DEFINITION

The posterolateral corner (PLC) of the knee is a complex area, both anatomically and functionally, that has the potential to cause great disability when injured.

Injuries to the structures of the PLC are uncommon, accounting for only 2% of all acute ligamentous knee injuries.6

Because of the high incidence of combined ligament injuries associated with PLC injuries,2 other ligament injuries in the knee always should be suspected when treating the PLC.

Conversely, cruciate ligament reconstructions have a tendency to fail if PLC injuries are left untreated,8,17 so one must always have a high index of suspicion for PLC injuries when treating other injuries in the knee.

The significance of a PLC knee injury can be great.

Chronic instability due to the untreated PLC injury can be debilitating.

The complex biomechanical relationships among the structures of the PLC are important in resisting varus and external rotation forces.

Insufficiency in the posterolateral structures of the knee can lead to a varus-thrust gait and the sensation of instability, especially when the knee is in extension during the toe-off phase of walking.2

The convexity of the lateral tibial plateau and lateral femoral condyle may contribute to this instability.17

This instability may hinder stair-climbing or cutting activities, and patients may complain of lateral knee pain.

Chronic PLC insufficiency also may lead to tricompartmental degenerative joint disease.2

An increase in patellofemoral joint contact pressure has been found to occur with PLC and posterior cruciate ligament (PCL) sectioning in cadaveric studies.26

 

ANATOMY

 

 

Before treating a patient with a PLC injury, one must be familiar with the complex anatomy of the area. The PLC is made up of both dynamic and static stabilizers.5

 

Seebacher et al 25 organized the posterolateral structures into three layers (FIG 1A).

 

The superficial layer is made up of the iliotibial (IT) tract anteriorly and the biceps femoris posteriorly.

 

The common peroneal nerve lies deep and posterior to the biceps femoris in this layer at the level of the distal femur.

 

The IT tract or band, which inserts on Gerdy tubercle on the tibia, is tight and moves posteriorly in knee flexion. It actually places an external rotation force on the tibia during knee flexion. During knee extension,

the IT band moves anteriorly and becomes less taut. Because of its relaxed state in knee extension, this structure rarely is injured in PLC injuries, so it is a good reference point for the location of other structures in surgery.

 

The biceps femoris inserts on the fibular head but also has attachments to the IT band, Gerdy tubercle, the lateral collateral ligament (LCL), and the posterolateral capsule.2,6 It adds dynamic stability to the PLC.

 

The middle layer of the PLC consists of the quadriceps retinaculum anteriorly, the patellofemoral ligaments posteriorly, and the patellomeniscal ligament.25

 

These structures add accessory static stability to the PLC.

 

The deep layer, which is the most important (FIG 1B), consists of the lateral part of the joint capsule and the coronary ligament, which inserts on the lateral meniscus; the popliteus tendon and the popliteofibular

ligament; the arcuate ligament; the LCL; and the fabellofibular ligament.25

 

 

The popliteus originates on the posterior tibia, passes through the hiatus of the coronary ligament, and inserts on the lateral femoral condyle.2 It also has attachments to the lateral meniscus.

 

The popliteofibular ligament exists as a direct static attachment of the popliteus tendon from the posterior fibular head to the lateral femoral epicondyle.

 

The arcuate ligament is a Y-shaped ligament that reinforces the posterolateral capsule of the knee and runs from the fibular styloid to the lateral femoral condyle. In radiographs, the arcuate fracture shows an

avulsion of this ligament off of the fibular styloid.14

 

The LCL originates on the lateral epicondyle of the femur and inserts on the fibular head. This ligament is

the primary static restraint to varus stress from 0 to 30 degrees of knee flexion.6,7,17 The LCL becomes progressively more lax in greater degrees of flexion, however. Aponeurotic layers of the biceps femoris

provide tension to the LCL to assist in dynamic resistance to varus stress.7,17 The LCL also provides resistance to external rotation stress.2

 

Much anatomic variation has been noted in the structures of the deep layer, especially the arcuate and fabellofibular ligaments.25

 

Hughston et al 9 described the importance of an arcuate ligament complex consisting of the LCL, arcuate ligament, popliteus, and the lateral head of the gastrocnemius. This complex acts as a “sling” of static and dynamic restraint to rotation of the lateral tibiofemoral articulation.

