Sports Medicine

MCL Tear

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

The medial collateral ligament (MCL) is a broad, thick band that runs down the inner part of the knee, from the femur (thighbone) to about four to six inches from the top of the tibia (shinbone).The MCL's primary function is to prevent the leg from over-extending inward, but it also is part of the mechanism that stabilizes the knee and allows it to rotate.

Injuries to the MCL commonly occur as a result of a strong force hitting the outside of the knee that causes the MCL -- and, possibly, other ligaments on the inside of the knee, such as the anterior cruciate ligament (ACL) -- to stretch or tear. This can happen while playing sports, for example during a clip block in football, where one player collides with another player from the side. In addition, MCL tears occur in sports where there are a lot of quick stops and turns, such as soccer, basketball and skiing. Slipping on ice, if your lower leg splays out, also can produce the same result. Another cause of injury is repeated stress, where the MCL loses its normal elasticity and becomes limp, like a worn-out rubber band.

Initial symptoms of a MCL tear include pain, stiffness, swelling and tenderness along the inside part of the knee. Depending on the severity of the injury, the pain can range from mild to acute. In addition, the knee may feel unsteady, or it may lock or "catch."

Reviewed by health care specialists at UCSF Medical Center.
Last updated May 8, 2007