Abstract
Foot pressure measurement under the rheumatoid arthritic foot has been performed using a newly designed gum sensor measurement device. The sensor can pick up the pressure from changing capacitance. The sensitivity of the sensor is below 20g/cm2and the range is from 450g/cm2to 2500g/cm2. The device is composed of 960 of these sensors and 8 frames/second of foot pressure measurement can be made. The clinical measurement was made on classical rhuematoid arthritic patients.
The pressure distributions and foot deformities could be divided into 3 types. Type 1 had minimum foot deformity but the pressure under the toes was decreased (5 feet) . Type 2 had a moderately deformed forefoot and there was almost no pressure under the toes (6 feet) . Type 3 was a markedlly deformed foot with no forefoot pressure distribution (10 feet) . In Type 2 the pressure under the metatarsal head was calculated and compared to that of the normal subject. In rheumatoid arthritic patients, the peak of the pressure was 2 times larger than that of normal persons (pressure/cm2/weight) and the location of the peak was shifted laterally. These results suggest that sole pain in rheumatoid arthritic is related not only to static foot deformity but also to the dynamic abnormality in walking.
