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The primary soft tissue restraint to tibial internal rotation has been found to be the deep layer of the iliotibial tract, connecting from Kaplan fibers on the femur to Gerdy’s tubercle on the tibia.
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The anterolateral ligament has been found to be relatively weak and poorly aligned to resist tibial internal rotation, but damage here does increase laxity and may be a sign of other structures being damaged.
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Although lateral tenodeses are not anatomic, they are effective in controlling tibial
Biomechanics of the Anterolateral Structures of the Knee
Section snippets
Key points
Background
Previously, the term anterolateral rotatory instability (ALRI) was synonymous for the instability caused by an isolated anterior cruciate ligament (ACL) injury. Hughston and colleagues1 were the first to popularize the idea that only a concomitant anterolateral capsular injury can induce this excessive anterior subluxation of the lateral tibial plateau. With the introduction of arthroscopic ACL surgery, these peripheral injuries fell out of focus. Although intra-articular reconstruction of the
Anatomy of the anterolateral structures
The anatomy on the anterolateral side of the knee can best be described in a layer-by-layer fashion. The first relevant layer is the iliotibial tract (ITT), which inserts onto the tibia at the Gerdy’s tubercle and extents proximally as the fascia lata, merging into the gluteus maximus, gluteus medius, and tensor fascia lata muscles. The second layer is formed by the posterior fiber region of the superficial tract, which merges with the deep and capsulo-osseous structures of the ITT (Fig. 1).12
Anterolateral rotatory instability of the knee
The ACL is the primary restraint to anterior tibial translation and the posterior cruciate ligament to posterior tibial translation.22 It has been found that the tibia can be translated 30% more if it is free to rotate.23 This “coupled” rotation in response to an anterior translation of the tibia results in a 3° to 10° internal rotation when examined by hand and slightly more in an ACL rupture. This is due to the more mobile lateral knee compartment, caused by the convex articular surfaces, the
Structural properties of the anterolateral structures
When Werner Müller34 dissected the lateral knee structures in his knee anatomy video for the European Society of Sports Traumatology, Knee Surgery and Arthroscopy, he mentioned one basic biomechanical principle: “Big structures, big function, small structures, small function.” This does not necessarily mean that the bigger structures control anterior displacement of the lateral tibial plateau better than smaller structures. It strongly depends on fiber orientation (axis of alignment) to resist
Confusion surrounding the role of the anterolateral structures
Hughston and colleagues1 were the first to popularize the term “anterolateral rotatory instability” and associated it with a rupture of the mid-third lateral capsular ligament and the ACL. However, they did not mention the capsulo-osseous layer of the ITT, which obviously runs directly above the anterolateral knee capsule. Terry and colleagues15 and later Vieira and colleagues,13 described the capsulo-osseous layer of the ITT forming a sling around the posterolateral femur and called it the
Summary
Tibial internal rotation is controlled mostly by the lateral extra-articular structures, which are the lateral capsule and the iliotibial band. Based on recent findings, the ITT is the primary restraint to internal tibial rotation and the pivot-shift phenomenon as the knee flexes. The ALL is a capsular thickening, which has, similar to the deep MCL, only a secondary role in restraining the anterior subluxation of the lateral tibial plateau.
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Cited by (25)
Lateral Extra-articular Tenodesis: The Onlay Technique
2023, Arthroscopy TechniquesAnterolateral Structure Reconstruction Similarly Improves the Stability and Causes Less Overconstraint in Anterior Cruciate Ligament-Reconstructed Knees Compared With Modified Lemaire Lateral Extra-articular Tenodesis: A Biomechanical Study
2022, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :Therefore we preloaded the specimens before testing by applying 100 N anterior load and 5 N·m internal rotation torque at 30°of knee flexion for 10 minutes, respectively. The ITB has been shown to be stronger than any ALS and plays an important role in controlling internal rotation.27,42,43 Recent biomechanical studies recommended maintaining its tension when investigating the ALSR or LET27,44; therefore in every test, a force of 30 N was applied to the ITB parallel to the femoral axis (i.e., 0° lateral relative to the femoral axis), perpendicular to the cross-sectional area (Fig 2, black arrows).44-47
A Secondary Injury of the Anterolateral Structure Plays a Minor Role in Anterior and Anterolateral Instability of Anterior Cruciate Ligament-Deficient Knees in the Case of Functional Iliotibial Band
2021, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :We hypothesize that the poor structural properties of ALS or ALL might contribute to it. The ALL has been reported with a mean tensile strength of 175 N and stiffness of 20 N/mm, which were similar to those of deep medial collateral ligament (MCL).15,16 Therefore, ALL might be sheltered by the ITB, just as the deep MCL is protected by the superficial MCL.15,16
Knee laxity in anterolateral complex injuries versus medial meniscus posterior horn injuries in anterior cruciate ligament injured knees: A cadaveric study
2020, Orthopaedics and Traumatology: Surgery and ResearchCitation Excerpt :Stentz-Olsen et al. also reported that reconstructing the ALL did not decrease the internal rotation laxity in the ACL-reconstructed knee [22]. Recent studies report that not only ALL but also distal femur attachment of anterolateral capsule and iliotibial band (ITB) play an important role in knee stability [24–27]. The results of several biomechanical studies corroborate the existence of an anterolateral complex rather than the ALL [24,28].
Disclosures: The authors declare that they have no conflicts of interest relating to this article. However, work that led up to this article was supported as follows: C. Kittl: AGA (Arthroscopy Association of the German-speaking countries); E. Inderhaug: Bergen Regional Health Authority; A. Williams and A.A. Amis: Smith & Nephew Co supported research studies at Imperial College London and educational lectures at conferences.