A Histological Evaluation of Lateral Ankle Ligaments in Human Cadavers: Implications for Connective Tissue Integrity.

Background and objective Ligament integrity is determined by collagen composition and organization, primarily type I collagen (tensile strength) and type III collagen (remodeling). The lateral ankle ligaments, specifically the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL), differ in susceptibility to injury, likely due to structural variations. This study aimed to compare the histological characteristics of the ATFL and CFL and correlate these findings with functional implications. Methods A cadaveric observational study was performed on adult lower limb specimens. The ATFL and CFL were dissected, processed using standard histological techniques, and stained with hematoxylin and eosin. Sections were evaluated using a semi-quantitative scoring system (0-3) assessing collagen fiber organization, fiber density, cellularity, and vascularity. Interobserver reliability was calculated, and statistical analysis included comparisons of means, confidence intervals (CIs), and effect size calculations. Results The ATFL demonstrated loosely arranged collagen fibers, lower density, and higher cellularity and vascularity, indicating increased remodeling but reduced structural strength. In contrast, the CFL exhibited dense, well-organized parallel collagen bundles with lower cellularity, reflecting greater mechanical stability. These differences were statistically significant. The findings suggest a predominance of type I collagen in the CFL and relatively higher remodeling activity in the ATFL. Conclusions Histological differences between the ATFL and CFL explain their differing mechanical properties and injury patterns. The structurally weaker ATFL is more prone to injury, whereas the CFL provides greater stability. These insights may inform surgical reconstruction and rehabilitation strategies.