Chấn thương dây chằng ppsx

Vol 9, No 5, September/October 2001 297 Treatment recommendations for posterior cruciate ligament (PCL) injuries have evolved as our understanding of the natural history of the injury increases and surgical techniques improve. Experience with treatment of PCL tears lags behind that of anterior cruciate ligament (ACL) tears because they are less common and are more difficult to treat surgically. Some surgeons have ample experience treating ACL tears; however, because of the het- erogeneity of PCL injuries, relatively few surgeons have accumulated sufficient numbers of patients to study the effects of different treatment modalities. The PCL treatment con- troversy has been difficult to resolve because of the diverse nature of PCL injuries, the poor understanding of the natural history of untreated injuries, and the limitations of the clinical studies performed. The most controversial issue remains the indi- cations for surgical intervention. Epidemiology Posterior cruciate ligament tears have historically been underdiag- nosed because they are often asymp- tomatic. It now appears that PCL tears occur more frequently than has been previously appreciated, ac- counting for one fifth or more of all knee ligament injuries. Shelbourne et al 1 recently reviewed the literature and reported that PCL tears occur in 1% to 44% of all acute knee injuries. A renewed interest in PCL injuries has led to improved understanding of both the injury mechanism and the presenting signs and symptoms. Mechanism of Injury Posterior cruciate ligament injuries can be a consequence of both trauma and sports participation. The most common mechanism is a posteriorly directed force to the proximal tibia of the flexed knee. 2 This frequently occurs during a motor vehicle accident when a knee of the driver or the front-seat passenger strikes the dashboard on impact. A similar mechanism can occur in contact sports such as wrestling and football when striking an opponent’s lower leg can drive the tibia back- ward, rupturing the PCL (Fig. 1). The posterior force can be combined with a varus or rotational force, leading to concomitant lateral or posterolateral injury. Another mechanism is a fall onto a flexed knee, particularly when the foot is plantar- flexed. This is a common cause of isolated PCL tears in sports. 3 For example, this mechanism is ob- served in football when a player lands forcefully on a flexed knee. Dr. Cosgarea is Associate Professor, Depart- ment of Orthopaedic Surgery, Johns Hopkins Sports Medicine, Baltimore, Md. Dr. Jay is in private practice in Williamsville, NY. Reprint requests: Dr. Cosgarea, Johns Hopkins Sports Medicine, Suite 215, 10753 Falls Road, Lutherville, MD 21093. Copyright 2001 by the American Academy of Orthopaedic Surgeons. Abstract Posterior cruciate ligament (PCL) injuries commonly occur during sports participation or as a result of motor vehicle accidents. Careful history taking and a comprehensive physical examination are generally sufficient to identify PCL injuries. Most authors recommend nonoperative treatment for acute isolated PCL tears. This involves initial splinting in extension followed by range-of- motion and strengthening exercises. Recovery of quadriceps strength is necessary to compensate for posterior tibial subluxation and to facilitate return to preinjury activity levels. In isolated PCL tears, surgical treatment is reserved for acute bone avulsions and symptomatic chronic high-grade PCL tears. Arthroscopic single-tunnel reconstruction techniques will improve posterior laxity only moderately. Newer double-tunnel and tibial-inlay techniques offer theoretical advantages, but the available clinical results are only preliminary. When a PCL injury occurs in combination with other ligament injuries, most patients will require surgical treatment. J Am Acad Orthop Surg 2001;9:297-307 Posterior Cruciate Ligament Injuries: Evaluation and Management Andrew J. Cosgarea, MD, and Peter R. Jay, MD Other indirect mechanisms of injury that occur during athletic participation involve cutting, twisting, and hyperextension. Although these mechanisms are less commonly the cause of isolated PCL injuries, it is important to recognize them, as they often lead to combined ligament injuries. 4 Anatomy The PCL originates in an irregular semicircle on the lateral border of the medial femoral condyle where the roof of the intercondylar notch joins the wall. 2,5 The midpoint of the PCL attachment is approximately 1 cm posterior to the articular car- tilage. 2 The PCL inserts approximately 1.0 to 1.5 cm inferior to the posterior rim of the tibia in a de- pression between the posterior medial and lateral tibial plateaus called the PCL facet, or fovea. The location of the tibial insertion may complicate reconstruction techniques due to the close proximity of the popliteal neurovascular bundle. The average length of the PCL is 38 mm, and its average width is 13 mm. 6 The PCL originates in an anterior-to-posterior direction on the femur and attaches in a lateral- to-medial direction on the tibia. The PCL can be described as having multiple bundles or fiber regions. In a simplified functional model, the PCL can be considered to have two bundles (anterolateral and posteromedial bands), which are named for their specific insertion positions on the femur (anterior or posterior) and tibia (lateral or medial) 7 (Fig. 2). The anterolateral band is larger and stronger than the posteromedial band. Biomechanics Biomechanical studies of PCL fiber- attachment sites have shown that very little of the PCL is truly iso- metric during the knee flexion arc. Because of differences in anatomic origin and insertion, the anterolateral band becomes tighter (and is, therefore, relatively more important) in knee flexion, while the posteromedial band plays a relatively greater role in stabilizing the knee during extension. 