Review Article
Extensor Mechanism Disruption After Total Knee Arthroplasty Abstract Michael D. Bates, MD Bryan D. Springer, MD
Extensor mechanism disruption is a rare and potentially devastating complication associated with total knee arthroplasty. Disruption can occur at the quadriceps or patellar tendons or, in the setting of a fracture, at the patella. Recognition of the risk factors for disruption and prevention via meticulous surgical technique are critical to avoid this complication. Various management techniques and the challenges associated with treatment have been described. Nonsurgical management consists of the use of walking aids and/or knee braces, which may not be acceptable for the active patient. Surgical options include primary repair and reconstructive techniques using allograft, autograft, synthetic material, and gastrocnemius rotational flaps. However, no single method has reliably demonstrated satisfactory outcomes. Although research on reconstructive procedures with synthetic materials has been promising, further study is need to assess the use of these materials.
E
From the Department of Orthopaedic Surgery, Carolinas Medical Center (Dr. Bates) and the Hip and Knee Center, OrthoCarolina (Dr. Springer), Charlotte, NC. Dr. Bates or an immediate family member serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. Dr. Springer or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of DePuy and CeramTec, and serves as a paid consultant to Stryker, ConvaTec, and CardioMEMS. J Am Acad Orthop Surg 2015;23: 95-106 http://dx.doi.org/10.5435/ JAAOS-D-13-00205 Copyright 2015 by the American Academy of Orthopaedic Surgeons.
xtensor mechanism (EM) disruption is an uncommon but potentially devastating complication after total knee arthroplasty (TKA). Disruption can occur at the level of the quadriceps tendon, patella (with fracture), or the patellar tendon.1-3 Inadequate repair of the failed EM invariably leads to significant functional deficits in ambulation that affect the quality of life.2-4 Studies published over the past 40 years have described a wide variety of techniques as well as the challenges associated with treatment. Dismal results associated with primary repair led to the development of reconstructive techniques that have become the primary management method.5-9 Reconstructive techniques using allograft,4-9 autograft,3,10 synthetic material,1,11 and local flaps have been described. No single method has demonstrated stellar results; however, progress has been made with regard to
the evolution and improvement of surgical techniques. The sparse available literature reports the difficulty in achieving satisfactory outcomes.
Incidence and Risk Factors The true incidence of EM disruption may be underreported in the literature. Several national registries fail to report specifically on this mode of failure,12 and much of the reported incidence comes from older studies.1-3,10 The incidence of quadriceps tendon rupture that complicates TKA has ranged from 0.1% to 1.1%,1,13 and the incidence of patellar tendon disruption following TKA has ranged from 0.17%3 to 1.4%.2,10 Several studies have found that the multiply operated knee is a risk factor for EM disruption after TKA.1,8,9,14,15 Two studies reported that patients with EM disruption had undergone, on average, three to four previous
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
95
Extensor Mechanism Disruption After Total Knee Arthroplasty
Figure 1
Illustrations of the vascular structures about the knee demonstrating genicular artery circulation, anterior artery anastomosis (A), and the vascular circle around the patella (B). According to Scapinelli,18 the vascular circle supplies the patella via nutrient arteries that enter predominantly at the inferior pole. The genicular arteries and their branches lie in the most superficial layer of the deep fascia.
knee surgeries before disruption.8,9 Other risk factors for disruption include systemic conditions such as renal disease, diabetes mellitus, rheumatoid arthritis, and obesity.2,14,16 Iatrogenic injury at the time of TKA can also cause EM disruption,8 which often occurs with attempts to gain exposure to the stiff knee. Quadriceps tendon rupture may result from trauma such as a fall or a vascular insult.17 Aggressive resection of the patella may also compromise the insertion of the quadriceps tendon, increasing the risk of rupture. Vascular insult specifically
96
related to the superior lateral genicular artery contributes to the risk, as well2 (Figure 1). In a study of EM disruption following 281 TKAs with patella resurfacing, all three patients with quadriceps tendon rupture had undergone previous lateral retinacular release, which suggests a possible injury to the superior lateral genicular artery.2 The authors concluded that, when performing a lateral retinacular release, the surgeon should stay well lateral to the patella and avoid veering toward the quadriceps tendon proximally to avoid the peripatellar anastamosing vessels and the superior lateral genicular artery.
EM disruption can also occur in the setting of patellar fracture. The risk of patellar fracture after TKA has been well documented;19-21 however, improvements in implant design and surgical technique have led to decreased complication rates.22,23 Iatrogenic factors, such as overresection of the patella, implant malalignment, or disruption of the patellar blood supply, place the patella at increased risk of fracture, and all efforts should be made to avoid creating these risk factors.24 Studies by Tria et al20 and Scott et al21 revealed an increased risk of patellar fracture associated with lateral release. The
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
authors subsequently recommended preserving the superior lateral genicular artery during surgical exposure. Risk factors for patellar tendon disruption after TKA include systemic disease such as rheumatoid arthritis and factors that lead to a stiff knee preoperatively, including revision surgery, previous patellar realignment surgery, and previous high tibial osteotomy. Exposure of the stiff knee can be quite challenging; obtaining patellar eversion and knee flexion intraoperatively places significant strain on the patellar tendon and its insertion. Safer techniques for exposure of the stiff knee include resection of an intra-articular scar and the quadriceps snip.12 The quadriceps snip is similar to the medial parapatellar arthrotomy but differs in that the arthrotomy veers laterally within the quadriceps tendon, dividing it at an angle of approximately 45°. Tibial tubercle osteotomy is also an option for exposure of the stiff knee, but the risk of proximal migration after fixation and tibial fracture must be considered. Some surgeons advocate placing a pin or Kirschner wire through the patellar tendon insertion and into the tibial tubercle during difficult exposures; however, it is uncertain whether this provides much physical protection against tendon avulsion or functions more as a visible reminder to exercise caution throughout the surgery. Some authors have suggested that ruptures that occur within the first few weeks postoperatively are likely associated with the surgical technique, whereas ruptures that occur later are more likely associated with factors that increase patellar strain, such as an elevated joint line.8,10 Sound surgical technique, especially in the stiff knee, cannot be overstressed. Malposition of the implant and knee instability also are contributing factors in the etiology of EM disrup-
tion.8,9,15 Several case series have reported the need for simultaneous component revision in most patients undergoing EM reconstruction (78% to 83%).8,9,15 Common errors that should be avoided include excessive elevation of the joint line, internal rotation of the femoral or tibial components, lateralization of the patellar component, or excessive resection of patellar bone. Because malpositioned components can contribute to EM disruption, it is critical that the surgeon be prepared to revise the tibial or femoral components at the time of EM repair or reconstruction.
Anatomy The EM is composed of the quadriceps tendon, patella, and patellar tendon. The quadriceps tendon is the distal confluence of the quadriceps muscle complex. It has been described as having a trilaminar structure, with the rectus femoris forming the superficial layer, the vastus medialis and vastus lateralis muscles forming the middle layer, and the vastus intermedius muscle forming the deep layer.25,26 The superficial fibers, predominantly from the rectus femoris, continue over the anterior aspect of the patella in continuity with the patellar tendon.26 The patellar tendon is flat, approximately 4 to 6 mm thick,27 and 5 cm long.12 It originates from the inferior pole of the patella and inserts into the tibial tubercle. It is helpful for the surgeon to have an appreciation of the relative amount of force the quadriceps exerts on the rest of the EM during specific activities. Forces across the patellofemoral joint vary substantially based on activity, with forces of approximately 0.5 times the patient’s body weight with walking, approximately 3.1 times body weight with ascending and descending stairs, and 7 times body weight with squatting.28 These relative values help
explain the tremendous force placed across the EM and the importance of a solid reconstruction to permit restoration of knee function. The branches of the genicular arteries, which form a plexus surrounding the patella, are the primary blood supply to the patella and patellar tendon12 (Figure 1). The medial and lateral inferior genicular arteries contribute to vascular pedicles that perfuse the patellar tendon.29 The recurrent anterior tibial artery helps to supply blood to the tendon, as well. Ruptures of the quadriceps tendon in the native knee commonly occur proximal to the superior pole of the patella, which corresponds to a watershed area 1 to 2 cm proximal to the superior pole of the patella.30 This zone of the quadriceps tendon has been shown to be less vascular than the areas immediately adjacent to it.31 The superior lateral genicular artery, which contributes to the blood supply of the patella and distal quadriceps tendon, is of particular clinical importance because of the risk of injury with lateral retinacular release.2 Iatrogenic injury can occur during certain extensile approaches used in revision TKA (eg, V-Y turndown)32 that can disrupt the vascular supply to the EM.33 Techniques such as the quadriceps snip theoretically prevent this risk by avoiding the superior lateral genicular artery.32
Evaluation It is important to assess the patient for factors that can contribute to EM disruption. A thorough history may reveal symptoms that suggest instability or patellar maltracking, making the need for component revision more apparent.12 It is important to evaluate for infection, as well; the C-reactive protein level and erythrocyte sedimentation rate can be used as screening tools.34 Prior radiographs can aid in the evaluation
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
97
Extensor Mechanism Disruption After Total Knee Arthroplasty
ambulating and have a lever to unlock the brace so that it will flex, allowing the patient to sit. Nonsurgical treatment is rarely satisfactory for the active patient; however, for the sedentary, elderly patient, it may be acceptable. Patients who are poor candidates for reconstruction may be better served with bracing or arthrodesis.16
Figure 2
Surgical
Photograph of a whole extensor mechanism allograft before preparation. It is composed of the proximal tibia, patellar tendon, patella, and several centimeters of the quadriceps tendon. The bone plug from the proximal tibia will be removed in a reverse dovetail fashion, which results in a proximally directed apex on the resultant bone plug. This apex will fit with a corresponding recess fashioned into the host proximal tibia.
of component position as well as assessment of component migration over time.12 In addition to radiography, CT can provide detailed information regarding rotational malalignment of the femoral or tibial component.35 Lastly, the surgeon should determine whether EM reconstruction is appropriate for the patient. Patients who are unable to comply with the relatively lengthy and stringent postoperative protocols7-11,15,17 should not undergo reconstruction. Absolute contraindications include active periprosthetic infection and inability to withstand surgery.
