Injury to the posterolateral ligament structures of the

Anatomic Reconstruction of the Posterolateral Corner of the Knee: A Case Series With Isolated Reconstructions in 27 Patients Bent Wulff Jakobsen, M.D., Bent Lund, M.D., Svend Erik Christiansen, M.D. and Martin C. Lind, M.D., Ph.D. Purpose: This study presents clinical results of a case series of isolated reconstruction of the posterolateral corner (PLC) with a new technique that aims to reconstruct the lateral collateral ligament (LCL), popliteus tendon, and popliteofibular ligament. Methods: From 1997 to 2005, 27 patients available for follow-up with isolated posterolateral instability were treated with primary reconstruction of the LCL and PLC. The median age was 28 years, and there were 16 male patients. Of the patients, 26% had remaining instability after anterior or posterior cruciate ligament reconstruction. All underwent reconstruction with a novel technique addressing both the LCL and the PLC by use of hamstring autografts. Follow-up was more than 24 months, and patients were examined by an independent observer using the International Knee Documentation Committee objective measures and subjective Knee Injury and Osteoarthritis Outcome Scores. Results: In our series 95% of patients with isolated lateral rotatory instability had rotatory stability after PLC reconstruction. On the basis of International Knee Documentation Committee scoring, 71% were normal or nearly normal. Subjective Knee Injury and Osteoarthritis Outcome Scores were comparable to scores in patients after meniscectomy. One patient had a deep infection, but none had any peroneal nerve injury. Conclusions: This case series presents a new method for combined reconstruction of the LCL and the PLC. Despite the extensiveness of procedure, complications were low. The technique restores lateral stability clinically at 2 years follow-up. Level of Evidence: Level IV, therapeutic case series. Injury to the posterolateral ligament structures of the knee is uncommon and frequently related to highenergy trauma and knee dislocations. Isolated injuries are rare and seen in only 2% of all knee ligament injuries. 1 Among combined knee ligament injuries, posterolateral injuries are more common and are seen From the EIRA Private Hospital, Science Center Skejby (B.W.J.), and the Division of Sports Trauma, University Hospital of Aarhus (B.L., S.E.C., M.C.L.), Aarhus, Denmark. The authors report no conflict of interest. Received May 3, 2009; accepted November 23, 2009. Address correspondence and reprint requests to Bent Wulff Jakobsen, M.D., EIRA Private Hospital, Science Center Skejby, Brendstrupgaardsvej 21, 8200 Aarhus N, Denmark. E-mail: bwj@ eiradanmark.dk 2010 by the Arthroscopy Association of North America 0749-8063/9265/$36.00 doi:10.1016/j.arthro.2009.11.019 in 60% of cases with posterior cruciate ligament (PCL) injury. 2 Overlooked injuries to the posterolateral complex in patients with multiligament injuries have been seen to lead to failure of reconstructed anterior cruciate ligaments (ACLs) and PCLs. 3,4 Conservative treatment of posterolateral injuries has been shown to lead to residual posterolateral laxity clinically. 5 The lateral and posterolateral complex (lateral collateral ligament [LCL]/posterolateral corner [PLC]) consists of numerous structures and has been divided into the iliotibial tract, long and short heads of the biceps femoris muscle, fibular collateral ligament (LCL), midthird lateral capsular ligament, fabellofibular ligament, posterior arcuate ligament, popliteus muscle complex, lateral coronary ligament, and posterior capsule. 6 Knee instability due to lesions of the lateral and posterolateral structures causes increased 918 Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 26, No 7 (July), 2010: pp 918-925

