Why Do Authors Differ With Regard to the Femoral and Meniscal Anatomic Parameters of the Knee Anterolateral Ligament?

Abstract

Background:No consensus exists regarding the anatomic characteristics of the knee anterolateral ligament (ALL). A critical analysis of the dissections described in previous studies allows the division of the ALL into 2 groups with similar characteristics. The presence of considerable variability suggests that the authors may not be referring to the same structure.Purpose/Hypothesis:To perform a lateral anatomic dissection, by layers, seeking to characterize the 2 variants described for the ALL on the same knee. We hypothesized that we would identify the 2 variants described for the ALL and that these variants would have distinct characteristics.Study Design:Descriptive laboratory study.Methods:Thirteen unpaired cadaveric knees were used in this study. The dissection protocol followed the parameters described in previous studies. Immediately below the iliotibial tract, we isolated a structure designated as the superficial ALL, whereas between this structure and the articular capsule, we isolated a structure designated as the deep ALL. The 2 structures were measured for length at full extension and at 90° of flexion and for distance from the tibial insertion relative to the Gerdy tubercle. Potential contact with the lateral meniscus was also evaluated. After measurements were obtained, the 2 dissected structures underwent histologic analysis.Results:The superficial ALL presented a posterior and proximal origin to the center of the lateral epicondyle, its length increased on knee extension, and it exhibited no contact with the lateral meniscus. The deep ALL was located in the center of the lateral epicondyle, its length increased on knee flexion, and it presented a meniscal insertion. Both structures had a similar tibial insertion site; however, the insertion site of the deep ALL was located more posteriorly. The analysis of the histological sections for both structures indicated the presence of dense and well-organized collagen fibers.Conclusion:This anatomic study clearly identified 2 structures, described as the superficial and deep ALL, which were consistent with previous but conflicting descriptions of the ALL.Clinical Relevance:This study clarifies numerous controversies encountered in anatomic studies of the ALL. Knowledge regarding the existence of 2 distinct structures in the anterolateral knee will allow more accurate evaluation of their functions and characteristics.

The anterolateral ligament: A cadaveric study in fetuses

“…All authors agree that the ALL is attached in the lateral femoral epicondyle (Vieira et al, ; Claes et al, ; Helito et al, ; Dodds et al, ; Bonasia et al, ; Caterine et al, ; Daggett et al, ; Guenther et al, ; Kosy and Mandalia, ; Pomajzl et al, ; Roessler et al, ; Taneja et al, ; Van der Watt et al, ; Cavaignac et al, ; Helito et al, 2016a, 2016b; Macchi et al, ; Musahl et al, ; Parker and Smith, ; Runer et al, , Stijak et al, ; Roessler et al, ), but there are controversies regarding the attachment in relation to the FCL and the popliteus muscle tendon.…”

“…However, there is no consensus about the association between injuries to the ALL and lateral meniscal tears. Whereas Van Dyck et al () suggested that ALL injuries are highly associated with lateral meniscal and osseus injuries, Helito et al (2016a, 2016b) found no statistical association between injuries to the ALL and the lateral meniscus.…”

“…Therefore, the embalmed specimens could be firmer so it could be more difficult to perform a proper flexion‐internal rotation maneuver during dissection, making identification of the ALL in the lateral region of the knee difficult or impossible. Another consideration is that not all authors used the same protocol to dissect and identify this ligament (Helito et al, ; Musahl et al, ; Stijak et al, ; Vieira et al, ; Vincent et al, ), which could have caused disagreements among them concerning the anatomy of the ALL (Helito et al, 2016a, 2016b). We agree with Helito et al (2016a, 2016b) that improved dissection techniques and a better understanding of the anatomy of the ALL have allowed a more detailed description of this ligament to be achieved, resulting in less controversy about its anatomy.…”

“…Three different patterns have been reported in relation to the landmark represented by the FCL: (1) The ALL is always anterior and distal to the FCL (Vincent et al, ; Claes et al, ; Helito et al, ; Dombrowski et al, ; Stijak et al, ); (2) The ALL is always proximal and posterior to the FCL (Dodds et al, ; Cavaignac et al, ); or (3) The ALL and the FCL share a common attachment (Kosy and Mandalia, ; Runer et al, ). Another group of authors observed a variant set of three patterns (Kosy and Mandalia, ; Caterine et al, ; Daggett et al, ; Rezansoff et al, ; Helito et al, 2016a, 2016b; Runer et al, ; Kosy et al, ; Macchi et al, ; Shea et al, ; Watanabe et al, ).…”

“…Helito et al (2016a, 2016b) identified two distinct layers of the ALL, superficial and deep. The superficial ALL had its origin posterior and proximal to the FCL, while the femoral attachment of the deep ALL was located either in the center of the lateral epicondyle in most cases, slightly posterior and proximal, or slightly distal.…”