Design and evaluation of a custom contoured pneumatic insole for active plantar pressure offloading.

Introduction: Diabetic foot ulcers (DFUs) are a major cause of morbidity, amputation, and mortality in people with diabetes. Excessive and repetitive plantar loading contributes significantly, and although therapeutic footwear is widely prescribed, its effectiveness varies. Custom insoles improve pressure redistribution but do not address repetitive loading. Emerging active offloading technologies offer targeted relief, yet fully custom-contoured active systems remain untested. Methods: This study compared a custom-contoured active insole with a non-custom flat active insole under static and dynamic conditions in an individual without DFU risk. Both designs used seven pneumatically actuated air cells and were tested at 1.5 and 2.0 psi. Pressures were measured using a high-resolution in-shoe sensor and quantified using maximum mean pressure (MMP) and peak pressure (PP). Results: The custom insole consistently produced lower pressures, with substantial reductions in midfoot and heel regions and frequent MMP and PP decreases exceeding 45 percent during walking. Conclusion: Integrating patient-specific geometry with active pneumatic offloading enhances plantar pressure redistribution and may help prevent DFUs.