RECONSTRUCTION OF POSTEROLATERAL CORNER 919 load on the ACL during varus loading and internal rotation and increased load on the PCL during varus loading and external rotation. 4,7 Tibial internal rotation is restrained by the medial and posteromedial structures, whereas tibial external rotation is restrained by the lateral and posterolateral structures. 8,9 Early anatomic repair has been advocated for acute injuries with significant clinical instability. The repair needs to be performed within 2 weeks of injury to be able to identify anatomic structures. Repair of the LCL-PLC structures has been reported to fail in 37% of cases and with a higher failure rate than with PLC reconstructions performed nonacutely. 10 In addition, there is a risk of treating lesions that could have healed with conservative treatment. Several reconstructive procedures have been described. These techniques typically aim to reconstruct the LCL without addressing posterolateral structures or use combined techniques that address both the LCL and PLC. Biceps tenodesis with release of part of the biceps tendon and fixation of the free end to the LCL attachment at the femoral condyle is an isolated LCL reconstruction. 11,12 Similarly, several loop procedures using a tendon graft through the fibular head and fixation to the LCL attachment at the femoral condyle have been described. 13-16 Finally, combined LCL-PLC reconstruction has been described by LaPrade et al 17 and other authors. 18,19 Studies presenting clinical results with the different techniques are very limited. In a case series with 22 patients, 15 with multiligament injuries and 8 with isolated PLC injuries, 83% of patients with multiligament injuries and 88% of those with isolated PLC injuries obtained normal or nearly normal results according to International Knee Documentation Committee (IKDC) scoring after reconstruction with a modified sling technique. 10 A recent study compared PLC reconstructions using fibular and tibial canals and found better rotational stability with the fibular technique in 47 patients with multiligament injuries. 20 No clinical studies have presented clinical results after isolated PLC injuries treated with combined LCL-PLC reconstructions. The aim of this study is to present clinical results of a retrospective case series after isolated PLC reconstruction using a novel PLC reconstruction technique that addresses both LCL and popliteal tendon ligaments. From October 1997 to April 2005, a total of 40 patients with isolated lateral and posterolateral instability had combined LCL and PLC reconstruction. Inclusion criteria were isolated LCL/PLC reconstruction for isolated LCL/PLC instability or isolated LCL/ PLC reconstruction for remaining lateral instability after ACL or PCL reconstruction. Exclusion criteria were combined knee ligament reconstructions. Of the 40 patients, 7 had previous knee ligament surgery and thus had isolated posterolateral instability after cruciate ligament reconstruction. In the same time period a total of 2,293 patients had a knee ligament reconstruction performed at our clinic. Of the total number who underwent surgery, 27 responded to a follow-up visit in 2007, and all patients had more than 2 years follow-up. All patients complained of subjective knee instability and were diagnosed with isolated objective varus and external rotation instability. The varus instability was confirmed intraoperatively by an excessive opening of the lateral tibiofemoral joint of more than 6 mm. The rotatory instability was measured with the dial test with patients in the prone position and the knee flexed 90 and 30 (Fig 1). 19 A greater than 10 side-to-side difference in external rotation was considered clinically significant. The indication for surgery was clinically established rotatory and varus laxity. Therefore magnetic resonance imaging described PLC soft-tissue injury without laxity would not indicate surgery. That is why magnetic resonance imaging was not systematically used for diagnosis of PLC injury. For similar reasons, plain radiographs were not obtained in all patients to assess osteoarthritis because METHODS Patients FIGURE 1. Dial test performed in a patient with excessive external rotation ability. The test is performed with the patient in the prone position and the knee in 90 and 30 of flexion.