7 During the flexion- extension cycle, tension in the two bundles develops in a reciprocal fashion; this fact explains some of the difficulty surgeons have had in trying to reproduce normal knee kinematics with a single-graft PCL reconstruction. Biomechanical studies have also shown that alteration of the normal femoral attachment sites leads to greater differences in graft tension during knee flexion than alteration of the tibial attachment site. This has led to an emphasis on determining the proper placement of the femoral tunnel during PCL reconstruction. 7 The PCL is the primary restraint to posterior tibial translation. It re- sists 85% to 100% of a posteriorly directed knee force at both 30 and 90 degrees of flexion. 8 The lateral collateral ligament (LCL), posterolateral corner, and medial collateral ligament (MCL) are important secondary restraints. 7 They play a minimal role in resisting posterior translation when the PCL is intact, but play a vital role in maintaining stability during rehabilitation of a patient with a torn PCL. 7 The amount of pathologic displacement increases substantially when both primary and secondary restraints are torn. Loss of the PCL results in an increase in pos- PCL Injuries Journal of the American Academy of Orthopaedic Surgeons 298 Figure 1 Mechanism of a PCL tear during a football tackle. (Adapted with permission from Miller MD, Harner CD, Koshiwaguchi S: Acute posterior cruciate ligament injuries, in Fu FH, Harner CD, Vince KG [eds]: Knee Surgery. Baltimore: Williams & Wilkins, 1994, p 750.) Figure 2 Anatomy of the PCL insertion. A, Outline of the anterolateral bundle (AL) and posteromedial bundle (PM) of the PCL tibial insertion. B, Femoral origin. (Adapted with permission from Harner CD, Hoher J: Evaluation and treatment of posterior cruciate ligament injuries. Am J Sports Med 1998;26:471-482.) A B AL PM AL PM terior translation to a maximum of 15 to 20 mm at 90 degrees of flexion. 8 Concomitant loss of the LCL, MCL, or posterolateral corner results in even greater increases in posterior translation. The PCL is also a secondary restraint to external rotation, an important fact when dealing with concomitant posterolateral corner injuries. 7 The posterolateral corner is the primary restraint to external rotation and aids the PCL in preventing pathologic posterior translation. 3,7 Damage to posterolateral structures results in higher forces in the intact native PCL. 3,7 Clinical Evaluation Careful history taking is an essential part of evaluating the patient with a PCL injury. Patients with partial or even complete isolated PCL tears usually present with relatively benign symptoms. Therefore, it is essential that the clinician have a thorough understanding of the spectrum of pathologic changes in the knee in order to be able to deduce which mechanism of injury described by the patient may be responsible for a PCL injury. Being cognizant of the time interval from injury to evaluation is very important, as the pre- sentation and the findings from the physical examination moderate substantially as time passes. The physical examination should begin by observing gait and check- ing static weight-bearing alignment. The skin is assessed for signs of external trauma, such as an abrasion or contusion, particularly over the proximal tibia. Evaluation of acute knee injuries can be challenging, as patients who have sustained an isolated PCL tear may have very little pain and only a small effusion. Knee motion may be nearly symmetrical compared with the normal contralateral knee or substantially decreased if there are concomitant injuries. It is crucial to examine the knee for signs of collateral ligament and posterolateral corner disorders. After palpating the LCL and MCL, varus and valgus stress testing should be performed with the knee in both full extension and 30 degrees of flexion. The posterior drawer test, performed at 90 degrees of flexion, is the most accurate test for PCL injury. 3,5,6 It is critical to recognize that if the tibia is resting in a posteriorly subluxated position, the result may be a false-positive Lachman or anterior drawer test. In most normal knees, the medial tibial plateau is approximately 1 cm anterior to the adjacent medial femoral condyle. 3,7 If the examiner cannot palpate the normal 1-cm step-off or if the consis- tency of the end point on posterior drawer testing is soft, a PCL injury should be suspected. If the PCL tear is incomplete, pal- pation of the tibial plateau–medial femoral condyle step-off forms the basis for the most commonly used grading scheme. With a grade 1 tear, the tibial plateau remains anterior to the medial femoral condyle with manual posterior translation. In grade 2 tears, the tibial plateau is palpated flush with the condyle. In grade 3 tears, the plateau is posterior to the condyle. Many authors believe that a grade 3 PCL tear must involve other ligamentous structures, most commonly the posterolateral corner. 