Increased foot pressures after great toe amputation in diabetes

To compare peak pressures on the sole of the foot in non-insulin-dependent diabetic patients with isolated, unilateral amputations of the great toe and first metatarsal with the patients' contralateral, intact foot.

Eleven patients with a unilateral great toe and partial first metatarsal amputation of at least 6 months duration were evaluated with the F-Scan in-shoe pressure measurement system. Patients were studied in the same brand and style of footwear--a thin, rubber-soled, canvas boat shoe. We compared mean peak plantar foot pressures under the first metatarsal, lesser metatarsals, lesser toes, and heel in feet with and without a great toe amputation using the Wilcoxon's matched pairs signed-rank test.

Peak foot pressures were significantly higher under the first metatarsal head (P = 0.046), lesser metatarsal heads (P < 0.001), and toes (P < 0.001) in feet with a great toe amputation compared with the contralateral foot without an amputation. Pressure under the heel was higher on the contralateral foot (P < 0.01).

After a great toe amputation, pressure distribution of the foot is significantly altered. Because preamputation risk factors such as peripheral neuropathy, foot deformity, and limited joint mobility for many of these patients remain unchanged, an increase in foot pressures contributes to an increased risk of reulceration and reamputation in these patients.