920 B. W. JAKOBSEN ET AL. they were relatively young, with a mean age around 28 years. Demographics Twenty-seven patients underwent follow-up for more than 24 months postoperatively. The median follow-up was 46 months (range, 24 to 86 months). There were 11 female patients and 16 male patients. The median age was 28 years, with a range from 13 to 57 years. Causes of initial injury were traffic accidents in 25% of cases and sports in 53%. Seven patients had remaining varus and rotatory instability after ACL or PCL reconstruction. One patient had a PCL reconstruction, and the remainder (6 patients) had ACL reconstruction. There was no significant difference in gender, age, body mass index, time from injury to surgery, and frequency of other previous surgeries between all operated patients and the patients available for follow-up (Table 1). Only 3 patients had a body mass index between 30 and 35, so obesity was not frequent in this patient material. Evaluation All patients with a minimum of 2 years follow-up were seen for follow-up in 2007. Objective examination was performed by an independent observer who was an experienced physiotherapist. Patients were evaluated by preoperative and followup IKDC objective scores. 21 At follow-up, a subjective Knee Injury and Osteoarthritis Outcome Score (KOOS) profile was obtained. 22 The follow-up KOOS profiles were compared with published profiles from normal subjects, ACL-reconstructed subjects, and subjects who had undergone meniscectomy. Anteriorposterior instability was objectively assessed by KT- 1000 testing (MEDmetric, San Diego, CA) because it has been recognized that the PLC also plays a role in anterior-posterior stability. Any complications and reoperations were registered. Range-of-motion evaluation was based on objective IKDC scores. Patients were asked to describe any problems with pain. Surgical Technique The semitendinosus and gracilis tendons are harvested at the pes anserinus. Tendons are prepared with No. 2 FiberWire baseball suture (Arthrex, Naples, FL) at 1 end. Lateral structures are exposed through a hockey-stick incision. The peroneal nerve is exposed distal to the fibular head for visual nerve protection during drilling. An incision above the biceps tendon insertion enables palpation of the posterolateral aspect of the tibial condyle. A tibial tunnel is then drilled from the anterior aspect of the lateral tibial condyle at the level of the fibula head to the posterior corner of the lateral tibial condyle. The drill hole should exit 10 mm below the tibial plateau posteriorly at the center of the popliteus muscle. The tunnel diameter is the size of the semitendinosus graft, which typically will be 6 mm. An oblique tunnel is drilled through the proximal fibula at the insertion site of the LCL, heading toward the posterior tip of the fibula. The iliotibial tract is split over the lateral femoral condyle to expose the insertion sites of the LCL and popliteus tendon. Two femoral tunnels are then drilled at the LCL and popliteus tendon femoral insertion sites sized according to the measured diameter of the double looped tendon grafts. The semitendinosus tendon is passed from posterior through the tibial condyle hole. Then, it is passed from anterior through the fibular hole and subsequently under the fascia to the femoral insertion site of the popliteus tendon, creating a double looped TABLE 1. Epidemiologic Data in All Patients Operated on With Isolated Lateral Reconstruction, Patients With More Than 24 Months Follow-Up, and Patients With Previous Cruciate Ligament Reconstruction All Patients Patients With 24 mo Follow-Up Patients With Previous Cruciate Ligament Reconstruction Number 40 27 7 Gender (F/M) 18/22 11/16 1/6 Median age (range) (yr) 29 (13-57) 28 (13-57) 36 (23-46) Chronic cases 42.5% 29.6% 100% *Time from injury to surgery (mo) 36 32 50 Previous surgery 32.5% 25.9% 100% *Body mass index 25.1 25.6 26.8 NOTE. A chronic case is defined as more than 12 months from injury to surgery. *Data are presented as mean.

