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:
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.
Lateral collateral ligament tears do not heal as well as medial collateral ligament (MCL) tears do. If the torn ligament does not heal sufficiently, you may experience instability in the joint, making it more susceptible to re-injury. Although more-severe injuries often require surgery, lesser damage to the LCL usually responds very well to non-surgical treatment. Recovery time depends on the severity of the injury.
Rehabilitation for an LCL tear consists of:
Once pain and swelling have subsided, you should be able to begin exercises to restore strength and normal range of motion to your knee.
Surgical repair of a torn LCL usually takes about one to two hours but can be longer if there are other injuries to the knee that also require treatment, such as an ACL tear. General anesthesia or a spinal or epidural anesthetic is used. An incision is made on the outside of your knee to gain access the torn ligament. The ligament is re-attached to the bone using screws, sutures or both. The skin is sewn back together using sutures or staples.
Rehabilitation depends on the extent of the damage done by additional injuries.