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Dislocation of a constrained total knee arthroplasty with patellar tendon rupture after trivial trauma
Chinese Journal of Traumatology 18 (2015) 241e244
H O S T E D BY
Contents lists available at ScienceDirect
Chinese Journal of Traumatology journal homepage: http://www.elsevier.com/locate/CJTEE
Case report
Dislocation of a constrained total knee arthroplasty with patellar tendon rupture after trivial trauma Raju Vaishya*, Vipul Vijay, Abhishek Vaish Orthopedics and Joint Replacement Surgery, Indraprastha Apollo Hospitals, Sarita Vihar Mathura Road, New Delhi 110076, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 August 2014 Received in revised form 20 January 2015 Accepted 30 January 2015 Available online 30 November 2015
Constrained total knee prostheses are used in knees with severe deformities and insufficiency of collaterals to provide stable and mobile knees. Dislocation after constrained knee prosthesis is an extremely rare and dreaded complication. When dislocation is associated with patellar tendon rupture, the management includes restoration of the extensor apparatus along with a stable knee. Repair of the patellar tendon is challenging due to poor soft tissue coverage in the area and a bulky repair can put tension on the wound closure. Ideal method of restoration of the extensor apparatus is a matter of debate. There are various modalities used ranging from primary end-to-end repair, augmentation by medial gastrocnemius flap, semitendinosus and synthetic implants and allograft tendoachilles. We report a rare case of a posterior dislocation of a constrained total knee arthroplasty in association with patellar tendon rupture due to a minor fall after a few weeks of surgery. The first episode was managed by reposition of the dislocation and VeY plasty of the quadriceps and primary repair. The second episode of dislocation with re-rupture needed augmentation by semitendinosus along with the insertion of the thicker insert. The management of this complex problem along with the review of literature is discussed in this case report. © 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords: Dislocations Patellar ligament Arthroplasty Replacement Knee
1. Introduction Posterior dislocation of the prosthesis after total knee arthroplasty (TKA) is an infrequent but serious complication.1e3 Knee dislocation after revised TKA can be dangerous and can lead to neurovascular compromise and permanent disability.4 Dislocation of a constrained TKA is even rarer and, to the best of our knowledge, its association with patellar tendon rupture has not been reported in the literature. Rupture of the patellar tendon after TKA is itself a catastrophic and debilitating complication, and its association with dislocation of prosthesis makes it even more challenging. Proper surgical management of this condition is often very difficult and remains controversial. 2. Case report A 70-year-old female, with chronic seropositive rheumatoid polyarthritis with 40 of valgus deformity of the right knee (Fig. 1)
* Corresponding author. Tel.: þ91 9810123331; fax: þ91 1126823629. E-mail address: [email protected] (R. Vaishya). Peer review under responsibility of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University.
had total knee replacement using Scorpio (TS type) constrained prosthesis (Figs. 2 and 3), and extensive lateral release. Due to the correction of severe deformity, she developed common peroneal nerve palsy which was noticed immediately in the postoperative period and it recovered spontaneously at 3 months. One month following surgery, patient presented with right knee pain and deformity, following a fall on a wet floor. Clinical examination revealed a defect in the infrapatellar region with inability to perform active knee extension. This raised the suspicion of an infrapatellar rupture of the quadriceps. Radiographs revealed posterior dislocation of the knee prosthesis (Fig. 4). Intraoperative findings included dislocated TKA with patellar tendon rupture from patellar insertion and complete rupture of the medial and lateral retinaculae with friable soft tissues. This case was managed by reposition of dislocated TKA with primary repair of the patellar tendon. Since the patellar tendon was shortened following debridement, VeY plasty of the quadriceps tendon was performed to gain length of the quadriceps by raising an inverted V proximally in the quadriceps tendon with the free limb in the vastus lateralis with care to preserve the lateral genicular artery. After deciding the amount of lengthening necessary for closing the patellar tendon defect, the lateral limb of the inverted V was advanced distally and laterally, detaching the vastus lateralis
http://dx.doi.org/10.1016/j.cjtee.2015.01.007 1008-1275/© 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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Fig. 1. Preoperative X-rays showing severe arthritis of the right knee with valgus deformity and previously done TKA.
