AN ANALYSIS OF DYNAMIC FORCES TRANSMITTED THROUGH THE FOOT IN DIABETIC NEUROPATHY

OBJECTlVE - Biomechanical studies in diabetic neuropathy have clearly demonstrated abnormal foot pressures, but information on other aspects of gait is Limited. This study aimed to investigate and describe the forces transmitted through the foot during walking in diabetic subject s with varying degrees of peripheral neuropathy and to determine if ab normalities in these forces might contribute to the risk of plantar ul ceration. RESEARCH DESIGN AND METHODS - Subjects from the following gr oups were included: healthy control subjects (C); diabetic controlsubj ects (D); subjects with diabetic neuropathy (DN); subjects with previo us neuropathic ulceration (DNU); and subjects with Charcot neuro-arthr opathy (CH). Gait analysis was performed as subjects walked over a Kis tler force plate. Peak forces were measured las percent body weight) i n the vertical and horizontal planes. Comparisons were made between al l of the groups and between each diabetic group and a healthy control group matched for walking speed. RESULTS - There were 181 subjects stu died. In comparison with that of the speed-matched controls, the mean peak vertical force was higher in each of the diabetic groups, especia lly in the most neuropathic subjects (DNU, 113 vs. 110%, P < 0.01). Th is increase was entirely due to higher forces during heel contact (DNU , 111 vs. 106%, P < 0.001). The single peak force occurred during heel strike (rather than during foot push-off) in 23-38% of footsteps of h ealthy and diabetic control subjects but in 53-73% of footsteps of neu ropathic subjects. There was also a trend for higher peak medial force s (CH, 6.2 vs. 5.5%, P < 0.05). CONCLUSIONS - Diabetic neuropathy is a ssociated with a change in the time pattern of the forces transmitted through the foot and an increase in the vertical forces through the he el. The magnitude of the changes is small in absolute terms, but these changes may contribute to the risk of plantar foot ulceration.