RECONSTRUCTION OF POSTEROLATERAL CORNER 921 PLC reconstruction with tendon strand coming from the posterior tibial condyle and posterior fibular head. The gracilis graft is passed through the fibular tunnel and passed under the fascia as a sling to the femoral LCL insertion (Fig 2). The other end of the grafts are measured and cut according to femoral drill holes, with 15 to 20 mm over length, and the free end is sutured with a No. 2 FiberWire. The graft ends are then passed into the femoral tunnels with a Bio-Tenodesis screwdriver (Arthrex) and fixed with Bio-Tenodesis screws with a diameter equal to the diameter of graft and bone tunnel with the knee in 60 of flexion, neutral rotation, and valgus stress. LCL sling graft is fixed in the same manner with the knee in near extension, neutral rotation, and valgus stress. The LaPrade technique entails a single-strand LCL and popliteal tendon reconstruction. In addition, the popliteofibular ligament is reconstructed from the posterolateral aspect of the tibia to the posterior aspect of the fibula. Our technique entails double-stranded LCL reconstruction with a sling technique and a singlestranded popliteal tendon reconstruction. In addition, a popliteofibular ligament is reconstructed but in a more anatomic manner, going from the posterior aspect of the fibula to the popliteal tendon insertion on the femur. For an experienced surgeon, the procedure is estimated to take approximately 60 minutes. Rehabilitation We used a hinged brace with 0 to 90 of motion for the first 2 weeks and partial weight bearing. Starting in week 2, continued brace use is recommended, with unlimited degrees of range of motion and weight bearing during standing and walking. After 6 weeks, unrestricted activity was allowed. Controlled sports activities after 3 months and contact sports after 6 months were allowed. Statistics Demographic data were compared between responders and nonresponders with the Student t test and 2 test. Preoperative and postoperative IKDC values were compared with the 2 test. KOOS data were compared between isolated LCL-PLC operated patients and those with previous cruciate ligament reconstructions with the Student t test. FIGURE 2. The posterolateral reconstruction is shown at the lateral aspect of the knee. The reconstruction consist of 2 parts. First, a gracilis autograft sling is placed through the proximal fibula to the LCL insertion point at the lateral femoral condyle to reconstruct the LCL. Second, a semitendinosus autograft is used to reconstruct both the popliteus tendon and popliteofibular ligament. The popliteus tendon is reconstructed by a graft strand going from the drill hole opening at the posterolateral tibial condyle to the popliteus tendon insertion point at the femoral condyle. The popliteofibular ligament is reconstructed by a graft strand starting from the posterior aspect of the proximal fibula to the popliteus tendon insertion point at the femoral condyle. Resorbable interference screws are used for fixation of the graft in the femoral drill holes. Objective IKDC Score RESULTS Rotatory instability evaluated by the dial test was abnormal in 60% of patients preoperatively and in only 5% of patients at follow-up (P.05). A similar outcome was found for varus stability. The overall objective IKDC score improved, with an abnormal score of C or D in 60% of patients preoperatively and in 28.6% of patients at follow-up (P.05) (Table 2). On the basis of KT-1000 measurements, there was no

922 B. W. JAKOBSEN ET AL. TABLE 2. Patients Divided Into Groups Preoperatively and at Follow-up Based on IKDC Rotational Instability and Overall Score IKDC Level Rotational Stability Varus Stability Anterior-Posterior Stability Overall Preoperatively Follow-up Preoperatively Follow-up Preoperatively Follow-up Preoperatively Follow-up A (%) 76 89 52 62 14 B (%) 40 19 15 7 36 33 40 57 C (%) 48 5 67 4 12 5 48 29 D (%) 12 13 12 significant change in anterior-posterior stability, with normal scores in 88% of patients preoperatively and 94% of patients at follow-up. Of the 27 patients, 4 had flexion deficits. Two patients had a 10 deficit, and two had a 5 deficit. When we compared the patients who had previous cruciate ligament reconstruction with the patients with true isolated LCL-PLC injury, objective rotational and varus instability was not significantly different between groups. Both groups had only 1 patient with IKDC grade B varus and external rotational instability; the remainder were grade A. KOOS Profile The KOOS profile showed that the ability to perform sports/recreational activities and quality of life were the subscores that were most affected after PLC reconstruction (Table 3). When we compared the KOOS profile with published results after other procedures, PLC-reconstructed patients were similar to patients after meniscectomy and had a moderately poorer outcome compared with patients who had undergone ACL reconstruction. 23,24 When we compared the patients who had previous cruciate ligament reconstruction with the patients with true isolated LCL- PLC injury, the KOOS was significantly worse for patients with previous cruciate ligament reconstruction, with subscores for activities of daily living, sports and recreation, and quality of life that were 17, 26, and 30 points lower, respectively. Return to Sports Tegner score at follow-up was 4.6 (2,2). Of 27 patients, 3 had Tegner scores of 1 and 2, indicating poor function level. Seven patients returned to a high level of sports participation, and the remainder returned to recreational sports. Of the 27 patients, 13 had a higher level of sports function after reconstruction than preoperatively. Complications There was 1 major complication, which was a deep infection along the tibial drill tunnel. The infection was treated successfully with intravenous antibiotics, and the reconstruction was preserved. One patient had deep knee pain that was treated with arthroscopic partial synovectomy without success. Two patients complained of moderate function related knee pain, and one patient had rotatory pain during examination. TABLE 3. KOOS at Follow-up in Present Study Compared With ACL-Reconstructed Patients After 1 Year and Partial Meniscectomy After 15 Years* KOOS Subscale Isolated LCL-PLC Patients with Previous ACL/PCL Reconstruction ACL Reconstruction in Danish ACL Registry Long-Term Results of Partial Meniscectomy Pain 75 (39-100) 60 (39-86) 61 84 Symptoms 77 (42-100) 62 (42-75) 84 86 Activities of daily living 83 (38-100) 66 (38-87)** 89 88 Sports/recreation 55 (0-100) 29 (0-55)** 63 64 Quality of life 59 (15-100) 29 (13-56)** 60 71 NOTE. Data are presented as median (range). *Based on data from references 23 and 24. **Significantly different from isolated LCL-PLC group.