muscle. The VeY advancement thus gave approximately 2 cm of further length to repair the patellar tendon defect. Postoperatively, the patient was immobilized in knee extension following surgery and discharged with brace and static quadriceps exercises. The patient came back 10 days after surgery with recurrent pain and deformity of the right knee. She denied any further injury. Xrays revealed posterior dislocation of the prosthesis and superior
Fig. 3. Postoperative X-ray (lateral view) of left TKA using Scorpio TS prosthesis.
migration of the patella. On exploration of the knee, re-rupture of the infrapatellar tendon was found with dislocation of the prosthesis. The polyethylene insert was exchanged using one size thicker polyethylene. The patellar tendon reconstruction was done using ipsilateral hamstring (semitendinosus) tendon (Fig. 5). A drill hole of 4.5 mm was made through the tibia at tibial tuberosity level and another hole was made through the patella in a medio-lateral direction. The harvested tendon was passed through these drill holes, sutured back to it, and further anchored to the surrounding soft tissues. An above knee cast was applied for immobilization for 1 month followed by physiotherapy exercises. At 2 years follow-up there was no recurrence of dislocation or any signs of loosening (Fig. 6). There was an extensor lag of 45 (Fig. 7), however, the range of motion was up to 100 flexion (Fig. 8). 3. Discussion
Fig. 2. Postoperative X-ray (AP view) of left TKA using Scorpio TS prosthesis.
Although tibiofemoral instability has classically been reported with cruciate-retaining prostheses, it is known that the dislocation of TKA can happen in both cruciate-retaining and cruciatesubstituting TKAs.1 Wrong surgical technique and wrong choice of constraint for the prostheses are the main causes of instability. Malalignment, malrotation, and intraoperatively uncorrected instability (especially in flexion) may lead to unstable TKA.2 Constrained prosthesis like Scorpio TS (Stryker) is designed to maintain a constant center of rotation throughout the range of motion. This provides uniform ligament tension during the transition from full extension to deep flexion by preserving ligament isometry. This eliminates mid-flexion instability, which is a common concern especially in revision and complex knee surgery. The Scorpio TS eminence is designed to provide ±2 of varus/valgus constraint and allows up to 10 of internal/external rotation. Hence, dislocation of such a constrained prosthesis per se is extremely
R. Vaishya et al. / Chinese Journal of Traumatology 18 (2015) 241e244
243
Fig. 6. Postpatellar tendon reconstruction X-ray showing stable reduction of TKA.
Fig. 4. X-ray (lateral view) showing posterior dislocation of the prosthesis.
uncommon. However, associated factors like ligament imbalance, quadriceps mechanism disruption among others may cause dislocation of even such constrained prosthesis. We believe that in our case, the association of posttraumatic quadriceps tendon rupture was the most probable cause for dislocation of the prosthesis, as the reconstruction of the patellar tendon by using semi-tendinosus autograft restored the stability at 2 years follow-up. Sharkey et al3 in a series of 7 cases of dislocation of TKA reported an identifiable problem with the knee extensor mechanism: five had patellar dislocations, one patellar tendon rupture, and one patellar fracture. In three of the posterior dislocations, there was also an imbalance of the flexion and extension gaps with excessive laxity of
Fig. 5. Patellar tendon reconstruction using semitendinosus tendon.
Fig. 7. Residual extensor lag after patellar tendon reconstruction.
the ligaments in flexion. This study again emphasizes the importance of quadriceps mechanism in the stability of knee after TKA and any compromise in it may lead to instability of TKA. Instability is an important cause of failure following TKA. Increasing component constraint may reduce instability,5 but doing so can also cause increased forces to be transmitted to fixation and
Fig. 8. Satisfactory flexion range after patellar tendon reconstruction.