7,9 Shelbourne et al 1 have pointed out that only 2 weeks from injury, patients often have no pain and a firm end point on posterior drawer testing. 1 The KT-1000 arthrometer (MEDmetric Corp, San Diego, Calif) can be used to objec- tively quantify posterior translation. This kind of instrumented laxity measurement is particularly useful when trying to compare or report surgical results. The posterior sag test is performed with the knee flexed 90 degrees and the foot resting on the examination table. When the PCL is torn, the examiner may see an abnormal con- tour or sag centered at the proximal anterior tibia. With the quadriceps active test (Fig. 3), the examiner stabilizes the foot and then asks the patient to slide the foot down the Andrew J. Cosgarea, MD, and Peter R. Jay, MD Vol 9, No 5, September/October 2001 299 Figure 3 Quadriceps active test. The examiner asks the patient to slide the foot down the table. Quadriceps contraction causes the tibia to translate anteriorly from a subluxated position, confirming PCL insufficiency. (Adapted with permission from DeLee JC, Bergfeld JA, Drez D Jr, Parker AW: The posterior cruciate ligament, in DeLee JC, Drez D Jr [eds]: Orthopaedic Sports Medicine: Principles and Practice. Philadelphia: WB Saunders, 1994, vol 2, p 1383.) examination table. When the quadriceps muscles contract, the examiner will observe reduction of the posteriorly subluxated tibia. Interpretation of these tests is easier with higher- grade and chronic PCL tears. The dynamic posterior shift test is performed with the patient’s hip flexed 90 degrees. Starting with the knee flexed, the examiner slowly extends the patient’s knee until the posteriorly subluxated tibia suddenly reduces with a clunk as the knee reaches full extension. The reverse pivot shift test is used to evaluate posterolateral stability. 2,3 The examiner externally rotates the foot and brings the knee into extension as a valgus stress is applied to the knee. Palpable reduction of the displaced tibia is considered a positive test, but is present bilaterally in one third of normal subjects. The posterolateral drawer test is performed with the knee flexed 90 degrees and externally rotated 15 degrees. With a positive test, the tibia rotates posteriorly and laterally off the lateral femoral condyle. 2 The tibial external rotation test (also called the dial test) is performed with the knee in both 30 and 90 degrees of flexion. It is considered positive when the medial border of the foot or the tibial tubercle externally rotates 10 to 15 degrees or more than the contralateral side. 10 Increased external rotation at 30 and 90 degrees is consistent with a posterolateral corner injury. With a combined PCL and posterolateral corner injury, greater increases in external rotation are noted, especially at 90 degrees. 8 Radiologic Evaluation Patients who sustain knee trauma should undergo a complete radiographic evaluation consisting of anteroposterior (AP), lateral, sun- rise, and tunnel views. Occasion- ally, avulsion fractures of the PCL tibial insertion will be identified. Avulsion fractures may also be seen at the LCL attachment on the fibular head (Fig. 4, A). Oblique views are sometimes helpful in ruling out tibial plateau fractures. Calcification adjacent to the medial femoral epicondyle (Pellegrini-Stieda lesion) suggests an old MCL injury (Fig. 4, B). Gross posterior subluxation can oc- casionally be seen on lateral views. Patients with chronic PCL tears are more likely to have evidence of degenerative changes in the medial and patellofemoral compartments. Weight-bearing 45-degree-flexed PA views are helpful in demonstrating tibiofemoral joint-space narrowing. Stress radiographs, with or without instrumentation, and contralateral comparison views can be helpful in borderline cases (Fig. 4, C). Magnetic resonance (MR) imaging is highly accurate in establish- ing the diagnosis and location of an acute tear, as well as in identifying concomitant ligamentous lesions PCL Injuries Journal of the American Academy of Orthopaedic Surgeons 300 A B C Figure 4 Radiographic appearance of PCL lesions. A, AP radiograph demonstrating an avulsion fracture of the fibular head (arrow) in a patient with combined PCL, posterolateral corner, and LCL injuries. B, AP radiograph demonstrates a Pellegrini-Stieda lesion (arrow), indicative of a chronic MCL injury. C, Posterior subluxation of the tibia seen on a lateral stress radiograph of a patient with combined grade 3 PCL and MCL injury. (Fig. 5). 7,11 There is some evidence that PCL tears can heal in an elon- gated position much like MCL tears. Chronic PCL tears may then look relatively normal on MR imaging. 12 Meniscal tears are less common with PCL tears than with ACL tears. 1 This is probably because the pathologic posterior tibial translation decreases the load on the posterior horns of the medial and lateral menisci. Bone bruises are also seen less commonly than with ACL tears. Bone scans may be helpful for evaluating patients with chronic PCL injuries who present with pain and instability. 7 Patients with chronic PCL tears have a higher risk of patellofemoral and medial- compartment degenerative changes. If bone scans show increased activity in these areas but no frank arthri- tis, the patient may be a candidate for PCL reconstruction. 