RECONSTRUCTION OF POSTEROLATERAL CORNER 923 DISCUSSION Though a rare condition, isolated symptomatic LCL-PLC insufficiency exists and may require surgical treatment. Our series of 40 isolated PLC reconstructions was part of a total of 2,293 ligament reconstructions performed in the inclusion period, resulting in isolated LCL-PLC reconstructions being performed in only 1.7% of all ligament reconstructions at our university clinic. This correlated well with previous findings of DeLee et al. 1 The rareness of the condition can lead to injuries being overlooked because of the lack of a routine clinical instability examination that addresses the posterolateral structures. In addition, the rare need for surgical treatment may cause surgeons to be reluctant to perform a posterolateral reconstruction procedure because of the relatively advanced technique necessary and the extra time that the LCL-PLC procedure adds to other ligament reconstruction procedures. In this study we present a new technique for combined LCL-PLC reconstruction. We found a good ability of the procedure to restore rotational stability and therefore considered the clinical outcome of the procedure acceptable. In addition, the complications were acceptable, with 1 deep infection and a few patients with postoperative knee pain, which in 1 patient was related to lateral structures. Our case series included patients with isolated PLC instability after either ACL or PCL reconstruction. The injuries in these patients did not represent true isolated injuries but are surgical cases in which isolated PLC reconstruction is performed. The patients with previous surgery were older and had a longer period from injury to surgery than patients with isolated injuries. The clinical outcome based on the KOOS was poorer when previous surgery had been performed despite the fact that objective instability did not differ between the groups. The knee stability obtained by the PLC reconstruction is relatively good, with more than 90% of the patients having good and excellent IKDC results. For the subjective KOOS profiles, the outcome of PLC reconstruction in patients without previous surgery was comparable to that in patients with primary ACL reconstruction. In contrast, the KOOS was significantly lower for patients who had had a previous cruciate ligament reconstruction. Several reconstructive procedures for reconstruction of the lateral knee ligament structure have been described. Biceps tenodesis as shown by Bousquet et al. 11 did not restore lateral stability because of femoral fixation performed too proximally. 12 Biceps tenodesis alone with a fixation point located 1 cm anterior to the LCL insertion on the femur was effective at restoring external rotation and varus laxity in a cadaveric study, 12 but biceps tenodesis is not an anatomic reconstruction, and the technique has no widespread clinical usage. Similarly, several loop procedures restore varus stability biomechanically and clinically, but they do not reconstruct the popliteal tendon and the popliteal fibular complex. 13-16 A recent study showed that a single-loop allograft reconstruction passed through a drilled tunnel in the head of the fibula at a 45 angle and fixed in the femoral tunnel at the lateral epicondyle with a Bio-Tenodesis screw seems to restore LCL and popliteal ligament function, but similar to the sling techniques, this method does not address the popliteus tendon component. 25 A cadaveric study found that the posterolateral structures play an important role at full extension in intact knees and at all angles of flexion in PCLdeficient knees, and the popliteus muscle appears to be a major stabilizer under this loading condition. 