Management Nonsurgical Nonsurgical management of a deficient EM requires the patient to depend on walking aids and/or knee braces (eg, drop lock braces).3 These braces lock into extension when the patient is
98
Primary Repair Although successful results of primary repair of EM disruption in the native knee have been reported,36 management of EM disruptions following TKA is fraught with substantial complications, and largely marginal results have been reported. Rand et al3 performed primary repair for patellar tendon rupture using a variety of fixation methods, including suture fixation and staple fixation. The authors reported poor results with both of these techniques. Because outcomes associated with primary repair have been poor, the technique has largely been abandoned. However, these outcomes spurred interest in alternative techniques for reconstructing the EM. Reconstruction With Allograft or Autograft Most of the literature on reconstruction for EM disruption focuses on reconstruction using allograft, with modestly successful outcomes reported.2,3,6-10 However, several early studies reported that a significant number of patients had residual extensor lags, unacceptable range of motion (ROM), or dependence on assistive devices for ambulation and management of persistent instability.4,7,9 Two primary forms of allograft are used for EM reconstruction: Achilles tendon allograft and whole EM allograft.16 The first graft is composed of the Achilles tendon and a bone block of the calcaneus, whereas the whole EM allograft is composed of
the proximal tibia, patellar tendon, patella, and several centimeters of the quadriceps tendon16 (Figure 2). Whole EM allografts are used routinely for reconstruction, but these grafts are particularly helpful when the patient has a deficient patella or if the patella cannot be mobilized to within 3 to 4 cm of the joint line.16 Achilles tendon allografts can be used when the patella and patellar component are intact and the patella can be mobilized to within 3 to 4 cm of the joint line.6,16 Because of its increased length, Achilles tendon allograft can also be used for chronic quadriceps tendon rupture associated with significant proximal retraction.6,16 Regardless of which type of allograft is used, it should be fresh-frozen; inferior results have been reported with the use of freeze-dried grafts.5 Reconstruction with Achilles tendon allograft has evolved over the last three decades. The basic procedure9 involves the creation of a rectangular trough in the host proximal tibia to receive the calcaneal bone block of the allograft, which is contoured to fit the trough. The trough is slightly medial and distal to the tibial tubercle. The bone plug is press-fit into the trough and secured with wire or screw fixation. The tendinous portion of the allograft is pulled proximally and sutured to the underlying native EM tissue. It is critical that the graft be tensioned tightly with the knee in full extension to prevent postoperative extensor lag.7 The subcutaneous tissues and skin are then closed over the allograft. Postoperatively, the patient should be immobilized with the knee in full extension and casted for at least 6 to 8 weeks before beginning any ROM.4,6-8 When an entire EM allograft is used, a midline incision is created to expose the host EM.36 A midline incision is made through the quadriceps and patellar tendons, and a midline bisection of the patella is performed with a saw, essentially splitting the host
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
Figure 3
Illustration of the lateral view of the allograft bone (A), which is marked to outline the rectangular cut (inset). B, Illustration of rectangular bone plug cut in reverse dovetail fashion.
EM into medial and lateral halves. The patellar remnants are subsequently resected. The tibial component of the allograft is fashioned into a rectangular block and a reverse dovetail cut is made. The block is then placed into a corresponding trough cut into the proximal tibia (Figure 3). The allograft is drawn proximally under the host quadriceps using heavy, nonabsorbable suture. Simultaneously, heavy sutures are used to the pull the host quadriceps distally to create maximal tension. The allograft is then sutured to the overlying host quadriceps with heavy nonabsorbable suture. The previously elevated medial and lateral flaps of the host EM are then closed over the allograft, and closure of the subcutaneous tissue and skin is performed. Postoperatively, the knee is immobi-
lized in a cast in full extension or hyperextension for at least 6 to 8 weeks before any ROM is initiated. It should be noted that the allograft patella is not resurfaced, and the graft is sutured in place under maximal tension.5,7,8 The use of autograft for EM reconstruction with various techniques has been reported in the literature.3,10,37 The semitendinosus tendon is one of the more commonly used structures. Cadambi and Engh10 described a technique that involved a posteromedial incision through which the semitendinosus tendon is divided at its musculotendinous junction in addition to the standard midline incision used for knee arthroplasty. The distal tibial attachment of the tendon is preserved. After the free end of the proximal tendon is subcutaneously brought
through the anterior wound, it is tunneled through a 5-mm drill hole in the patella that was made transversely in a medial-to-lateral direction. The free end of the tibia is then secured to itself or to the proximal tibia. In some instances, the gracilis is used to augment the semitendinosus tendon.
Reconstruction With Synthetic Material Browne and Hanssen11 reported on a reconstruction technique in which Marlex mesh (C.R. Bard) is used instead of allograft tissue. The authors cited several concerns regarding allograft tissue, including cost, availability, disease transmission, and stretching of the tissue over time. The technique involves approaching
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
99
Extensor Mechanism Disruption After Total Knee Arthroplasty
Figure 4
A through G, Illustrations demonstrating the Marlex mesh (C.R. Bard) reconstruction technique described by Browne and Hanssen.11 A, If the tibial component is retained, a burr is used to create a trough for the mesh graft in the anteromedial aspect of the tibia. B, The graft is inserted into this trough and secured with polymethyl methacrylate, a transfixion screw, and washer. C, A laterally based flap of host tissue is elevated and interposed between the graft and the polyethylene, with the tissue secured to the medial soft tissue and the undersurface of the mesh. D, A portal is created in the lateral soft tissues to facilitate graft delivery from deep to superficial in relation to the extensor retinaculum and patella. E, To restore patellar height, the surgeon mobilizes and advances the patella and the quadriceps tendon. The surgeon then sutures the graft to the lateral retinaculum, vastus lateralis, and quadriceps tendon. Redundant mesh may be removed proximally. F, The vastus medialis muscle and medial retinaculum are mobilized to allow these medial soft tissues to advance in an overlapping manner (inset) over the mesh graft. The inset image demonstrates the envelopment of the graft by the vastus lateralis (deep) and the vastus medialis (superficial) muscles at the level of the distal femur. The construct is secured with suture. G, The distal arthrotomy is closed, completely covering the mesh graft with soft tissue. (Reproduced with permission from Browne JA, Hanssen AD: Reconstruction of patellar tendon disruption after total knee arthroplasty: Results of a new technique utilizing synthetic mesh. J Bone Joint Surg Am 2011;93[12]:1137-1143.)
the knee through a medial parapatellar arthrotomy and developing full-thickness subcutaneous flaps medially and laterally to expose the
100
EM (Figure 4). The distal end of the synthetic mesh construct is secured to a trough in the proximal tibia using cement and screw fixation. The
proximal end of the mesh is then tunneled from deep to superficial on the lateral aspect of the host patellar tendon and subsequently sutured to
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
the quadriceps tendon proximally. The entire graft is ultimately covered with the medial and lateral flaps of the host tissue. After surgery, the knee is immobilized in a long leg cast for 6 to 8 weeks, with only touchdown weight bearing allowed. Gastrocnemius Rotational Flaps Jaureguito et al15 and Busfield et al38 reported on the use of medial gastrocnemius rotational flaps for reconstruction of the EM. The technique involves mobilizing the medial half of the gastrocnemius muscle to cover the proximal anterior aspect of the tibia, thus serving as an anchor point to which the residual EM can be secured.15 The distal extent of the mobilization is the musculotendinous junction of the Achilles tendon. The extended medial gastrocnemius flap is a variation of the procedure in which the medial one third to one half of the tendon is mobilized with the muscle38 (Figure 5). The added length provided by the Achilles tendon allows reconstruction of more proximally disrupted EMs (eg, quadriceps tendon rupture).38 After EM reconstruction, postoperative management typically involves immobilization in a long leg cast for 6 to 8 weeks because extensor lag tends to be more of a concern than stiffness.7-11,15,17 The immobilization period is typically followed by a gradual increase in the amount of active knee flexion with the assistance of a hinged knee brace (HKB) over several weeks.7,8,10,11,15-17 Passive flexion is typically avoided to prevent damage to the reconstructed EM.16 At the senior author’s (B.D.S.) institution, the HKB is discontinued once the knee has reached 90° of flexion. Outcomes Limited literature on EM disruption is available. Although there are no randomized controlled trials comparing treatment methods, small retro-
Figure 5
A through C, Illustrations of the posterior aspect of the lower extremity demonstrating the use of gastrocnemius rotational flaps for reconstruction of the extensor mechanism. A, The medial half of the gastrocnemius muscle is released from the remaining muscle. B, The gastrocnemius muscle belly is tunneled subcutaneously around the medial border of the tibia. C, The fascia of the gastrocnemius is secured to the anterior tibial periosteum. In the extended technique, the Achilles tendon is then sutured to the distal aspect of the quadriceps tendon.