3,11 Natural History of PCL Injury To compare the results of operative and nonoperative treatment, one must first know the natural history of the injury. The natural history of isolated PCL tears is relatively benign. It is not unusual to discover a PCL insufficiency as an incidental finding during routine preseason sports examinations. Parolie and Bergfeld 13 reported in 1986 that about 2% of college-senior football players at the National Football League predraft examination were consistently found to have chronic PCL-deficient knees. There are few natural history studies in the literature. Fowler and Messieh 14 prospectively followed 13 athletes with arthroscopically con- firmed isolated PCL injuries treated with physical therapy. The average age at injury was 22 years, and the average follow-up interval was 2.6 years. All patients were able to return to their previous activities without limitation. At follow-up examination, all 13 had slight translation on a posterior drawer test. The MR imaging studies of 3 patients with arthroscopically documented complete midsubstance tears revealed continuity of the ligament at 2-year follow-up. Parolie and Bergfeld 13 evaluated 25 athletes with isolated PCL tears at a mean of 6.2 years after injury. Eleven patients with acute injuries were treated with early range-of- motion and quadriceps-strengthening exercises. Patients returned to sports in a PCL brace at an average of 6 weeks after injury. Seventeen patients (68%) were able to return to sports at the preinjury level; 4 (16%), at a decreased level of performance. Twenty patients (80%) were satis- fied with their knee function. Pos- terior laxity as measured with a KT- 1000 arthrometer did not correlate with patient satisfaction or ability to return to sports. Mean quadriceps strength was 100% of that on the normal contralateral side or greater in patients who returned to sports and was less than 100% in patients who did not. The authors concluded that most athletes with isolated PCL injuries who are able to maintain quadriceps strength are able to suc- cessfully return to sports without surgery. Torg et al 15 documented the clinical course of 14 patients with isolated PCL instability. Eleven of the 14 sustained their injuries during sports activities. KT-1000 arthrometer testing showed a mean side-to- side difference of 5 mm (range, 3 to 8 mm) at 20 lb. Five patients (36%) were rated as having an excellent result (full return to the same or a similar sport). Seven patients (50%) were rated as having a good result (mild instability during sports participation, no problems with activities of daily living). They found no correlation between laxity or chro- nicity of injury and functional status. The authors concluded that individuals with isolated PCL insufficiency do not require surgical treatment. Shelbourne et al 1 prospectively followed up 133 athletes with isolated PCL tears treated nonoperatively over a mean interval of 5.4 years. Patients completed yearly question- naires, and approximately half returned for long-term follow-up examination. The authors found little change in PCL laxity grade from the initial injury to the final examination, and there was no correlation between objective and subjective knee scores and the PCL laxity grade. When a progression in laxity occurred, there was no deterioration in outcome. They were unable to identify particular characteristics that predisposed to deterioration of function. Regardless of the laxity grade, 50% of the patients were able to resume sports at the same level or higher, and 50% were unable to do so. Nonoperative Treatment Patients with acute isolated partial (grade 1 or 2) PCL tears can be treated with a brief period of splinting and Andrew J. Cosgarea, MD, and Peter R. Jay, MD Vol 9, No 5, September/October 2001 301 Figure 5 MR image demonstrates an acute complete PCL tear. protected weight bearing followed by an early range-of-motion and quadriceps-strengthening rehabilitation program. Recovery of strength and motion generally occurs quickly, and many patients are able to return to sports within 4 weeks. 7 Treatment of an acute grade 3 PCL tear is more controversial. Be- cause of the possibility of unrecog- nized posterolateral corner damage, which may result in further subluxation, the current recommendation is that the knee be splinted in full extension for 2 to 4 weeks. 7 Immo- bilization in extension decreases tension on the anterolateral bundle fibers and minimizes the antagonis- tic effect on the hamstring muscles. Cast immobilization may be indicated when such an injury happens in a pediatric patient, which is an infrequent occurrence. Early rehabilitation should emphasize range-of-motion and quadriceps-strengthening exercises; hamstring-strengthening exercises are initiated later. Use of functional braces may facilitate the return to sports activities, but has had limited success in patients with symptomatic chronic tears. Surgical Treatment The history of PCL reconstruction has been summarized by Andrews and Soffer, 16 who credit Hey Groves with the first report in the literature (in 1917). The semitendinosus tendon was detached distally, rerouted through femoral and tibial tunnels, and then reattached to the anterior tibial periosteum. Multiple varia- tions of this technique have been subsequently described; these involve the use of the proximally or distally detached semitendinosus tendon with or without the gracilis tendon. In general, these techniques have yielded disappointing results. Other grafts have been used to reconstruct the PCL, including a slip of iliotibial band, the proximally detached popliteus, and the lateral or medial meniscus. Since the early 1980s, there have been several series in which primary suture repair of the PCL was used, but most researchers have concluded that this technique does not restore PCL function. 