26 In addition, Suda et al. 27 found that combined reconstruction of the PCL, LCL, and popliteus tendon is essential and adequate for treating severe chronic posterolateral rotatory instability. Although surgical reconstruction of the popliteal tendon will not be able to provide the dynamic stabilization of the popliteus muscle, 28,29 the importance of an anatomic reconstruction including the popliteal tendon in an attempt to address the complete posterolateral complex seems evident. 17 The clinical significance of reconstructing both structures has been shown in a study by Yoon et al. 30 In their study comparing 2 case series using the sling technique and an anatomic reconstruction of both the LCL and the popliteus tendon with an Achilles tendon allograft, the anatomic reconstruction showed superior rotational and varus stability and a higher Lysholm score. The best documented technique biomechanically is that described by LaPrade et al. 17 This technique combines LCL and PLC reconstruction using split Achilles tendon allograft. Through bone canals in the fibular head and lateral tibial condyle, the LCL and PLC are reconstructed to normal femoral attachments. This reconstruction has been shown to restore both varus and external rotational instability biomechanically. 17 A recent report has described a posterolateral reconstruction technique that attempts the same combined LCL and popliteofibular ligament reconstruction by use of Achilles tendon allograft. 17

924 B. W. JAKOBSEN ET AL. The technique presented in this study uses a sling technique for the LCL reconstruction and a second tendon graft from the posterolateral tibial condyles to the popliteal insertion on the femur for popliteal reconstruction. In addition, a fibular popliteal ligament reconstruction is included, with a tendon graft going from the posterior part of the fibular head to the popliteal insertion on the femur. Despite the extensive exposure and the complex tendon reconstruction in multiple drill holes in both the lateral femoral and tibial condyles, we observed very limited postoperative morbidity that could be related to the procedure. Peroneal nerve injury is an important complication that needs to be avoided when one is performing lateral knee procedures. 31 In our technique we exposed the peroneal nerve early in the procedure where the nerve passes the fibular neck. This enables visual confirmation of nerve protection during the drilling procedures that most likely could cause nerve injury. In our series no nerve injuries were observed. However, in combined reconstructions for multiligament injuries, especially when the trauma is a knee dislocation, very careful nerve exposure must be performed because the nerve can be dislocated from its anatomic position, due to severe soft-tissue injury during the dislocation. Only a few clinical studies have presented outcomes after PLC reconstruction. These studies are typically small case series with the majority of patients having multiligament injuries. Zhao et al. 32 reported good objective stability in 95% of 28 PLC reconstructed patients. Noyes and Barber-Westin 33 reported excellent objective knee stability in 13 patients, 12 of whom had multiligament injuries. Stannard et al. 34 found no failures in 7 isolated PLC reconstructions, with generally good objective stability in a total of 22 patients who underwent reconstruction. A recent study by Schechinger et al. 35 showed a follow-up subjective IKDC score of 80 in 16 patients with PLC reconstruction. Our data are difficult to compare with these studies because a majority of patients in our material had isolated PLC injuries compared with the previously mentioned studies. However, overall, the results are similar to PLC reconstruction, showing good objective stability for all patient types and a good clinical outcome overall for patients with isolated PLC injuries. This study is limited by the fact that it is a retrospective case series. However, the rareness of posterolateral injuries has thus far resulted in no published randomized studies that address lateral and posterolateral ligament reconstructions. Another