Sports Medicine

LCL Tear

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

The lateral collateral ligament (LCL) is a thin band that runs along the outside of the knee and connects the thighbone (femur) to the fibula, which is the small bone that runs down the side of the knee and connects to the ankle. Similar to the medial collateral ligament (MCL), the LCL's primary function is to stabilize the knee as it moves.

Tears to the LCL commonly occur as a result of direct blows to the inside of the knee, which can over-stretch the ligaments on the outside of the knee and, in some cases, cause them to tear. The tear can occur in the middle or at either end of the ligament. LCL tears often occur while playing sports in which there are violent collisions (such as football or hockey). It is important to note that an LCL tear rarely occurs in isolation -- it usually is in conjunction with another knee injury.

The most common symptoms of an LCL tear are pain, stiffness, swelling and tenderness along the outside part of the knee. Your knee may feel loose, as though it will give way under stress, or it may lock. More severe tears can cause numbness or weakness in the foot, which occurs in the peroneal nerve (located near the LCL) if it is stretched at the time of injury or squeezed by swelling of the surrounding tissues.

Reviewed by health care specialists at UCSF Medical Center.
Last updated May 8, 2007