Dial Test for Posterolateral Rotatory Instability (PLRI) The knee joint is like an elbow joint just with a loose sesamoid bone in form of the patellar in comparison to the olecranon. And of course, we can have posterolateral rotatory instability in the knee joint as well. These injuries often need surgical intervention as an injury to the posterolateral complex (PLC) often includes tears of the: - ACL - PCL - Popliteal tendon - Lateral collateral ligament - Popliteofibular ligament Watch the vid