others emphasized meticulous surgical approach during TKA if patient has limited preoperative motion of the knee [2,4]. In the current report, the patient had a trauma event 4 weeks after TKA, which resulted in rupture of the patellar tendon. The results of the treatment of patellar tendon rupture after TKA varied. Rand et al reported 18 ruptures of patellar ligament after TKA, 16 of whom had operative procedures that included
Rupture of the Patellar Tendon after Total Knee Arthroplasty ! Lin and Wang 937
direct repair in nine, staple fixation in four, xenograft reconstruction in two, and semitendinosus reconstruction in one. Only two with a staple repair and two having a reconstruction with a xenograft succeeded [2]. The results of direct suture repair of the ruptured tendon were discouraging. In a series of complications of the extensor mechanism after TKA reported by Lynch et al, results in 4 cases of direct suture repair were reruptured tendon in one, deep infection in one, and extension lags of 188 and 228 in two [1]. Oglesby and Wilson reported direct repairs in 5 patients; only one of them had full active extension [13]. The use of composite allografts that included a quadriceps tendon, a patella with a cemented patellar component, the patellar tendon, and the tibial tubercle reported by Emerson et al had gained a satisfactory result in 9 patients followed up for 4 years [10]. Three of them had an extension lag ranging from 208 to 408. The report by Leopold et al using the same technique was discouraging, however, because of the poor recovery of quadriceps power, with a mean extension lag of 598 in 7 patients followed up for 39 months [14]. Recently, with the improvement of the surgical technique by fixation of the allograft distally with multiple wires and tightening of the grafts in full extension, the clinical results of extensor tendon allografts have become much better [15]. Cadambi and Engh reported successful recovery of the extension mechanism using double semitendinosus tendon reconstruction and cast and brace protection for 18 weeks in 7 knees [3]. However, the active knee flexion was restricted, with 4 knees having less than 808 of knee flexion possibly because of prolonged immobilization. The use of a medial gastrocnemius flap provides improved soft-tissue coverage and allows the return of the extensor mechanism for a chronic disruption of the patellar tendon after TKA [6,7,16]. However, it has the disadvantages of a poor cosmesis and residual weakness of ankle plantar flexion [17]. A residual extension lag ranging from 258 to 508 in 4 of 6 treated knees has been reported [6]. Our surgical technique of reconstruction of the ruptured patellar tendon using a turndown quadriceps tendon flap was derived from Scuderi who used a triangular turndown flap of the quadriceps tendon to reinforce and lengthen the rupture of the quadriceps tendon [18]. Because our case was ruptured patellar tendon, we created a longer quadriceps flap (8 1.5 cm) rather than a triangular flap to cover the repaired tendon. In the report by Scuderi, he used Bunnell pullout wires after reconstruction to release tension on the repaired tendon.
Our technique of tension release was a circumferential wire passing through the patellar bone and the tibial tuberosity. Scuderi claimed the patients gained good extension and flexion of the knee postoperatively and that the method was better than the others that he had tried before. The increased tendon volume at the sutured line and the living tissue reinforcement are the causes of the successful results [18]. In the current report, the patient started early rehabilitation (3 weeks postoperatively) based on strong augmentation of the repaired tendon and protection of the repair by a circumferential wire, which resulted in the quick recovery of the quadriceps power (6 weeks postoperatively) because of strong reinforcement of the living tissue at the repaired tendon.
Acknowledgment The authors would like to thank Mr Jui-Hsing Chen for his excellent work of line drawings in this article.
References 1. Lynch AF, Rorabeck CH, Bourne RB. Extensor mechanism complications following total knee arthroplasty. J Arthroplasty 1987;2:135. 2. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop 1989;244:233. 3. Cadambi A, Engh GA. Use of a semitendinosus tendon autogenous graft for rupture of the patellar ligament after total knee arthroplasty. A report of seven cases. J Bone Joint Surg 1992;74A:974. 4. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture following total knee arthroplasty. Tech Orthop 1988;3:45. 5. Abril JC, Alvarez L, Vallejo JC. Patellar tendon avulsion after total knee arthroplasty. A new technique. J Arthroplasty 1995;10:275. 6. Jaureguito JW, Dubois CM, Smith SR, et al. Medial gastrocnemius transposition flap for the treatment of disruption of the extensor mechanism. J Bone Joint Surg 1997;79A:886. 7. Patel NS, Ibrahim DT, Finn HA. Knee extensor mechanism reconstruction with medial gastrocnemius flap. Clin Orthop 2002;398:176. 8. Crossett LS, Sinha RK, Sechriest VN, et al. Reconstruction of a ruptured patellar tendon with Achilles tendon allograft following total knee arthroplasty. J Bone Joint Surg 2002;84A:1354. 9. Barrack RL, Stanley T, Butler RA. Treating extensor mechanism disruption after total knee arthroplasty. Clin Orthop 2003;416:98. 10. Emerson Jr RH, Head WC, Malinin TI. Reconstruction of patellar tendon rupture after total knee
938 The Journal of Arthroplasty Vol. 22 No. 6 September 2007 arthroplasty with an extensor mechanism allograft. Clin Orthop 1990;260:154. 11. Insall JN, Dorr LD, Scott RD, et al. Rationale of the Knee Society clinical rating system. Clin Orthop 1989;248:13. 12. Gustilo RB, Thompson R. Quadriceps and patellar tendon ruptures following total knee arthroplasty. In: Rand JA, Dorr LD, editors. Total arthroplasty of the kneeProceedings of the Knee Society, 1985-1986. Rockville (Md): Aspen; 1987. p. 41. 13. Oglesby JW, Wilson FC. The evolution of knee arthroplasty: results with three generations of prosthesis. Clin orthop 1984;186:96.
14. Leopold SS, Greidanus N, Paprosky WG, et al. High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg 1999;81A:1574. 15. Nazarian DG, Booth RE. Extensor mechanism allografts in total knee arthroplasty. Clin Orthop 1999;367:123. 16. Pagnano MW. Patellar tendon and quadriceps tendon tears after total knee arthroplasty. J Knee Surg 2003;16:242. 17. Rand JA. Extensor mechanism complications following total knee arthroplasty. J Bone Joint Surg 2004; 86A:2062. 18. Scuderi C. Ruptures of the quadriceps tendon. Am J Surg 1958;95:626.