Anatomic description of the anterolateral ligament of the knee

The anterolateral ligament, a structure that has been known for 130 years, has again attracted the attention both of orthopaedic doctors and anatomists. Since its initial description until now, this structure has had different names. Whether labelled as the mid-third lateral capsular ligament, the anterior oblique band of the fibular collateral ligament or the anterolateral ligament of the knee, this structure has been responsible for the so-called Segond avulsion fractures. The aim of this study was to determine the precise position and layer of the lateral knee compartment within which the anterolateral ligament is located, as well as its type.

In this study, the anatomical dissection of the lateral segment of 14 cadaveric knees (six male, eight female; seven right, seven left; average age of subjects: 78 years) was performed. The dissection was carried out in keeping with Seebacher, layer by layer.

The anterolateral ligament was identified in seven out of 14 cadaveric knee joints (50 %). The length of the ligament was 41 ± 3 mm, while the width was 4 ± 1 mm and the thickness 1 mm (in the middle section). In 14 % of the cases, the anterior oblique band was identified as a part of the FCL. In all of the knee joints, a part of the fibres of the ITT with the same insertions and direction as the ALL was found, located, however, at a much more superficial level than the ALL.

Analysis of the current scientific literature related to the anterolateral ligament and layer-by-layer dissection of the lateral region of 14 cadaveric knees has led to the conclusion that the anterolateral ligament is a thickening of the knee joint capsule located in the third layer of the lateral region of the knee (according to Seebacher) which is not always clearly morphologically differentiated from the remainder of the joint capsule. The anterolateral ligament is unequivocally a part of the joint capsule, which is why any damage to it should be treated in the same way as any other damage to the joint capsule.