Corpus: Tibial collateral ligament

The tibial collateral ligament is one of the four most important ligaments of the knee joint that extends along the inside of the knee.

The tibial collateral ligament is a broad and flat ligament located on the medial side of the knee, slightly shifted dorsally. Proximally, it attaches to the medial epicondyle of the femur, and distally, it attaches below the medial condyle of the tibia. The ligament has an anterior and a posterior part, with fibers that diverge slightly in a V-shape towards the distal end. The deep fibers are fused to the medial meniscus.

The lower part of the tibial collateral ligament is overlaid by the superficial pes anserinus, which can lead to shearing forces. To alleviate this, a bursa called the anserine bursa is situated between the superficial pes anserinus and the ligament.

The tibial collateral ligament stabilizes the knee joint against forces directed medially (valgus stress), preventing the opening of the medial joint space and a valgus position. Together with the fibular collateral ligament, it also restricts external rotation of the knee joint.

The integrity of the tibial collateral ligament can be assessed clinically using the valgus stress test. In the case of a collateral ligament injury, pain and/or medial unfolding of the knee joint occurs when the lower leg is abducted. A bony avulsion of the tibial collateral ligament is known as a Stieda fracture.