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ORTHOPAEDIC SPORTS MEDICINE BOARD REVIEW MANUAL STATEMENT OF EDITORIAL PURPOSE The Hospital Physician Orthopaedic Sports Medicine Board Review Manual is a peerreviewed study guide for orthopaedic sports medicine fellows and practicing orthopaedic surgeons. Each quarterly manual reviews a topic essential to the current practice of orthopaedic sports medicine.

PUBLISHING STAFF PRESIDENT, GROUP PUBLISHER

Bruce M. White EDITORIAL DIRECTOR

Debra Dreger ASSISTANT EDITOR

Tricia Faggioli EXECUTIVE VICE PRESIDENT

Barbara T. White EXECUTIVE DIRECTOR OF OPERATIONS

Jean M. Gaul PRODUCTION DIRECTOR

Posterior Cruciate Ligament and Posterolateral Corner Injuries Editor: Andrew J. Cosgarea, MD Associate Professor Department of Orthopaedic Surgery Johns Hopkins University School of Medicine Baltimore, MD

Contributors: Daniel C. Wascher, MD Associate Professor Department of Orthopaedics University of New Mexico Albuquerque, NM

Andrew J. Veitch, MD Assistant Professor Department of Orthopaedics University of New Mexico Albuquerque, NM

Suzanne S. Banish PRODUCTION ASSISTANT

Kathryn K. Johnson ADVERTISING/PROJECT MANAGER

Table of Contents

Patricia Payne Castle

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SALES & MARKETING MANAGER

Anatomy and Biomechanical Properties . . . . . . . . . . . . . 2

Deborah D. Chavis

Detection and Evaluation of Injury . . . . . . . . . . . . . . . . . 4 NOTE FROM THE PUBLISHER: This publication has been developed without involvement of or review by the American Board of Orthopaedic Surgery.

Treatment of PCL Injuries . . . . . . . . . . . . . . . . . . . . . . . 7 Treatment of Posterolateral Corner Injuries. . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Endorsed by the Association for Hospital Medical Education

Cover Illustration by mb cunney

Copyright 2004, Turner White Communications, Inc., 125 Strafford Avenue, Suite 220, Wayne, PA 19087-3391, www.turner-white.com. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission of Turner White Communications, Inc. The editors are solely responsible for selecting content. Although the editors take great care to ensure accuracy, Turner White Communications, Inc., will not be liable for any errors of omission or inaccuracies in this publication. Opinions expressed are those of the authors and do not necessarily reflect those of Turner White Communications, Inc.

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Orthopaedic Sports Medicine Volume 1, Part 1 1

ORTHOPAEDIC SPORTS MEDICINE BOARD REVIEW MANUAL

Posterior Cruciate Ligament and Posterolateral Corner Injuries Daniel C. Wascher, MD, and Andrew J. Veitch, MD

INTRODUCTION Injuries of the posterior cruciate ligament (PCL) and the ligaments of the posterolateral corner of the knee are less common and historically have been less successfully treated than injuries of the anterior cruciate ligament (ACL). Adequate treatment of these injuries requires a thorough understanding of anatomy and biomechanical properties, the ability to accurately diagnose and determine extent of injury, and knowledge of the available treatment options. Failure to recognize and treat posterolateral corner injuries can jeopardize the success of cruciate ligament reconstructions. Although the true incidence of PCL and posterolateral corner injuries is unclear, it is known that some of these injuries go unrecognized. A recent review found that PCL tears occur in 1% to 44% of all acute knee injuries.1,2 The overall incidence of PCL injuries and the frequency of associated ligamentous injuries are higher in series from level I trauma centers.3 The PCL appears to be injured less frequently than the ACL or medial collateral ligament (MCL), although improved awareness about PCL tears has resulted in these injuries being diagnosed more frequently. Injuries of the posterolateral corner ligaments are even less common but are being recognized more frequently due to recent advances in clinical examination and imaging techniques. Most posterolateral corner injuries occur in combination with tears of one or both cruciate ligaments; isolated injuries are uncommon. Although isolated PCL injuries do occur, it is imperative to assess the knee for combined ligamentous injuries. Failure to identify and address all injuries at the time of surgical intervention may lead to failure of the reconstructed ligaments. The classic mechanism of an isolated PCL tear is a posteriorly directed force on the proximal tibia with the knee flexed. This is the so-called dashboard injury, which may occur as a result of the knee striking the dashboard during a car accident. Another mechanism of isolated PCL injury is landing directly on a flexed knee with the foot in plantar flexion, as may occur during athletic

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competition or with a fall. PCL ruptures associated with other ligamentous injuries can occur with forced hyperextension or high varus/valgus or rotational loads. In these injuries, the PCL tears only after failure of the other ligaments. Most posterolateral corner injuries result from a contact or noncontact hyperextension injury, a severe varus load, or a posteriorly directed force to the anteromedial aspect of the knee.4 Common causes include car accidents, athletic injuries, and falls.