study weakness is the suboptimal follow-up completeness of 27 patients compared with the 40 patients who underwent the procedure. The main reason for this poor follow-up is that our clinic is a national referral center for advanced knee ligament reconstruction and, therefore, many patients live far from the clinic and did not want to travel for a study followup. This study is, to our knowledge, the largest case series published thus far and the only study to present clinical results after isolated LCL-PLC reconstructions. In the study we present a new technique for combined LCL-PLC reconstruction, but we lack in vitro biomechanical documentation to describe the degree to which the reconstruction restores normal knee biomechanics. Such a study is currently being performed and will enable comparison to other in vitro documented techniques such as the LaPrade technique. 17 When one is performing posterolateral reconstruction, a popliteal tendon reconstruction is necessary. However, the normal muscle and tendon complex is a dynamic entity that is activated during rotation, and this dynamic function can never be restored with a static tendon reconstruction as presented. CONCLUSIONS This case series presents a new method for combined reconstruction of the LCL and the PLC. Despite the extensiveness of procedure, complications were low. The technique restores lateral stability clinically at 2 years follow-up. REFERENCES 1. DeLee JC, Riley MB, Rockwood CA Jr. Acute posterolateral rotatory instability of the knee. Am J Sports Med 1983;11:199-207. 2. Fanelli GC, Edson CJ. Posterior cruciate ligament injuries in trauma patients: Part II. Arthroscopy 1995;11:526-529. 3. Wentorf FA, LaPrade RF, Lewis JL, Resig S. The influence of the integrity of posterolateral structures on tibiofemoral orientation when an anterior cruciate ligament graft is tensioned. Am J Sports Med 2002;30:796-799. 4. LaPrade RF, Resig S, Wentorf F, Lewis JL. The effects of grade III posterolateral knee complex injuries on anterior cruciate ligament graft force. A biomechanical analysis. Am J Sports Med 1999;27:469-475. 5. Kannus P. Nonoperative treatment of grade II and III sprains of the lateral ligament compartment of the knee. Am J Sports Med 1989;17:83-88. 6. Terry GC, LaPrade RF. The posterolateral aspect of the knee. Anatomy and surgical approach. Am J Sports Med 1996;24: 732-739. 7. LaPrade RF, Muench C, Wentorf F, Lewis JL. The effect of

RECONSTRUCTION OF POSTEROLATERAL CORNER 925 injury to the posterolateral structures of the knee on force in a posterior cruciate ligament graft: A biomechanical study. Am J Sports Med 2002;30:233-238. 8. Amis AA, Bull AM, Gupte CM, Hijazi I, Race A, Robinson JR. Biomechanics of the PCL and related structures: Posterolateral, posteromedial and meniscofemoral ligaments. Knee Surg Sports Traumatol Arthrosc 2003;11:271-281. 9. Gupte CM, Smith A, Jamieson N, Bull AM, Thomas RD, Amis AA. Meniscofemoral ligaments Structural and material properties. J Biomech 2002;35:1623-1629. 10. Stannard JP, Brown SL, Farris RC, McGwin G Jr, Volgas DA. The posterolateral corner of the knee: Repair versus reconstruction. Am J Sports Med 2005;33:881-888. 11. Bousquet G, Charmion L, Passot JP, Girardin P, Relave M, Gazielly D. Stabilization of the external condyle of the knee in chronic anterior laxity. Importance of the popliteal muscle. Rev Chir Orthop Reparatrice Appar Mot 1986;72:427-434 (in French). 12. Wascher DC, Grauer JD, Markoff KL. Biceps tendon tenodesis for posterolateral instability of the knee. An in vitro study. Am J Sports Med 1993;21:400-406. 13. Buzzi R, Aglietti P, Vena LM, Giron F. Lateral collateral ligament reconstruction using a semitendinosus graft. Knee Surg Sports Traumatol Arthrosc 2004;12:36-42. 14. Latimer HA, Tibone JE, ElAttrache NS, McMahon PJ. Reconstruction of the lateral collateral ligament of the knee with patellar tendon allograft. Report of a new technique in combined ligament injuries. Am J Sports Med 1998;26:656-662. 