 

PATHOGENESIS

 

 

PLC knee injuries most commonly are caused by sports injuries (40%), motor vehicle accidents, and falls.2,5 Any mechanism that can cause a knee dislocation theoretically can cause an injury to the PLC.

 

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FIG 1 • A. The PLC is made up of three layers. B. The deep layer of the PLC consists of the joint capsule and the coronary ligament, the popliteofibular ligament, the arcuate ligament, the LCL, and the fabellofibular ligament.

 

 

The most common mechanism for an isolated PLC injury is hyperextension of the knee with a varus moment. This mechanism can be caused by blunt posterolaterally forced trauma to the medial proximal tibia, such as a helmet to the knee in football.

 

Other mechanisms of injury include hyperextension alone, hyperextension with an external rotation force, a severe varus force alone, or a severe external rotation torque to the tibia.

 

As mentioned earlier, an isolated PLC knee injury is rare.6

 

A flexed knee with tibial external rotation and posterior translation can cause a PCL/PLC combined injury.

 

NATURAL HISTORY

 

Posterolateral knee injuries rarely occur as isolated ligament disruptions.

 

They most often are associated with injury to the PCL, the anterior cruciate ligament (ACL), or both. Therefore, the true natural history of these injuries is unknown.

 

If left untreated, they will contribute to failure of other ligament reconstruction.

 

Repair, and often supplementation with exogenous grafts, is recommended in all cases of combined PLC injury.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Methods for examining the PLC include the following:

 

 

Dial test. More than 10 degrees difference between limbs is consistent with ligamentous PLC injury.28 Increased rotation at 30 degrees but not at 90 degrees indicates isolated PLC injury. Increased rotation at both 30 degrees and 90 degrees indicates PLC and PCL injuries.

 

Posterolateral external rotation test.25 Increased posterior translation and external rotation at 90 degrees are suspicious for PLC or PCL injury. Subluxation at 30 degrees is consistent with isolated PLC injury.

 

Posterior drawer test (PCL testing). More than 10 mm translation is highly suggestive of multiligamentous

knee injury.

 

Varus stress test (LCL testing). An isolated tear of the LCL causes maximal varus angulation at 30 degrees.

 

Quadriceps active test. Forward translation of the tibia after attempted knee extension is positive for PCL insufficiency (reduction of posterior tibial sag).

 

Gait. The patient may walk with a slightly flexed knee to avoid pain and instability with hyperextension of the knee.25 Varus thrust also may be present.

 

Reverse pivot shift test. Palpable shift of the lateral tibial plateau is positive but not specific for PLC injury. This test is difficult to perform on the awake patient.

 

External rotation recurvatum test.2 Hyperextension and increased varus of the knee and external rotation of the tibia are positive for PLC injury.

 

Range of motion (ROM). The normal range is 0 to 135 degrees of motion. Loss of extension may be due to a displaced meniscus tear. Loss of flexion may be due to effusion.

 

Effusion. A large effusion suggests other intra-articular pathology, such as an ACL or PCL tear or a peripheral meniscus tear. Effusion may be diminished if the capsule is torn.

 

Neurovascular examination (serial). The incidence of popliteal artery injury is increased in knee dislocations. An arteriogram should be obtained if the vascular examination

 

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is different from that in the contralateral leg. The incidence of peroneal nerve injury is increased by 10% to 33% with PLC injuries.1,6,16

 

It is important to obtain a good history from the patient with an acute PLC injury. A history of a tibiofemoral dislocation should cause suspicion of a PLC injury.

