In this Section
The MCL, Injuries, and Surgery
The medial collateral ligament (MCL) is located on the inside of the knee. It is a strong flat band of fibrous tissue that extends from the medial epicondyle of the femur (thigh bone) to the medial plateau of the tibia (shin bone). The MCL is one of four ligaments that are critical to the stability of the knee joint. The other three ligaments are the anterior and posterior cruciate ligaments (ACL and PCL, respectively), and the lateral collateral ligament (LCL/posterolateral corner complex). The MCL functions to limit how much the inside of the knee opens during movement.
The MCL is typically injured from a blow to the outside of the knee. An MCL tear can occur as an isolated injury or it can be associated with other knee injuries, in particular tears of the ACL and medial meniscus. The combination of an ACL tear, MCL tear, and medial meniscus tear is referred to as the “unhappy triad.”
The most common symptom following an MCL injury is pain directly over the ligament on the inside (medial side) of the knee. Symptoms of a medial collateral ligament (MCL) injury tend to correlate with the extent of the injury. The severity of the injury is graded from I (minor) to III (complete tear).
Most MCL tears heal on their own, without the need for surgery. In higher-grade injuries a brace is often prescribed to protect the ligament while it heals. Grade I and grade II injuries are usually resolved within 4-6 weeks, though full recovery may take longer. During this time, it is important to regain and maintain knee motion, while also working on strengthening the surrounding muscle groups.
Grade III injuries are more severe injuries that are often associated with tears of other ligaments in the knee. Surgical repair of the MCL may be needed for some grade III injuries, and occasionally for chronic MCL injuries that have not healed appropriately. Surgery is usually done through an open incision that involves stitching the ligament back down to the bone. In chronic injury locations it is necessary to secure a tendon graft to the bone. Postoperative recovery is variable and depends on other injuries that are present in the knee.