A Resource-Efficient Plantar Pressure Evaluation System for Diabetic Foot Risk Assessment

Diabetic foot complications constitute a large and rapidly growing global health problem, causing one million lower-extremity amputations annually. These amputations are typically preceded by preventable diabetic foot ulcers (DFUs). However, 80% of the world’s diabetics now reside in low- and middle-income countries, where many healthcare settings lack the resources required to implement recommended DFU risk assessment and prevention strategies. There is an unmet need for a more resource-efficient DFU risk assessment method. In this study, a low-cost, purely mechanical plantar pressure evaluation device was designed toward this end. The device consists of a grid of plastic bistable compliant mechanisms, which present a visual series of binary outputs in response to applied pressure. By having diabetic patients step on the device, non-specialist healthcare providers can easily assess patients’ plantar pressures, which are predictive of future DFUs. A prototype was fabricated and pilot-tested with 41 healthy subjects. It demonstrated a sensitivity of 25.6%, although sensitivity reached 60% for heavier subjects. Sensitivity could likely be significantly improved by lowering the device’s profile and increasing the sensing area. Strained health systems may then be able to use this device to allocate scarce healthcare resources more efficiently to prevent costly DFUs and amputations.