Posterolateral Corner Injuries
The posterolateral corner (PLC) of the knee is a complex network of ligaments and tendons on the outer back portion of the joint, including the lateral collateral ligament (LCL), popliteus tendon, and popliteofibular ligament. These structures work together to resist varus stress, external rotation of the tibia, and posterior tibial translation. PLC injuries are among the most technically challenging knee injuries to diagnose and treat.
How PLC Injuries Occur
PLC injuries typically result from high-energy trauma — direct blows to the front-inner aspect of the knee, hyperextension injuries, or contact sports collisions. They rarely occur in isolation; the majority are combined with ACL or PCL tears, making comprehensive ligament assessment essential at the time of evaluation.
Symptoms and Diagnosis
Patients with PLC injuries report lateral knee pain, swelling, and instability — particularly with activities requiring straight-leg stance or pivoting. A sensation that the knee is bowing outward or giving way is common. Dr. Cooper performs specialized physical examination tests including the dial test, varus stress test, and reverse pivot shift to identify PLC injury and quantify its severity. MRI is essential to characterize the extent of damage to individual structures and identify concomitant ligament injuries.
Treatment
Low-grade PLC injuries may respond to bracing and physical therapy. Complete or high-grade PLC tears, however, require surgical intervention — ideally within the first two to three weeks of injury when tissue planes are easiest to identify and repair primarily. Chronic PLC insufficiency requires reconstruction using tendon grafts to recreate the damaged structures anatomically.
Because PLC injuries so often accompany cruciate ligament tears, Dr. Cooper addresses all injured structures in a coordinated surgical plan. Failure to recognize and treat PLC pathology is one of the most common reasons for ACL or PCL reconstruction failure.
Recovery
Rehabilitation following PLC reconstruction is lengthy and structured, typically spanning nine to twelve months before return to sport. Neuromuscular training and gradual strength progression are essential to restoring rotational stability and confidence in the repaired knee.
