Development of a Generic Numerical Transtibial Model for Limb–Prosthesis System Evaluation

Abstract

The well-established finite element method (FEM) has been used successfully to evaluate and develop medical devices for lower-limb prosthetics over recent decades. Most numerical models are based on a specific 3D geometry, which, although allowing for an accurate analysis of a specific case, may differ significantly from the target group that is often geometrically closer to the average residual limb. In order to address this issue, a generic numerical transtibial model was developed with the corresponding definitive socket and silicone liner. Three load cases were performed to analyse the applicability of the model: donning, single-leg stance, and the static P5 test according to ISO 10328. While the first two cases were used commonly in previous studies, the ISO test was only used in physical tests and not in a numerical environment. The results of the simulations in terms of contact pressure, as well as the relative deformation of the socket, fit into the range reported in the literature for similar boundary conditions, thus verifying the model in biomechanical terms. The generic transtibial model serves as a numerical tool for the relative comparison of different socket-liner designs prior to the fabrication, providing insights into results that are otherwise difficult to obtain.

Keywords

• transtibial limb
• prosthetic socket
• numerical model
• finite element method
• generic model
• prosthetic liner