Pressure Offloading Device for Diabetic Footwear Based on Magnetorheological Fluids

Intelligent plantar pressure offloading for the prevention of diabetic foot ulcers and amputations

“…The module’s performance and the system’s ability to reduce PP across the insole have been tested. In the module’s on state, it could sustain a load of 55N, which corresponds to 357 kPa ( 39 ) with a residual deformation of only 0.5 mm. Thus, the performance of the module while on meets performance standards; with a PP of this magnitude, the module would likely be turned off to offload that region to prevent a foot ulcer.…”

“…Thus, the performance of the module while on meets performance standards; with a PP of this magnitude, the module would likely be turned off to offload that region to prevent a foot ulcer. When the module was turned off during the tests, the module instantaneously deformed to 1.5 mm which was the maximum deformation allowed for this test, and the force was reduced to 30 N (corresponding to 214 kPa) ( 39 ). This final force was linked to the features of the deformable bellow and the hydraulic resistance.…”

“…The pressure-offloading modules operate independently and are connected to the control electronics via flex PCB through channels on the underside of the housing insole. Each pressure-offloading module consists of three primary parts: 1) Topdeformable bellow filled with magnetorheological (MR) fluid and top plug, 2) Middle -flow channels and valve, and 3) Bottom -deformable reflow membrane and auxiliary reservoir (Figure 4) (37). The pressuresensing insole consists of piezoresistive sensors (dynamic range: 0-800kPa; sampling frequency: 200 Hz) aligned directly over each corresponding pressure-offloading module.…”