spective series and case reports are available.1-11,13-15,38-40 The largest reported series8 had only 36 patients, and many other studies have ,10 patients.1,4,10,14,15,38,39 The limitations of the literature highlight the complexity of this uncommon problem. Primary Repair Poor results of primary repair of EM disruption have been consistently reported2,3,13 (Table 1). Lynch et al2 reported on seven patients who underwent primary repair for disruption of the patellar tendon (three patients) or quadriceps tendon (four patients). All patients had poor results. The failure rate was a result of the unacceptable extensor lag and/or limited knee flexion in six patients and
deep infection in one patient. Two additional studies3,13 reviewed the outcomes of primary repair in a total of 23 patients; 21 patients had clinical failures, which were commonly caused by rerupture of the EM. In contrast, Abril et al reported39 positive results in two of two patients with patellar tendon disruption treated with primary suture repair and a wire tension band construct for reinforcement. Follow-up was 21 months. Similarly, a good functional outcome at 1 year postoperatively was reported in another case report.17 The patient was treated with primary suture repair augmented with Dacron tape. These positive short-term results should be considered outliers compared with the otherwise poor results
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
101
Extensor Mechanism Disruption After Total Knee Arthroplasty
Table 1 Outcomes of Primary Repair of Extensor Mechanism Disruption No. of Patients
Followup (mo)
Technique
Immobilization
Lynch et al2
7a
42
NR
NR
Rand et al3
16
42
Dobbs et al13
10
34
FernandezBaillo et al17
1
12
Reconstruction with suture, staples, xenograft, or semitendinosus graft Tensioning method not reported. 8 patients had standard primary repair, 2 patients had primary repair augmented with synthetic mesh Suture repair and Dacron tape reinforcement
Abril et al39
2
21
Study
Outcomes
Ext lag: 5 patients (21°); ROM: NR; Ambulation with aid: NR; Complications: 3 patients (43%) Cast immobilization in 11 Ext lag: NR; ROM: NR; patients for 5.5 wkb Ambulation with aid: 14 patients (82%); Complications: 12 patients (75%) NR Ext lag: NR; ROM: 3°-101°; Ambulation with aid: NR; Complications: 6 patients (60%) Long leg cast for 6 wk in full extension
No immobilization Wire tension band reinforcement placed at 45° flexion
Ext lag: 0; Flex: 110°; Ambulation with aid: 0; Complications: 0 Ext lag: 0; Flex: 87°; Ambulation with aid: 0; Complications: 0
Ext = extensor, Flex = flexion, NR = not reported, ROM = range of motion a Excluding those with patella fractures b Degree of extension or tensioning not reported.
associated with primary repair of EM disruption after TKA.
Reconstruction With Allograft or Autograft Allograft reconstruction has the potential to improve EM function, augment host tissue, maintain ROM, and decrease dependence on walking aids. The incidence of many of the complications reported in earlier studies, including progressive extensor lag, poor ROM, and rerupture, decreased in later studies because surgical technique and postoperative regimens were refined, which contributed to improved clinical outcomes associated with the evolution of allograft reconstruction for EM reconstruction7 (Table 2). Despite the known limitations of the procedure, outcomes of allograft reconstruction have been substantially better than those of primary repair, and
102
allograft reconstruction comprises the bulk of the literature with regard to EM repair techniques.4-9,14,40,41 However, outcomes of this technique vary.4,5 Emerson et al5 reported marginal outcomes in nine patients treated with entire EM allografts in which the patella was resurfaced. At an average follow-up of 4 years, three patients had persistent extensor lags, three had flexion contractures, and four required walking aids. Notably, the allografts were sutured to the host tissue under slight tension, a technique that has fallen out of favor. In an effort to minimize extensor lag, immobilizing patients in full extension or even hyperextension is currently recommended.7 Emerson et al5 also realized that resurfacing the allograft patella was unnecessary because it is insensate, and they recommended against the practice. Later studies would incorporate these two modifications in technique.6-8,41
Leopold et al4 reported on the use of whole EM allografts in six patients. Similar to Emerson et al,5 the authors did not resurface the patella and used only fresh-frozen allografts; however, they also failed to tension the grafts with the knee in full extension. All of the procedures were deemed clinical failures; the average extensor lag was 59° and most patients required ambulatory aids. This study is the last published report in which grafts were not tensioned with the knee in full extension. The authors postulated that improving the intraoperative tension may lead to improved outcomes, which was later shown in the comparative study by Burnett et al.7 This retrospective study compared the outcomes of patients with minimally tensioned allografts with those of patients with maximally tensioned allografts.7 The authors reported markedly improved results in the
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
Table 2 Outcomes of Allograft Reconstruction for Extensor Mechanism Disruption Study
No. of Patients
Follow-up (mo)
Leopold et al4
6
39
Sutured under slight Knee brace, full extension 6–8 wk tension with knee fully extended
Emerson et al5
9
49.2
Minimal. Knee flexed Motion after wound intraoperatively healed
Barrack et al6
14
42
Burnett et al7
20 total; 7 minimal tension group, 13 maximal tension group
38 minimal tension group, 37 maximal tension group
Tensioning Method
Entire ext mechanism sewn to quadriceps tendon under tension, with the knee flexed 30°. Achilles allograft with knee fully extended Minimal tension group: knee flexed intraoperatively
Maximal tension group: knee fully extended
Nazarian and Booth8
36
43.2
Crossett9
9
28
Maximally tensioned, knee fully extended
“Tendon taut/ unwrinkled,” knee fully extended
Immobilization
4 wk splint, with the knee flexed 0°, 4 wk with the knee flexed 45°, 8 wk with the knee flexed 90°
Outcomes Ext lag: 7 patients (59°) ROM: NR Ambulation with aids: 6 patients (86%) Complications: 4 patients (57%) Ext lag: 3 patients (28°) ROM: 3.8°–106° Ambulation with aids: 4 patients (44%) Complications: 5 patients (56%) Ext lag: NR Flex: 98° Ambulation with aids: 7 patients (50%) Complications: 1 patient (7%)
Minimal tension Minimal tension group group Ext lag: 59° Brace with knee Flex: 108° flexed 0° for 6–8 Ambulation with wk, then aids: 5 patients progressive (83%) ROM to 90°. Complications: 6 knees (86%) Maximal tension Maximal tension group group: Ext lag: 4.3° Cast with knee Flex: 104° flexed 0° for 8 Ambulation with wk, then ROM to aids: 4 patients 30° for 4 wk, then (31%) progressive Complications: 3 ROM to 90° at 12 patients (23%) wk Cast 6 wk, HKB 6 wk Ext lag: 15 patients (31°) with knee flexed ROM: 1.4°– 98° 0°–30° Ambulation with aids: 12 patients (33%) Complications: 8 patients (22%) 4 wk HKB with knee Ext lag: 3 patients flexed 0°, 4 wk HKB (10°) ROM: 1.7°–108° with knee flexed 0°–40°, 4 wk HKB Ambulation with aids: 8 patients (89%) with knee flexed Complications: 3 0°–90° patients (33%)
Ext =extensor, Flex = flexion, HKB = hinged knee brace, NR = not reported, ROM = range of motion
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
103
Extensor Mechanism Disruption After Total Knee Arthroplasty
maximal tension group. In the first group, the seven patients who had a minimally tensioned allograft had an average extensor lag of 59° and Hospital for Special Surgery (HSS) scores of 52. In the second group, 13 patients had a maximally tensioned allograft. The average extensor lag was 4.3° and the average HSS score was 88, both of which were statistically significant differences (P , 0.0001). Immobilizing the knee in full extension (or hyperextension) remains a critical component of the technique today. Nazarian and Booth8 modified the technique by using maximal tensioning of the fresh-frozen whole EM allograft with the knee fully extended, and flexion was avoided intraoperatively after the graft was tensioned. The knees were immobilized in full extension in a cast for 6 weeks followed by limited motion (0° to 30°) in a HKB for an additional 6 weeks. Successful outcomes were reported in 34 of 36 patients, although 8 patients had to undergo revision reconstruction of the EM due to graft rupture. Most patients did not have an extensor lag. In the literature, limited success has been reported with the use of autograft for EM reconstruction.3,10,37 The largest study included only seven patients treated with semitendinosus reconstruction using an autograft, with an average follow-up of 2.5 years.10 The knees were immobilized in a cast or knee immobilizer for 6 weeks and then a HKB for 6 weeks. The authors reported an average postoperative knee flexion of 80°, and 5 patients had extensor lag. Rand et al3 and Gustillo and Thompson37 each reported on one patient treated with semitendinosus reconstruction of the EM using autograft. Both procedures were clinical failures. In general, local autograft reconstruction in the patient with chronic disruption of the EM is avoided because of the lack of good host tissue.
104
Reconstruction With Synthetic Material Decreased cost, decreased risk of disease transmission, and availability of synthetic material for EM reconstruction are attractive potential benefits of reconstruction with synthetic material. Reports on the use of synthetic material for reconstruction of the EM are limited to two studies with short-term follow-up.1,11 Aracil et al1 reported fair results with the use of synthetic material for primary repair of the EM augmented with woven polyester ligament in five patients, although the incidence of extensor lag was not reported. Postoperative ROM was 99°. Browne and Hanssen11 provided the most compelling evidence to date to support the use of synthetic material. Of 13 patients who underwent patellar ligament reconstruction (without primary repair) using synthetic polypropylene mesh, 5 with no prior EM reconstruction had marked improvement in extensor lag at an average follow-up of 42 months. Seven patients had undergone previous failed attempts at reconstruction with allograft. In these patients, four complications were reported: three sustained graft failure within 6 months and 1 developed infection that required knee arthrodesis. Notably, there was no gradual stretching out of the graft noted in patients treated with the mesh, a problem that was reported in several earlier studies of allograft reconstruction.4,5 Further research on this relatively inexpensive treatment method is warranted in light of the results obtained. Gastrocnemius Rotational Flaps Gastrocnemius rotational flap reconstruction has typically been used for soft-tissue coverage of the knee. However, its use for EM reconstruction also has been studied, with modest results reported in two studies.15,38 Benefits of the technique include its ability to provide concomitant soft-
tissue coverage of the knee, the beneficial vascularity of muscle, and the lack of dependence on the quality of the patellar bone, as is required for the semitendinosus reconstruction technique.10 The use of gastrocnemius rotational flaps also plays a critical role in orthopaedic oncology because it allows reconstruction of the EM in patients who have undergone resection of the proximal tibia.15 Jaureguito et al15 reported overall positive outcomes at a mean 33-month follow-up in six patients treated with gastrocnemius flap (4 patients) or an extended gastrocnemius flap (2 patients), with an average ROM of 103° reported. Busfield et al38 used an extended gastrocnemius flap in five TKA patients, most of whom were undergoing a revision of a previous failed allograft reconstruction. At an average 21-month follow-up, all of the patients were able to ambulate independently, and only one had an unacceptable extensor lag of 50˚. The authors concluded that extended medial gastrocnemius flap reconstruction was a viable option for revision of EM reconstruction.
