The medial collateral ligament (MCL) is a thick fibrous band of tissue that spans the distance between the bottom of the thighbone (femur) and the top of the leg bone (tibia). The MCL is located on the inside of the knee joint and is a part of the “posteromedial corner” (PMC), and when it is stressed beyond its normal range of function, it can stretch, partially tear, or completely rupture. MCL knee injuries occur when extreme force is applied to the outside of the knee joint. An example would be when someone is tackled from the side during soccer, or when someone catches the inside of their ski during snow skiing.

Symptoms and Diagnosis

Symptoms of an MCL knee injury will vary depending on the severity of the injury. Local pain and swelling on the inside of the knee are common. Bruising may also appear on the inside of the knee. In some cases, instability will lead a patient to believe that his or her knee will give out when complete weight is placed on the leg.

Your physician will conduct a thorough examination of the knee and conduct a series of tests to check for range of motion, pain level, strength and function. A variety of tests may be utilized to determine the extent of the injury, including a valgus stress test. This test will check to see if the medial knee gaps open on side-to-side stressing. If this occurs, then a complete tear is likely. Your physician will order an X-ray and MRI to confirm the diagnosis, to assess the extent and exact location of the injury, and to check to see if any other ligaments, tendons, menisci, or cartilage is damaged along with the MCL.


For most MCL injuries that involve a stretch or partial tear, where there is only limited gapping, non-surgical treatment is recommended. Injuries that are considered complete or Grade 3 may be braced for 6 weeks and sometimes heal. If gapping persists, or if the injury exists in association with the ACL or PCL or other knee injuries, surgery will need to be performed. Whether the MCL tear is partial or complete, your physician will be most concerned about the overall stability of the joint. If the MCL injury has occurred with an ACL tear, an ACL reconstruction will need to be performed once the MCL has fully healed, and if the MCL does not heal properly, your physician may also repair or reconstruct the MCL. Failure to reconstruct a loose MCL, in combination with an ACL tear, can result in ACL surgery failure. Thus, a careful examination is required, and frequently, the final decision is made at the time of surgery after ACL reconstruction. In all cases, your physician performs ACL and PCL surgery via an arthroscopic approach, while the collateral ligaments are on the outside of the joint, and require an open procedure.


Following MCL surgery, a thorough rehabilitation program will be prescribed. Therapy will be a progressive process and will initially focus on returning motion to the injured knee and surrounding muscles while protecting the healing ligament. Following this phase, an active and progressive strengthening program will help to re gain strength and control to the knee and leg allowing patients to slowly return to normal activities.

For more information on MCL knee injuries, please request a consultation with orthopedic knee specialist, Dr. Lubowitz, by clicking the link below.