Overview of the anterolateral complex of the knee

Abstract

In the last few years, much more information on the anterolateral complex of the knee has become available. It has now been demonstrated how it works in conjunction with the anterior cruciate ligament (ACL) controlling anterolateral rotatory laxity. Biomechanical studies have shown that the anterolateral complex (ALC) has a role as a secondary stabilizer to the ACL in opposing anterior tibial translation and internal tibial rotation. It is of utmost importance that surgeons comprehend the intricate anatomy of the entire anterolateral aspect of the knee. Although most studies have only focused on the anterolateral ligament (ALL), the ALC of the knee consists of a functional unit formed by the layers of the iliotibial band combined with the anterolateral joint capsule. Considerable interest has also been given to imaging evaluation using magnetic resonance and several studies have targeted the evaluation of the ALC in the setting of ACL injury. Results are inconsistent with a lack of association between magnetic resonance imaging evidence of injury and clinical findings. Isolated ACL reconstruction may not always reestablish knee rotatory stability in patients with associated ALC injury. In such cases, additional procedures, such as anterolateral reconstruction or lateral tenodesis, may be indicated. There are several techniques available for ALL reconstruction. Graft options include the iliotibial band, gracilis or semitendinosus tendon autograft, or allograft.

Keywords: Anterolateral complex, Knee instability, Anterolateral ligament, Anterior cruciate ligament reconstruction

Core Tip: Although research on anterolateral ligament (ALL) has increased considerably in recent years, some debate remains regarding its anatomy and further refinement is still ongoing. Biomechanical studies have revealed that anterolateral structures contribute significantly to rotational stability of the knee and should be accounted for in the setting of an anterior cruciate ligament (ACL) injury. Surgical indications for ALL reconstruction are not currently evidence-based and the ideal graft type and fixation have not yet been determined. Further clinical research remains to be conducted to determine the most appropriate scenarios for augmentation of a primary ACL reconstruction with an anterolateral procedure to enhance patient outcomes.