Impact of Varus Ankle Deformity on Tibiotalar Joint Articular Cartilage: A Finite Element Analysis

The distribution of forces within the ankle joint is crucial for its health and longevity. Loading disorders affecting the ankle joint can significantly impair daily life and activity levels. This study employs finite element analysis (FEA) to investigate the effects of Varus ankle deformity on the mechanical behavior of tibiotalar joint articular cartilage. Utilizing CT scan images, a personalized model of the Varus ankle was constructed. Four static loading scenarios were simulated at the center of pressure (COP), coupled with the hindfoot complex. For each cartilage, the contact area, contact pressure, and von Mises stress were computed. The results reveal an altered contact pattern in all loading conditions, consistent with clinical studies. The contact area shifted medially, and a critical region beneath the medial malleolus exhibited an average von Mises stress of 1.22 and 1.58 MPa on tibial and talar cartilages, respectively. Additionally, the study demonstrates a 9.4% reduction in contact area and a 14.3% increase in maximum von Mises stress compared to healthy ankles. These findings emphasize the significance of early diagnosis and treatment of ankle deformities to prevent further damage. Moreover, the utilization of patient-specific modeling offers improved insights into joint behavior under various conditions and aids in guiding clinical decision-making.