The Lateral Collateral Ligament

By Ben Benjamin, PhD

Question: Injury to the lateral collateral ligament is often confused with injury to the:

a) lateral coronary ligament
b) biceps femoris tendon
c) tenser fascia lata 
d) all of the above

Answer: d) all of the above

Injuries to the lateral collateral ligament can be confused with injuries to any of the above mentioned structures, because all are located close to one another and cause pain when stressed in similar ways. Each of these injuries can cause a similar pain when running, performing cutting movements that involve sudden changes in direction, crossing the legs or squatting down. The structures are close neighbors. The lateral collateral ligament is located just to one side of a section of the lateral coronary ligament. The biceps femoris and the lateral hamstring are attached to the head of the fibula - the same attachment point as the superior attachment as for the lateral collateral ligament. The tenser fascia lata is attached to the lateral condyle of the tibia, less than an inch from the fibula head. In general, it is easier to locate injuries at the knee because there is little or no referred pain. What you feel is where it is. If you know precisely where each structure is, and can palpate it clearly, you are halfway there. Knowing how to test for each injury is the other half of the equation. In the case of the knee, the client can assist the therapist in pinpointing the precise area of injury.

Question: Which positive test indicates injury to the lateral collateral ligament?

a) resisted flexion of the knee
b) varus stress to the knee
c) passive internal rotation of the knee
d) pain on deep knee bends

Answer: b) varus stress to the knee

The lateral collateral ligament (B).Resisted flexion of the knee tests the hamstrings; passive internal rotation of the knee tests the lateral coronary ligament. Pain on deep knee bends indicates any number of injuries. Varus stress to the knee means that you are putting stress on the lateral aspect of the knee joint, and placing tension on the lateral collateral ligament. You accomplish this by applying a lateral force to the medial knee, and simultaneously applying a medial force to the lateral ankle, while keeping the knee straight.

Question: True or False: Some of the fibers of the lateral collateral ligament of the knee are contiguous with the knee joint, and stimulate profuse swelling when injured.

Answer: False.

The lateral collateral ligament of the knee is not contiguous with the knee joint, as is the case with the medial collateral ligament. It is separate from the joint capsule. This is why there is often minimal swelling from a lateral collateral ligament sprain. One of the signals that the lateral collateral ligament is injured is minimal swelling. Its neighbor, the coronary ligament, causes profound swelling, and the tenser fascia and biceps femoris cause no swelling at all.