ANATOMY AND BIOMECHANICAL PROPERTIES The past decade has seen significant growth in the understanding of the structure and function of the PCL and the ligaments of the posterolateral corner, and the biomechanical properties of these ligaments have been well described by several authors. ANATOMY PCL The PCL has a comma-shaped origin located on the lateral border of the medial femoral condyle at the junction of the wall and the roof of the intercondylar notch. The insertion of the PCL is approximately 1.0 to 1.5 cm distal to the posterior rim of the tibia, in a depression between the posterior medial and lateral tibial plateaus (the so-called PCL fovea or facet). The tibial attachment of the PCL is in close proximity to the neurovascular structures in the popliteal fossa, separated only by the posterior capsule. The average width of the PCL is 13 mm, and the average length is 38 mm.5 The PCL consists of 2 distinct bundles of fibers. The anterolateral fibers attach anteriorly within the femoral footprint and laterally on the posterior tibia. The posteromedial fibers attach posteriorly within the femoral footprint and medially on the posterior tibia (Figure 1). The 2 components function in a reciprocal fashion as the knee moves through the flexion-extension cycle.4 With increasing knee flexion, the anterolateral fibers become taut and play a greater role in posterior knee stability. The posteromedial fibers tighten as the knee is

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Posterior Cruciate Ligament and Posterolateral Corner Injuries A

B AL

Lateral gastrocnemius tendon

PM

Lateral collateral ligament

PM AL

Figure 1. Location of the (A) femoral origin and (B) tibial insertion of the 2 functional components of the posterior cruciate ligament: the anterolateral (AL) bundle and the posteromedial (PM) bundle. (Adapted with permission from Harner CD, Hoher J. Evaluation and treatment of posterior cruciate injuries. Am J Sports Med 1998;26:471–82.)

extended and are an important stabilizer as the knee reaches full extension. Two variable meniscofemoral ligaments originate adjacent to the femoral attachment of the PCL and insert on the posterior horn of the lateral meniscus: the anterior meniscofemoral ligament (ligament of Humphrey), located anterior to the PCL, and the posterior meniscofemoral ligament (ligament of Wrisberg), found posterior to the PCL. In a cadaver study, at least one meniscofemoral ligament was found in 93% of specimens evaluated.6 The ligament of Humphrey was present in 74%, the ligament of Wrisberg was present in 69%, and both ligaments occurred in 50% of specimens; these latter specimens were from a significantly younger population, suggesting that the meniscofemoral ligaments may degenerate with age. Posterolateral Corner The ligamentous anatomy of the lateral aspect of the knee is complex and variable. An early description by Seebacher et al7 divided the lateral structures into 3 distinct layers, the deepest and most important of which includes the lateral (fibular) collateral ligament (LCL), the popliteus tendon, the popliteofibular ligament (PFL), the arcuate ligament, the fabellofibular ligament, and the lateral joint capsule. The LCL is the smallest of the 4 major knee ligaments. It arises from a fovea located immediately posterior to the ridge of the lateral femoral epicondyle and inserts onto a superiorly and laterally facing V-shaped plateau on the lateral aspect of the fibular head (Figure 2).8,9 The average length of the LCL is approximately 70 mm. The cross-sectional area of the LCL attachment sites on the femur and fibula is approximately 0.45 cm2.9

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Popliteus tendon

Popliteofibular ligament Figure 2. Schematic illustration showing the attachment sites of the important stabilizing structures of the posterolateral corner of the knee. (Adapted with permission from LaPrade RF, Ly TV, Wentorf FA, Engebretsen L. The posterolateral attachments of the knee: a qualitative and quantitative morphologic analysis of the fibular collateral ligament, popliteus tendon, popliteofibular tendon, and lateral gastrocnemius tendon. Am J Sports Med 2003;31:856.)

The popliteus muscle arises from the posterior aspect of the proximal tibia and courses around the lateral side of the knee. The popliteus tendon travels through the popliteal hiatus of the lateral meniscus, deep to the LCL, to insert anterior to the lateral femoral epicondyle at the proximal and anterior aspect of the popliteal sulcus (Figure 2). Three fasciculi extend from the popliteus tendon to the lateral meniscus, providing stability to the meniscus. The PFL is a strong, direct attachment of the popliteus tendon to the fibula.10,11 Present in 94% of knees,12 the PFL arises from the musculotendinous junction of the popliteus muscle to attach to the posteromedial aspect of the fibular styloid process. In cross-sectional area, the PFL is only slightly smaller than the LCL.10 The PFL is better oriented than the LCL to resist external rotation at all flexion angles.8 The posterior part of the lateral capsule is reinforced by the arcuate ligament and the fabellofibular ligament. The arcuate ligament originates from the fibular head superficial to the PFL and arches medially to attach to the posterior knee capsule and blend with the oblique popliteal ligament (ligament of Winslow).10,13 The fabellofibular ligament originates along the lateral edge of the fabella and attaches on the fibular styloid process,

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Posterior Cruciate Ligament and Posterolateral Corner Injuries just posterior to the arcuate ligament.13 If no fabella is present, the fabellofibular ligament arises from the posterior aspect of the supracondylar process of the femur. The arcuate ligament and the fabellofibular ligament are of variable size and are not uniformly present in all knees.7,12 The midthird lateral capsular ligament is a thickening of the lateral joint capsule.13 This ligament arises from the femur, has attachments to the lateral meniscus, and then courses to the tibia. The tibial attachment is from just posterior to Gerdy’s tubercle to the popliteal hiatus. The superficial layer of the iliotibial band forms Seebacher’s layer I anterior to the intermuscular septum and inserts distally on the anterolateral tibia at Gerdy’s tubercle.13 A deep layer of the iliotibial band attaches to the lateral intermuscular septum of the distal femur. Even deeper, the capsule-osseous layer of the iliotibial band is found, which also extends from the region of the lateral intermuscular septum, blends with a confluence from the short head of the biceps femoris, and attaches just posterior to Gerdy’s tubercle. The biceps femoris tendon is also located in Seebacher’s layer I but is posterior to the intermuscular septum. The tendon inserts primarily into the posterolateral edge of the fibular head, but it has additional attachments to the tibia, lateral joint capsule, iliotibial tract, and LCL.13 Injuries to any or all of these musculotendinous structures can occur in posterolateral corner injuries. BIOMECHANICS Biomechanical testing has shown that the PCL has an ultimate load of approximately 1600 N.14 Ultimate loads for the individual components are 1120 N for the anterolateral bundle, 419 N for the posteromedial bundle, and 297 N for the meniscofemoral ligaments.15 Because the anterolateral bundle is the strongest component, most surgical techniques have focused on reconstructing this portion of the PCL. Biomechanical testing of the posterolateral structures in cadaveric specimens has shown that the PFL has a load to failure of 186 N compared with 309 N for the LCL.8 Sectioning studies have shown that the primary function of the PCL is to prevent posterior translation of the tibia. The PCL provides approximately 95% of the restraint to posterior drawer force.14 Secondary restraints to posterior translation include the meniscofemoral ligaments, the ligaments of the posterolateral corner, and the MCL.16 Coexisting injury to the secondary restraints increases the posterior laxity in the PCL-deficient knee.16 The PCL also functions as a secondary restraint to external rotation and varus loads.16 Sectioning of all posterolateral structures causes in-

