# The Anterior Intermeniscal Ligament: A Comparative Study of Morphology in Male and Female Cadavers

## TL;DR

This study compares the structure of a ligament in the knee between male and female cadavers to understand potential sex-based differences.

## Contribution

The study provides new empirical data on sex-based morphological differences in the anterior intermeniscal ligament.

## Key findings

- Male cadavers showed greater medial AIML thickness in the right knee compared to female cadavers (p=0.04).
- Male cadavers exhibited a trend toward larger mid-point AIML thickness bilaterally, though not statistically significant.
- The study suggests sex-related factors may influence AIML morphology, but further research is needed.

## Abstract

Introduction: The anterior intermeniscal ligament (AIML) is a highly prevalent and functionally debated anatomical structure within the knee joint. While previous studies have suggested its potential role in meniscal stability, load distribution, and proprioception, detailed anatomical analyses are limited. This study aimed to assess the architectural characteristics of the AIML in male and female cadavers to elucidate potential sex-based differences.

Methods: This observational study was based on 112 available cadaveric knee specimens, with a female-to-male ratio of 1:1, sourced from the anatomy labs of the Tilman J. Fertitta Family College of Medicine and Baylor College of Medicine. After blunt dissection, the AIML was exposed and measured using a Mitutoyo digital caliper 500-172-30 (Takatsu-ku, Kawasaki, Kanagawa, Japan). Various measurements of the AIML and surrounding soft tissue structures were performed, and the recorded averages were organized in Microsoft Excel (Microsoft Corporation, Redmond, Washington, United States). Statistical analysis was conducted utilizing GraphPad Prism 10.2.0 (GraphPad Software, Inc., San Diego, California, United States).

Results: Statistical analyses revealed almost no significant differences in AIML dimensions other than greater medial AIML thickness in the right knee of male cadavers compared to female cadavers (right knee: t(110)=2.14; p=0.04). In the left knee, male cadavers demonstrated a trend toward increased medial AIML thickness, though this did not reach statistical significance (left knee: t(110)=-1.18; p=0.24). Additionally, male cadavers exhibited a trend toward larger mid-point AIML thickness bilaterally compared to female cadavers (right knee: t(110)=1.65 and p=0.10; left knee: t(110)=1.48 and p=0.14). These findings may suggest that sex-related factors influence AIML morphology, though further research with a larger sample size is necessary to determine statistical significance.

Conclusions: The absence of significant anatomical differences between sexes illuminates a potential contribution to sex-based disparities in knee pathology. Understanding AIML's structural properties may have implications for meniscal and anterior cruciate ligament (ACL) surgeries, improving surgical precision and patient outcomes. Future studies could investigate other sex-related factors, such as q-angles or estrogen exposure, and their effect on AIML morphology. Additionally, other avenues of research could investigate and compare morphological measurements in younger and older populations to evaluate whether this structure is sensitive to osteoarthritic insults, better defining its functional role in knee joint stability.