Postero-lateral Rotatory Instability of the Knee Wheeless

Description: - is apparent when with stress testing lateral tibial plateau rotates posteriorly in relation to the femur with lateral opening of joint;
- atraumatic type:
- presents as chronic laxity, often with a varus knee deformity;
- this ligamentous laxity often occurs without ACL or PCL laxity;
- traumatic type:
- mechanism: knee hyperextension combined with a varus stress;
- posterolateraly directed blow to the anteromedial tibia with the knee in hyperextension is most common mechanism;
- most often associated w/ either ACL or PCL injury, and is commonly found in knee dislocations
Wheeless' Textbook of Orthopaedics