5,16-19 The use of a bone–patellar tendon– bone autograft became popular in the 1980s. Clancy et al 17 demonstrated the efficacy of this technique in the rhesus monkey in a 1981 study. In 1983, Clancy et al 20 reported the results in a human series. Of the 23 patients, 21 had good to excellent objective results at a minimum follow-up interval of 2 years. The use of allograft patellar tendon and Achilles tendon has the advantage of decreased morbidity compared with autograft. 2,3,5-7 More recently, qua- druple hamstring and quadriceps free grafts have been used with increasing frequency. 3,7 Bone Avulsion Most authors agree that acute surgical intervention is indicated when there is a displaced PCL bone avulsion. 6,7 Avulsion fractures usually involve the tibial insertion and can be seen on routine lateral radiographs. The avulsion site is exposed through a standard posterior approach with the patient in the prone position. If the bone fragment is large, fixation is accomplished with one or two screws, with or without washers. For smaller or comminuted bone fragments, suture fixation through small drill holes may be necessary. The knee is braced in extension, and weight bearing is initially protected. The nature of postoperative rehabilitation is based on the quality of fixation. In all cases, once bone healing has occurred (6 to 8 weeks after surgery), rehabilitation can proceed more aggressively. As with other knee stabilization proce- dures performed in the acute setting, postoperative stiffness is a common complication. Suture Repair Primary repair with sutures is most efficacious when treating insertion-site avulsions. To be suc- cessful, repair must be done in the acute period (less than 3 weeks after injury). Most of these injuries are the result of avulsion from the femoral insertion. Cooper 9 reported that as many as 80% of PCL tears found in knee dislocations were either avulsed or stripped subperiosteally. Repair can be performed by placing nonabsorbable sutures through the avulsed ligament. The sutures are passed through drill holes at the avulsion site and tied over a bone bridge or suture button. The results of suture repair of acute midsubstance or chronic tears have generally been unsatisfactory, and reconstruction is typically recommended in that situation. 5,16-19 Single-Bundle Reconstruction Both open and arthroscopic PCL reconstructions have been performed with a single graft bundle through a single femoral tunnel. Be- cause of the size of the femoral origin, only a portion of the PCL can be reconstructed with a single-bundle technique. Since the anterolateral bundle is larger and stronger than the posteromedial bundle, the femoral tunnel is drilled where the anterolateral fibers of the PCL origi- nate on the femoral condyle. 3,7 The procedure is performed with the patient supine. After treating any meniscal or chondral lesions, the torn PCL is debrided to enhance visualization. A posteromedial portal is established under direct arthroscopic visualization to gain access to the tibial insertion, which extends well below the posterior joint line. Use of a cannula with a one-way valve can decrease fluid extravasation from the posteromedial portal and facilitate repeated introduction and removal of instru- ments. The PCL insertion fibers are meticulously debrided with a shaver PCL Injuries Journal of the American Academy of Orthopaedic Surgeons 302 placed through a posteromedial portal. The arthroscope is passed through the intercondylar notch in order to debride the stump. The 70- degree scope can be particularly useful at this point for visualization over the back of the tibial plateau. Once the space has been cleared, a PCL drill guide is placed through the femoral notch. A Kirschner wire is inserted just distal and medial to the tibial tubercle and is passed proximal and posterior in a line roughly parallel to the proximal tibiofibular joint. The wire is placed so that the tunnel exits the posterior tibial cortex in the distal lateral aspect of the PCL “footprint” (Fig. 6). Passage of the wire and subsequent drilling should be visualized either arthroscopically or under fluoroscopic guidance. A curette or ribbon retractor is used to protect the posterior neurovascular structures during drilling. The rough inner edge of the tibial tunnel is then gently smoothed with a bone rasp. When preparing the femoral tunnel, it is helpful to leave the PCL femoral insertion fibers intact so that the outline of the PCL footprint can be readily appreciated. The anterolateral bundle origin is best described as being in the anterior half of the femoral PCL insertion, 8 to 9 mm proximal to the articular surface of the medial femoral condyle. A drill guide is used to place a Kirschner wire in position so that the femoral tunnel entrance into the joint is lo- cated at the origin of the anterolateral bundle fibers. A small incision is made over the medial femoral condyle midway between the patella and the medial epicondyle. The entry point should be proximal to maintain sufficient subchondral bone and reduce the risk of osteonecrosis of the medial femoral condyle. 