In vivo identification of the mechanical properties of thigh tissues from FreeHand Ultrasound for the numerical investigation of loads at the socket/residual limb interface of amputee people

Abstract

Prosthetic sockets are custom-designed and are decisive for functionality and comfort of limb prosthesis. To ensure load transmission and stability, high interface stresses are applied. Several computer models of the socket/residual limb assembly have been designed to identify critical stress accumulations that may induce discomfort or trauma. However, clinically relevant personalized Finite Element (FE) models represent a bottleneck. While material definition of tissues is critical for the evaluation of socket/tissues interactions, personalization of deep Soft Tissue (ST) material properties remains challenging. For clinical purpose, it has to be simple, in vivo and thus non-invasive. This work explores the feasibility of freehand ultrasound with an inverse method for assessing mechanical properties of the ST of the thigh. To be relevant for socket design, the residual strain from donning socket was simulated by compressing tissues (5% of initial circumference).