Foot plantar pressure offloading: How to select the right material for a custom made insole

The custom-made insole is largely recognized as the most important orthotics for decreasing the foot plantar pressure, using additions or cutouts, which modify the geometry of the insole. This paper proposes a procedure for supporting the clinicians in prescribing innovative custom made insoles for offloading the plantar pressure by using specific combinations of materials for the foot peak-pressure areas, without modifying the geometry of the insole. The process starts with the acquisition of the plantar pressure map of the customer and ends with the definition of the customised insole. The aim of the procedure is choosing the best combination of materials for each foot anatomical area for reducing the plantar pressure peaks below a maximum admissible pressure value decided by the physician. The positions and dimensions of the inserts are defined through analyzing the customer plantar pressure while the inserts materials are defined using FEM simulations of the insole-foot interaction. The case study showed a plantar pressure reduction congruent with the FEM simulations results. This procedure is applicable both for subtractive and additive manufacture techniques.