 

Pain and swelling of the posterolateral knee are common.

 

 

A rapid knee effusion suggests the possibility of concurrent intra-articular pathology.

 

Neurologic changes also must be investigated because of the increased incidence of peroneal nerve injuries in the patient with an injured PLC.1,6,16

 

Patients with chronic posterolateral instability commonly present with the sensation of instability with the knee in extension and lateral or posterolateral aching pain in the knee.

 

PLC injuries can be graded5 as 1, 2, or 3.

 

 

 

Grade 1 injuries involve minimal tearing of the ligaments and are not associated with abnormal joint motion. Grade 2 injuries have partial tearing but still have no abnormal joint motion.

 

Grade 3 injuries have complete tearing of the ligaments and abnormal joint motion.

 

 

Hughston et al 28 graded PLC injuries based on ligamentous instability. Cases of mild, moderate, and severe instability are graded as 1+, 2+, and 3+, respectively.

 

Because PLC knee injuries have such a high association with combined ligament injuries, a careful examination for other knee pathology is necessary.

 

 

PCL injury can be recognized by a positive posterior drawer test, tibial sag or recurvatum, and hemarthrosis.

 

A positive Lachman test is the most sensitive test for an ACL tear. The examiner should not be fooled by a false end point caused by a tight effusion or a displaced meniscal tear. A positive pivot shift also is a sensitive

test for an ACL tear, although it is difficult to perform on an acute patient because of discomfort and apprehension.

 

Meniscal tears can also be associated with PLC injuries. Joint line tenderness is the most sensitive test for meniscal tears. A lateral meniscus tear may give lateral-sided knee pain, which could be confused with a posterolateral knee injury. Mechanical symptoms also raise concern for meniscal tears. Loss of full extension of the knee hints at the possibility of a locked bucket-handle meniscus tear.

 

Although it is rare to have LCL and medial collateral ligament (MCL) tears from the same injury, one must examine all ligaments after trauma to the knee. The MCL is tested by valgus stress at 0 and 30 degrees of knee flexion. Medial knee tenderness and ecchymosis are often present in an MCL injury.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

The initial diagnostic imaging examination should begin with standard anteroposterior (AP) and lateral radiographs of the knee.

 

 

Laprade and Wentorf17 recommend obtaining full-length standing AP radiographs to evaluate for varus malalignment in chronic patients.

 

Plain radiographs may show increased joint space laterally or a frank knee dislocation.2,5

 

Plain radiographs also can be obtained to evaluate associated fractures, such as an arcuate avulsion fracture of the fibular head, a Gerdy tubercle avulsion, and a Segond fracture, which is an avulsion of the lateral

capsule off of the tibia.5

 

 

 

FIG 2 • Varus stress radiograph showing widening of the lateral compartment.

 

 

Segond fractures typically are thought to be associated with ACL injuries, but they also can be associated with posterolateral ligament injuries.

 

Patellofemoral or tricompartmental arthritis may be associated with chronic instability. Typically, the lateral compartment is more involved than the medial compartment.2

 

An effusion in the suprapatellar pouch also can be visualized on plain radiographs and hints at the presence of an intra-articular pathology, such as an ACL or PCL tear.

 

Varus stress films may be used to evaluate the integrity of the LCL as well (FIG 2).

 

MRI is useful in evaluating the soft tissues of the knee and in looking for bone contusions or edema.

 

 

Laprade et al 14 recommend obtaining not only the standard coronal, sagittal, and axial cuts of the knee but also coronal oblique 2-mm thin cuts to include the entire fibular head and styloid, to better evaluate the popliteus tendon and the LCL.

 

 

Laprade and Wentorf17 also recommend using a magnet with a signal of at least 1.5T. A bony contusion of the anteromedial femoral condyle is concerning for a PLC injury.24

 

Arthroscopy can be useful in diagnosing posterolateral ligament pathology.17

 

 

An avulsion of the popliteus off of the femur can be visualized directly, as can injuries to the coronary ligament of the posterior horn of the lateral meniscus (FIG 3A).

