About Posterolateral Corner Tears
Injuries to the posterolateral corner of the knee joint often occur with ACL ruptures and PCL ruptures. Unfortunately, the injury to the corner of the knee is often missed on the physical examination and even on the MRI. Injury to the soft tissue structures that exist just behind the popliteus tendon insertion in the lateral collateral ligament result in rotational abnormalities of the tibia. This can be demonstrated on physical examination by holding the knee at 90° and turning the tibia or also holding the knee at 30° and providing a varus or bending force on the joint. The posterolateral corner injury results in increased rotation of the tibia. Therefore, when an ACL or PCL is reconstructed and the posterolateral corner is not reconstructed, abnormal rotational forces cause the ACL or PCL reconstruction to sometimes fail early.  

Treatment for Posterolateral Corner Tears