The medial collateral ligament, or MCL, is located on the inside of the knee and is the most commonly damaged ligament in the knee. It can be sprained or torn by direct impact to the outside of the knee, by twisting the knee, or by quickly changing directions while walking or running.

MCL injury most often occurs during sports activities, such as skiing, playing soccer, or during football when a player is “clipped” or hit on the outer side of the knee. It can also be caused by a car accident, or simply by sharply turning the knee while the foot is planted on the ground.

Most people who suffer an injury to the medial collateral ligament experience these symptoms:

• A “popping” sound when the injury occurs
• Pain on the inside of the knee
• Swelling or stiffness on the inside of the knee
• Difficulty moving the knee
• Pain or difficulty walking, sitting down, rising from a chair, or climbing stairs

To diagnose an MCL injury, a sports medicine specialist at Lancaster Orthopedic Group will evaluate the knee and may order tests, such as an X-ray or MRI, to rule out other damage to the knee.

Treatment for a sprained or partially torn MCL includes rest, ice, anti-inflammatory and pain medication, and immobilization to promote healing. A complete MCL tear may require knee surgery followed by physical therapy.