Medial Collateral Ligament Injury (MCL)

What is a MCL Injury?

The medial collateral ligament (MCL) runs from the inside surface of the upper shin bone to the inner surface of the bottom thigh bone. This ligament keeps your shin bone (tibia) in place.

The MCL is usually injured by pressure or stress on the outside part of the knee. A block to the outside part of the knee during football is a common way for this ligament to be injured.

An MCL injury can be a stretch, partial tear, or complete tear of the ligament. MCL injuries also often occur at the same time as an anterior cruciate ligament (ACL) injury.

Common symptoms of an injury to the medial collateral ligament are:

• Knee swelling
• Locking or catching of the knee when you move it
• Pain and tenderness along the inside of the joint
• A knee that gives way or feels like it is going to give when it is active or stressed in a certain way

If you are being treated for an MCL injury or were recently, be sure to contact your health care provider if you notice:

• Increased instability in your knee
• Pain or swelling after they initially faded
• That your injury is not getting better with time
• You re-injure your knee

Diagnosis of a MCL Injury

If you believe you may have a medial collateral ligament injury, it's important to see a specialist who can make a proper diagnosis. Specialists at the Penn Medicine will conduct a physical exam of your knee.

Treatment at Penn

The initial treatment for a medial collateral ligament (MCL) injury involves basic first aid. After swelling has gone down, though, it’s important to work with a team of specialists who can determine whether surgery is required and help create a rehabilitation plan that’s best for you.

Penn Programs & Services for MCL Injury