Summary EM disruption is a severe complication of TKA. Although this complication is rare, it rivals infection as the most devastating outcome after TKA.12 Recognition of the risk factors for EM disruption and a focus on preventive efforts through meticulous surgical exposure and technique are paramount. The variety of management options available highlights the lack of consistently satisfactory results from any single treatment method. Primary repair has resulted in consistently poor outcomes and is not typically indicated.2,3,13 Reconstruction using allograft presently remains the most studied technique.4-9,14,40,41 The importance of appropriate
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
surgical technique and maximal allograft tensioning when attempting reconstruction cannot be overemphasized. Research into the use of synthetic materials for reconstruction of EM disruptions offers promise, but more data are needed to fully evaluate the use of these materials.
References Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 22 and 23 are level I studies. Reference 14 is a level II study. References 7 and 19 are level III studies. References 1-6, 8-13, 15-17, 19, 21, 24-41 are level IV studies. References printed in bold type are those published within the past 5 years. 1. Aracil J, Salom M, Aroca JE, Torro V, Lopez-Quiles D: Extensor apparatus reconstruction with Leeds-Keio ligament in total knee arthroplasty. J Arthroplasty 1999;14(2):204-208. 2. Lynch AF, Rorabeck CH, Bourne RB: Extensor mechanism complications following total knee arthroplasty. J Arthroplasty 1987;2(2):135-140. 3. Rand JA, Morrey BF, Bryan RS: Patellar tendon rupture after total knee arthroplasty. Clin Orthop Relat Res 1989; 244:233-238. 4. Leopold SS, Greidanus N, Paprosky WG, Berger RA, Rosenberg AG: High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg Am 1999; 81(11):1574-1579. 5. Emerson RH Jr, Head WC, Malinin TI: Extensor mechanism reconstruction with an allograft after total knee arthroplasty. Clin Orthop Relat Res 1994;303:79-85. 6. Barrack RL, Stanley T, Allen Butler R: Treating extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res 2003;416:98-104. 7. Burnett RS, Berger RA, Paprosky WG, Della Valle CJ, Jacobs JJ, Rosenberg AG: Extensor mechanism allograft reconstruction after total knee arthroplasty: A comparison of two techniques. J Bone Joint Surg Am 2004;86:2694-2699. 8. Nazarian DG, Booth RE Jr: Extensor mechanism allografts in total knee
arthroplasty. Clin Orthop Relat Res 1999; 367:123-129. 9. Crossett LS, Sinha RK, Sechriest VF, Rubash HE: Reconstruction of a ruptured patellar tendon with achilles tendon allograft following total knee arthroplasty. J Bone Joint Surg Am 2002;84(8): 1354-1361. 10. 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 Am 1992;74(7): 974-979. 11. Browne JA, Hanssen AD: Reconstruction of patellar tendon disruption after total knee arthroplasty: Results of a new technique utilizing synthetic mesh. J Bone Joint Surg Am 2011;93(12): 1137-1143. 12. Scott WN: Insall and Scott Surgery of the Knee. Philadelphia, PA, Elsevier Health Sciences, 2011. 13. Dobbs RE, Hanssen AD, Lewallen DG, Pagnano MW: Quadriceps tendon rupture after total knee arthroplasty: Prevalence, complications, and outcomes. J Bone Joint Surg Am 2005;87(1):37-45. 14. Schoderbek RJ Jr, Brown TE, Mulhall KJ, et al: Extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res 2006;446:176-185. 15. Jaureguito JW, Dubois CM, Smith SR, Gottlieb LJ, Finn HA: Medial gastrocnemius transposition flap for the treatment of disruption of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg Am 1997;79(6):866-873. 16. Springer BD, Della Valle CJ: Extensor mechanism allograft reconstruction after total knee arthroplasty. J Arthroplasty 2008;23(7 suppl):35-38. 17. Fernandez-Baillo N, Garay EG, Ordoñez JM: Rupture of the quadriceps tendon after total knee arthroplasty: A case report. J Arthroplasty 1993;8(3):331-333. 18. Scapinelli R: Blood supply of the human patella: Its relation to ischaemic necrosis after fracture. J Bone Joint Surg Br 1967;49 (3):563-570. 19. Grace JN, Sim FH: Fracture of the patella after total knee arthroplasty. Clin Orthop Relat Res 1988;230:168-175. 20. Tria AJ Jr, Harwood DA, Alicea JA, Cody RP: Patellar fractures in posterior stabilized knee arthroplasties. Clin Orthop Relat Res 1994;299:131-138. 21. Scott RD, Turoff N, Ewald FC: Stress fracture of the patella following duopatellar total knee arthroplasty with patellar resurfacing. Clin Orthop Relat Res 1982; 170:147-151. 22. Wood DJ, Smith AJ, Collopy D, White B, Brankov B, Bulsara MK: Patellar
resurfacing in total knee arthroplasty: A prospective, randomized trial. J Bone Joint Surg Am 2002;84(2):187-193. 23. Waters TS, Bentley G: Patellar resurfacing in total knee arthroplasty: A prospective, randomized study. J Bone Joint Surg Am 2003;85(2):212-217. 24. Ortiguera CJ, Berry DJ: Patellar fracture after total knee arthroplasty. J Bone Joint Surg Am 2002;84 (4):532-540. 25. Last RJ: Some anatomical details of the knee joint. J Bone Joint Surg Br 1948;30B (4):683-688. 26. Reider B, Marshall JL, Koslin B, Ring B, Girgis FG: The anterior aspect of the knee joint. J Bone Joint Surg Am 1981;63(3): 351-356. 27.
Rodríguez-Merchán EC: Traumatic Injuries of the Knee. Milan, Italy, SpringerVerlag Italia, 2013.
28. Reilly DT, Martens M: Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthop Scand 1972; 43(2):126-137. 29. Soldado F, Reina F, Yuguero M, Rodríguez-Baeza A: Clinical anatomy of the arterial supply of the human patellar ligament. Surg Radiol Anat 2002;24(3-4): 177-182. 30. Scuderi C: Ruptures of the quadriceps tendon: Study of twenty tendon ruptures. Am J Surg 1958;95(4):626-635. 31. Yepes H, Tang M, Morris SF, Stanish WD: Relationship between hypovascular zones and patterns of ruptures of the quadriceps tendon. J Bone Joint Surg Am 2008;90(10): 2135-2141. 32. Barrack RL: Specialized surgical exposure for revision total knee: Quadriceps snip and patellar turndown. Instr Course Lect 1999; 48:149-152. 33. Scott RD, Siliski JM: The use of a modified V-Y quadricepsplasty during total knee replacement to gain exposure and improve flexion in the ankylosed knee. Orthopedics 1985;8(1):45-48. 34. Della Valle C, Parvizi J, Bauer TW, et al; American Academy of Orthopaedic Surgeons: Diagnosis of periprosthetic joint infections of the hip and knee. J Am Acad Orthop Surg 2010;18(12):760-770. 35. Berger RA, Crossett LS, Jacobs JJ, Rubash HE: Malrotation causing patellofemoral complications after total knee arthroplasty. Clin Orthop Relat Res 1998;356:144-153. 36. Siwek CW, Rao JP: Ruptures of the extensor mechanism of the knee joint. J Bone Joint Surg Am 1981;63(6): 932-937. 37. Gustillo RB, Thompson R: Quadriceps and patellar tendon ruptures
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
105
Extensor Mechanism Disruption After Total Knee Arthroplasty following total knee arthroplasty, in Rand JA, Dorr LD, eds: Total Arthroplasty of the Knee: Proceedings of the Knee Society, 1985-1986. Rockville, MD, Aspen Publishers, 1987, pp 41–47. 38. Busfield BT, Huffman GR, Nahai F, Hoffman W, Ries MD: Extended medial gastrocnemius rotational flap for
106
treatment of chronic knee extensor mechanism deficiency in patients with and without total knee arthroplasty. Clin Orthop Relat Res 2004;428: 190-197.
40. Emerson RH Jr, Head WC, Malinin TI: Reconstruction of patellar tendon rupture after total knee arthroplasty with an extensor mechanism allograft. Clin Orthop Relat Res 1990;260:154-161.
39. Abril JC, Alvarez L, Vallejo JC: Patellar tendon avulsion after total knee arthroplasty. A new technique. J Arthroplasty 1995;10(3):275-279.
41. Burnett RS, Berger RA, Della Valle CJ, et al: Extensor mechanism allograft reconstruction after total knee arthroplasty. J Bone Joint Surg Am 2005;87(suppl 1, pt 2):175-194.