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creased varus and external rotation laxity that is greatest at 30° of flexion.11,17 A small increase in posterior translation is seen, which is greatest at 30° to 45° of flexion.11 A coupled external rotation with posterior translation also occurs after isolated posterolateral sectioning. Additional cutting of the PCL causes a further increase in varus and external rotation laxity and a marked increase in posterior translation. Combined sectioning of the ACL and the posterolateral corner causes increased internal rotation laxity at 30° and 60° of flexion. The LCL is the primary restraint to varus loading. However, the PFL, popliteus tendon, and lateral joint capsule also play an important role in resisting varus bending, external rotation, and posterior translation forces.8,18 The posterolateral structures (ie, LCL, PFL, popliteus tendon, and lateral joint capsule) function as a unit to resist external tibial rotation and varus bending.19 In situ forces in the PCL increase from full extension to 90° of flexion.20 These loads are reduced with quadriceps loading and are increased with hamstring loading. The popliteus muscle also reduces the in situ forces on the PCL. In situ forces on the posterolateral structures resulting from posterior tibial loading are greatest at full extension; sectioning of the PCL increases posterolateral forces at all angles of knee flexion. Complete sectioning of the posterolateral structures increases the forces exerted on the native cruciate ligaments and on ACL and PCL grafts.21,22

DETECTION AND EVALUATION OF INJURY HISTORY Patients with acute isolated PCL tears may present with relatively benign symptoms and initially complain of pain, swelling, and a sensation of the knee giving way. Patients with chronic PCL injuries may complain of pain and a sensation of instability, especially while decelerating or descending stairs. Injuries to multiple ligaments usually cause more severe pain and marked instability. Patients with acute posterolateral injuries complain of pain in the posterolateral aspect of the knee and usually report profound knee instability when attempting to ambulate. Marked lateral swelling and/or ecchymosis is commonly seen. Peroneal nerve symptoms occur in 15% of patients with posterolateral injuries.4 Patients with chronic posterolateral injuries complain of instability with hyperextension or with agility maneuvers and ambulate with a varus thrust gait. Pain with activity may be present in the medial joint line or in the posterolateral structures of the knee.

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Posterior Cruciate Ligament and Posterolateral Corner Injuries PHYSICAL EXAMINATION After a careful history is obtained, a complete physical examination of the knee should be performed. Range of motion, neurovascular status, gait, and alignment should be assessed and documented. A hemarthrosis can occur but is frequently small in isolated PCL ruptures. In PCL-deficient knees, the Lachman examination (used to evaluate ACL injuries) may appear abnormal as a result of the tibia resting in a posteriorly subluxed position. In this case, the Lachman examination may reveal increased anterior translation but a firm end point. This finding should raise suspicion of a PCL injury. Gait pattern is particularly important to assess in patients with suspected chronic posterolateral injuries. These patients may demonstrate a varus thrust pattern, where the lateral compartment of the knee opens up at foot strike. This pattern can be readily observed by viewing the patient’s walk from behind. The varus thrust is often accentuated in patients with a preexisting genu varus alignment. Some patients learn to alter their gait by walking with a flexed knee, thereby avoiding the thrust at foot strike.

Figure 3. Schematic illustration of the dial test. The patient is placed in the prone position with the knee flexed 30º, and the feet are externally rotated by the examiner. The test is considered positive if external rotation on the injured side is more than 10º greater than that on the normal side. (Adapted with permission from Veltri DM, Warren RF. Isolated and combined posterior cruciate ligament injuries. J Am Acad Orthop Surg 1993;1:70. Copyright © 1993, American Academy of Orthopaedic Surgeons.)

Tests of the PCL Posterior drawer test. The most accurate test to evaluate the PCL is the posterior drawer test performed with the knee flexed 90° and the tibia in neutral rotation.23 Before assessing posterior drawer, it is imperative to identify any posterior subluxation of the tibia. With the knee flexed 90°, the examiner should palpate the location of the medial tibial plateau in relation to the medial femoral condyle. Normally, the medial tibial plateau is 1 cm anterior to the medial femoral condyle. In the PCLinjured knee, the tibia is posteriorly subluxated in relation to the femur, causing a posterior sag. To ensure an accurate measurement of the posterior drawer, the examiner should first impart an anteriorly directed force to reproduce the normal tibiofemoral step-off. Posterior laxity of 3 to 5 mm constitutes a grade I injury (the medial tibial plateau remains anterior to the medial femoral condyle). Laxity of 5 to 10 mm indicates a grade II injury (the medial tibial plateau is flush with the medial femoral condyle). Laxity greater than 10 mm indicates a grade III injury (the medial tibial plateau is posterior to the medial femoral condyle). A grade III injury should raise suspicion of injuries to other ligaments. Quadriceps active drawer test. In this test, the patient is asked to contract the quadriceps with the knee flexed 90° and the foot stabilized. In a PCL-deficient knee, contraction of the quadriceps will translate the tibia anteriorly, visibly reducing the posterior sag.

