Definition of Medial collateral ligament (MCL) injury of the knee:

Medial collateral ligament (MCL) injury is a stretch, partial tear, or complete tear of the ligament on the inside of the knee.

Considerations:

The medial collateral ligament (MCL) extends from the upper-inside surface of the shin bone to the bottom-inside surface of the thigh bone. The ligament stabilizes the joint on the inside of the knee.

Causes:

The MCL is usually injured by pressure placed on the knee joint from the outside.

It is often injured at the same time as an anterior cruciate ligament (ACL) injury.