The structures of the postero-lateral corner jointly act as a check ligament to control movement of the lateral side of the knee joint. Another name for these structures is the postero-lateral complex reflecting the fact that there are a number of structures that contribute to it. The three main structures involved are the LCL, the popliteus tendon, and the popliteo-fibular ligament. The bony shape of the lateral side of the knee makes it inherently more unstable than the medial side and additional stability is provided by the PLC to control sideways movement, and a combination of external rotation and backwards movement of the outer side of the upper tibia. Without the PLC, the knee tends to be rotationally unstable, that is there is an excessive twisting movement of the tibia under certain types of loading.

The postero-lateral corner is an area where about which we have learned a great deal about in the last few years. Its importance was not realised at one time but it is now recognised that it is quite commonly injured in association with ACL and PCL tears. Even so PLC tears are still difficult to diagnose and are missed in a number of cases with a resulting poor outcome following reconstruction of the ACL. 


Copyright London Knee Clinic 2014.