 

 

The “drive-through” sign is another arthroscopic finding in the patient with a PLC injury.13 This is defined as more than

 

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1 cm of the lateral joint line opening to varus stress during arthroscopic evaluation of a posterolaterally insufficient knee (FIG 3B).

 

 

 

 

FIG 3 • Arthroscopic views demonstrating popliteal tendon injury (A) and excessive opening, or drive-through sign (B).

DIFFERENTIAL DIAGNOSIS

 

Lateral meniscus tear

 

 

Other ligamentous injury (eg, PCL, ACL) Tibial plateau fracture

 

 

Supracondylar femur fracture Contusion

 

Degenerative joint disease with varus malalignment

 

NONOPERATIVE MANAGEMENT

 

Grade 1 and most grade 2 posterolateral ligament injuries of the knee usually are treated successfully without surgery.2 These patients typically do well without significant lingering symptoms or instability.

 

 

For grade 1 and 2 injuries, patients are immobilized for 2 to 4 weeks in either an immobilizer or cast. Quadriceps sets and straight-leg raises are allowed in the immobilizer only.17

 

Weight bearing also is restricted during this period.17

 

After 3 or 4 weeks in an immobilizer, protected ROM exercises are initiated in a hinged knee brace.

 

 

The patient is allowed to bear weight as tolerated, and closed-chain quadriceps strengthening is begun. Hamstring strengthening is avoided for 6 to 10 weeks after the injury.17

 

Because of altered gait mechanics, formal gait instruction should be initiated once the patient begins weight

bearing.

 

Although patients with grade 1 or 2 injuries typically do well with nonoperative treatment, residual laxity and instability may require surgical intervention.

 

SURGICAL MANAGEMENT

 

Grade 3 PLC injuries tend to do poorly with nonoperative management.11

 

 

Indications for operative treatment of PLC injuries consist of 5 to 10 mm of opening to varus stress at 30

degrees of knee flexion and a positive dial test or posterolateral external rotation test.2 These findings are consistent with a grade 3 PLC injury.

 

Ideally, PLC injuries should be treated between 10 days and 3 weeks after injury.2,4,12,23

 

 

Before 10 days, the knee usually is significantly swollen and still is in the acute inflammatory stage of the injury.

 

It also is possible to regain some quadriceps tone and ROM if surgery is postponed more than 10 days. Theoretically, the risk of arthrofibrosis would, therefore, be diminished.23

 

Waiting more than 3 weeks to operate results in increased scarring and difficulty in repairing the posterolateral structures primarily.23

 

 

Identifying and protecting the peroneal nerve becomes more difficult with increased scarring.17 Results of chronic repair are inferior to those of acute repair.2

Preoperative Planning

 

In treating posterolateral ligament injuries, one must decide whether to repair the torn structures primarily, augment the repair, do an advancement, or perform a reconstruction of the PLC using allograft or autograft.

 

Much of the preoperative planning is contingent on whether the PLC injury is isolated or combined with other ligamentous injuries.

 

Preoperative radiographs are important to evaluate for fractures or other bony abnormalities.

 

 

Hip-to-ankle films may be helpful in chronic cases to evaluate for varus malalignment.

 

If malalignment is present, a valgus opening wedge osteotomy of the medial tibia should be considered because unrecognized varus malalignment may lead to failure of a PLC reconstruction.2

 

MRI helps evaluate for other associated ligamentous or meniscal injuries and should be used in preoperative planning if possible.

 

If cruciate ligamentous injuries exist, they should be reconstructed prior to or concurrently with the PLC repair and reconstruction; otherwise, there is an increased risk that the PLC reconstruction will fail.2

 

Positioning

 

Positioning for posterolateral surgery is contingent on the presence of other ligamentous injuries and the method used to address those concurrent injuries.