Tests of the Posterolateral Corner Varus stress test. A varus stress test should be performed with the knee at 30° and 0° of flexion. The distal thigh is stabilized while the examiner applies varus stress to the knee by grasping the foot. The examiner then places a finger or thumb directly over the lateral joint line to estimate the amount of lateral joint opening. At 30° of flexion, lateral joint laxity 1 cm greater than the uninjured side usually indicates a complete tear of the LCL and other posterolateral structures. Smaller degrees of laxity suggest a partial tear of the LCL. A positive varus stress test at 0° of flexion indicates a severe posterolateral corner injury usually associated with an injury to the ACL and/or PCL. Dial test. The dial test (Figure 3) assesses external rotation laxity of the knee and should be performed at 30° and 90° of knee flexion.24 The patient should be in the prone position (ideally) or supine. The thighs are stabilized and the examiner applies an external tibial rotation force through the feet. At 30° of flexion, an increase in external rotation of greater than 10° to 15° compared with the normal knee is indicative of a posterolateral corner injury.25 An increase in external rotation laxity at 90° of flexion indicates a combined injury of the posterolateral corner and the PCL or ACL.26 Posterolateral drawer test. This test is performed by placing the knee in 90° of flexion with the foot fixed in 15° external rotation.27 A posterolateral rotation force is

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Posterior Cruciate Ligament and Posterolateral Corner Injuries

Figure 4. Anteroposterior radiograph of an 18-year-old woman who was ejected from a car in a motor vehicle accident. The patient sustained a severe varus injury to her right knee. Note the lateral joint line opening and the avulsion fracture of the head of the fibula (arcuate sign). At surgery, the patient was found to have tears of both the anterior cruciate and posterior cruciate ligaments in addition to the posterolateral corner.

applied, and the examiner assesses the amount of posterolateral rotation as compared with the normal knee. A positive test usually indicates a popliteus tendon or PFL injury. The reverse pivot shift test is a dynamic posterolateral drawer test,28 which is performed with the knee flexed to 60° and the foot externally rotated. A valgus stress is then applied to the knee as it is slowly extended. In the presence of a posterolateral corner injury, the knee is subluxed in the flexed position. With extension of the knee, a noticeable reduction occurs at approximately 25° of flexion because of the change in pull of the iliotibial band. External rotation recurvatum test. This test is performed by lifting the patient’s leg by the great toe while stabilizing the thigh.27 The test is positive if the knee demonstrates increased recurvatum (hyperextension) relative to the normal knee. An associated varus and external rotation alignment to the injured knee is common when this test is positive. A positive test indicates a severe posterolateral corner injury usually in association with an injury to the ACL and/or PCL. IMAGING Radiography Radiographs should be obtained in all patients with traumatic knee injuries and should include anteropos-

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terior, lateral, and patellofemoral views. Plain radiographs typically reveal no bony abnormalities in patients with PCL and/or posterolateral corner injuries. Occasionally, an avulsion fracture of the PCL off of the tibial plateau may be seen on the lateral or notch view. An avulsion fracture of the fibular styloid can also occur; this has been termed the arcuate sign (Figure 4). This fragment contains the attachment site of the PFL. A recent study found that all patients with an arcuate sign also had disruption of the PCL.29 A weightbearing posteroanterior radiograph with the knee flexed 45° should be obtained in chronic PCL-injured knees to assess for medial compartment arthrosis. Stress radiographs can be useful for diagnosing PCL injuries.30 An 89 N posterior load is applied to the proximal tibia, and lateral radiographs are obtained of both knees in 70° of flexion. Increased posterior translation of 8 mm or more on stress radiographs is indicative of a complete PCL tear. Smaller increases (4 to 7 mm) in posterior translation suggest a partial PCL injury. Patients with chronic posterolateral knee injuries should have weightbearing long-leg (hip to ankle) radiographs obtained to evaluate the mechanical alignment of the extremity.31 Posterolateral reconstructions will frequently fail in patients with varus alignment of the extremity; these patients may require a tibial osteotomy prior to posterolateral ligament reconstruction. Magnetic Resonance Imaging Magnetic resonance imaging (MRI) is useful for evaluating patients with traumatic knee injuries. The images should include thin sections using high field magnets to visualize the individual structures of the posterolateral corner. MRI can accurately identify the presence and location of tears of the PCL, LCL, biceps tendon, popliteus tendon, or iliotibial band and can reveal meniscal or articular cartilage pathology; however, MRI is less accurate for evaluating the PFL.32 A secondary sign of PCL injury is a contusion pattern on the proximal anterior tibia.33 Secondary signs of posterolateral corner injury include separation of the coronary ligament of the lateral meniscus and a bony contusion on the anteromedial femoral condyle or medial tibial plateau (Figure 5).32 Although quite sensitive in detecting ligamentous injuries, MRI cannot determine the amount of laxity present or predict functional stability. Additionally, because PCL tears may heal in an elongated state, the PCL can appear intact by MRI criteria while there is increased posterior laxity on physical examination.34 Thus, it is important that information from MRI be combined with a careful physical examination and stress radiographs to best determine the injury pattern.

