The lateral collateral ligament (LCL) is rarely injured in isolation. Injuries to this ligament typically occur in association with more significant multi-ligament injuries to the knee.

The LCL is attached to the lateral epicondyle of the femur between the lateral gastrocnemius above and the popliteus below. Inferiorly it attaches to the head of the fibula. The LCL is the primary restraint to varus stress. In full extension, varus stability is also contributed to by the posterior capsule and postero-lateral corner (PLC). The PLC is a complex structure which includes the LCL, popliteus, biceps femoris and the popliteofibular ligament. Forty per cent of PLC injuries occur as a result of sport. 5

 

History

The LCL and PLC are typically injured during a varus and/or hyperextension injury. A blow (directed in a posterolateral direction) to the medial tibia when the athlete’s knee is extended is another common mechanism. There is often damage to other ligaments within the knee, including the ACL and PCL. As with an isolated injury to the ACL, the injury does not necessarily involve significant trauma.

To view an injury to the LCL and (and other knee ligaments), click on this video. Please note the initial varus stress, followed by valgus and internal rotation, to the right knee of the injured player.

Examination

A comprehensive knee examination and assessment for other ligamentous examination and signs with particular reference to the following:

  • hyperextension of the knee
  • laxity of LCL in extension and 30 degrees knee flexion
  • dial test
  • posterior draw

A reverse pivot shift test has been described – but this is rarely useful outside of theatre. 6 The test starts in a position of knee flexion and the knee is moved into extension while an external rotation and valgus force are applied. The ITB reduces the knee as it moves from being a flexor to an extensor.

It is important to document the neurovascular status in patients with multi-ligament injuries.