The lateral collateral ligament (LCL) is one of the four knee ligaments. It spans the distance from the end of the femur (thigh bone) to the top of the fibula (thin, outer, lower leg bone) and is on the outside of the knee.

The lateral collateral ligament resists widening of the outside of the joint. A lateral collateral ligament injury happens from a direct force from the side of the knee, causing moderate to severe knee pain and ligament injury which often leads to knee surgery.

It is a much less frequent ligament injury than the medial collateral ligament (MCL) but commonly occurs with other ligament injury to the knee.

The MCL spans the distance from the end of the femur (thigh bone) to the top of the tibia (shin bone) and is on the inside of the knee joint. The medial collateral ligament resists widening of the inside of the joint, or prevents “opening-up” of the knee.

Nonsurgical Treatment

Ice. Icing your injury is important in the healing process. The proper way to ice an injury is to use crushed ice directly to the injured area for 15 to 20 minutes at a time, with at least 1 hour between icing sessions. Chemical cold products (“blue” ice) should not be placed directly on the skin and are not as effective.

Bracing. Your knee must be protected from the same sideways force that caused the injury. You may need to change your daily activities to avoid risky movements. Your doctor may recommend a brace to protect the injured ligament from stress. To further protect your knee, you may be given crutches to keep you from putting weight on your leg.

Physical therapy. Your doctor may suggest strengthening exercises. Specific exercises will restore function to your knee and strengthen the leg muscles that support it.

Surgical Treatment

Most isolated collateral ligament injuries can be successfully treated without surgery. If the collateral ligament is torn in such a way that it cannot heal or is associated with other ligament injuries, your doctor may suggest surgery to repair it.

More severe injuries with instability of the knee may require surgical repair or reconstruction. Repair may be performed for injuries within a few weeks if the tear of the ligament is from the upper or lower attachment.

If the ligament is torn in the middle or the injury is older than three weeks, then a reconstruction is performed to stabilize the knee.

The reconstruction can be performed using a tendon graft (either from the patient or a cadaver tendon) through bone tunnels.