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Posterior Cruciate Ligament and Posterolateral Corner Injuries Bone Scan In chronic PCL tears there may be increased contact loads in the medial and patellofemoral compartments.35 A bone scan can identify early degenerative changes in these compartments prior to any findings on plain radiographs. A positive bone scan in a patient with instability and pain is an indication for PCL reconstruction.36

TREATMENT OF PCL INJURIES NATURAL HISTORY Several studies have investigated the natural history of PCL-deficient knees.2,37–39 Approximately two thirds of the patients in these studies were able to return to athletics. There is a correlation between a good functional outcome and the ability to regain quadriceps strength in the affected leg of at least 100% of the unaffected leg.37 In contrast, the amount of posterior laxity does not correlate with the functional result. However, it remains unknown what effect posterior instability has on articular cartilage in the long term. In a cadaver model, sectioning the PCL did increase contact pressures in the medial and patellofemoral compartments.22 Retrospective clinical studies have described degenerative changes in some knees with chronic PCL ruptures.40,41 However, no prospective studies assessing the occurrence of degenerative changes after isolated PCL tears have been completed to date. Patients with PCL tears and associated ligamentous injuries that are treated nonoperatively usually have symptoms of pain and instability that limit their function. Surgery is usually recommended for such patients. APPROACH TO TREATMENT Nonoperative treatment should be undertaken for most isolated grade I and II PCL tears.5 A brief period of immobilization should be followed by range of motion and quadriceps-strengthening exercises; however, hamstring-strengthening exercises should be delayed for 4 months to minimize their antagonistic effect on PCL function. Return to sport may be considered after range of motion and strength have returned to normal; this may be as short as 4 weeks. The treatment of grade III PCL tears is more controversial. Some authors recommend PCL reconstruction for isolated grade III injuries, whereas others advocate a nonoperative approach. Nonoperative treatment of isolated grade III PCL tears would include immobilization in full extension for 2 to 4 weeks followed by range of motion and quadriceps-strengthening exercises. Although several PCL functional braces are com-

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Figure 5. Coronal T2-weighted magnetic resonance imaging scan of a 32-year-old man who sustained a varus-external rotation injury to his right knee while playing rugby. The scan shows complete avulsion of the lateral collateral ligament off of the fibula and complete avulsion of the lateral capsule and coronary ligament from the tibia. Also note the bony contusion on the extreme medial aspect of the medial femoral condyle.

mercially available, their benefit has not been proven. Posterior laxity greater than 10 mm is highly suggestive of an associated ligamentous injury, especially to the posterolateral corner or MCL. The presence of a combined ligamentous injury pattern is an indication for operative treatment. Additional indications for surgical treatment include: (1) an avulsion fracture involving the PCL tibial insertion, (2) an avulsion of the femoral attachment of the PCL, and (3) functional instability and pain after nonoperative treatment of an isolated PCL tear. Although prevention of late degenerative changes may be a logical rationale for surgery, PCL reconstruction in a cadaver model did not significantly improve contact pressures in the medial and patellofemoral compartments.35 Additionally, no clinical studies have shown a decreased incidence of degenerative changes in patients undergoing PCL reconstruction. SURGICAL TREATMENT Techniques The past decade has seen significant improvement in surgical techniques for treating PCL injuries. When performing a PCL reconstruction, several options must be considered. Autograft versus allograft. A variety of grafts have

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Posterior Cruciate Ligament and Posterolateral Corner Injuries

A

B

Figure 6. Options for patient positioning for tibial inlay technique. (A) Lateral decubitus position, with knee flexion and hip external rotation for anterior access. (B) With leg extension, access to the popliteal fossa is possible. (Adapted from Berg EE. Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995;11:70. Copyright 1995, with permission from the Arthroscopy Associates of North America.)

been described, each with inherent advantages.42 Autograft options include the patellar tendon, the central quadriceps tendon, and the semitendinosus and gracilis tendons. Allograft tissue (eg, patellar tendon, Achilles tendon) also is an option. Secure fixation is easier to achieve with grafts that contain their bony attachments; however, grafts without bony attachments are more easily passed through bony tunnels. As quadriceps strength is an important factor in the outcome of the PCL-injured knee, careful consideration must be undertaken before choosing a patellar tendon or quadriceps tendon autograft. The graft harvest may weaken the extensor mechanism of the knee and affect the final functional result. PCL reconstructions using the semitendinosus and gracilis tendons have resulted in a large number of patients with persistent laxity and instability. For these reasons, most authors have used allograft tissue to reconstruct the PCL. In the case of multiple ligamentous injuries, allografts offer the additional benefit of avoiding further insult to the already severely traumatized knee. Trans-tibial tunnel versus tibial inlay technique. The next consideration for PCL reconstruction is whether to use the trans-tibial tunnel or the tibial inlay technique. At this time, there are no prospective studies comparing these 2 techniques.