244
R. Vaishya et al. / Chinese Journal of Traumatology 18 (2015) 241e244
implant interfaces, which may lead to premature aseptic loosening. Constraint is defined as that feature of knee implant design that provides the stability needed to counteract forces about the knee after arthroplasty in the presence of a deficient soft-tissue envelope. Determining the amount of constraint necessary can be challenging. Most primary TKA are performed for knees without substantial deformity or the need for difficult ligament balancing; in these cases, either a posterior-stabilized or a posterior cruciateretaining design is appropriate. In certain situations, such as patients with prior patellectomy, rheumatoid arthritis, or substantial preoperative deformities, a posterior-stabilized knee may be favored. With their large posts, varus-valgus constrained implants typically are reserved for patients with substantial coronal plane instability, which is difficult to balance with a posterior-stabilized or cruciate-retaining implant alone. Rotating-hinge knee implants usually are recommended for patients with severe deformity or instability that can not be managed with a varus-valgus constrained implant. Disruption of the extensor mechanism is a devastating complication of TKA, with a prevalence of 0.17%e2.5% in series ranging in size from 2812 to 8288 knees.6 Disruption can occur intraoperatively usually related to surgical technique or postoperatively usually due to vascular interruption, increased patellofemoral strain, or chronic tendon attenuation. Patella tendon rupture is usually associated with patient comorbidities, tissue devascularization from multiple previous procedures, trauma or stiff knees. The treatment options for repair of the quadriceps include observation, direct primary repair, direct primary repair with synthetic ligament or autogenous tissue augmentation, or reconstruction with allograft tissue.7 Patellar tendon tears usually can be divided on the basis of their presentation into acute and chronic ones. Although there are no clear guidelines available in the literature for describing the chronicity of patellar tendon tear, in our clinical practice we consider an acute tear to be less than 3 weeks. We label subacute tears as tears between 3 and 6 weeks and chronic tears beyond 6 weeks. Acute tears are still amenable to direct repair.8 The direct repair is often difficult or not possible in subacute and chronic cases due to poor quality and inadequate amount of tendon tissue. In the subacute and chronic cases, the primary repair of the tendon is routinely not possible and the repair usually requires augmentation with either other soft tissue procedures or allografts.8 Busfield et al9 successfully performed medial gastrocnemius flap for providing adequate soft tissue coverage and augmentation to the repair. Crossett et al7 used hamstring (semitendinosus) graft for repair in chronic cases with good muscle strength and function. Achilles tendon allograft with calcaneal bone block has also been used for augmentation of these chronic tears. Allograft tissue may provide the best means to adequately reconstruct the disrupted patellar tendon. Composite allografts like quadriceps tendon-patella-patellar tendon-tibial tubercle have controversial results with one study by Rosenberg et al10 reporting 30% reoperation rates. Important surgical principals while using allograft tendon grafts include rigid fixation of the host allograft junction, coverage of the allograft tissue with as much autologous tissue as possible to reduce the risk of infection, tensioning the graft in full extension, and not testing the completed repair. Although the allografts are attractive options for repair of chronic patellar tendon repair, they are associated with many inherent problems, like nonuniversal availability, high cost, possibility of disease transmission and doubtful in corporation. We considered using allograft for reconstruction in this case but since allografts are not easily available in our setup, we used hamstring tendon autograft, as they were easily available locally around the knee and cost-effective.
The repair or reconstruction of infrapatellar ruptures of the quadriceps tendon are often associated with poor results and have residual extensor lag postoperatively. Rand et al11 reviewed the literature and reported consistently poor results with all modes of treatment when compared to patients who had not undergone total knee replacement and concluded that prevention of this dreaded complication is better. Only 4 out of 25 cases treated with primary repair and one treated with semitendinosus were successful. We chose to treat the first rupture with primary end-to-end repair, and to achieve adequate approximation we added VeY plasty of the quadriceps. For the second episode of re-rupture, we used an autograft of semi-tendinosus as the augment for the repair, consistent with the findings of Rand et al. Although, allografts have given encouraging results, we could not use it due to nonavailability of the allografts in our setup. Our patient had an extensor lag but she reported improved functional status and active knee extension post surgery. The reason for extensor lag post surgery can be explained by the decreased strength of the semi-tendinosus tendon as compared to the quadriceps tendon. The semitendinosus has a tensile strength equal to 40%e50% of the quadriceps tendon.12 The semitendinosus tends to stretch out over time and this can finally lead to an extensor lag. She was also saved from more extensive salvage surgery like revision arthroplasty or arthrodesis, etc. Extensor mechanism rupture is a rare and serious complication following TKA and prevention of this complication should be the goal during surgery. The patient, intraoperative and component factors should be recognized which may predispose to this complication. Treatment options have been increased due to the addition of composite allograft and synthetic grafts and the results have been improved with acceptable functional results. We believe that dislocation of the TKA with ruptured patellar tendon is a rare combination and is extremely challenging to treat even surgically. Subacute and chronic tendon ruptures are best treated with augmentation by auto- or allo-graft. The suboptimal results after reconstruction of infrapatellar tendon rupture may be disappointing but may save the knee from more severe salvage surgery and provides a reasonable functional outcome.
