Multi-ligament Knee Injuries

The knee depends on four primary ligaments for stability: the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and lateral collateral ligament.

The anterior cruciate ligament, or ACL, is located inside the knee joint. It helps prevent the tibia, or shinbone, from sliding too far forward in relation to the femur, or thighbone, and contributes to rotational stability.

The posterior cruciate ligament, or PCL, is also located within the knee joint. It helps prevent the shinbone from moving too far backward in relation to the femur.

The medial collateral ligament, or MCL, runs along the inside of the knee and helps resist forces that push the knee inward. The lateral collateral ligament, or LCL, runs along the outside and helps resist forces that push the knee outward.

A multi-ligament knee injury occurs when at least two of the knee’s major stabilizing ligaments are sprained or torn during the same injury. The combination can vary and may involve the ACL and MCL, the ACL and PCL, or several ligaments at once.

Each ligament injury can range from a mild sprain to a complete tear. Some injuries may also involve the meniscus or other supporting structures.

In severe cases, nearby nerves or blood vessels may also be affected. Numbness, weakness, unusual coolness of the foot, or changes in skin color can indicate a more serious injury.

Multi-ligament knee injuries usually occur when significant force is placed across the knee.

Sports are a common cause. Football, soccer, skiing, basketball, hockey, and other activities involving contact or sudden changes in direction can place substantial stress on the knee.

A player may be struck while the foot is planted, causing the knee to bend, twist, or shift abnormally. Non-contact injuries can also occur when a sudden pivot or awkward landing creates enough rotational force to damage more than one ligament.

Motor vehicle collisions, motorcycle accidents, and significant falls can also cause extensive ligament damage. Lower-energy falls may occasionally cause injury when the knee is forced into an unusual position.

Some multi-ligament injuries occur during a knee dislocation, in which the bones temporarily move out of normal alignment. The joint may return to its normal position before evaluation, so a dislocation is not always obvious afterward.

Pain is one of the most common symptoms and may occur in several areas of the knee. Swelling may develop quickly, causing stiffness and limiting normal bending or straightening.

Instability is another important symptom. The knee may feel loose, unreliable, or unable to support normal body weight. It may buckle or give way when standing, walking, or changing direction.

Bruising and tenderness can occur along the inner, outer, front, or back of the knee. Some people hear or feel a pop at the time of injury or recognize that the knee moved or twisted abnormally.

Difficulty bearing weight is common with more severe injuries. Numbness, tingling, weakness, unusual coolness of the foot, or changes in skin color may indicate injury to nearby nerves or blood vessels.

Diagnosing a multi-ligament knee injury requires careful evaluation because more than one stabilizing structure is damaged. Your physician will ask how the injury occurred and what symptoms developed afterward.

A physical examination may assess swelling, tenderness, range of motion, and stability in multiple directions. The knee will be tested for abnormal movement that can indicate ligament damage. Because pain and swelling can make an early examination difficult, the knee may need to be evaluated again as symptoms change.

Imaging includes X-rays to evaluate the bones and an MRI to assess the ligaments, menisci, cartilage, and other soft tissues.

Your physician may also evaluate circulation and nerve function in the lower leg and foot by checking pulses, skin temperature, sensation, and muscle function. Additional vascular imaging may be ordered if there is concern about blood vessel injury.