Plantar pressure distribution in Type 2 diabetic patients without peripheral neuropathy and peripheral vascular disease.

AIMS: To evaluate the distribution of plantar pressure during walking on a level gradient in patients with Type 2 diabetes mellitus without any microvascular and macrovascular complications and to compare them with non-diabetic control subjects.
METHODS: A group of 15 patients with Type 2 diabetes mellitus without either peripheral neuropathy or peripheral vascular disease (PVD), as well as without both diabetic retinopathy and nephropathy, was compared with a group of 15 non-diabetic subjects matched for age, sex, body weight and height. The plantar pressure and duration of plantar pressure were measured on big toe, 1st, 3rd and 5th metatarsal heads, and on the heel of both feet by Force Sensing Resistors sensors. The static contact plantar surface was measured by method of Harris footprints.
RESULTS: The diabetic group showed a significant increase in peak plantar pressure at the level of the big toe [right foot 205 +/- 94 vs. 101 +/- 39 kPa (mean +/- SD), P = 0.01; left foot 165 +/- 61 vs. 104 +/- 43 kPa, P = 0.05] and 5th metatarsal head (right foot 160 +/- 68 vs. 97 +/- 32 kPa, P = 0.05; left foot 174 +/- 65 vs. 91 +/- 42 kPa, P = 0.02) with a significantly prolonged duration of plantar pressure at each step. Under the heel, the peak plantar pressure was significantly lower in the diabetic group (right foot 187 +/- 54 vs. 321 +/- 91 kPa, P = 0.05; left foot 184 +/- 63 vs. 298 +/- 110 kPa, P = 0.05). No significant differences were noted under 1st and 3rd metatarsal heads. The contact plantar surface was significantly reduced in the diabetic group compared with control subjects (right foot 118.2 +/- 10.8 vs. 141.5 +/- 12.7 cm2, P = 0.05; left foot 127.5 +/- 8.7 vs. 140.0 +/- 11.1 cm2, P = 0.05).
CONCLUSIONS: We observed an anterior displacement of weight-bearing during walking on a level gradient as well as a reduced static contact plantar surface in diabetic patients without evidence of any complications compared with the non-diabetic control group. This could be a premature sign of peripheral neuropathy, which is not evaluated on clinical examination or quantitative sensory testing used in clinics.