References 1. Vaishya R, Langde V, Ahmad S, et al. Dislocation following total knee arthroplasty. Indian J Orthop. 2011;45:283e284. 2. Pietsch M, Hofmann S. From tibiofemoral instability to dislocation in total knee arthroplasty. Orthopedics. 2007;36:917e922. 3. Sharkey PF, Hozack WJ, Booth Jr JE, et al. Posterior dislocation of total knee arthroplasty. Clin Orthop Relat Res. 1992;278:128e133. 4. Hagedorn J, Levine BR. Revision surgery for a dislocated constrained total knee arthroplasty. Orthopedics. 2012;35:1099e1103. 5. Mogrgan H, Battista V, Leopold SS. Constraint in primary total knee arthroplasty. J Am Acad Orthop Surg. 2005;13:515e524. 6. Venkataramanan NS, Sinha RK, Crossett LS. Extensor Mechanism Reconstruction after Total Knee Arthroplasty with Achilles Tendon Allograft. Techniques in Knee Surgery. Philadelphia: Lippincott, Williams and Wilkins; 2004:117e121. 7. Crossett LS, Sinha RK, Sechriest VK, et al. Reconstruction of a ruptured patellar tendon with achilles tendon allograft following total knee arthroplasty. J Bone Jt Surg Am. 2004;84:1354e1361. 8. Papalia R, Vasta S, D'Adamio S, et al. Complications involving the extensor mechanism after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2014 [Epub ahead of print]. 9. Busfield BT, Huffman GR, Nahai F, et al. Extended medial gastrocnemius rotational flap for treatment of chronic knee extensor mechanism deficiency in patients with and without total knee arthroplasty. Clin Orthop Relat Res. 2004;428:190e197. 10. Rosenberg AG. Management of extensor mechanism rupture after TKA. J Bone Jt Surg Br. 2012;94:116e119. 11. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop Relat Res. 1989;244:233e238. 12. Mine T, Tanaka H, Taguchi T, et al. Patellar tendon rupture and marked joint instability after total knee arthroplasty. Arch Orthop Trauma Surg. 2004;124: 267e271.
H O S T E D BY
Contents lists available at ScienceDirect
Chinese Journal of Traumatology journal homepage: http://www.elsevier.com/locate/CJTEE
Case report
Dislocation of a constrained total knee arthroplasty with patellar tendon rupture after trivial trauma Raju Vaishya*, Vipul Vijay, Abhishek Vaish Orthopedics and Joint Replacement Surgery, Indraprastha Apollo Hospitals, Sarita Vihar Mathura Road, New Delhi 110076, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 August 2014 Received in revised form 20 January 2015 Accepted 30 January 2015 Available online 30 November 2015
Constrained total knee prostheses are used in knees with severe deformities and insufficiency of collaterals to provide stable and mobile knees. Dislocation after constrained knee prosthesis is an extremely rare and dreaded complication. When dislocation is associated with patellar tendon rupture, the management includes restoration of the extensor apparatus along with a stable knee. Repair of the patellar tendon is challenging due to poor soft tissue coverage in the area and a bulky repair can put tension on the wound closure. Ideal method of restoration of the extensor apparatus is a matter of debate. There are various modalities used ranging from primary end-to-end repair, augmentation by medial gastrocnemius flap, semitendinosus and synthetic implants and allograft tendoachilles. We report a rare case of a posterior dislocation of a constrained total knee arthroplasty in association with patellar tendon rupture due to a minor fall after a few weeks of surgery. The first episode was managed by reposition of the dislocation and VeY plasty of the quadriceps and primary repair. The second episode of dislocation with re-rupture needed augmentation by semitendinosus along with the insertion of the thicker insert. The management of this complex problem along with the review of literature is discussed in this case report. © 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords: Dislocations Patellar ligament Arthroplasty Replacement Knee
1. Introduction Posterior dislocation of the prosthesis after total knee arthroplasty (TKA) is an infrequent but serious complication.1e3 Knee dislocation after revised TKA can be dangerous and can lead to neurovascular compromise and permanent disability.4 Dislocation of a constrained TKA is even rarer and, to the best of our knowledge, its association with patellar tendon rupture has not been reported in the literature. Rupture of the patellar tendon after TKA is itself a catastrophic and debilitating complication, and its association with dislocation of prosthesis makes it even more challenging. Proper surgical management of this condition is often very difficult and remains controversial. 2. Case report A 70-year-old female, with chronic seropositive rheumatoid polyarthritis with 40 of valgus deformity of the right knee (Fig. 1)
* Corresponding author. Tel.: þ91 9810123331; fax: þ91 1126823629. E-mail address: [email protected] (R. Vaishya). Peer review under responsibility of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University.