 

Placing the patient in a lazy lateral position with a beanbag allows the surgeon to rotate the hip and leg externally for intra-articular work. The surgeon can then internally rotate the leg into the lateral decubitus position for lateral knee work and for access to the popliteal fossa for an inlay PCL reconstruction.

 

 

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If access to the popliteal fossa is not necessary, an Alvarado foot holder can be used for intra-articular and lateral work, and the patient can be positioned supine.

 

A well-padded tourniquet is placed high on the patient's thigh to avoid interference with the operative field.

 

Approach

 

Arthroscopic visualization of the lateral compartment may demonstrate injuries or excessive opening (the drive-through sign).

 

After arthroscopy and additional procedures, as indicated, the surgical approach is carried out as described in Techniques.

 

TECHNIQUES

• Exposure

A lateral hockey stick, straight, or curvilinear incision can be used in the approach to the posterolateral

structures.5 The incision typically measures 12 to 18 cm, begins just superior to the lateral epicondyle, and runs along the posterior border of the IT band (TECH FIG 1). The incision typically ends midway between the fibular head and Gerdy tubercle.23

The peroneal nerve is identified proximally as it runs posterior to the biceps femoris tendon.23 The nerve is traced distally around the fibular head and is protected throughout the case. It is important to mobilize the nerve far enough distal to drill tunnels through the fibular head.

 

 

Blunt dissection is taken down between the IT band and the biceps femoris.

 

 

At this point, the structures of the PLC are identified and evaluated for pathology. Terry and Laprade27 described three fascial incisions for exposure of the PLC:

 

The first incision bisects the IT band.

 

The second incision is made between the posterior border of the IT band and the short head of the biceps femoris.

 

The third incision is made along the posterior border of the long head of the biceps.

 

A capsular incision can be made along the anterior border of the LCL.

 

 

 

TECH FIG 1 • Exposure begins with an incision along the posterior border of the IT band.

• Direct Primary Repair

   

  For best results, primary repair should be done within 2 to 3 weeks of injury.17

   

  The structures should be repaired with the knee in 60 degrees of flexion and neutral tibial rotation.23

   

  A tibial avulsion of the popliteus can be repaired directly to the posterolateral tibia using suture anchors, sutures and button, or a cancellous screw with soft tissue washer (TECH FIG 2).

   

  A femoral avulsion of the popliteus typically occurs with an avulsion of the LCL.

   

  Both of these structures can be sutured back to the lateral femoral condyle using transosseous drill holes.

   

  Laprade and Wentorf17 described the use of a recess procedure for treatment of a femoral avulsion of the popliteus or LCL.

   

  In this procedure, a whipstitch is placed in the proximal popliteus, a small bone tunnel is made at the original femoral insertion of the popliteus, a stylette pin is used to pass the sutures from the whipstitch to the medial side of the knee, and the popliteus is pulled into the tunnel with the sutures.

   

  The sutures are then tied over a button medially.

   

  A popliteofibular ligament avulsion off the fibula can be treated with tenodesis of the popliteus tendon to the

  posterior fibular head using suture anchors.2

   

  The tenodesis can be reinforced with the fabellofibular ligament.

   

  An avulsion of the LCL and arcuate ligament off of the fibular head can be reattached with transosseous sutures into the fibular head.2

   

   

   

  TECH FIG 2 • Direct primary repair of the popliteus tendon using a transosseous suture and button.

   

   

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• Augmentation

   

  If the repair of the structures of the PLC is tenuous or the tissue is poor, the surgeon should consider augmentation of the repair.

   

  The tibial attachment of the popliteus can be augmented with a strip of IT band left attached distally to Gerdy tubercle (TECH FIG 3A).