5,19,21 A Kirschner wire is passed anterograde, entering the joint at the tip of the drill guide. The lateral condyle should be protected with an instru- ment during passage of the wire and subsequent overdrilling. Alterna- tively, the femoral tunnel can be drilled retrograde through an acces- sory inferolateral portal, either leav- ing a blind tunnel or exiting through the femoral cortex. 3 The most popular choice for graft material has been Achilles tendon allograft, although ipsilateral or contralateral patellar tendon auto- grafts, patellar tendon allografts, and the hamstring and quadriceps tendons are reasonable alternatives. One of the more difficult parts of the procedure is passing the graft around the sharp turn at the back of the tibial plateau and into the proximal tibial tunnel. A looped wire is inserted in the anterior opening of the tibial tunnel, retrieved inside the joint with a grabber, and directed out the femoral tunnel. The soft-tissue end of the Achilles tendon graft can then be passed anterograde through the femoral tunnel, into the joint, around the back of the tibia, and into the tibial tunnel. Femoral fixation is achieved with use of an interference screw. The knee is cycled, and the graft is tensioned and fixed at 90 degrees of flexion while an anterior drawer force is applied to the tibia. Tibial fixation can be achieved by using a variety of post and spiked-washer devices with or without concomitant metal or bio- absorbable interference screws. Postoperatively, the extremity is braced in extension, and range-of- motion exercises are started in the first week. Most surgeons allow crutch-assisted ambulation with progression to weight bearing as tolerated in the brace. Closed-chain quadriceps-strengthening exercises are initiated early. Bent-knee hamstring-strengthening exercises are avoided so as to minimize the risk of posterior subluxation of the tibia. Use of crutches is discontinued at 8 weeks, and balance and pro- prioception exercises are initiated. Progression to treadmill walking and pool jogging begins after 3 months. It may take 6 months to achieve full knee motion. Patients generally return to regular sporting activities after 9 months. The few studies reporting results of single- tunnel PCL reconstruction show that most patients do have some improvement, but many continue to have persistent posterior laxity. 22 Double-Bundle Reconstruction Single-tunnel PCL reconstruction techniques replace only the antero- Andrew J. Cosgarea, MD, and Peter R. Jay, MD Vol 9, No 5, September/October 2001 303 Figure 6 Optimal position for tibial (A) and femoral (B) tunnels for single-bundle PCL reconstruction. (Adapted with permission from Miller MD, Harner CD, Koshiwaguchi S: Acute posterior cruciate ligament injuries, in Fu FH, Harner CD, Vince KG [eds]: Knee Surgery. Baltimore: Williams & Wilkins, 1994, p 753.) A B lateral bundle fibers. The major theoretical advantage of the double- bundle technique is that it also re- places the posteromedial bundle fibers and is therefore biomechani- cally superior to single-bundle techniques. In a recent cadaveric study, Harner et al 23 showed that use of the additional posteromedial bundle decreased posterior laxity by 3.5 mm (Fig. 7). Although the two-bundle technique is conceptually attractive, it is technically more challenging, and clinical experience is limited. The superiority of this approach over less demanding methods has yet to be documented clinically. The technique of double reconstruction is identical to the single- bundle technique through the tibial tunnel preparation. A tunnel is drilled in the anterior portion of the femoral footprint for the anterolateral bundle, and a smaller posterior femoral tunnel is drilled for the posteromedial bundle (Fig. 8). The Achilles tendon allograft is still frequently utilized for the larger anterolateral bundle; a double semitendinosus or gracilis graft can be used for the posteromedial bundle. Both grafts are routed through a single tibial tunnel. The anterolateral graft is tensioned and fixed at 90 degrees. The posteromedial graft is tensioned and separately fixed at 30 degrees. Tibial Inlay Technique In 1990, Burks and Schaffer 24 described a posterior approach to PCL tibial avulsion fixation. In one of their two cases, they used this approach to fix a patellar tendon graft during PCL reconstruction. Berg 18 subsequently described the tibial inlay technique in 1995. He devised the procedure to cir- cumvent the technical difficulties caused by using the long tibial tunnel that is necessary with an anteri- or approach. Not only is it difficult to pass a graft around the sharp angle at the back of the tibial tunnel, but the close proximity of the neurovascular structures puts these structures at risk during tunnel preparation and graft passage. Several authors have theorized that abrasion of graft where it passes around the sharp turn at the back of the tibia might be a cause of failure. Berg reported improvement in all four patients in his study at a minimum