Design and Fabrication of Customised Diabetic Insoles for Optimised Foot Pressure Distribution Using Finite Element Analysis and Additive Manufacturing Technology

Diabetic foot ulcers (DFUs) are a serious complication of diabetes and a leading cause of lower-limb amputations. Excessive plantar pressure in high-risk regions such as the heel and forefoot contributes significantly to their development. This study presents the design, simulation, and three-dimensional prototyping of customised diabetic insoles aimed at redistributing pressure and reducing ulcer risk. Insole models are created in Autodesk Inventor, evaluated with finite element analysis (FEA) in ANSYS Workbench, and fabricated using 3D printing technology. Three designs are evaluated, i.e., a standard insole, a circular-cutout insole, and an irregular-cutout insole, using four different materials, i.e., Ethylene Vinyl Acetate (EVA)1, EVA2, EVA3, and polyurethane (PU). Under applied pressure of 0.3 MPa by a diabetic foot, a customised EVA1 insole reduces barefoot peak stress from 3.97 MPa to 1.51 MPa (61.96% reduction), while irregular isolations lower ulcer-rim stress from 0.87 MPa to 0.63 MPa (27.8% reduction). EVA-based insoles outperformed the PU one, and prototypes are successfully printed in EVA and PU, demonstrating feasibility for low-cost and patient-specific applications.