The medial collateral ligament is the most common ligament injury in the knee, accounting for up to 50% of ligamentous knee injuries. The injury is caused by a sudden valgus ( knock kneed ) force sustained from a direct blow to the outside of the knee or during a twisting type fall.

The MCL is responsible for stability to the medial side of the knee. It provides the resistance to valgus, or an inward directed force on the knee. When the ligament is torn, there is no resistance and the knee’s medial sided instability can be easily assessed.

Most MCL injuries can be successfully managed with conservative/nonsurgical treatment. Depending on the severity of the injury, a stabilizing brace is usually prescribed for 4-6 weeks. There are some patterns of injury that will not heal well and are best managed with surgery.

If the MCL tear and instability are recognized and addressed early after injury, the surgeon and patient can decide together which treatment option would work best for them. Treatment early after the injury does give the surgeon the option of doing a repair of the torn ligament, particularly when combining the repair with an intraarticular ligament reconstruction like an ACL or PCL reconstruction.

When a patient presents with chronic MCL instability, often a repair will not sufficently address the instability. In these situations, a reconstruction of the MCL can be performed using a tendon harvested from the patient or a tendon graft obtained for a cadaveric donor.

Watch a video of an MCL and posterior oblique ligament reconstruction using an autogenous semitendinosis tendon graft.