   

  The strip is passed through a drill hole in the proximal tibia from anterior to posterior and sutured to the popliteus.2

   

   

   

  TECH FIG 3 • A. Augmentation with the IT band. B. Augmentation with a central slip of biceps femoris passed posteriorly around the remaining biceps and inserted into the distal lateral femur using a soft tissue washer.

   

   

  The popliteofibular ligament can be augmented using a central slip of the biceps femoris.29

   

  The biceps distal attachment is left intact, and the slip is sutured to the posterior fibula, passed under the remaining biceps posteriorly, and attached to the lateral femur with suture anchors or screw and soft tissue washer (TECH FIG 3B).

• Advancement

   

  In the patient in whom the posterolateral structures are insufficient for primary repair or in chronic cases, an arcuate complex advancement can be performed.10

   

  The LCL must be of normal integrity, and the popliteofibular ligament must be intact.

   

  The LCL, popliteus, lateral gastrocnemius, arcuate ligament, and posterolateral capsule are advanced en bloc in line with the LCL, tensioned with the knee at 30 degrees of flexion and neutral tibial rotation, and inserted into a trough in the distal lateral femur (TECH FIG 4).

   

  The disadvantage of this procedure is that the advancement does not restore isometry, thus leading to stretching of the reconstruction over time.20

   

   

   

  TECH FIG 4 • Proximal arcuate complex advancement. The LCL, popliteus, lateral head of the gastrocnemius, arcuate ligament, and posterolateral capsule are advanced and inserted en bloc to the distal lateral femur.

   

   

   

• Reconstruction

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  Reconstruction of the PLC is used in acute injuries when the tissue is poor or irreparable and in chronic cases in which the tissues are scarred and attenuated.

   

  The LCL, the popliteofibular ligament, and the popliteus are the three most important structures to be reconstructed in the PLC.20

   

  Reconstruction of the LCL using local tissue, allograft, and autograft has been described.

• Biceps Tenodesis Technique

 

Clancy et al 3 reconstructed the LCL using a biceps tenodesis technique (TECH FIG 5).

 

In this technique, the entire biceps is transferred to the lateral femoral condyle 1 cm anterior to the LCL

origin.

 

The distal biceps is left attached to the fibular head.

 

Disadvantages of this technique are that it does not reconstruct the popliteus or popliteofibular ligament, and it sacrifices the dynamic stabilizing effect of the biceps femoris.20

Collateral Ligament Reconstruction

 

Isolated LCL reconstruction also can be performed using Achilles tendon allograft, patellar tendon auto- or allograft, or a central tubularized slip of the biceps tendon (TECH FIG 6).

 

Fluoroscopy can be used to ensure proper placement of the proximal end of the graft to the lateral femoral epicondyle.2,27

 

Plication of the remaining posterolateral structures can be performed.

 

 

 

TECH FIG 5 • LCL reconstruction using the biceps tenodesis. The biceps femoris is transferred 1 cm anterior to the LCL origin while leaving the distal insertion on the fibular head intact.

 

 

 

TECH FIG 6 • A. LCL reconstruction with tendon allo- or autograft. B. LCL reconstruction using a central tubularized slip of the biceps tendon. The distal insertion of the slip on the fibular head is left intact while the proximal portion is inserted on the lateral femoral epicondyle.

 

 

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TECH FIG 7 • Two-graft technique for PLC reconstruction. A. The first graft is inserted into the femur at the anatomic insertion site of the popliteus and then passed from posterior to anterior in the tibia. The second graft is inserted into the lateral epicondyle and is passed from lateral to posteromedial in the fibula and then into the same tibial tunnel used by the first graft. Both grafts are secured to the tibia using either an interference screw or suture button. B. Hamstring grafts can be used for this reconstruction. We tubularize our grafts using a whipstitch and ensure that no extraneous soft tissue remains on the graft that could hinder graft passage.

Two-Graft Technique

 

 

Laprade et al15 have described an anatomic posterolateral knee reconstruction (TECH FIG 7) using a two-graft technique (ie, Achilles tendon allograft split in half).