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Extensor Mechanism Disruption After Total Knee Arthroplasty Abstract Michael D. Bates, MD Bryan D. Springer, MD
Extensor mechanism disruption is a rare and potentially devastating complication associated with total knee arthroplasty. Disruption can occur at the quadriceps or patellar tendons or, in the setting of a fracture, at the patella. Recognition of the risk factors for disruption and prevention via meticulous surgical technique are critical to avoid this complication. Various management techniques and the challenges associated with treatment have been described. Nonsurgical management consists of the use of walking aids and/or knee braces, which may not be acceptable for the active patient. Surgical options include primary repair and reconstructive techniques using allograft, autograft, synthetic material, and gastrocnemius rotational flaps. However, no single method has reliably demonstrated satisfactory outcomes. Although research on reconstructive procedures with synthetic materials has been promising, further study is need to assess the use of these materials.
E
From the Department of Orthopaedic Surgery, Carolinas Medical Center (Dr. Bates) and the Hip and Knee Center, OrthoCarolina (Dr. Springer), Charlotte, NC. Dr. Bates or an immediate family member serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. Dr. Springer or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of DePuy and CeramTec, and serves as a paid consultant to Stryker, ConvaTec, and CardioMEMS. J Am Acad Orthop Surg 2015;23: 95-106 http://dx.doi.org/10.5435/ JAAOS-D-13-00205 Copyright 2015 by the American Academy of Orthopaedic Surgeons.
xtensor mechanism (EM) disruption is an uncommon but potentially devastating complication after total knee arthroplasty (TKA). Disruption can occur at the level of the quadriceps tendon, patella (with fracture), or the patellar tendon.1-3 Inadequate repair of the failed EM invariably leads to significant functional deficits in ambulation that affect the quality of life.2-4 Studies published over the past 40 years have described a wide variety of techniques as well as the challenges associated with treatment. Dismal results associated with primary repair led to the development of reconstructive techniques that have become the primary management method.5-9 Reconstructive techniques using allograft,4-9 autograft,3,10 synthetic material,1,11 and local flaps have been described. No single method has demonstrated stellar results; however, progress has been made with regard to
the evolution and improvement of surgical techniques. The sparse available literature reports the difficulty in achieving satisfactory outcomes.
Incidence and Risk Factors The true incidence of EM disruption may be underreported in the literature. Several national registries fail to report specifically on this mode of failure,12 and much of the reported incidence comes from older studies.1-3,10 The incidence of quadriceps tendon rupture that complicates TKA has ranged from 0.1% to 1.1%,1,13 and the incidence of patellar tendon disruption following TKA has ranged from 0.17%3 to 1.4%.2,10 Several studies have found that the multiply operated knee is a risk factor for EM disruption after TKA.1,8,9,14,15 Two studies reported that patients with EM disruption had undergone, on average, three to four previous
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
95
Extensor Mechanism Disruption After Total Knee Arthroplasty
Figure 1
Illustrations of the vascular structures about the knee demonstrating genicular artery circulation, anterior artery anastomosis (A), and the vascular circle around the patella (B). According to Scapinelli,18 the vascular circle supplies the patella via nutrient arteries that enter predominantly at the inferior pole. The genicular arteries and their branches lie in the most superficial layer of the deep fascia.
knee surgeries before disruption.8,9 Other risk factors for disruption include systemic conditions such as renal disease, diabetes mellitus, rheumatoid arthritis, and obesity.2,14,16 Iatrogenic injury at the time of TKA can also cause EM disruption,8 which often occurs with attempts to gain exposure to the stiff knee. Quadriceps tendon rupture may result from trauma such as a fall or a vascular insult.17 Aggressive resection of the patella may also compromise the insertion of the quadriceps tendon, increasing the risk of rupture. Vascular insult specifically
96
related to the superior lateral genicular artery contributes to the risk, as well2 (Figure 1). In a study of EM disruption following 281 TKAs with patella resurfacing, all three patients with quadriceps tendon rupture had undergone previous lateral retinacular release, which suggests a possible injury to the superior lateral genicular artery.2 The authors concluded that, when performing a lateral retinacular release, the surgeon should stay well lateral to the patella and avoid veering toward the quadriceps tendon proximally to avoid the peripatellar anastamosing vessels and the superior lateral genicular artery.
EM disruption can also occur in the setting of patellar fracture. The risk of patellar fracture after TKA has been well documented;19-21 however, improvements in implant design and surgical technique have led to decreased complication rates.22,23 Iatrogenic factors, such as overresection of the patella, implant malalignment, or disruption of the patellar blood supply, place the patella at increased risk of fracture, and all efforts should be made to avoid creating these risk factors.24 Studies by Tria et al20 and Scott et al21 revealed an increased risk of patellar fracture associated with lateral release. The
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
authors subsequently recommended preserving the superior lateral genicular artery during surgical exposure. Risk factors for patellar tendon disruption after TKA include systemic disease such as rheumatoid arthritis and factors that lead to a stiff knee preoperatively, including revision surgery, previous patellar realignment surgery, and previous high tibial osteotomy. Exposure of the stiff knee can be quite challenging; obtaining patellar eversion and knee flexion intraoperatively places significant strain on the patellar tendon and its insertion. Safer techniques for exposure of the stiff knee include resection of an intra-articular scar and the quadriceps snip.12 The quadriceps snip is similar to the medial parapatellar arthrotomy but differs in that the arthrotomy veers laterally within the quadriceps tendon, dividing it at an angle of approximately 45°. Tibial tubercle osteotomy is also an option for exposure of the stiff knee, but the risk of proximal migration after fixation and tibial fracture must be considered. Some surgeons advocate placing a pin or Kirschner wire through the patellar tendon insertion and into the tibial tubercle during difficult exposures; however, it is uncertain whether this provides much physical protection against tendon avulsion or functions more as a visible reminder to exercise caution throughout the surgery. Some authors have suggested that ruptures that occur within the first few weeks postoperatively are likely associated with the surgical technique, whereas ruptures that occur later are more likely associated with factors that increase patellar strain, such as an elevated joint line.8,10 Sound surgical technique, especially in the stiff knee, cannot be overstressed. Malposition of the implant and knee instability also are contributing factors in the etiology of EM disrup-
tion.8,9,15 Several case series have reported the need for simultaneous component revision in most patients undergoing EM reconstruction (78% to 83%).8,9,15 Common errors that should be avoided include excessive elevation of the joint line, internal rotation of the femoral or tibial components, lateralization of the patellar component, or excessive resection of patellar bone. Because malpositioned components can contribute to EM disruption, it is critical that the surgeon be prepared to revise the tibial or femoral components at the time of EM repair or reconstruction.
Anatomy The EM is composed of the quadriceps tendon, patella, and patellar tendon. The quadriceps tendon is the distal confluence of the quadriceps muscle complex. It has been described as having a trilaminar structure, with the rectus femoris forming the superficial layer, the vastus medialis and vastus lateralis muscles forming the middle layer, and the vastus intermedius muscle forming the deep layer.25,26 The superficial fibers, predominantly from the rectus femoris, continue over the anterior aspect of the patella in continuity with the patellar tendon.26 The patellar tendon is flat, approximately 4 to 6 mm thick,27 and 5 cm long.12 It originates from the inferior pole of the patella and inserts into the tibial tubercle. It is helpful for the surgeon to have an appreciation of the relative amount of force the quadriceps exerts on the rest of the EM during specific activities. Forces across the patellofemoral joint vary substantially based on activity, with forces of approximately 0.5 times the patient’s body weight with walking, approximately 3.1 times body weight with ascending and descending stairs, and 7 times body weight with squatting.28 These relative values help
explain the tremendous force placed across the EM and the importance of a solid reconstruction to permit restoration of knee function. The branches of the genicular arteries, which form a plexus surrounding the patella, are the primary blood supply to the patella and patellar tendon12 (Figure 1). The medial and lateral inferior genicular arteries contribute to vascular pedicles that perfuse the patellar tendon.29 The recurrent anterior tibial artery helps to supply blood to the tendon, as well. Ruptures of the quadriceps tendon in the native knee commonly occur proximal to the superior pole of the patella, which corresponds to a watershed area 1 to 2 cm proximal to the superior pole of the patella.30 This zone of the quadriceps tendon has been shown to be less vascular than the areas immediately adjacent to it.31 The superior lateral genicular artery, which contributes to the blood supply of the patella and distal quadriceps tendon, is of particular clinical importance because of the risk of injury with lateral retinacular release.2 Iatrogenic injury can occur during certain extensile approaches used in revision TKA (eg, V-Y turndown)32 that can disrupt the vascular supply to the EM.33 Techniques such as the quadriceps snip theoretically prevent this risk by avoiding the superior lateral genicular artery.32
Evaluation It is important to assess the patient for factors that can contribute to EM disruption. A thorough history may reveal symptoms that suggest instability or patellar maltracking, making the need for component revision more apparent.12 It is important to evaluate for infection, as well; the C-reactive protein level and erythrocyte sedimentation rate can be used as screening tools.34 Prior radiographs can aid in the evaluation
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
97
Extensor Mechanism Disruption After Total Knee Arthroplasty
ambulating and have a lever to unlock the brace so that it will flex, allowing the patient to sit. Nonsurgical treatment is rarely satisfactory for the active patient; however, for the sedentary, elderly patient, it may be acceptable. Patients who are poor candidates for reconstruction may be better served with bracing or arthrodesis.16
Figure 2
Surgical
Photograph of a whole extensor mechanism allograft before preparation. It is composed of the proximal tibia, patellar tendon, patella, and several centimeters of the quadriceps tendon. The bone plug from the proximal tibia will be removed in a reverse dovetail fashion, which results in a proximally directed apex on the resultant bone plug. This apex will fit with a corresponding recess fashioned into the host proximal tibia.
of component position as well as assessment of component migration over time.12 In addition to radiography, CT can provide detailed information regarding rotational malalignment of the femoral or tibial component.35 Lastly, the surgeon should determine whether EM reconstruction is appropriate for the patient. Patients who are unable to comply with the relatively lengthy and stringent postoperative protocols7-11,15,17 should not undergo reconstruction. Absolute contraindications include active periprosthetic infection and inability to withstand surgery.
