Anatomical features and significance of the anterolateral ligament of the knee.

BACKGROUND: The anterolateral ligament (ALL) was discovered in 1879. For over 130 years, this anatomical structure did not enjoy much attention, but the situation started to change when a number of researchers described its contribution to the rotational stability of the knee joint.

PURPOSE OF THE STUDY: To estimate the occurrence of the ALL and describe the aspects of its anatomy that should be factored into the outcome of stabilizing surgeries of the knee joint.

MATERIALS AND METHODS: The study was conducted in 60 knee specimens of 30 unfixed human cadavers. Once the anterolateral ligament was identified, we assessed its relationships with the body of the lateral meniscus, the lateral collateral ligament to which it is attached mainly by connective tissue fibers, and the lateral inferior genicular blood vessels. We also identified ALL attachment points on the lateral epicondyle of the femur and the lateral condyle of the tibia.

RESULTS: ALL has been identified in 56.6% of the dissected knee pairs in both knees. ALL was present in 66.7% of female joints (24 of 36 specimens) and in 41.6% of male joints (10 of 24 specimens). The average length of the ALL was 38.5 ± 4.4 mm. The average width near the joint space was 4.45 ± 0.85 mm. The attachment point on the lateral epicondyle of the femur varied: it was posterior-proximal to the lateral collateral ligament in 64.7% of the dissected knees, anterior to the lateral collateral ligament in 23.5% of cases, and on the popliteus tendon insertion or next to it in 11.8% of cases. The point of the anterolateral ligament's attachment on the lateral condyle of the tibia typically lied halfway between the fibular head and Gerdy's tubercle.

CONCLUSION: The best site for a bone tunnel is the region on the lateral epicondyle of the femur, lying posterior and proximal to the origin of the lateral collateral ligament. The identified anatomical pattern in the course of the lateral inferior genicular vessels will help to spare these important blood suppliers in the course of a reconstructive surgery of the anterolateral knee joint region.