Have You Suffered An MCL Injury?

An MCL injury can be a significant injury leading to many questions. What is the MCL? What are my treatment options? And most importantly, will I need surgery? If you have an MCL tear, learn answers to these questions that will help you understand what you can do to get back in the game.

What Is An MCL?

The MCL, or medial collateral ligament, is one of the four main ligaments that support the knee. A ligament, by definition, is a piece of soft tissue that connects bone to bone. In the knee there are four ligaments that support the joint: ACL (anterior cruciate ligament), PCL (posterior cruciate ligament), MCL (medial collateral ligament), and the LCL (lateral collateral ligament).

The MCL is located on the medial or inner aspect of the knee and helps to provide medial knee joint stability. The LCL is on the lateral or outside of the knee joint and supports the lateral knee joint. The ACL and PCL are located inside the knee and help to provide stability for movement of the tibia below, specifically rotation.

Unique to the MCL ligament is its association with the medial meniscus. A portion of the MCL directly attaches to the medial meniscus thus injury to the MCL ligament can involve the medial meniscus as well.

How Do MCL Injuries Occur?

A MCL injury can occur from both contact and non contact. A contact MCL injury occurs from a blow or force coming from the outside or lateral aspect of the knee being directed medially. MCL tears can also occur from a twist or rotation mechanism, especially when associated with an injury to the ACL. A combination of an ACL and MCL tear also associated with a meniscus tear is termed the “unhappy triad”.

MCL Injury: Signs and Symptoms

One of the more commons signs associated with a ligament tear is a sensation of a “pop” when the injury occurs. With a MCL tear, pain will be localized over the medial aspect of the knee. Swelling generally occurs within a couple of hours.

Depending on the severity of the injury, you may or may not be able to walk on the injured knee. Most pain will occur with the knee if full extension (straightening) or with any medial stress. After the swelling is minimized, with more significant MCL injuries, a feeling of instability, or giving way, can occur.

Severity of MCL Tears

As will all ligament tears, a MCL injury can be classified into three types: first, second, and third degree sprains.

A first degree knee sprain occurs when tension is placed across the ligament and a mild stretch, but no tearing, occurs. With a first degree MCL sprain you will not feel or hear a “pop”, there will be mild tenderness and mild swelling over the inside aspect of the knee, but there is generally no limitation with the ability to walk on the knee.

A second degree MCL injury occurs when there is partial tearing of the MCL ligament. More swelling and tenderness will occur and you may not be able to put weight on the injured knee. In some cases the knee may feel slightly unstable.

A third degree MCL tear is when there is a complete rupture of the MCL ligament. Generally a “pop” is heard or felt, swelling and pain occurs quickly after the injury, and often you will not be able to walk on the injured leg. Over time a feeling of instability can occur, especially if associated with an injury to another ligament such as the ACL.

Diagnosis of MCL Tear

As part of the evaluation of the knee, a series of physical tests can be performed to determine if any ligament instability is noted. The most common test of the MCL is a ligament test called the Valgus stress test. With this test a stress is placed medially over the knee a full knee extension and at 30 degrees to determine if there is any pain or laxity. If the knee joint moves more on the injured compared to the uninjured side, a MCL sprain is suspected.

The only way to clearly diagnose the severity of the MCL injury is via MRI. MRIs show soft tissue (muscles, ligaments, tendons) whereas x-rays only show bone. Upon initial injury an x-ray may be performed to rule out any fracture. However, if the x-ray is negative for a fracture this does not mean a MCL injury has not occurred.

Treatment Options

As with any acute knee injury, the use rest, ice, compression, and elevation are the initial treatment recommendation. Depending on the severity of the sprain, crutches and a brace may be recommended.

Research indicates that early range of motion exercises are helpful to maintaining normal mobility and function thus physical therapy may be an important early treatment option. In first and second degree MCL injuries, typical recovery time is six to eight weeks.


First and second degree MCL tears are generally not surgical situations, even when injured in combination with other ligaments. Surgical intervention for grade three MCL tears most often occurs in cases in which either the MCL is injured in combination with other ligament injuries, or in the case of isolated grade three MCL tears, if chronic instability continues even after conservative treatment.

Research is unclear as to if it is necessary for the MCL to be repaired in cases in which an ACL tear also occurs. In such combination injuries the ACL reconstruction is most often recommended but debate remains if the MCL needs to be surgically repaired or if surgical management is necessary only if instability remains. In most cases that surgical intervention of the MCL is recommended, the surgical technique involves repairing the MCL. Less commonly is the MCL reconstructed, or a new ligament, put in its place.

A MCL tear can be a significant injury but surgery is generally not necessary. Early diagnosis and treatment, including physical therapy, are most helpful in returning patients to full recovery.


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