Management Nonsurgical Nonsurgical management of a deficient EM requires the patient to depend on walking aids and/or knee braces (eg, drop lock braces).3 These braces lock into extension when the patient is
98
Primary Repair Although successful results of primary repair of EM disruption in the native knee have been reported,36 management of EM disruptions following TKA is fraught with substantial complications, and largely marginal results have been reported. Rand et al3 performed primary repair for patellar tendon rupture using a variety of fixation methods, including suture fixation and staple fixation. The authors reported poor results with both of these techniques. Because outcomes associated with primary repair have been poor, the technique has largely been abandoned. However, these outcomes spurred interest in alternative techniques for reconstructing the EM. Reconstruction With Allograft or Autograft Most of the literature on reconstruction for EM disruption focuses on reconstruction using allograft, with modestly successful outcomes reported.2,3,6-10 However, several early studies reported that a significant number of patients had residual extensor lags, unacceptable range of motion (ROM), or dependence on assistive devices for ambulation and management of persistent instability.4,7,9 Two primary forms of allograft are used for EM reconstruction: Achilles tendon allograft and whole EM allograft.16 The first graft is composed of the Achilles tendon and a bone block of the calcaneus, whereas the whole EM allograft is composed of
the proximal tibia, patellar tendon, patella, and several centimeters of the quadriceps tendon16 (Figure 2). Whole EM allografts are used routinely for reconstruction, but these grafts are particularly helpful when the patient has a deficient patella or if the patella cannot be mobilized to within 3 to 4 cm of the joint line.16 Achilles tendon allografts can be used when the patella and patellar component are intact and the patella can be mobilized to within 3 to 4 cm of the joint line.6,16 Because of its increased length, Achilles tendon allograft can also be used for chronic quadriceps tendon rupture associated with significant proximal retraction.6,16 Regardless of which type of allograft is used, it should be fresh-frozen; inferior results have been reported with the use of freeze-dried grafts.5 Reconstruction with Achilles tendon allograft has evolved over the last three decades. The basic procedure9 involves the creation of a rectangular trough in the host proximal tibia to receive the calcaneal bone block of the allograft, which is contoured to fit the trough. The trough is slightly medial and distal to the tibial tubercle. The bone plug is press-fit into the trough and secured with wire or screw fixation. The tendinous portion of the allograft is pulled proximally and sutured to the underlying native EM tissue. It is critical that the graft be tensioned tightly with the knee in full extension to prevent postoperative extensor lag.7 The subcutaneous tissues and skin are then closed over the allograft. Postoperatively, the patient should be immobilized with the knee in full extension and casted for at least 6 to 8 weeks before beginning any ROM.4,6-8 When an entire EM allograft is used, a midline incision is created to expose the host EM.36 A midline incision is made through the quadriceps and patellar tendons, and a midline bisection of the patella is performed with a saw, essentially splitting the host
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
Figure 3
Illustration of the lateral view of the allograft bone (A), which is marked to outline the rectangular cut (inset). B, Illustration of rectangular bone plug cut in reverse dovetail fashion.
EM into medial and lateral halves. The patellar remnants are subsequently resected. The tibial component of the allograft is fashioned into a rectangular block and a reverse dovetail cut is made. The block is then placed into a corresponding trough cut into the proximal tibia (Figure 3). The allograft is drawn proximally under the host quadriceps using heavy, nonabsorbable suture. Simultaneously, heavy sutures are used to the pull the host quadriceps distally to create maximal tension. The allograft is then sutured to the overlying host quadriceps with heavy nonabsorbable suture. The previously elevated medial and lateral flaps of the host EM are then closed over the allograft, and closure of the subcutaneous tissue and skin is performed. Postoperatively, the knee is immobi-
lized in a cast in full extension or hyperextension for at least 6 to 8 weeks before any ROM is initiated. It should be noted that the allograft patella is not resurfaced, and the graft is sutured in place under maximal tension.5,7,8 The use of autograft for EM reconstruction with various techniques has been reported in the literature.3,10,37 The semitendinosus tendon is one of the more commonly used structures. Cadambi and Engh10 described a technique that involved a posteromedial incision through which the semitendinosus tendon is divided at its musculotendinous junction in addition to the standard midline incision used for knee arthroplasty. The distal tibial attachment of the tendon is preserved. After the free end of the proximal tendon is subcutaneously brought
through the anterior wound, it is tunneled through a 5-mm drill hole in the patella that was made transversely in a medial-to-lateral direction. The free end of the tibia is then secured to itself or to the proximal tibia. In some instances, the gracilis is used to augment the semitendinosus tendon.
Reconstruction With Synthetic Material Browne and Hanssen11 reported on a reconstruction technique in which Marlex mesh (C.R. Bard) is used instead of allograft tissue. The authors cited several concerns regarding allograft tissue, including cost, availability, disease transmission, and stretching of the tissue over time. The technique involves approaching
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
99
Extensor Mechanism Disruption After Total Knee Arthroplasty
Figure 4
A through G, Illustrations demonstrating the Marlex mesh (C.R. Bard) reconstruction technique described by Browne and Hanssen.11 A, If the tibial component is retained, a burr is used to create a trough for the mesh graft in the anteromedial aspect of the tibia. B, The graft is inserted into this trough and secured with polymethyl methacrylate, a transfixion screw, and washer. C, A laterally based flap of host tissue is elevated and interposed between the graft and the polyethylene, with the tissue secured to the medial soft tissue and the undersurface of the mesh. D, A portal is created in the lateral soft tissues to facilitate graft delivery from deep to superficial in relation to the extensor retinaculum and patella. E, To restore patellar height, the surgeon mobilizes and advances the patella and the quadriceps tendon. The surgeon then sutures the graft to the lateral retinaculum, vastus lateralis, and quadriceps tendon. Redundant mesh may be removed proximally. F, The vastus medialis muscle and medial retinaculum are mobilized to allow these medial soft tissues to advance in an overlapping manner (inset) over the mesh graft. The inset image demonstrates the envelopment of the graft by the vastus lateralis (deep) and the vastus medialis (superficial) muscles at the level of the distal femur. The construct is secured with suture. G, The distal arthrotomy is closed, completely covering the mesh graft with soft tissue. (Reproduced with permission from Browne JA, Hanssen AD: Reconstruction of patellar tendon disruption after total knee arthroplasty: Results of a new technique utilizing synthetic mesh. J Bone Joint Surg Am 2011;93[12]:1137-1143.)
the knee through a medial parapatellar arthrotomy and developing full-thickness subcutaneous flaps medially and laterally to expose the
100
EM (Figure 4). The distal end of the synthetic mesh construct is secured to a trough in the proximal tibia using cement and screw fixation. The
proximal end of the mesh is then tunneled from deep to superficial on the lateral aspect of the host patellar tendon and subsequently sutured to
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
the quadriceps tendon proximally. The entire graft is ultimately covered with the medial and lateral flaps of the host tissue. After surgery, the knee is immobilized in a long leg cast for 6 to 8 weeks, with only touchdown weight bearing allowed. Gastrocnemius Rotational Flaps Jaureguito et al15 and Busfield et al38 reported on the use of medial gastrocnemius rotational flaps for reconstruction of the EM. The technique involves mobilizing the medial half of the gastrocnemius muscle to cover the proximal anterior aspect of the tibia, thus serving as an anchor point to which the residual EM can be secured.15 The distal extent of the mobilization is the musculotendinous junction of the Achilles tendon. The extended medial gastrocnemius flap is a variation of the procedure in which the medial one third to one half of the tendon is mobilized with the muscle38 (Figure 5). The added length provided by the Achilles tendon allows reconstruction of more proximally disrupted EMs (eg, quadriceps tendon rupture).38 After EM reconstruction, postoperative management typically involves immobilization in a long leg cast for 6 to 8 weeks because extensor lag tends to be more of a concern than stiffness.7-11,15,17 The immobilization period is typically followed by a gradual increase in the amount of active knee flexion with the assistance of a hinged knee brace (HKB) over several weeks.7,8,10,11,15-17 Passive flexion is typically avoided to prevent damage to the reconstructed EM.16 At the senior author’s (B.D.S.) institution, the HKB is discontinued once the knee has reached 90° of flexion. Outcomes Limited literature on EM disruption is available. Although there are no randomized controlled trials comparing treatment methods, small retro-
Figure 5
A through C, Illustrations of the posterior aspect of the lower extremity demonstrating the use of gastrocnemius rotational flaps for reconstruction of the extensor mechanism. A, The medial half of the gastrocnemius muscle is released from the remaining muscle. B, The gastrocnemius muscle belly is tunneled subcutaneously around the medial border of the tibia. C, The fascia of the gastrocnemius is secured to the anterior tibial periosteum. In the extended technique, the Achilles tendon is then sutured to the distal aspect of the quadriceps tendon.