had total knee replacement using Scorpio (TS type) constrained prosthesis (Figs. 2 and 3), and extensive lateral release. Due to the correction of severe deformity, she developed common peroneal nerve palsy which was noticed immediately in the postoperative period and it recovered spontaneously at 3 months. One month following surgery, patient presented with right knee pain and deformity, following a fall on a wet floor. Clinical examination revealed a defect in the infrapatellar region with inability to perform active knee extension. This raised the suspicion of an infrapatellar rupture of the quadriceps. Radiographs revealed posterior dislocation of the knee prosthesis (Fig. 4). Intraoperative findings included dislocated TKA with patellar tendon rupture from patellar insertion and complete rupture of the medial and lateral retinaculae with friable soft tissues. This case was managed by reposition of dislocated TKA with primary repair of the patellar tendon. Since the patellar tendon was shortened following debridement, VeY plasty of the quadriceps tendon was performed to gain length of the quadriceps by raising an inverted V proximally in the quadriceps tendon with the free limb in the vastus lateralis with care to preserve the lateral genicular artery. After deciding the amount of lengthening necessary for closing the patellar tendon defect, the lateral limb of the inverted V was advanced distally and laterally, detaching the vastus lateralis
http://dx.doi.org/10.1016/j.cjtee.2015.01.007 1008-1275/© 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
242
R. Vaishya et al. / Chinese Journal of Traumatology 18 (2015) 241e244
Fig. 1. Preoperative X-rays showing severe arthritis of the right knee with valgus deformity and previously done TKA.
muscle. The VeY advancement thus gave approximately 2 cm of further length to repair the patellar tendon defect. Postoperatively, the patient was immobilized in knee extension following surgery and discharged with brace and static quadriceps exercises. The patient came back 10 days after surgery with recurrent pain and deformity of the right knee. She denied any further injury. Xrays revealed posterior dislocation of the prosthesis and superior
Fig. 3. Postoperative X-ray (lateral view) of left TKA using Scorpio TS prosthesis.
migration of the patella. On exploration of the knee, re-rupture of the infrapatellar tendon was found with dislocation of the prosthesis. The polyethylene insert was exchanged using one size thicker polyethylene. The patellar tendon reconstruction was done using ipsilateral hamstring (semitendinosus) tendon (Fig. 5). A drill hole of 4.5 mm was made through the tibia at tibial tuberosity level and another hole was made through the patella in a medio-lateral direction. The harvested tendon was passed through these drill holes, sutured back to it, and further anchored to the surrounding soft tissues. An above knee cast was applied for immobilization for 1 month followed by physiotherapy exercises. At 2 years follow-up there was no recurrence of dislocation or any signs of loosening (Fig. 6). There was an extensor lag of 45 (Fig. 7), however, the range of motion was up to 100 flexion (Fig. 8). 3. Discussion
Fig. 2. Postoperative X-ray (AP view) of left TKA using Scorpio TS prosthesis.
Although tibiofemoral instability has classically been reported with cruciate-retaining prostheses, it is known that the dislocation of TKA can happen in both cruciate-retaining and cruciatesubstituting TKAs.1 Wrong surgical technique and wrong choice of constraint for the prostheses are the main causes of instability. Malalignment, malrotation, and intraoperatively uncorrected instability (especially in flexion) may lead to unstable TKA.2 Constrained prosthesis like Scorpio TS (Stryker) is designed to maintain a constant center of rotation throughout the range of motion. This provides uniform ligament tension during the transition from full extension to deep flexion by preserving ligament isometry. This eliminates mid-flexion instability, which is a common concern especially in revision and complex knee surgery. The Scorpio TS eminence is designed to provide ±2 of varus/valgus constraint and allows up to 10 of internal/external rotation. Hence, dislocation of such a constrained prosthesis per se is extremely
R. Vaishya et al. / Chinese Journal of Traumatology 18 (2015) 241e244
243
Fig. 6. Postpatellar tendon reconstruction X-ray showing stable reduction of TKA.
