Medial and posteromedial instability of the knee: evaluation, treatment, and results.

Medial-sided knee ligament injuries are complex and require a thorough understanding of the anatomy and the scope of injury to successfully treat. Patients with isolated medical collateral ligament (MCL) tears can normally be treated with bracing followed by physical therapy with outstanding results. Patients with isolated Grade III injuries to the MCL are controversial. A reason for the disparity in results reported may be due to the fact that many (if not most) Grade III MCL tears have associated injuries to the anterior cruciate ligament and/or posteromedial corner injury. Patients with combination injuries should be treated surgically with repair or reconstruction in most cases. Either allograft or autograft reconstructions of both the MCL and posteromedial corner can be successful. Successful elimination of anteromedial rotary instability is the key to successfully treating posteromedial corner injuries.