Posterolateral Corner (PLC) Injury

What is the Posterolateral Corner?

The Posterolateral Corner (PLC) of the knee refers to the ligaments and tendons at the back (posterior) and outside (lateral) part of the knee. This includes the lateral collateral ligament (LCL), some of the hamstring tendons (biceps), the popliteus tendon, the capsule (outer surrounding layer) of the knee and other smaller ligaments.

What is a Posterolateral Corner Injury?

PLC injury is a tear of one or more of those tendons and ligaments. It may occur with a twisting injury, a hyperextension injury (knee being pushed too far back past straight), a blow to the inside or front of the knee. It may also occur with dislocation of the knee when one or more of the other major ligaments (ACL, MCL or PCL) is also ruptured. There may also be injury to the nearby common peroneal nerve, causing weakness and numbness in the leg and foot.

What problems can Posterolateral Corner Injury Cause?

Initially at the time of injury there is pain and swelling. There may be a feeling of instability (feels like it will give way beneath you), but that is not always the case. The PLC heals poorly, and it is common to have long term problems with instability. The knee may give way or feel unstable even with normal day to day activities such as stair climbing or turning.

How is a Posterolateral Corner Injury treated?

The initial treatment is rest, ice, elevation, compression bandage and a splint. However, PLC injury heals poorly by itself and often requires surgery. Ideally this is done within 3 weeks of the injury; during this stage the torn ends will heal if they are stitched together. If the injury is not treated within 3 weeks, there is too much scarring to stitch it back, and the ligaments need to be reconstructed with graft ligaments taken from elsewhere. Sometimes PLC injury occurs in association with other injuries (ACL, PCL, knee dislocation); in that case repair of the tears or reconstruction with new ligaments is almost always needed.