 

The first graft is used to reconstruct the popliteus.

 

The bone plug is secured in the anatomic location of the popliteus insertion on the femur, and the graft is passed from posterior to anterior through an anatomically placed tibial tunnel.

 

The second graft is used to reconstruct both the LCL and the popliteofibular ligament.

 

The bone plug is secured in the femoral tunnel at the anatomic location of the LCL origin.

 

 

 

TECH FIG 8 • Reconstruction with a split patella tendon graft.

 

 

The graft is then passed through a tunnel from lateral to posteromedial in the fibula. It is then pulled through the same tibial tunnel from posterior to anterior.

 

Interference screws are used to secure the grafts in their tunnels, and soft tissue staples are used for secondary fixation.

Split Patellar Tendon Technique

 

 

Veltri and Warren29 have described a technique of reconstructing the PLC using a split patellar tendon allograft or autograft (TECH FIG 8).

 

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The patellar bone plug is fixed in a tunnel in the lateral femoral condyle using a suture button on the medial femoral cortex.

 

The graft is then split. The anterior limb is brought from posterior to anterior through a tunnel in the fibular head reproducing the popliteofibular ligament. The posterior limb is brought through a tibial tunnel from posterior to anterior. Both limbs are secured with suture buttons.

 

A central slip of biceps can be used to reconstruct the LCL, as described earlier.

Popliteus Bypass Technique

 

 

Muller21 described a popliteus bypass technique (TECH FIG 9) in which a free graft is passed through a tibial tunnel from anterior to the posterolateral proximal tibia and secured to the anterior aspect of the lateral femoral condyle.

 

This technique does not reproduce either the LCL or the popliteofibular ligament.

Figure-8 Technique

 

Hamstring autograft can be used to reconstruct the popliteofibular ligament and LCL concurrently.

 

Larson18 described a figure-8 technique in which he used hamstring autograft passed through a fibular tunnel, crossed in a figure-8 pattern, and wrapped around a screw and soft tissue washer at an isometric point on the lateral femoral condyle (TECH FIG 10).

Lateral Collateral Ligament Reconstruction Using Bone-Patellar Tendon-Bone Allograft

 

 

Lattimer et al19 described using a bone-patellar tendon-bone allograft fixed distally to the fibular head with an interference

 

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screw and proximally to the lateral femoral condyle 5 mm anterior to the femoral origin of the LCL.

 

 

 

 

TECH FIG 9 • Popliteus bypass reconstruction technique. A hamstring graft is passed from anterior to posterolateral in the tibia. The graft is then passed from the posterolateral tibia to the anterior aspect of the lateral femoral condyle. The graft may be secured with suture buttons, soft tissue screws, interference screws, or staples.

 

 

 

TECH FIG 10 • Figure-8 reconstruction technique. A. A guide pin is placed in the lateral femoral condyle and is checked by fluoroscopy to ensure proper placement. The hamstring is then wrapped around the guide pin in a figure-8 fashion and secured with a cannulated soft tissue screw and washer. The pin is then removed. B. The graft is passed through the fibular head and secured by an interference screw and by sewing the graft to itself. This step is done after proper tensioning of the graft has been achieved. C. A soft tissue screw and washer are used to fix the grafts to the femoral condyle.

 

 

The graft is tensioned with a valgus forced placed on the 30-degree flexed knee.

 

The large cross-sectional area of the graft theoretically restores LCL and arcuate and popliteofibular ligament function.

 

This reconstruction neglects the popliteus, however.

Authors' Preferred Technique

 

We have found that a combination of the Larson and Muller techniques is an effective approach to reconstructing the LCL, popliteofibular ligament, and popliteus.

 

PEARLS AND PITFALLS

Monitor for fluid extravasation and increased compartment pressures during the arthroscopic portion of the

 

procedure because the capsule usually is disrupted in PLC injuries.

