Study of Surgical Simulation of Flatfoot Using a Finite Element Model

A finite element (FE) model of flatfoot deformity was proposed in this paper for use in surgical simulations to improve individualized treatments. The external geometries of the flatfoot skeleton and encapsulated soft tissue were obtained by 3D reconstruction of CT images. A total of 63 major ligaments and the plantar fascia were manually created with wire parts to connect the corresponding attachment points on the bone surfaces. The bones, ligaments, and plantar fascia were defined as linearly elastic materials, while the encapsulated soft tissue was defined as nonlinearly hyperelastic material. The model was implemented in Abaqus^®, and simulations of balanced standing were performed. The simulated plantar stress distribution was compared to actual measurements. Surgical simulations of medializing calcaneal osteotomy (MCO) and lateral column lengthening (LCL) were conducted, and we found that both surgeries alleviated the stress around the talo-navicular joint and shifted high stress from the medial area towards the center and lateral areas, but the improvement instilled by LCL was more obvious than that instilled by MCO.