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The trans-tibial tunnel technique involves the placement of a guide pin from the anterior aspect of the proximal tibia to the posterior tibial insertion of the PCL. Care must be taken to protect the popliteal artery, which lies just posterior to the capsule where the pin exits. After correct pin placement is confirmed with radiographs and/or an arthroscope, the tibial tunnel is drilled from anterior to posterior over the guide pin. The advantages of this technique include single positioning of the patient and the avoidance of posterior dissection. A disadvantage is that the graft must be maneuvered through the sharp (“killer”) turn from the knee joint into the tunnel. Additionally, abnormal forces have been reported at the junction of a patellar tendon graft and the posterior tibia. In a cadaver model, this has been shown to have an abrading effect on the graft, which weakens the graft.43 The clinical importance of this effect is currently unknown. The tibial inlay technique uses a posterior approach to the knee through the plane between the tendons of the medial head of the gastrocnemius muscle and the semimembranosus muscle. Lateral retraction of the medial head of the gastrocnemius protects the neurovascular bundle and exposes the posterior capsule.44 The capsule is incised longitudinally to directly expose the PCL tibial attachment. An osteotome or burr is used to create a trough in the posterior tibia beginning at the PCL insertion. The bone block of the graft is inlaid on this trough and secured with 1 or 2 screws. Advantages of this technique are the ease of graft passage and avoidance of the killer turn. One disadvantage is that the surgeon must expose both the front and back of the knee. This requires repositioning the patient intraoperatively or placing the patient in a lateral decubitus position and rotating the hip to allow access to the anterior and posterior aspects of the knee (Figure 6). Another potential disadvantage is that graft tunnel mismatch can occur on the femur. Single bundle versus double bundle technique. The final consideration in PCL reconstruction involves the choice of a single or a double bundle technique. As previously noted, the anterolateral bundle is the larger, stronger functional component of the PCL and takes most of the load when the knee is in a flexed position. The goal of single bundle reconstruction is to recreate the anterolateral bundle. With this technique, a single femoral tunnel is drilled to the origin of the anterolateral bundle. The alternative (double bundle) technique involves using a split graft or 2 grafts to recreate both bundles of the PCL. This technique is technically demanding, as it requires 2 femoral tunnels to be drilled and 2 separate graft passages into these tunnels. The anterolateral bundle is tensioned and secured at 90° of flexion,

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Posterior Cruciate Ligament and Posterolateral Corner Injuries and the posteromedial bundle is secured at 30° of flexion. The major theoretical advantage of the double bundle technique is that reconstruction of both the anterolateral and posteromedial bundles will better reproduce PCL function throughout all angles of knee flexion. In a cadaver model, Harner et al45 reported that the addition of the posteromedial bundle decreased posterior laxity by 3.5 mm at all flexion angles. Conversely, in a small clinical series, there were no significant differences in objective stability or functional outcome between a single bundle and a double bundle reconstruction.46 At this time, it is unclear whether the theoretical advantage of the double bundle technique will translate into improved clinical outcomes. Both techniques require careful attention when drilling the femoral tunnel so that a sufficient rim of subchondral bone remains. Otherwise, osteonecrosis of the medial femoral condyle may occur.47,48

tween 9 and 12 months after surgery. The role of functional bracing after PCL reconstruction is unknown.

Outcomes Although most clinical reports on PCL reconstructions indicate an objective improvement in knee stability and functional activities in most patients, a significant number of patients have persistent posterior laxity.46 Addressing concomitant ligament instabilities at the time of PCL reconstruction appears to be improving the functional and objective results.3,49 It is hoped that the newer techniques described above will also improve the results of PCL reconstruction. At present, the surgeon must balance the theoretical advantages of these techniques with the increased technical difficulty required. Long-term prospective studies are needed to determine the optimal technique for PCL reconstruction.

NATURAL HISTORY The natural history of posterolateral corner injuries is not well defined, in part, because these injuries are uncommon and are often not diagnosed acutely. Additionally, since most of these injuries occur in combination with a cruciate ligament injury, it is difficult to isolate the effect of the posterolateral corner injury.

Rehabilitation The goals of rehabilitation after PCL reconstruction are to restore range of motion and strength to the knee while minimizing stress on the graft in the early postoperative period. An initial period of immobilization with the leg in full extension allows for minimal forces on the graft. Full range of motion should be obtained by 6 weeks. Quadriceps-setting exercises are allowed immediately. Closed chain and open chain quadriceps progressive resistance exercises are allowed when range of motion and pain level permit. Open chain hamstring exercises cause high forces in the graft and may induce stretching of the graft. These exercises should be avoided until the graft has adequately matured. A gradual return to running and agility and sports-specific training occurs. Return to full athletic activities should be delayed until the quadriceps strength is greater than 90% of the contralateral leg. This usually occurs be-

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Complications Arthrofibrosis, painful hardware, infection, delayed wound healing, and deep venous thrombosis can occur after any surgical procedure on the knee. Complications specific to PCL reconstructions include iatrogenic injury to the popliteal artery and osteonecrosis of the medial femoral condyle. Residual laxity is common after these procedures. Careful attention to surgical technique and rehabilitation can eliminate most of these complications.

TREATMENT OF POSTEROLATERAL CORNER INJURIES

APPROACH TO TREATMENT Partial (grade I or II) posterolateral corner injuries are managed nonoperatively.50 For the first 3 to 4 weeks after injury, the patient is kept immobilized in full extension, with no weightbearing. Straight leg raises and quadriceps exercises are allowed only in the immobilizer. The patient should then work toward regaining motion and strength, but isolated hamstring exercises should be avoided for 6 to 10 weeks. Patients with complete (grade III) posterolateral corner injuries generally do poorly with nonoperative treatment.51 Additionally, it has been shown that results with acute repair of the posterolateral structures are better than those with delayed reconstructions.50 Primary repair is possible in the first 2 weeks after injury; however after 3 weeks, extensive scarring occurs, making identification and repair of the posterolateral structures difficult. Patients with chronic posterolateral injuries (either from a delay in diagnosis or from associated injuries that preclude early treatment) will require a reconstruction of the posterolateral structures. SURGICAL TREATMENT Techniques Acute injuries to the posterolateral corner should be treated with a primary repair. Chronic posterolateral

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Posterior Cruciate Ligament and Posterolateral Corner Injuries

