IN VIVO MECHANICAL AND PHYSIOLOGICAL CHARACTERISATION OF LOWER LIMB SOFT TISSUE BY A LOCAL INDENTATION TECHNIQUE

Abstract

The purpose of this study was to determine appropriate mechanical properties of the bulk soft tissue for future stump socket interface finite element modelling. In vivo indentation experiments were carried out on lower limbs of 2 amputees and 3 normal subjects wearing individual RMM prosthetic sockets and braces respectively, using a custom designed indentation system. Indentation locations around the limb were chosen according to a grid system. The indentation force-displacement response of the soft tissue was then used as the inputs to calculate tissue modulus using Hayesa?? equation. In addition, discomfort and pain were also investigated during the experiments. Consequently a comprehensive map of tissue modulus and discomfort/pain threshold tolerance for the entire residual limb was generated. Highest tissue modulus was observed at bony prominences locality followed by tendon and then soft tissue for both amputee and normal subjects. For pain threshold, regions with tendon were noted to be the highest, followed by bony prominences and then soft tissue for normal subjects.