Insole-Type Simultaneous Measurement System of Plantar Pressure and Shear Force During Gait for Diabetic Patients

Plantar foot ulceration is one diabetic complication shown to be associated with both pressure and shear force. There are plantar pressure measurement systems, but it is still difficult to measure plantar shear force while walking. The aim of this study is to establish a simultaneous in-shoe measurement system of plantar pressure and shear force during a gait. The design of the measurement system is based on F-scan pressure-distribution-sensor sheets and shear-sensor sheets. An insole with a shear-sensor sheet was arranged to be applicable for measurement of diabetic having neuropathy patients without damaging their skin. It was found that the system gets proper different shear force data in response to gait patterns, such as shuffle walking and flat-floored walking. We confirmed, moreover, the repeatability of the system for 5 healthy individuals. Experimental results show that weight-adjusted plantar shear stress during the pushoff phase of a gait increases in diabetic patients with calluses more than in patients without calluses. After a clinical study of diabetic patients, the system can be applied not only for the prevention of diabetic foot but also for the broad evaluation of gait posture.