The ratios of area of foot print to area of foot outline and diabetic sole ulcer formation.

The ratio of area of foot print to area of foot outline for each foot was studied in 50 normal and 70 diabetic subjects. The diabetic group was divided into 2 groups: 44 patients without and 26 patients with sole ulcers. The chief aim was to find a ratio that could predict ulcer formation. One hundred feet in the normal subjects had a mean ratio of 0.621 with a range of 0.51-0.72. The 88 non-ulcerated feet in the diabetic patients had a mean ratio of 0.611 with a range of 0.49-0.70. The difference was statistically not significant (p > 0.05). Thirty-two ulcerated feet in the 26 diabetic patients had a mean ratio of 0.580 with a range of 0.47-0.68. The difference between the ulcer and the non-ulcer group was statistically significant (p < 0.01). Twenty non-ulcerated feet in 20 diabetic patients with unilateral involvement had a mean ratio of 0.60 with a range of 0.50-0.69. The difference between the ulcerated and non ulcerated feet in these 20 unilateral involved patients was also statistically significant (p < 0.01). The sole ulcers in our study were distributed mainly beneath the metatarsal heads and calcaneum. Analysis of the foot prints revealed multiple dark print areas. They were at the locations corresponding to the above bony prominences. As these bony prominences were high pressure points, the dark print areas could serve as crude indicators of excessive pressure. The diabetic ulcer group had smaller mean ratio and the reduction of the contact area could contribute to the formation of sole ulcers.(ABSTRACT TRUNCATED AT 250 WORDS)