LCL

PLT

PLT PFL

LCL

Figure 7. Schematic illustration of a posterolateral corner reconstruction that replaces the lateral collateral ligament (LCL), popliteofibular ligament (PFL), and popliteus tendon (PLT). (Adapted with permission from LaPrade RF, Johansen S, Wentorf FA, et al. An analysis of an anatomical posterolateral knee reconstruction: an in vitro biomechanical study and development of a surgical technique. Am J Sports Med 2004;32:1410.)

injuries require advancement or reconstruction of the injured structures; however, some surgeons prefer to perform a posterolateral reconstruction for all chronic posterolateral injuries. If the posterolateral structures are irreparable or deficient, a posterolateral reconstruction must be performed. Surgical approach. A surgical approach to the posterolateral structures has been described that provides access to all potentially injured posterolateral structures.12 An extended curvilinear incision is made overlying the lateral epicondyle and centered distally between Gerdy’s tubercle and the anterior aspect of the fibular head. This exposes the superficial fascia of the iliotibial tract and biceps femoris. Three fascial incisions are then made. • The first fascial incision, along the posterior aspect of the biceps femoris muscle and tendon, allows exposure of the peroneal nerve. The peroneal nerve should always be identified and protected during posterolateral corner surgery. This fascial incision also provides access to the popliteus muscle, the tibial attachments of the posterolateral capsule, and the lateral gastrocnemius muscle. • The second fascial incision is made in the interval between the superior aspect of the

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biceps femoris and the posterior aspect of the iliotibial tract. Dissection in this interval gives exposure to the distal attachments of the LCL, PFL, and posterolateral capsule. • The third fascial incision splits the iliotibial tract over the lateral epicondyle and is extended to Gerdy’s tubercle. This incision provides access to the proximal attachments of the LCL and PFL, as well as the femoral attachments of the posterolateral capsule. Primary repair. The goals of primary repair are to achieve anatomic reduction and secure fixation of all posterolateral structures to allow early range of motion.50 Avulsions of the LCL or popliteus tendon off the femur are repaired with suture anchors, a screw and washer, or direct suture to bone. Large arcuate fractures of the fibular head can be secured to the fibular shaft with a 6.5-mm screw and washer. Smaller fragments are repaired with nonabsorbable sutures passed through the fibular head or with suture anchors. Midsubstance tears of the LCL can be repaired with whipstitch sutures but may require augmentation with autograft or allograft. Capsular injuries usually occur as an avulsion off the tibia or femur and can be repaired with a series of suture anchors. Biceps tendon and iliotibial band injuries are primarily sutured to soft tissue or bone. Posterolateral advancement. If the posterolateral complex is structurally intact but lax, a posterolateral advancement can be performed.35 A bony flap containing the femoral attachment of the LCL, popliteus tendon or PFL, and lateral gastrocnemius tendon is osteotomized and advanced proximally in line with the LCL. It is tensioned at 30° of flexion and secured with a staple or screw and washer. This may improve posterolateral laxity in patients with a lax but structurally intact posterolateral complex. Posterolateral reconstruction. A variety of surgical procedures to reconstruct the posterolateral structures have been described.52–55 Depending on the pathology and the surgeon’s preference, one can reconstruct the LCL, PFL, and/or popliteus tendon using autograft or allograft tissue. Regardless of the technique, the goal is to secure adequate tissue at the anatomic attachments of the ligaments that are to be reconstructed. Anatomic placement and secure fixation are required to allow early range of motion. A recent biomechanical study showed that anatomic reconstruction of the LCL, PFL, and popliteus tendon was able to restore static stability to knees with grade III posterolateral injuries (Figure 7).55 Patients with a varus mechanical alignment of the lower limb should have a valgus-producing osteotomy

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Posterior Cruciate Ligament and Posterolateral Corner Injuries performed prior to any posterolateral reconstruction. Although most reported series of posterolateral reconstruction have small numbers of patients with variable injury patterns, it appears that these reconstructions are able to restore functional stability to the majority of patients.24,52,53 No comparative clinical studies have been published to help the surgeon decide which technique is most beneficial. Rehabilitation Rehabilitation after posterolateral repair or reconstruction must be individualized depending on the injury pattern and the quality of the tissue at the time of repair.50 The principles of rehabilitation are: (1) early range of motion should be initiated within a safe zone determined at the time of surgery, (2) full range of motion should be achieved by 6 to 8 weeks, (3) hyperextension should be avoided to prevent stretching of the posterolateral capsule, (4) weightbearing should be avoided for 6 to 8 weeks, and (5) open chain hamstring and abduction exercises should be avoided for 4 months. Closed chain and quadriceps exercises are emphasized in the early postoperative period. Return to full athletic competition usually occurs after 12 months. Complications Complications specific to posterolateral corner injuries can include residual laxity, arthrofibrosis, painful fixation hardware, and peroneal nerve injury. Careful attention to the complex anatomy, surgical technique, and rehabilitation is necessary to minimize the risk of these complications.

