Lateral collateral ligament (LCL) tear

This picture shows the right knee, viewed from the front. The lateral collateral ligament is shown in red on the left hand side of the image.

This picture shows the right knee, viewed from the front. The lateral collateral ligament is shown in red on the left hand side of the image.

The LCL is found on the lateral (outer) side of the knee. It attaches the femur (thigh bone) to the fibula (smaller bone which runs alongside the tibia in the lower leg). The LCL stabilises the outside of the knee by preventing widening of the knee joint.

Injuries to the LCL are much less common than that of the MCL and typically occur because of direct high-energy blow/impact to the knee causing a varus stress (i.e. a force hitting directly the inside of the knee). The severity of these injuries is graded the same as MCL injuries.

Complete (Grade 3) LCL tears rarely occur in without other injuries. In contrast to the MCL, Grade 3 tears of the LCL should be repaired surgically and soon after the injury because late repairs are associated with poorer outcomes. Other damaged ligaments may be treated at the same time.

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