Collateral ligaments are located on the sides of the knee, controlling its side-to-side motion and bracing it against unusual movement. The medial collateral ligament (MCL) is on the inside of the knee, connecting the femur to the tibia. The lateral collateral ligament (LCL) is on the outside of the knee and connects the femur to the smaller bone in the lower leg (fibula).

Injuries to the collateral ligaments are usually caused by force pushing the knee sideways. While they are typically a result of physical contact while playing sports, they are not exclusive to athletes. The MCL is injured more often than the LCL due to the more complex anatomy of the outside of the knee—those who experience an LCL injury usually injure other joint structures as well.

Who Needs It

Injuries to the medial collateral ligament are often treated with a hinged brace and rarely require surgical intervention. However, injuries to the lateral collateral ligament are more likely to need surgery, especially in cases where the ligament has pulled off the bone or if the LCL injury involves other structures in the knee. If multiple injuries are present, the orthopaedic surgeon will likely treat all the issues during the same procedure.

How Does It Work

Most isolated collateral ligament injuries can be successfully treated without surgery. However, if the tear cannot properly heal or is associated with other ligaments or injuries to the knee, your orthopaedic surgeon may suggest a surgical repair. The appropriate surgical technique depends on a variety of factors.

Recovery

Properly icing collateral ligament injuries is essential in the healing process. This includes applying crushed ice directly to the affected area for 15-to-20-minute intervals with an hour between icing sessions. Recovery may also include a brace that protects the injured ligament from stress or the same sideways force that caused the injury. Patients may also be given crutches to avoid putting weight on the injured leg.

A physical therapy treatment plan may also be part of the patient’s recovery, which includes specific exercises to restore function to the knee and strengthen the leg muscles that support it. Once the patient’s range of motion returns and they can walk without limping, the doctor may allow a gradual, progressive return to daily activities and playing sports.