Three-Dimensional Finite Element Modeling Study of Stress Distribution in Calcaneal Fracture

Abstract

The calcaneus is one of the biggest load-bearing tarsal bone in human body and therefore, many authors stress the importance of its biomechanical modeling and analysis in several aspects. We predicted possible fracture lines’ characteristics throughout the reconstruction of three-dimensional finite element modeling from CT slices and biomechanical analysis of stress state within talo-calcaneal complex, and its clinical validity was identified by comparing with radiographic/intraoperative findings. We reconstructed the 3-D finite element model based on CT images and predicted possible fracture-lines under various postures and loading conditions using ANSYS 15.0. Thereafter, predicted fracture-line were compared to X-ray films and intraoperative findings of patients with calcaneal fracture. In the 3-D finite element model of talo-calcaneal complex, stress was most highly elevated in the contact surface between the calcaneus and the talus, which transmits the weight-loading stress. Concentrated stress was observed in the concave site between anterior and posterior articular facets, the concave site between the ground-touching part of the calcaneal tuberosity and its mid-part, and on the connection line between most prominent part in the calcaneal tuberosity and the most concave site of plantar calcaneus. Simulation-predicted fracture lines were identified with high coincidence rate of 91.25% (292/320) in radiographic findings and intraoperative fracture findings of patients with calcaneal fracture. This 3-D finite element model of talo-calcaneal complex might be a powerful tool for simulative prediction of fracture-line and biomechanical simulation of appropriate implant’s stability, due to high potential of fracture-line prediction.