Foundation and static analysis of calcaneal three-dimensional finite element model.

Abstract

Objective To establish a more rapid and precise calcaneal three-dimensional (3D) finite element model based on the healthy human foot, to analyze the internal biomechanical properties of calcaneus, and to explore the relationship between caleaneal fracture pain with the stress imbalance factors in medial and lateral side of calcaneus. Methods One healthy male volunteer (28 years old, 64 kg) was selected. Input DICOM 3.0 standard CT sectional images into MIMICS10.1 software, set the threshold of 226-3071 Houfield unit, generate foot 3D model, extract caleaneus, optimize it into surface mesh model, and use ANSYS10.0 to develop grid mesh. According to CT sectional images of the gray value, the model materials were added, and the final 3D finite element model of ealeaneus was generated. The static standing posture was simulates using the static finite element analysis. Subtalar joint surface in the whole analysis process was fully constrained during the study period. The forces of 320 N and 160 N were loaded in perpendicular direction on heel and attachment point of Achilles tendon respectively to detect the Vonmises stress distribution of the calcaneus. Results MIMICS software can quickly establish a more accurate finite element model. When the vertical load acting on the calcaneus, there is a clear imbalance of factors about the calcaneal lateral and medial stress. The lateral calcaneal structure is a clearly weak area. The increased stress applied on the lateral wall of calcaneus, lead to secondary lateral deformity, which pressed the long and short muscle tendon of fibula and calcaneocubeid articulation, and generated pain. Conclusion The calcaneal finite element model is proved to be a correct and reliable model, which can help to understand the stress dispersion of calcaneal inner part. Key words: Finite element analysis; Calcaneus; Models, theoretical