spective series and case reports are available.1-11,13-15,38-40 The largest reported series8 had only 36 patients, and many other studies have ,10 patients.1,4,10,14,15,38,39 The limitations of the literature highlight the complexity of this uncommon problem. Primary Repair Poor results of primary repair of EM disruption have been consistently reported2,3,13 (Table 1). Lynch et al2 reported on seven patients who underwent primary repair for disruption of the patellar tendon (three patients) or quadriceps tendon (four patients). All patients had poor results. The failure rate was a result of the unacceptable extensor lag and/or limited knee flexion in six patients and
deep infection in one patient. Two additional studies3,13 reviewed the outcomes of primary repair in a total of 23 patients; 21 patients had clinical failures, which were commonly caused by rerupture of the EM. In contrast, Abril et al reported39 positive results in two of two patients with patellar tendon disruption treated with primary suture repair and a wire tension band construct for reinforcement. Follow-up was 21 months. Similarly, a good functional outcome at 1 year postoperatively was reported in another case report.17 The patient was treated with primary suture repair augmented with Dacron tape. These positive short-term results should be considered outliers compared with the otherwise poor results
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
101
Extensor Mechanism Disruption After Total Knee Arthroplasty
Table 1 Outcomes of Primary Repair of Extensor Mechanism Disruption No. of Patients
Followup (mo)
Technique
Immobilization
Lynch et al2
7a
42
NR
NR
Rand et al3
16
42
Dobbs et al13
10
34
FernandezBaillo et al17
1
12
Reconstruction with suture, staples, xenograft, or semitendinosus graft Tensioning method not reported. 8 patients had standard primary repair, 2 patients had primary repair augmented with synthetic mesh Suture repair and Dacron tape reinforcement
Abril et al39
2
21
Study
Outcomes
Ext lag: 5 patients (21°); ROM: NR; Ambulation with aid: NR; Complications: 3 patients (43%) Cast immobilization in 11 Ext lag: NR; ROM: NR; patients for 5.5 wkb Ambulation with aid: 14 patients (82%); Complications: 12 patients (75%) NR Ext lag: NR; ROM: 3°-101°; Ambulation with aid: NR; Complications: 6 patients (60%) Long leg cast for 6 wk in full extension
No immobilization Wire tension band reinforcement placed at 45° flexion
Ext lag: 0; Flex: 110°; Ambulation with aid: 0; Complications: 0 Ext lag: 0; Flex: 87°; Ambulation with aid: 0; Complications: 0
Ext = extensor, Flex = flexion, NR = not reported, ROM = range of motion a Excluding those with patella fractures b Degree of extension or tensioning not reported.
associated with primary repair of EM disruption after TKA.
Reconstruction With Allograft or Autograft Allograft reconstruction has the potential to improve EM function, augment host tissue, maintain ROM, and decrease dependence on walking aids. The incidence of many of the complications reported in earlier studies, including progressive extensor lag, poor ROM, and rerupture, decreased in later studies because surgical technique and postoperative regimens were refined, which contributed to improved clinical outcomes associated with the evolution of allograft reconstruction for EM reconstruction7 (Table 2). Despite the known limitations of the procedure, outcomes of allograft reconstruction have been substantially better than those of primary repair, and
102
allograft reconstruction comprises the bulk of the literature with regard to EM repair techniques.4-9,14,40,41 However, outcomes of this technique vary.4,5 Emerson et al5 reported marginal outcomes in nine patients treated with entire EM allografts in which the patella was resurfaced. At an average follow-up of 4 years, three patients had persistent extensor lags, three had flexion contractures, and four required walking aids. Notably, the allografts were sutured to the host tissue under slight tension, a technique that has fallen out of favor. In an effort to minimize extensor lag, immobilizing patients in full extension or even hyperextension is currently recommended.7 Emerson et al5 also realized that resurfacing the allograft patella was unnecessary because it is insensate, and they recommended against the practice. Later studies would incorporate these two modifications in technique.6-8,41
Leopold et al4 reported on the use of whole EM allografts in six patients. Similar to Emerson et al,5 the authors did not resurface the patella and used only fresh-frozen allografts; however, they also failed to tension the grafts with the knee in full extension. All of the procedures were deemed clinical failures; the average extensor lag was 59° and most patients required ambulatory aids. This study is the last published report in which grafts were not tensioned with the knee in full extension. The authors postulated that improving the intraoperative tension may lead to improved outcomes, which was later shown in the comparative study by Burnett et al.7 This retrospective study compared the outcomes of patients with minimally tensioned allografts with those of patients with maximally tensioned allografts.7 The authors reported markedly improved results in the
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
Table 2 Outcomes of Allograft Reconstruction for Extensor Mechanism Disruption Study
No. of Patients
Follow-up (mo)
Leopold et al4
6
39
Sutured under slight Knee brace, full extension 6–8 wk tension with knee fully extended
Emerson et al5
9
49.2
Minimal. Knee flexed Motion after wound intraoperatively healed
Barrack et al6
14
42
Burnett et al7
20 total; 7 minimal tension group, 13 maximal tension group
38 minimal tension group, 37 maximal tension group
Tensioning Method
Entire ext mechanism sewn to quadriceps tendon under tension, with the knee flexed 30°. Achilles allograft with knee fully extended Minimal tension group: knee flexed intraoperatively
Maximal tension group: knee fully extended
Nazarian and Booth8
36
43.2
Crossett9
9
28
Maximally tensioned, knee fully extended
“Tendon taut/ unwrinkled,” knee fully extended
Immobilization
4 wk splint, with the knee flexed 0°, 4 wk with the knee flexed 45°, 8 wk with the knee flexed 90°
Outcomes Ext lag: 7 patients (59°) ROM: NR Ambulation with aids: 6 patients (86%) Complications: 4 patients (57%) Ext lag: 3 patients (28°) ROM: 3.8°–106° Ambulation with aids: 4 patients (44%) Complications: 5 patients (56%) Ext lag: NR Flex: 98° Ambulation with aids: 7 patients (50%) Complications: 1 patient (7%)
Minimal tension Minimal tension group group Ext lag: 59° Brace with knee Flex: 108° flexed 0° for 6–8 Ambulation with wk, then aids: 5 patients progressive (83%) ROM to 90°. Complications: 6 knees (86%) Maximal tension Maximal tension group group: Ext lag: 4.3° Cast with knee Flex: 104° flexed 0° for 8 Ambulation with wk, then ROM to aids: 4 patients 30° for 4 wk, then (31%) progressive Complications: 3 ROM to 90° at 12 patients (23%) wk Cast 6 wk, HKB 6 wk Ext lag: 15 patients (31°) with knee flexed ROM: 1.4°– 98° 0°–30° Ambulation with aids: 12 patients (33%) Complications: 8 patients (22%) 4 wk HKB with knee Ext lag: 3 patients flexed 0°, 4 wk HKB (10°) ROM: 1.7°–108° with knee flexed 0°–40°, 4 wk HKB Ambulation with aids: 8 patients (89%) with knee flexed Complications: 3 0°–90° patients (33%)
Ext =extensor, Flex = flexion, HKB = hinged knee brace, NR = not reported, ROM = range of motion
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
103
Extensor Mechanism Disruption After Total Knee Arthroplasty
maximal tension group. In the first group, the seven patients who had a minimally tensioned allograft had an average extensor lag of 59° and Hospital for Special Surgery (HSS) scores of 52. In the second group, 13 patients had a maximally tensioned allograft. The average extensor lag was 4.3° and the average HSS score was 88, both of which were statistically significant differences (P , 0.0001). Immobilizing the knee in full extension (or hyperextension) remains a critical component of the technique today. Nazarian and Booth8 modified the technique by using maximal tensioning of the fresh-frozen whole EM allograft with the knee fully extended, and flexion was avoided intraoperatively after the graft was tensioned. The knees were immobilized in full extension in a cast for 6 weeks followed by limited motion (0° to 30°) in a HKB for an additional 6 weeks. Successful outcomes were reported in 34 of 36 patients, although 8 patients had to undergo revision reconstruction of the EM due to graft rupture. Most patients did not have an extensor lag. In the literature, limited success has been reported with the use of autograft for EM reconstruction.3,10,37 The largest study included only seven patients treated with semitendinosus reconstruction using an autograft, with an average follow-up of 2.5 years.10 The knees were immobilized in a cast or knee immobilizer for 6 weeks and then a HKB for 6 weeks. The authors reported an average postoperative knee flexion of 80°, and 5 patients had extensor lag. Rand et al3 and Gustillo and Thompson37 each reported on one patient treated with semitendinosus reconstruction of the EM using autograft. Both procedures were clinical failures. In general, local autograft reconstruction in the patient with chronic disruption of the EM is avoided because of the lack of good host tissue.
104
Reconstruction With Synthetic Material Decreased cost, decreased risk of disease transmission, and availability of synthetic material for EM reconstruction are attractive potential benefits of reconstruction with synthetic material. Reports on the use of synthetic material for reconstruction of the EM are limited to two studies with short-term follow-up.1,11 Aracil et al1 reported fair results with the use of synthetic material for primary repair of the EM augmented with woven polyester ligament in five patients, although the incidence of extensor lag was not reported. Postoperative ROM was 99°. Browne and Hanssen11 provided the most compelling evidence to date to support the use of synthetic material. Of 13 patients who underwent patellar ligament reconstruction (without primary repair) using synthetic polypropylene mesh, 5 with no prior EM reconstruction had marked improvement in extensor lag at an average follow-up of 42 months. Seven patients had undergone previous failed attempts at reconstruction with allograft. In these patients, four complications were reported: three sustained graft failure within 6 months and 1 developed infection that required knee arthrodesis. Notably, there was no gradual stretching out of the graft noted in patients treated with the mesh, a problem that was reported in several earlier studies of allograft reconstruction.4,5 Further research on this relatively inexpensive treatment method is warranted in light of the results obtained. Gastrocnemius Rotational Flaps Gastrocnemius rotational flap reconstruction has typically been used for soft-tissue coverage of the knee. However, its use for EM reconstruction also has been studied, with modest results reported in two studies.15,38 Benefits of the technique include its ability to provide concomitant soft-
tissue coverage of the knee, the beneficial vascularity of muscle, and the lack of dependence on the quality of the patellar bone, as is required for the semitendinosus reconstruction technique.10 The use of gastrocnemius rotational flaps also plays a critical role in orthopaedic oncology because it allows reconstruction of the EM in patients who have undergone resection of the proximal tibia.15 Jaureguito et al15 reported overall positive outcomes at a mean 33-month follow-up in six patients treated with gastrocnemius flap (4 patients) or an extended gastrocnemius flap (2 patients), with an average ROM of 103° reported. Busfield et al38 used an extended gastrocnemius flap in five TKA patients, most of whom were undergoing a revision of a previous failed allograft reconstruction. At an average 21-month follow-up, all of the patients were able to ambulate independently, and only one had an unacceptable extensor lag of 50˚. The authors concluded that extended medial gastrocnemius flap reconstruction was a viable option for revision of EM reconstruction.