Fig. 4. X-ray (lateral view) showing posterior dislocation of the prosthesis.
uncommon. However, associated factors like ligament imbalance, quadriceps mechanism disruption among others may cause dislocation of even such constrained prosthesis. We believe that in our case, the association of posttraumatic quadriceps tendon rupture was the most probable cause for dislocation of the prosthesis, as the reconstruction of the patellar tendon by using semi-tendinosus autograft restored the stability at 2 years follow-up. Sharkey et al3 in a series of 7 cases of dislocation of TKA reported an identifiable problem with the knee extensor mechanism: five had patellar dislocations, one patellar tendon rupture, and one patellar fracture. In three of the posterior dislocations, there was also an imbalance of the flexion and extension gaps with excessive laxity of
Fig. 5. Patellar tendon reconstruction using semitendinosus tendon.
Fig. 7. Residual extensor lag after patellar tendon reconstruction.
the ligaments in flexion. This study again emphasizes the importance of quadriceps mechanism in the stability of knee after TKA and any compromise in it may lead to instability of TKA. Instability is an important cause of failure following TKA. Increasing component constraint may reduce instability,5 but doing so can also cause increased forces to be transmitted to fixation and
Fig. 8. Satisfactory flexion range after patellar tendon reconstruction.
244
R. Vaishya et al. / Chinese Journal of Traumatology 18 (2015) 241e244
implant interfaces, which may lead to premature aseptic loosening. Constraint is defined as that feature of knee implant design that provides the stability needed to counteract forces about the knee after arthroplasty in the presence of a deficient soft-tissue envelope. Determining the amount of constraint necessary can be challenging. Most primary TKA are performed for knees without substantial deformity or the need for difficult ligament balancing; in these cases, either a posterior-stabilized or a posterior cruciateretaining design is appropriate. In certain situations, such as patients with prior patellectomy, rheumatoid arthritis, or substantial preoperative deformities, a posterior-stabilized knee may be favored. With their large posts, varus-valgus constrained implants typically are reserved for patients with substantial coronal plane instability, which is difficult to balance with a posterior-stabilized or cruciate-retaining implant alone. Rotating-hinge knee implants usually are recommended for patients with severe deformity or instability that can not be managed with a varus-valgus constrained implant. Disruption of the extensor mechanism is a devastating complication of TKA, with a prevalence of 0.17%e2.5% in series ranging in size from 2812 to 8288 knees.6 Disruption can occur intraoperatively usually related to surgical technique or postoperatively usually due to vascular interruption, increased patellofemoral strain, or chronic tendon attenuation. Patella tendon rupture is usually associated with patient comorbidities, tissue devascularization from multiple previous procedures, trauma or stiff knees. The treatment options for repair of the quadriceps include observation, direct primary repair, direct primary repair with synthetic ligament or autogenous tissue augmentation, or reconstruction with allograft tissue.7 Patellar tendon tears usually can be divided on the basis of their presentation into acute and chronic ones. Although there are no clear guidelines available in the literature for describing the chronicity of patellar tendon tear, in our clinical practice we consider an acute tear to be less than 3 weeks. We label subacute tears as tears between 3 and 6 weeks and chronic tears beyond 6 weeks. Acute tears are still amenable to direct repair.8 The direct repair is often difficult or not possible in subacute and chronic cases due to poor quality and inadequate amount of tendon tissue. In the subacute and chronic cases, the primary repair of the tendon is routinely not possible and the repair usually requires augmentation with either other soft tissue procedures or allografts.8 Busfield et al9 successfully performed medial gastrocnemius flap for providing adequate soft tissue coverage and augmentation to the repair. Crossett et al7 used hamstring (semitendinosus) graft for repair in chronic cases with good muscle strength and function. Achilles tendon allograft with calcaneal bone block has also been used for augmentation of these chronic tears. Allograft tissue may provide the best means to adequately reconstruct the disrupted patellar tendon. Composite allografts like quadriceps tendon-patella-patellar tendon-tibial tubercle have controversial results with one study by Rosenberg et al10 reporting 30% reoperation rates. Important surgical principals while using allograft tendon grafts include rigid fixation of the host allograft junction, coverage of the allograft tissue with as much autologous tissue as possible to reduce the risk of infection, tensioning the graft in full extension, and not testing the completed repair. Although the allografts are attractive options for repair of chronic patellar tendon repair, they are associated with many inherent problems, like nonuniversal availability, high cost, possibility of disease transmission and doubtful in corporation. We considered using allograft for reconstruction in this case but since allografts are not easily available in our setup, we used hamstring tendon autograft, as they were easily available locally around the knee and cost-effective.