follow-up interval of 2 years. The KT-1000 arthrometer measurement of posterior translation decreased 4 mm postoperatively to within 2 mm of the value on the normal side. The procedure is performed with the patient in the lateral decubitus position with the operative leg up (Fig. 9). Once the initial arthroscopic work has been completed, single or double femoral tunnels are drilled. The patient is then repositioned for the posterior approach by extending the knee and placing the leg on bol- sters or a Mayo stand. An oblique incision over the medial head of the gastrocnemius allows exposure so that the interval between the medial head of the gastrocnemius and semi- membranosus can be developed. Lateral retraction protects the neurovascular structures and allows access to the posterior capsule. The posterior tibial facet and preposi- tioned wire loop can be palpated. The posterior capsule is incised ver- tically, and the PCL insertion is visualized. PCL Injuries Journal of the American Academy of Orthopaedic Surgeons 304 Figure 7 Comparison of the double-bundle PCL reconstruction with the single-bundle technique demonstrated significantly less (P<0.05) posterior tibial translation in response to a 134-N posteriorly directed load. (Reproduced with permission from Harner CD, Janaushek MA, Kanamori A, Yagi M, Vogrin TM, Woo SLY: Biomechanical analysis of a double-bundle posterior cruciate ligament reconstruction. Am J Sports Med 2000;28:144-151). Intact Full extension 30° 25 20 15 10 5 0 60° 90° 120° PCL-deficient Single-bundle Double-bundle P<0.05 Posterior Tibial Translation, mm Knee Flexion * * * * * * Figure 8 Optimal positions for placement of dual femoral tunnels during double- bundle PCL reconstruction. (Adapted with permission from Miller MD, Harner CD, Koshiwaguchi S: Acute posterior cruciate ligament injuries, in Fu FH, Harner CD, Vince KG [eds]: Knee Surgery. Baltimore: Williams & Wilkins, 1994, p 753.) The posterior tibial plateau is exposed subperiosteally and prepared for placement of the bone block. A unicortical window can be fash- ioned to fit the dimensions of the bone block. The popliteus muscle fibers can be undermined if necessary. The graft is inlayed flush and fixed with one or more screws with or without washers. The femoral bone block is then passed through the femoral tunnel for standard fixation. It is possible to estimate the length of the PCL and patellar tendon on the basis of the preoperative radiographs. If the patellar tendon graft is too long, the femoral bone block will protrude from the femoral tunnel. If that is the case, it is possible to place the tibial bone block distally on the posterior tibia or to use an alternative graft source. Combined Ligament Reconstruction Patients with multiple ligament injuries who are treated nonoperatively have relatively poor functional results. Torg et al 15 reported the results in a group of 29 patients with other ligament injuries associated with their PCL tears. Four patients (14%) were rated as having an excellent result (full return to the preinjury sport or a similar sport), and 10 (34%) were rated as having a good result (mild instability with sports, no problems with activities of daily living). KT-1000 arthrometer testing showed a mean side-to-side difference of 7.1 mm (range, 2 to 21 mm) at 20 lb. From these data, the authors concluded that serious consideration should be given to surgical treatment for patients with combined ligament injuries. Knee injuries that are severe enough to result in multiple ligament tears are usually the result of a collision or motor vehicle accident. 3 In some cases, damage to the secondary restraints leads to a greater degree of laxity; in other cases, the ligament damage results in instability in multiple planes. In most individuals, surgical treatment of each ligament is necessary to address combined in- stabilities. In most cases, a PCL tear combined with a posterolateral corner injury causes grade 3 posterior laxity. 19 This combination produces much more posterior translation and external rotation than either injury alone. 9 Patients are less likely to compensate and more likely to experience functional instability. Failure to address combined ligament injuries leads to a higher failure rate after surgical treatment. 7 Persistent posterolateral laxity after PCL reconstruction may increase forces in the graft that predispose it to ultimate failure. 3,7 The results of acute posterolateral corner repair are better than those of reconstruction; therefore, when feasible, posterolateral corner repair is preferable. Scar formation quickly obscures the anatomy, making repair difficult after 2 to 3 weeks. 3,7 Arthroscopic cruciate ligament reconstruction can usually be performed 2 to 3 weeks after the injury because of capsular sealing. 