Effect of foot posture on plantar sensory and pressure distribution in individuals with type 2 diabetes mellitus

This study was aimed to investigate the effects of different foot postures on plantar sensation, postural sway, static-dynamic plantar pressure distribution, gait characteristics and physical performance in type 2 diabetics. One hundred and forty-four type 2 diabetics with different foot postures and 48 healthy individuals with neutral foot posture aging between 24-65 participated in the study. The foot postures were evaluated according to the Foot Posture Index and diabetic subjects were divided into three groups: pronation (n=48), supination (n=47) and neutral foot posture (n=49). Light touch-pressure sensitivity of were evaluated with Semmes-Weinstein monofilament set and vibration perception thresholds were evaluated with biothesiometer, plantar pressures, postural sway and time-distance characteristics of gait were evaluated with pedobarography device. It was found that plantar sensitivity in diabetics with different foot postures was similar (p>0.05); light touch-pressure sensitivity is lessened (p<0.001), vibration perception threshold is increased (p<0.001) in diabetics with different foot postures with respect to healthy subjects. By static analysis, it was found that diabetics with pronation foot posture have more area percentage on midfoot (p=0.006, p=0.001, p<0.001), less pressure surface percentage on forefoot (p=0.003, p=0.008, p=0.007, p<0.001) than other diabetics. It was determined by dynamic analysis that diabetics with pronation foot posture have more midfoot weight percentage (p<0.001, p=0.001), and pressure area (p<0.001) and less forefoot weight percentage (p<0.001) than other diabetics. It was found that diabetics with pronation foot posture have shorter two-step length (p=0.006, p=0.001) than diabetics with neutral foot posture. Our study indicates that diabetic plantar sensitivity did not change in diabetics with different foot postures; plantar pressure, postural sway, gait characteristics and functional level changed; diabetics compared to healthy individuals plantar pressure and gait characteristics changed, decreased plantar sensitivity and mean velocity of postural sway increased. Key Words: Foot posture, Diabetes mellitus, Foot pronation, Foot supination, Plantar pressure, Plantar sensitivity