Do not miss PLC injury when treating cruciate ligament injuries to avoid failed cruciate ligament reconstruction.

Reconstruct the cruciate ligaments before or concurrently with PLC reconstruction. Repair structures of the PLC beginning from deep to superficial.

Varus malalignment may lead to failed PLC reconstruction; therefore, valgus osteotomy may be needed in chronic PLC insufficiency.

Determine safe ROM of the knee before leaving the operating room to guide postoperative rehabilitation.

 

 

POSTOPERATIVE CARE

 

A hinged knee brace locked in extension should be used, and protected weight bearing should be followed for 3 weeks following a reconstruction and 6 weeks following a direct primary repair.2,17

 

Weight bearing theoretically places tension on the repair because of the normal mechanical axis of the leg.

 

Straight-leg raises may be allowed in the knee brace initially.

 

Active knee extension and closed-chain kinetic quadriceps strengthening may be initiated at 4 to 8 weeks postoperatively.

 

Gentle leg presses, proprioceptive training, and squats may be initiated at 3 months.

 

 

 

Hamstring exercises should be strictly avoided until 12 to 16 weeks postoperatively.2,17 A fairly intensive rehabilitation protocol should be followed for 9 to 12 months.

 

The goal of rehabilitation is to achieve symmetrical quadriceps strength, knee stability, and full knee ROM.

 

 

OUTCOMES

Hughston and Jacobson10 reported good functional results at 4 years in 12 of 19 patients treated with arcuate complex advancement combined with distal primary repair.

DeLee et al6 also reported that 8 of 11 patients treated with advancement surgery had good results, with no arthritis or revisions at 7.5 years.

Noyes and Barber-Westin22 reported on 42 months of followup in 21 patients treated with Achilles tendon allograft reconstruction of the LCL with plication or advancement of attenuated posterolateral structures.

Failure occurred in two patients, and good to excellent functional results were reported in 16 (76%) patients.

Lattimer et al19 reported on 10 patients treated with bone-patellar tendon-bone reconstruction of the LCL as well as cruciate ligament reconstruction at 28 months of follow-up.

All 10 patients had a reduction in their sensation of instability.

The patients all had less than 5 mm of lateral opening to varus stress and less than 5 degrees of external rotation.

Nine of the 10 patients returned to within one level of their preinjury level of activity.

The long-term incidence of degenerative arthritis following PLC injuries treated with surgery remains unknown.

No long-term prospective studies exist that evaluate the different ways to ligamentously reconstruct the knee with a PLC injury. Because this injury is uncommon, large study populations are difficult to obtain.

Consequently, it is difficult to determine the clinically best method of treating this injury.

 

 

 

COMPLICATIONS

Because of the extensive trauma usually incurred by the PLC-injured knee, arthrofibrosis is one of the most common complications associated with this injury.

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Residual knee instability also can occur, especially in grade 3 PLC injuries treated nonoperatively.

These two conflicting complications make postoperative management as important as the surgical treatment itself for a good result.

Neurovascular complications are more often associated with the initial trauma rather than the surgical management. Delayed surgical treatment increases the incidence of iatrogenic peroneal nerve injury, however.

The incidence of wound complications can be decreased by delaying surgery until the skin has recovered from the acute phase of the injury, which usually is 10 days or more after the initial injury.

Bulky compressive dressings and elevation of the leg also may help decrease swelling before surgery. Skin incisions should be planned to avoid skin bridges less than 7 cm wide.

The incidence of degenerative joint disease is increased in patients with PLC injuries due to abnormal joint motion.2,17

The goal of surgical intervention is to reconstruct knee motion and stability to be as normal as possible. The lateral compartment and patellofemoral compartments are most commonly affected by PLC injuries.

Because of long surgical times and use of graft material, infection is a possible complication of PLC surgery.

Infection is a devastating complication. In order to clear the infecting organism, it is often necessary to débride the grafts that were used to reconstruct the knee.

 

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