Effect of prosthesis liner material properties on interface stresses between stump and trans-tibial socket

The liner materials of transtibial sockets have a direct influence on the stump-socket interface stress via its elastic property. The aim of this study is to evaluate the biomechanical efficiency of silicone liner, within a total surface bearing (TSB) socket by comparing with other three commonly used liner materials: soft pelite, regular plasyazone and poron within two finite element models of varied geometries. All subjects have been informed and agreed for suffering the computer tomography scan. Based on the images of computer tomography, the three-dimensional finite element models have been constructed. The surface-to-surface contact elements were employed at the stump-socket interface. All elements were assumed to be isotropic and linear elastic except for the material of silicone liner which assigned to be multi-linear elastic properties. The simulated results showed as the increasing of the elastic modulus of liner, interface pressure also increased. Generally, the lowest peak pressure of interface pressures of silicone liner demonstrated the nonlinear behavior can provide a good performance of load shearing. However, the results also showed the influence of stiffness of liner is limit to cause the interface redistribution.