Mechanical Contribution of the Anterior Talofibular Ligament to Ankle Stability: 3D Anatomical Finite Element Analysis.

Abstract

Ankle sprains are among the most common musculoskeletal injuries, with the anterior talofibular ligament (ATFL) most frequently affected. Although cadaveric and in vivo studies have demonstrated the ATFL's role in restraining anterior talar translation and inversion, its isolated mechanical contribution remains unclear due to technical challenges in selectively altering individual ligaments. In this study, we developed a three-dimensional finite element (FE) model of the human foot and ankle to investigate ATFL function. The model was validated against experimental data using the anterior drawer test (ADT), with talar translation in the ATFL-intact condition falling within reported ranges. Simulations compared ATFL-intact and ATFL-injured conditions under ADT, Telos loading, and ankle varus loading. The ATFL-injured model showed increased anterior talar translation, inversion, and internal rotation, suggesting that the ATFL plays an important role in ankle stability. Fascicular analysis in the present model suggested that the inferior fascicle mainly contributed to resisting anterior translation, whereas the superior fascicle experienced greater model-predicted loading under inversion and plantar-flexion positions representative of ankle-sprain-like postures, suggesting possible vulnerability to injury. These findings provide model-based biomechanical insight for the ATFL's role in ankle stability and may provide a computational platform for future investigations into chronic ankle instability and surgical reconstruction outcomes.