11 If sub- stantial fluid extravasation occurs during the procedure, causing an appreciable increase in calf or thigh pressure, it may be necessary to abandon arthroscopy and proceed with an open surgical technique. With acute injuries, an attempt should be made to repair all dam- aged structures. However, this is Andrew J. Cosgarea, MD, and Peter R. Jay, MD Vol 9, No 5, September/October 2001 305 Figure 9 Tibial inlay technique. A, Lateral decubitus position for initial arthroscopy and graft harvesting. B, With the knee extended and the leg abducted, the popliteal fossa is accessible for exposure of the posterior tibial graft-fixation site. (Adapted with permission from Berg EE: Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995;11:69-76.) B A not always possible, especially when a ligament fails in midsubstance. In the chronic setting, or if tissue is inadequate for suture repair, augmentation or reconstruction should be performed. Lateral collateral ligament augmentation and reconstruction can be performed by using a portion of the biceps tendon, the ipsilateral hamstring tendon, or an Achilles tendon allograft. The LCL and popliteofibular ligament can be reconstructed together with use of a looped hamstring graft. 9 In cases of chronic severe posterior and lateral laxity, consideration should be given to reconstructing both structures individually. Chronic injuries in individuals with varus alignment may require valgus osteotomy, particularly when a dynamic varus thrust is present. A PCL tear combined with an ACL tear may represent an unrecog- nized knee dislocation, with a substantially higher incidence of concomitant neurovascular injuries. 7 After neurovascular injury has been ruled out, the knee can be splinted, and early rehabilitation can be initiated. One of the complications of multiple ligament surgery is arthro- fibrosis; therefore, some authors recommend initiating early range- of-motion exercises and delaying surgery for a few weeks or more if necessary. Others advocate doing the reconstruction within 2 weeks, especially if there is any indication of a collateral ligament or posterolateral corner lesion. Magnetic resonance imaging is particularly helpful in evaluation. In either case, an elec- tive reconstruction should be performed under optimal circum- stances after adequate preoperative planning, rather than emergently. Treatment of a combined PCL- MCL injury is dictated largely by the extent of medial laxity. 25 A low- grade MCL tear will often heal with brace protection and joint mobiliza- tion. When a high-grade MCL tear occurs together with a high-grade PCL tear, the prognosis is worse. 25 Clinically, these patients will have gross valgus instability in full extension and may be functionally unsta- ble even during simple gait. Acute injuries should be treated with early repair of the parallel and posterior oblique portions of the superficial MCL, as well as repair or reconstruction of the PCL. In chronic cases, patellar or Achilles tendon allograft or hamstring autograft may be necessary for reconstruction of the MCL; in this situation, it is much more difficult to restore normal valgus laxity. Complications The most serious complication of PCL surgery is iatrogenic neurovascular injury. The popliteal artery is especially at risk for injury during tibial tunnel drilling and graft passage. The most common complication after PCL surgery is residual laxity. 21 Other potential complications include loss of motion, infec- tion, medial femoral condyle osteonecrosis, anterior knee pain, and painful hardware. Summary Injuries to the PCL commonly occur during sports participation or as a result of a motor vehicle accident. A careful history and physical examination will identify most PCL injuries. Most authors recommend nonoperative treatment for acute isolated PCL tears. This involves initial splinting in extension followed by range-of-motion and strengthening exercises. Recovery of quadriceps strength is necessary to compensate for posterior tibial translation and to allow a return to preinjury activity levels. Surgical treatment is reserved for acute combined ligament injuries, acute bone avulsions, or symptomatic chronic high-grade PCL tears. Single-tunnel reconstruction techniques improve posterior laxity only moderately. Newer double-tunnel and tibial inlay techniques offer theoretical advantages; however, few studies have been done, and clinical results are only preliminary. PCL Injuries Journal of the American Academy of Orthopaedic Surgeons 306 References 1. Shelbourne KD, Davis TJ, Patel DV: The natural history of acute, isolated, nonoperatively treated posterior cruciate ligament injuries: A prospec- tive study. Am J Sports Med 1999;27: 276-283. 2. DeLee JC, Bergfeld JA, Drez D Jr, Parker AW: The posterior cruciate ligament, in DeLee JC, Drez D Jr (eds): Orthopaedic Sports Medicine: Principles and Practice. Philadelphia: WB Saunders, 1994, vol 2, pp 1374-1400. 3. Petrie RS, Harner CD: Evaluation and management of the posterior cruciate in- jured knee. Operative Techniques Sports Med 1999;7:93-103. 4. Shelbourne KD, Nitz PA: Posterior cruciate ligament injuries, in Reider B (ed): Sports Medicine: The School-Age Athlete. Philadelphia: WB Saunders, 1991, pp 317-331. 5. Miller MD, Harner CD, Koshiwaguchi S: Acute posterior cruciate ligament injuries, in Fu FH, Harner CD, Vince KG (eds): Knee Surgery. Baltimore: Williams & Wilkins, 1994, pp 749-767. 6. Covey DC, Sapega AA: Injuries of the posterior cruciate ligament. J Bone Joint Surg Am 1993;75:1376-1386. 7. Harner CD, Hoher J: Evaluation and treatment of posterior cruciate ligament injuries. Am J Sports Med 1998; 26:471-482. 8. Fu FH, Harner CD, Johnson DL, Miller MD, Woo SLY: Biomechanics of knee ligaments: Basic concepts and clinical application. J Bone Joint Surg Am 1993; 75:1716-1727. 9. Cooper DE: Treatment of combined

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