15. Lee MC, Park YK, Lee SH, Jo H, Seong SC. Posterolateral reconstruction using split Achilles tendon allograft. Arthroscopy 2003;19:1043-1049. 16. Lill H, Glasmacher S, Korner J, Rose T, Verheyden P, Josten C. Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament and the lateral collateral ligament using hamstrings and absorbable screws. Arthroscopy 2001; 17:892-897. 17. LaPrade RF, Johansen S, Wentorf FA, Engebretsen L, Esterberg JL, Tso A. An analysis of an anatomical posterolateral knee reconstruction: An in vitro biomechanical study and development of a surgical technique. Am J Sports Med 2004; 32:1405-1414. 18. Bicos J, Arciero RA. Novel approach for reconstruction of the posterolateral corner using a free tendon graft technique. Sports Med Arthrosc 2006;14:28-36. 19. Veltri DM, Warren RF. Operative treatment of posterolateral instability of the knee. Clin Sports Med 1994;13:615-627. 20. Jung YB, Jung HJ, Kim SJ, et al. Posterolateral corner reconstruction for posterolateral rotatory instability combined with posterior cruciate ligament injuries: Comparison between fibular tunnel and tibial tunnel techniques. Knee Surg Sports Traumatol Arthrosc 2008;16:239-248. 21. Wright RW. Knee injury outcomes measures. J Am Acad Orthop Surg 2009;17:31-39. 22. Roos EM, Lohmander LS. The Knee injury and Osteoarthritis Outcome Score (KOOS): From joint injury to osteoarthritis. Health Qual Life Outcomes 2003;1:64. 23. Lind M, Menhert F, Pedersen AB. The first results from the Danish ACL reconstruction registry: Epidemiologic and 2 year follow-up results from 5,818 knee ligament reconstructions. Knee Surg Sports Traumatol Arthrosc 2009;17:117-124. 24. Englund M, Roos EM, Roos HP, Lohmander LS. Patientrelevant outcomes fourteen years after meniscectomy: Influence of type of meniscal tear and size of resection. Rheumatology (Oxford) 2001;40:631-639. 25. Kocabey Y, Nawab A, Caborn DN, Nyland J. Posterolateral corner reconstruction using a hamstring allograft and a bioabsorbable tenodesis screw: Description of a new surgical technique. Arthroscopy 2004;20:159-163 (Suppl 2). 26. Hoher J, Harner CD, Vogrin TM, Baek GH, Carlin GJ, Woo SL. In situ forces in the posterolateral structures of the knee under posterior tibial loading in the intact and posterior cruciate ligament-deficient knee. J Orthop Res 1998;16:675-681. 27. Suda Y, Seedhom BB, Matsumoto H, Otani T. Reconstructive treatment of posterolateral rotatory instability of the knee: A biomechanical study. Am J Knee Surg 2000;13:110-116. 28. Wang CJ, Chen CY, Chen LM, Yeh WL. Posterior cruciate ligament and coupled posterolateral instability of the knee. Arch Orthop Trauma Surg 2000;120:525-528. 29. Wang CJ, Chen HS, Huang TW, Yuan LJ. Outcome of surgical reconstruction for posterior cruciate and posterolateral instabilities of the knee. Injury 2002;33:815-821. 30. Yoon KH, Bae DK, Ha JH, Park SW. Anatomic reconstructive surgery for posterolateral instability of the knee. Arthroscopy 2006;22:159-165. 31. Lubowitz JH, Elson W, Guttmann D. Complications in the treatment of medial and lateral sided injuries of the knee joint. Sports Med Arthrosc 2006;14:51-55. 32. Zhao J, He Y, Wang J. Anatomical reconstruction of knee posterolateral complex with the tendon of the long head of biceps femoris. Am J Sports Med 2006;34:1615-1622. 33. Noyes FR, Barber-Westin SD. Posterolateral knee reconstruction with an anatomical bone-patellar tendon-bone reconstruction of the fibular collateral ligament. Am J Sports Med 2007; 35:259-273. 34. Stannard JP, Brown SL, Robinson JT, McGwin G Jr, Volgas DA. Reconstruction of the posterolateral corner of the knee. Arthroscopy 2005;21:1051-1059. 35. Schechinger SJ, Levy BA, Dajani KA, Shah JP, Herrera DA, Marx RG. Achilles tendon allograft reconstruction of the fibular collateral ligament and posterolateral corner. Arthroscopy 2009;25:232-242.