Knee ligament sprains or tears are some of the most common collateral ligament injuries. Athletes who participate in direct contact sports are most likely to injure their medial collateral ligament (MCL) and lateral collateral ligament (LCL) found on the sides of the knee. Collateral ligaments control the side-to-side motion of the knee and brace it against unusual movements. Common symptoms of a collateral ligament injury include pain at the sides of the knee, swelling over the injury site and knee instability.
Most injuries to the MCL are often treated with a hinged brace, while an injured LCL may require surgery, especially in cases where the ligament has pulled directly off the bone.