Finite Element Analysis of Ankle Stress with and without Ligaments in a Varus Knee Case

Accurate assessment of ankle joint biomechanics is challenging due to the complex joint geometry and the effects of lower-limb alignment. Varus knee deformity alters load transfer through the ankle and may contribute to abnormal stress distribution. The aim of this study was to evaluate the effect of ligament inclusion on ankle stress patterns using a patient-specific finite element (FE) model derived from computed tomography (CT) images of a subject with varus knee alignment. Two FE models were developed: one including major ankle ligaments and one without ligaments. Bones and cartilage were assigned material properties based on CT-derived data, and static loading conditions representing bipedal standing were applied. Peak von Mises stresses and stress distributions were compared between the two models. Ligament inclusion reduced peak stress in the tibia from ۹.۹۶ MPa to ۹.۱۳ MPa and in the talus from ۵.۳۸ MPa to ۴.۳۶ MPa. Moreover, ligament inclusion resulted in a wider and more uniform stress distribution, particularly in the diaphyseal and posterior regions. These findings demonstrate that ligaments play a crucial role in ankle load sharing and stress distribution. The absence of ligamentous structures may lead to overestimation of peak stresses and inaccurate stress patterns in ankle FE analyses, highlighting the importance of accounting for ligaments in patient-specific modeling under varus alignment.

کلیدواژه ها:

ankle stress analysis ، ankle ligaments ، finite element analysis ، ankle biomechanics ، varus knee