A modelling-simulation-analysis workflow for investigating socket-stump interaction

Abstract

In this thesis, a novel subject-specific modelling-simulation-analysis workflow is developed, which generates detailed stump models for analysis in a continuum-mechanical framework. With minimal human intervention, detailed stump models are generated from medical images, and are used in Finite Element (FE) simulations to study dynamic stump-socket interactions. Herein, the stump is composed of bone, individual muscles and fat, as opposed to the state-of-the-art models with fused muscles. An additional model representing the state-of-the-art stump geometry is generated for comparison with the proposed model. To showcase the necessity of detailed stump models, the state-of-the-art model is compared with the detailed model in a bipedal stance simulation. For this purpose, a nonlinear hyperelastic, transversely isotropic skeletal muscle constitutive law containing a deep tissue injury model, using continuum damage mechanics, is implemented in LS-DYNA. Internal strains and deep tissue injury during dynamic socket-stump interaction are analysed with bipedal stance and gait simulations. Further, the potential of forward dynamics with active stump models, and the possibility of realistic liner donning simulations are presented. Finally, the possibilities of using the proposed workflow in the context of determining socket fit and comfort are discussed.