Material analysis for therapeutic insoles — A short report

Objective: Customized footwear with appropriate insole material for offloading is widely used for preventing ulceration in diabetic and leprosy affected patients. Methods: Computer based finite element analysis was carried out on a 3 dimensionally modelled insole. The insole was tested with the boundary condition of constant geometry, constant loading and varied material properties to identify the biomechanical behaviour of material. Results: A total of 7 commonly used insole rubber materials including Butyl Rubber, Ethylene Vinyl Acetate (EVA), Isoprene, Natural Rubber, Neoprene, Polyurethane and Micro Cellular Rubber (MCR) were tested using finite element analysis. The study exhibited low deformation and stress values for EVA. High deformation and stress values were seen in MCR. Conclusion: The comparison of insole materials provides health workers with the required knowledge for selection of appropriate material for therapeutic insoles. The mechanical analysis of materials through the computer aided analysis will help the therapeutic footwear technician and designer to design, fabricate and use appropriate insoles.