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Posterior Cruciate Ligament and Posterolateral Corner Injuries Am J Sports Med 1999;27:469–75. 22. LaPrade RF, Muench C, Wentorf F, Lewis JL. The effect of injury to the posterolateral structures of the knee on force in posterior cruciate ligament graft. A biomechanical study. Am J Sports Med 2002;30:233–8. 23. Covey DC, Sapega AA. Injuries of the posterior cruciate ligament. J Bone Joint Surg Am 1993;75:1376–86. 24. Veltri DM, Warren RF. Isolated and combined posterior cruciate ligament injuries. J Am Acad Orthop Surg 1993; 1:67–75. 25. Miller MD, Cooper DE, Fanelli GC, et al. Posterior cruciate ligament: current concepts. Instructional Course Lectures 2002;51:347–51. 26. Wroble RR, Grood ED, Cummings JS, et al. The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee. Am J Sports Med 1993;21: 257–63. 27. Hughston JC, Norwood LA Jr. The posterolateral drawer test and external rotational recurvatum test for posterolateral instability of the knee. Clin Orthop 1980;147:82–7. 28. Jakob RP, Hassler H, Staeubli HU. Observations on rotatory instability of the lateral compartment of the knee: experimental studies on the functional anatomy and pathomechanism of the true and reverse pivot shift sign. Acta Orthop Scand Suppl 1981;191:1–32. 29. Huang GS, Yu JS, Munshi M, et al. Avulsion fracture of the head of the fibula (the ‘arcuate sign’): MR imaging findings predictive of injuries to the posterolateral ligaments and posterior cruciate ligament. Am J Roentgenol 2003;180:381–7. 30. Hewett TE, Noyes FR, Lee MD. Diagnosis of complete and partial posterior cruciate ligament ruptures. Stress radiography compared with KT-1000 arthrometer and posterior drawer testing. Am J Sports Med 1997;25:648–55. 31. Noyes FR, Barber-Westin SD. Surgical restoration to treat chronic deficiency of the posterolateral complex and cruciate ligaments of the knee joint. Am J Sports Med 1996;24:415–26. 32. Ross G, Chapman AW, Newberg AR, Scheller AD Jr. Magnetic resonance imaging for the evaluation of acute posterolateral complex injuries of the knee. Am J Sports Med 1997;169:1641–7. 33. Bari V, Murad M. Accuracy of magnetic resonance imaging in the knee. J Coll Physicians Surg 2003;13:408–11. 34. Shelbourne KD, Jennings RW, Vahey TN. Magnetic resonance imaging of posterior cruciate ligament injuries: assessment of healing. Am J Knee Surg 1999;12:209–13. 35. Skyhar MJ, Warren RF, Ortiz GJ, et al. The effects of sectioning of the posterior cruciate ligament and the posterolateral complex on the articular contact pressures within the knee. J Bone Joint Surg Am 1993;75:694–9. 36. Fanelli GC, Giannotti BF, Edison CJ. Arthroscopically assisted combined posterior cruciate ligament/posterior lateral complex reconstruction. Arthroscopy 1996;12:521–30. 37. Parolie JM, Bergfeld JA. Long term results of non-operative treatment of isolated posterior cruciate ligament injuries in the athlete. Am J Sports Med 1986;14:35–8.

38. Torg JS, Barton TM, Pavlov H, Stine R. Natural history of the posterior cruciate ligament-deficient knee. Clin Orthop 1989;246:208–16. 39. Fowler PJ, Messieh SS. Isolated posterior cruciate ligament injuries in athletes. Am J Sports Med 1987;15:553–7. 40. Boynton MD, Tietjens BR. Long-term followup of the untreated isolated posterior cruciate ligament-deficient knee. Am J Sports Med 1996;24:306–10. 41. Cross MJ, Powell JF. Long-term followup of posterior cruciate ligament rupture: a study of 116 cases. Am J Sports Med 1984;12:292–7. 42. Hoher J, Scheffler S, Weiler A. Graft choices and graft fixation in PCL reconstructions. Knee Surg Sports Traumatol Arthrosc 2003;11:297–306. 43. Markolf KL, Zemanovic JR, McAllister DR. Cyclic loading of posterior cruciate ligament replacements fixed with tibial tunnel and tibial inlay methods. J Bone Joint Surg Am 2002;84:518–24. 44. Burks RT, Schaffer JJ. A simplified approach to the tibial attachment of the posterior cruciate ligament. Clin Orthop 1990;254:216–9. 45. Harner CD, Janaushek MA, Kanamori A, et al. Biomechanical analysis of a double-bundle posterior cruciate ligament reconstruction. Am J Sports Med 2000;28:144–51. 46. Houe T, Jorgensen U. Arthroscopic posterior cruciate ligament reconstruction: one vs. two-tunnel technique. Scand J Med Sci Sports 2004;14:107–11. 47. Miller MD, Gordon WT. Posterior cruciate ligament reconstruction: tibial inlay technique–principles and procedure. Operative Tech Sports Med 1999;7:127–33. 48. Clancy WG Jr, Bisson LJ. Double tunnel technique for reconstruction of the posterior cruciate ligament. Operative Tech Sports Med 1999;7:110–7. 49. Cooper DE, Stewart D. Posterior cruciate ligament reconstruction using single-bundle patella tendon graft with tibial inlay fixation. 2- to 10-year follow-up. Am J Sports Med 2004;32:346–60. 50. LaPrade RF, Wentorf F. Diagnosis and treatment of posterolateral knee injuries. Clin Orthop 2002;402:110–21. 51. Kannus P, Bergfeld J, Jarvinen M, et al. Injuries to the posterior cruciate ligament of the knee. Sports Med 1991;12:110–31. 52. Noyes FR, Barber-Westin SD. Surgical reconstruction of severe chronic posterolateral complex injuries of the knee using allograft tissues. Am J Sports Med 1995;23:2–12. 53. Wascher DC, Grauer JD, Markoff KL. Biceps tendon tenodesis for posterolateral instability of the knee. An in vitro study. Am J Sports Med 1993;21:400–6. 54. 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;26:656–62. 55. LaPrade RF, Johansen S, Wentorf FA, et al. An analysis of an anatomical posterolateral knee reconstruction: an in vitro biomechanical study and development of a surgical technique. Am J Sports Med 2004;32:1405–14.

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