The effect of an innovative sandwich-structure liner on stress distribution in the residual limb: A transtibial Amputation model

Patients with lower limb amputations face challenges in restoring motor functions, particularly walking, due to high stresses on the prosthetic limb. This study aims to improve prosthetic liner performance by designing an interfacial liner with a sandwich structure to reduce stress concentrations and enhance load distribution. Three models were evaluated: Model 1 featured a fully elastomeric sandwich structure with a perforated elastomeric core designed to enhance flexibility and improve stress absorption; Model 2 used an elastomeric outer skin and a perforated polyurethane memory foam core for superior cushioning and stress redistribution; and Model 3, for comparison, was a fully elastomeric liner without a sandwich structure. Finite element analysis showed significant reductions in peak stresses from 7.23e-2 MPa in Model 3 to 4.23e-2 MPa and 5.59e-2 MPa in Models 1 and 2, respectively. Model 2 demonstrated superior stress redistribution, concentrating stresses in less sensitive regions such as the lateral tibial head (LTH). These results highlight the efficacy of a sandwich structure, particularly with a memory foam core, in enhancing comfort and functionality in prosthetic liners.