Operative treatment of posterolateral instability of the knee.

Acute and chronic posterolateral instability is often associated with cruciate injury. The results of surgical reconstructions for acute posterolateral instability are better than for chronic posterolateral instability. The authors recommend acute reconstruction of posterolateral injury when possible. In either acute or chronic instability, we first reconstruct any associated cruciate injury, and then expose the posterolateral corner through an open lateral incision. The authors believe that the LCL, popliteal attachment to the tibia, and the popliteofibular ligament are the most important posterolateral static stabilizers. Accordingly, we attempt to anatomically repair or reconstruct these structures in acute and chronic posterolateral instability. In acute injury the authors first attempt direct repair, advancement and recession, or augmentation of the LCL, the popliteal attachment to the fibula and popliteofibular ligament. Occasionally, reconstruction with patellar tendon autografts or allografts, or achilles allografts will be needed. In the patient with chronic posterolateral instability and varus alignment, a proximal, valgus tibial osteotomy is performed. Additional posterolateral reconstruction can be performed on a staged basis. In the patient with chronic posterolateral instability and valgus alignment, direct repair, advancement and recession, or augmentation can be attempted, but reconstruction with patellar tendon or achilles allograft often will be required. Proper anatomic reconstruction of all injured structures is recommended to achieve the best results in the operative treatment of posterolateral instability.