The prevalence and morphological characteristics of the knee anterolateral ligament in a Chinese population

The Anterolateral Ligament of the Knee Is a Nonisometric Thin Ligament With High Prevalence and Almost Constant Attachment to the Lateral Meniscus: A Systematic Review With Meta-analysis

PURPOSE

To provide comprehensive information about the anterolateral ligament (ALL) prevalence, morphometry, isometry, insertions, histology, and its relationship with the lateral meniscus (LM).

METHODS

The study was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Eligible cadaveric studies investigating the frequency of the ALL presence, and anatomical features were identified through an online search of the PubMed, Scopus, and Cochrane Central databases from inception to June 2022. Statistical analysis was conducted with the open-source R programming language using the "meta" package. The Higgins I2 statistic was used for quantifying heterogeneity.

RESULTS

Thirty-three studies (1,478 cadaveric knees) were included. The ALL had a 79% prevalence. It was attached to the LM periphery in 97% of studies. Most studies reported a femoral insertion of the ALL, just proximal and posterior to the lateral epicondyle. Tibial attachment is constant at the midpoint between Gerdy's tubercle and fibular head. The mean ALL thickness at the joint line was 1.6 [1.2; 2.0] mm. The ALL length was found to significantly change across the knee flexion (P < .01). It was increased from 0° to 60° and decreased after 60° flexion. Seven histological studies demonstrated a typical ligamentous microstructure.

CONCLUSION

The ALL is a thin ligament, distinct to the knee capsule, which may be found in 79% of the knees having an almost constant attachment to the LM. The ALL is not isometric. It becomes tense during internal rotation and between 30° and 60° knee flexion. Pooled results should be interpreted with caution due to the high heterogeneity among the included studies.

CLINICAL RELEVANCE

This study sheds light on controversial issues and provides comprehensive and accurate information about the essential anatomical knowledge on ALL, which may contribute to optimizing ALL reconstruction surgical techniques and biomechanical settings.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

Prevalence and morphometric characteristics of the anterolateral ligament of the knee in a sample of Colombian human cadavers

Introduction: The anatomy of the knee and its ligaments is clearly described in the relevant literature; however, several studies have found new structures associated with this joint, such as the anterolateral ligament (ALL) of the knee. The prevalence of this ligament varies a lot around the world, and studies addressing this topic in Colombian population are scarce. Objective: To determine the prevalence of ALL and its morphometric characteristics in a sample of Colombian human cadavers. Materials and methods: Cross-sectional study in which the knee joints of 15 human cadavers were dissected and analyzed. In order to ensure the integrity of anatomical structures such as ligaments and tendons, specimens should have not undergone previous dissections, so only 29 knees were included for analysis. The presence of the ligament was verified, and the proximal and distal insertion site, as well as its length and width, were established through the dissection. Results: The prevalence of ALL was 24.13%, as it was identified in 7 of the 29 dissected knees (4 left and 3 right knees). The average length and width of the ALLs found were 37.5mm (range: 24-52.4mm) and 3.9mm (range: 2.6-6mm), respectively. Conclusions: This study allowed confirming the presence of the ALL in Colombian population, although with a lower prevalence than that described in countries such as France, India, China, USA and Brazil. In turn, its morphometric characteristics were similar to those reported worldwide, since the average length and width found here are consistent with those described in the literature.

Research on the Anterolateral Ligament of the Knee: An Evaluation of PubMed Articles From 2010 to 2019

Background:

The anterolateral ligament (ALL) of the knee remains a topic of interest. All aspects of the ligament, including its anatomy, biomechanics, imaging, and clinical importance, are areas for research among knee surgeons.

Purpose:

To evaluate the trends in research on the ALL of the knee, as indicated by studies indexed in PubMed from 2010 to 2019.

Study Design:

Cross-sectional study.

Methods:

We searched PubMed for article titles from January 1, 2010, to December 31, 2019, that included the term “anterolateral ligament.” The initial search was performed with the terms “anterolateral ligament AND knee” and “anterolateral ligament NOT knee.” Next, we performed a search using “anterolateral complex OR anterolateral reconstruction OR lateral extra-articular tenodesis” to avoid missing any studies. A bibliometric evaluation was performed for the search results, and we noted the characteristics of the most cited articles in PubMed.

Results:

Published studies on the ALL peaked in 2017, with 56 studies, and then declined from 2017 to 2019. The 3 leading journals with articles on the ALL were Arthroscopy; Knee Surgery, Sports Traumatology, Arthroscopy; and The American Journal of Sports Medicine. Cadaveric anatomic, cadaveric biomechanical, and clinical imaging studies of the ALL were the most common types of studies published from 2010 to 2019. Clinical studies on the ALL consisted of 18 articles, with the majority displaying a low level of evidence.

Conclusion:

Cadaveric anatomic/histological, cadaveric biomechanical, and clinical imaging studies of the ALL were the most commonly published studies from 2010 to 2019. More clinical outcome studies with a high level of evidence are needed to increase the supporting data for the future practice of ALL reconstruction.