The posterolateral corner of the knee

Abstract

The posterolateral corner (PLC) of the knee refers to a complex of structures that play a key role in knee stability. The main three structures in the PLC of the knee are the lateral collateral ligament, the popliteus and the popliteofibular ligament. These are primarily restraints to varus and external rotation forces. As such, mechanisms of injury include varus and hyperextension, and are typically high energy. These injuries are rarely isolated and are commonly associated with other injuries such as cruciate ligament injury or tibiofemoral knee dislocation. If undetected or untreated, PLC injuries can cause severe long-term disability due to instability and cartilage degeneration. Failure to recognize these injuries can also jeopardize the results of concomitant anterior or posterior cruciate ligament reconstruction. Immediate management in acute injuries involves assessment and treatment of any associated neurovascular injury, especially to the popliteal artery or peroneal nerve, and reduction of knee dislocation. Acute repairs of the damaged structures can be undertaken, but ligament reconstruction is often required, using either autograft or allograft. Graft reconstruction procedures can be fibula-based or anatomic, each having their own merits. The timing of surgery can be acute, chronic or staged, depending on the exact nature of the injury and on timing.