Summary EM disruption is a severe complication of TKA. Although this complication is rare, it rivals infection as the most devastating outcome after TKA.12 Recognition of the risk factors for EM disruption and a focus on preventive efforts through meticulous surgical exposure and technique are paramount. The variety of management options available highlights the lack of consistently satisfactory results from any single treatment method. Primary repair has resulted in consistently poor outcomes and is not typically indicated.2,3,13 Reconstruction using allograft presently remains the most studied technique.4-9,14,40,41 The importance of appropriate
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
Michael D. Bates, MD, and Bryan D. Springer, MD
surgical technique and maximal allograft tensioning when attempting reconstruction cannot be overemphasized. Research into the use of synthetic materials for reconstruction of EM disruptions offers promise, but more data are needed to fully evaluate the use of these materials.
References Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 22 and 23 are level I studies. Reference 14 is a level II study. References 7 and 19 are level III studies. References 1-6, 8-13, 15-17, 19, 21, 24-41 are level IV studies. References printed in bold type are those published within the past 5 years. 1. Aracil J, Salom M, Aroca JE, Torro V, Lopez-Quiles D: Extensor apparatus reconstruction with Leeds-Keio ligament in total knee arthroplasty. J Arthroplasty 1999;14(2):204-208. 2. Lynch AF, Rorabeck CH, Bourne RB: Extensor mechanism complications following total knee arthroplasty. J Arthroplasty 1987;2(2):135-140. 3. Rand JA, Morrey BF, Bryan RS: Patellar tendon rupture after total knee arthroplasty. Clin Orthop Relat Res 1989; 244:233-238. 4. Leopold SS, Greidanus N, Paprosky WG, Berger RA, Rosenberg AG: High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg Am 1999; 81(11):1574-1579. 5. Emerson RH Jr, Head WC, Malinin TI: Extensor mechanism reconstruction with an allograft after total knee arthroplasty. Clin Orthop Relat Res 1994;303:79-85. 6. Barrack RL, Stanley T, Allen Butler R: Treating extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res 2003;416:98-104. 7. Burnett RS, Berger RA, Paprosky WG, Della Valle CJ, Jacobs JJ, Rosenberg AG: Extensor mechanism allograft reconstruction after total knee arthroplasty: A comparison of two techniques. J Bone Joint Surg Am 2004;86:2694-2699. 8. Nazarian DG, Booth RE Jr: Extensor mechanism allografts in total knee
arthroplasty. Clin Orthop Relat Res 1999; 367:123-129. 9. Crossett LS, Sinha RK, Sechriest VF, Rubash HE: Reconstruction of a ruptured patellar tendon with achilles tendon allograft following total knee arthroplasty. J Bone Joint Surg Am 2002;84(8): 1354-1361. 10. 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 Am 1992;74(7): 974-979. 11. Browne JA, Hanssen AD: Reconstruction of patellar tendon disruption after total knee arthroplasty: Results of a new technique utilizing synthetic mesh. J Bone Joint Surg Am 2011;93(12): 1137-1143. 12. Scott WN: Insall and Scott Surgery of the Knee. Philadelphia, PA, Elsevier Health Sciences, 2011. 13. Dobbs RE, Hanssen AD, Lewallen DG, Pagnano MW: Quadriceps tendon rupture after total knee arthroplasty: Prevalence, complications, and outcomes. J Bone Joint Surg Am 2005;87(1):37-45. 14. Schoderbek RJ Jr, Brown TE, Mulhall KJ, et al: Extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res 2006;446:176-185. 15. Jaureguito JW, Dubois CM, Smith SR, Gottlieb LJ, Finn HA: Medial gastrocnemius transposition flap for the treatment of disruption of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg Am 1997;79(6):866-873. 16. Springer BD, Della Valle CJ: Extensor mechanism allograft reconstruction after total knee arthroplasty. J Arthroplasty 2008;23(7 suppl):35-38. 17. Fernandez-Baillo N, Garay EG, Ordoñez JM: Rupture of the quadriceps tendon after total knee arthroplasty: A case report. J Arthroplasty 1993;8(3):331-333. 18. Scapinelli R: Blood supply of the human patella: Its relation to ischaemic necrosis after fracture. J Bone Joint Surg Br 1967;49 (3):563-570. 19. Grace JN, Sim FH: Fracture of the patella after total knee arthroplasty. Clin Orthop Relat Res 1988;230:168-175. 20. Tria AJ Jr, Harwood DA, Alicea JA, Cody RP: Patellar fractures in posterior stabilized knee arthroplasties. Clin Orthop Relat Res 1994;299:131-138. 21. Scott RD, Turoff N, Ewald FC: Stress fracture of the patella following duopatellar total knee arthroplasty with patellar resurfacing. Clin Orthop Relat Res 1982; 170:147-151. 22. Wood DJ, Smith AJ, Collopy D, White B, Brankov B, Bulsara MK: Patellar
resurfacing in total knee arthroplasty: A prospective, randomized trial. J Bone Joint Surg Am 2002;84(2):187-193. 23. Waters TS, Bentley G: Patellar resurfacing in total knee arthroplasty: A prospective, randomized study. J Bone Joint Surg Am 2003;85(2):212-217. 24. Ortiguera CJ, Berry DJ: Patellar fracture after total knee arthroplasty. J Bone Joint Surg Am 2002;84 (4):532-540. 25. Last RJ: Some anatomical details of the knee joint. J Bone Joint Surg Br 1948;30B (4):683-688. 26. Reider B, Marshall JL, Koslin B, Ring B, Girgis FG: The anterior aspect of the knee joint. J Bone Joint Surg Am 1981;63(3): 351-356. 27.
Rodríguez-Merchán EC: Traumatic Injuries of the Knee. Milan, Italy, SpringerVerlag Italia, 2013.
28. Reilly DT, Martens M: Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthop Scand 1972; 43(2):126-137. 29. Soldado F, Reina F, Yuguero M, Rodríguez-Baeza A: Clinical anatomy of the arterial supply of the human patellar ligament. Surg Radiol Anat 2002;24(3-4): 177-182. 30. Scuderi C: Ruptures of the quadriceps tendon: Study of twenty tendon ruptures. Am J Surg 1958;95(4):626-635. 31. Yepes H, Tang M, Morris SF, Stanish WD: Relationship between hypovascular zones and patterns of ruptures of the quadriceps tendon. J Bone Joint Surg Am 2008;90(10): 2135-2141. 32. Barrack RL: Specialized surgical exposure for revision total knee: Quadriceps snip and patellar turndown. Instr Course Lect 1999; 48:149-152. 33. Scott RD, Siliski JM: The use of a modified V-Y quadricepsplasty during total knee replacement to gain exposure and improve flexion in the ankylosed knee. Orthopedics 1985;8(1):45-48. 34. Della Valle C, Parvizi J, Bauer TW, et al; American Academy of Orthopaedic Surgeons: Diagnosis of periprosthetic joint infections of the hip and knee. J Am Acad Orthop Surg 2010;18(12):760-770. 35. Berger RA, Crossett LS, Jacobs JJ, Rubash HE: Malrotation causing patellofemoral complications after total knee arthroplasty. Clin Orthop Relat Res 1998;356:144-153. 36. Siwek CW, Rao JP: Ruptures of the extensor mechanism of the knee joint. J Bone Joint Surg Am 1981;63(6): 932-937. 37. Gustillo RB, Thompson R: Quadriceps and patellar tendon ruptures
February 2015, Vol 23, No 2
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
105
Extensor Mechanism Disruption After Total Knee Arthroplasty following total knee arthroplasty, in Rand JA, Dorr LD, eds: Total Arthroplasty of the Knee: Proceedings of the Knee Society, 1985-1986. Rockville, MD, Aspen Publishers, 1987, pp 41–47. 38. Busfield BT, Huffman GR, Nahai F, Hoffman W, Ries MD: Extended medial gastrocnemius rotational flap for
106
treatment of chronic knee extensor mechanism deficiency in patients with and without total knee arthroplasty. Clin Orthop Relat Res 2004;428: 190-197.
40. Emerson RH Jr, Head WC, Malinin TI: Reconstruction of patellar tendon rupture after total knee arthroplasty with an extensor mechanism allograft. Clin Orthop Relat Res 1990;260:154-161.
39. Abril JC, Alvarez L, Vallejo JC: Patellar tendon avulsion after total knee arthroplasty. A new technique. J Arthroplasty 1995;10(3):275-279.
41. Burnett RS, Berger RA, Della Valle CJ, et al: Extensor mechanism allograft reconstruction after total knee arthroplasty. J Bone Joint Surg Am 2005;87(suppl 1, pt 2):175-194.
Journal of the American Academy of Orthopaedic Surgeons
Copyright ª the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.
![[Treatment of extensor mechanism rupture after total knee arthroplasty].](/assets/img/hold.png)
