Posterolateral Corner Injury

The posterolateral corner (PLC) of the knee is a complex area of the knee formed by the interaction of multiple structures. Injuries to the PLC often occur in combination with other ligamentous injuries to the knee; most commonly the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). Injuries to the posterolateral corner can be debilitating to patients and require prompt recognition and treatment to avoid long term consequences.

Structures found in the posterolateral knee include the tibia, fibula, lateral femur, iliotibial band (ITB), the biceps femoris tendon, the lateral collateral ligament (LCL), the popliteus tendon, the popliteofibular ligament, the lateral gastrocnemius tendon, and the fabellofibular ligament. It has been reported that among these, the 3 most important static stabilizers of the posterolateral knee are the LCL, popliteus tendon, and popliteofibular ligament. Studies have reported that these structures work together to stabilize the knee by restraining varus, external rotation and combined posterior translation with external rotation to it.

The most common mechanisms of injury to the posterolateral corner are a hyperextension injury (contact or non-contact), direct trauma to the anteromedial knee, and non-contact varus force to the knee.

The majority of posterolateral knee injuries occur in combination with another ligamentous injury, such as a cruciate ligament tear.  This can make the diagnosis difficult as knee examination if usually painful and difficult to perform. In the majority of cases x-rays and an MRI are used to aid in the diagnosis.

Treatment of posterolateral corner injuries varies with the location and grade of severity of the injuries. Patients with grade I and II (partial) injuries to the posterolateral corner can usually be managed conservatively. Studies have reported that patients with grade III (complete) injuries do poorly with conservative management and typically will require surgical intervention followed by rehabilitation.