The Anterolateral Complex of the Knee

Abstract

Background:Significant controversy exists regarding the anterolateral structures of the knee.Purpose:To determine the layer-by-layer anatomic structure of the anterolateral complex of the knee.Study Design:Descriptive laboratory study.Methods:Twenty fresh-frozen cadaveric knees (age range, 38-56 years) underwent a layer-by-layer dissection to systematically expose and identify the various structures of the anterolateral complex. Quantitative measurements were performed, and each layer was documented with high-resolution digital imaging.Results:The anterolateral complex of the knee consisted of different distinct layers, with the superficial and deep iliotibial band (ITB) representing layer 1. The superficial ITB had a distinct connection to the distal femoral metaphysis and femoral condyle (Kaplan fibers), and the deep layers of the ITB were identified originating at the level of the Kaplan fibers proximally. This functional unit, consisting of the superficial and deep ITB, was reinforced by the capsulo-osseous layer of the ITB, which was continuous with the fascia of the lateral gastrocnemius and biceps femoris muscles. These 3 components of the ITB became confluent distally, and the insertion spanned from the Gerdy tubercle anteriorly to the lateral tibia posteriorly on a small tubercle (lateral tibial tuberosity). Layer 3 consisted of the anterolateral capsule, in which 35% (7/20) of specimens had a discreet mid-third capsular ligament.Conclusion:The anterolateral complex consists of the superficial and deep ITB, the capsulo-osseous layer of the ITB, and the anterolateral capsule. The anterolateral complex is defined by the part of the ITB between the Kaplan fibers proximally and its tibial insertion, which forms a functional unit. A discrete anterolateral ligament was not observed; however, the anterolateral ligament described in recent studies likely refers to the capsulo-osseous layer or the mid-third capsular ligament.Clinical Relevance:The anterolateral knee structures form a complex functional unit. Surgeons should use caution when attempting to restore this intricate structure with extra-articular procedures designed to re-create a single discreet ligament.

Long-Term Results of ACL Reconstruction Using a Nonanatomic Double-Bundle Technique with Extra-Articular Reinforcement

“…The clinical outcomes after combined ACL and ALL reconstruction are promising despite the ongoing debate about the biomechanical characteristics of the ALL. 20,21 Zaffagnini et al reported better control of static knee laxity, reduced mediolateral instability in early flexion, and reduced rotatory instability at 90°of flexion in patients operated using a single-bundle ACL reconstruction with extraarticular augmentation compared with double-bundle ACL reconstruction. 22 In this study, we observed that 80% of the patients had normal or nearly normal knees using IKDC rating system after at least 10 years of follow-up.…”

Editorial Commentary: Anatomy of the Anterolateral Ligament of the Knee—The Science of Looking for Bigfoot

“…Fortunately for orthopaedics, members of the University of Pittsburgh Orthopedic Department have provided this type of zeal and have advanced the concept of the anterolateral complex of the knee. [6][7][8][9] Their work would generally not support the concept that the ALL is a separate structure worthy of the term "ligament." Regrettably, much of their work on the subject was not reviewed because de Lima et al 1 limited their searches to "anterolateral ligament."…”

An Overview of Anatomy and Imaging of the Anterolateral Structures of the Knee

“…Possibly because of the complex anatomy of this region, new studies are still being published with new information with regard to these structures, and yet the results are often conflicting, mainly with regard to the presence or absence of a true ligamentous structure within the anterolateral capsule, and the anatomic parameters of the capsulous-osseous layer. 9 , 14 The studies of Herbst et al 14 and Godin et al 9 are examples of meticulous well-performed dissections that present innumerable similarities but some points of difference. Godin et al, 9 for example, described the capsulous-osseous layer as “attached just proximal to the lateral gastrocnemius tubercle on the distal ridge 19.1 mm proximal to the lateral epicondyle, with an attachment area of 48.9 mm 2 ,” and Herbst et al described it as a layer contiguous with the fascia of the lateral gastrocnemius and plantaris muscles, with only flimsy fibers variably inserted in the area of the lateral femoral epicondyle.…”