The repair or reconstruction of infrapatellar ruptures of the quadriceps tendon are often associated with poor results and have residual extensor lag postoperatively. Rand et al11 reviewed the literature and reported consistently poor results with all modes of treatment when compared to patients who had not undergone total knee replacement and concluded that prevention of this dreaded complication is better. Only 4 out of 25 cases treated with primary repair and one treated with semitendinosus were successful. We chose to treat the first rupture with primary end-to-end repair, and to achieve adequate approximation we added VeY plasty of the quadriceps. For the second episode of re-rupture, we used an autograft of semi-tendinosus as the augment for the repair, consistent with the findings of Rand et al. Although, allografts have given encouraging results, we could not use it due to nonavailability of the allografts in our setup. Our patient had an extensor lag but she reported improved functional status and active knee extension post surgery. The reason for extensor lag post surgery can be explained by the decreased strength of the semi-tendinosus tendon as compared to the quadriceps tendon. The semitendinosus has a tensile strength equal to 40%e50% of the quadriceps tendon.12 The semitendinosus tends to stretch out over time and this can finally lead to an extensor lag. She was also saved from more extensive salvage surgery like revision arthroplasty or arthrodesis, etc. Extensor mechanism rupture is a rare and serious complication following TKA and prevention of this complication should be the goal during surgery. The patient, intraoperative and component factors should be recognized which may predispose to this complication. Treatment options have been increased due to the addition of composite allograft and synthetic grafts and the results have been improved with acceptable functional results. We believe that dislocation of the TKA with ruptured patellar tendon is a rare combination and is extremely challenging to treat even surgically. Subacute and chronic tendon ruptures are best treated with augmentation by auto- or allo-graft. The suboptimal results after reconstruction of infrapatellar tendon rupture may be disappointing but may save the knee from more severe salvage surgery and provides a reasonable functional outcome.
References 1. Vaishya R, Langde V, Ahmad S, et al. Dislocation following total knee arthroplasty. Indian J Orthop. 2011;45:283e284. 2. Pietsch M, Hofmann S. From tibiofemoral instability to dislocation in total knee arthroplasty. Orthopedics. 2007;36:917e922. 3. Sharkey PF, Hozack WJ, Booth Jr JE, et al. Posterior dislocation of total knee arthroplasty. Clin Orthop Relat Res. 1992;278:128e133. 4. Hagedorn J, Levine BR. Revision surgery for a dislocated constrained total knee arthroplasty. Orthopedics. 2012;35:1099e1103. 5. Mogrgan H, Battista V, Leopold SS. Constraint in primary total knee arthroplasty. J Am Acad Orthop Surg. 2005;13:515e524. 6. Venkataramanan NS, Sinha RK, Crossett LS. Extensor Mechanism Reconstruction after Total Knee Arthroplasty with Achilles Tendon Allograft. Techniques in Knee Surgery. Philadelphia: Lippincott, Williams and Wilkins; 2004:117e121. 7. Crossett LS, Sinha RK, Sechriest VK, et al. Reconstruction of a ruptured patellar tendon with achilles tendon allograft following total knee arthroplasty. J Bone Jt Surg Am. 2004;84:1354e1361. 8. Papalia R, Vasta S, D'Adamio S, et al. Complications involving the extensor mechanism after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2014 [Epub ahead of print]. 9. Busfield BT, Huffman GR, Nahai F, et al. Extended medial gastrocnemius rotational flap for treatment of chronic knee extensor mechanism deficiency in patients with and without total knee arthroplasty. Clin Orthop Relat Res. 2004;428:190e197. 10. Rosenberg AG. Management of extensor mechanism rupture after TKA. J Bone Jt Surg Br. 2012;94:116e119. 11. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop Relat Res. 1989;244:233e238. 12. Mine T, Tanaka H, Taguchi T, et al. Patellar tendon rupture and marked joint instability after total knee arthroplasty. Arch Orthop Trauma Surg. 2004;124: 267e271.