The Anterolateral Ligament is Not the Whole Story: Reconsidering the Form and Function of the Anterolateral Knee and its Contribution to Rotatory Knee Instability

Abstract

The heterogeneity of available cadaveric, histologic, and radiographic results related to the anterolateral ligament (ALL) does not support its existence as a discrete anatomic structure. Moreover, focusing narrowly on the ALL in isolation, what has previously been referred to as “ALL myopia,” obscures a thorough appreciation for the stability contributions of both capsular and extracapsular structures. We consider injury to the soft tissues of the anterolateral knee–the anterolateral complex—just one component of what is frequently found to be a spectrum of pathology observed in the rotationally unstable, anterior cruciate ligament (ACL)-deficient knee. Increased lateral tibial slope, meniscal root tears, and “ramp” lesions of the medial meniscocapsular junction have all been implicated in persistent rotatory knee instability, and the restoration of rotational stability requires a stepwise approach to the assessment of each of these entities. Through an appreciation for the multifactorial nature of rotatory knee instability, surgeons will be better equipped to perform durable ACL reconstructions that maximize the likelihood of optimal clinical outcomes for patients. The purposes of this review are to provide an update on the relevant anatomy of the anterolateral knee soft tissues and to explain the multifactorial nature of rotatory knee instability in the setting of ACL deficiency.

Editorial Commentary: The Segond Fracture Has Multiple Attachments: Yet Another Demonstration of the Anatomical Complexity of the Anterolateral Complex of the Knee

“…Clearly, the ALL and the associated Segond fracture are not the whole story to understanding and treating rotatory knee instability. 15 As with all of medicine, treatment of any constellation of injuries must be tailored to each unique patient. In our practice of individualized, anatomic ACL reconstruction, appropriate graft choice and sizing is performed to best match the specific anatomy of the patient, while considering concomitant pathology (e.g., avoiding autografts with tendinopathic changes).…”

The Anterolateral Ligament of the Knee in Pediatric Patients: What Do We Know? A Scoping Review

“…Many recent studies have detected the ALL using diagnostic imaging (mainly MRI), cadaveric dissections, and surgically (using arthrotomy or arthroscopy) [ 15 , 16 , 17 ]. On the other hand, probably due to differences in anatomic dissection techniques, different authors denied the existence of this ligament, accentuating the relevance of other structures, like the deeper part of the iliotibial band (ITB) and the anterolateral capsule [ 18 , 19 ].…”

Anterolateral complex of the knee: State of the art

“…The anterolateral ligament of the knee is a distinct ligamentous structure about which there is no consensus regarding its function and existence. Some authors deny the existence of such a structure, emphasizing the importance of other anatomical structures, such as the deeper portion of the iliotibial band (ITB) and the anterolateral capsule[ 3 , 4 ]. In contrast, other studies have identified the ALL as a ligament in its own right[ 5 , 6 ].…”