THE ASSOCIATION BETWEEN CALLUS FORMATION, HIGH-PRESSURES AND NEUROPATHY IN DIABETIC FOOT ULCERATION

The presence of an ulcer beneath callus on the diabetic foot has been a well-documented and common clinical finding. We have conducted a pro spective study to examine whether callus can be used to predict planta r intrinsic neuropathic diabetic foot ulcer formation. Sixty-three dia betic patients (43 male, 25 Type 1), median age 62 years (IQ range 52, 67), median diabetes duration 17 years (IQ range 8,25) participated i n the study. All had neuropathy and peak plantar foot pressures (measu red using a dynamic optical pedobarograph) greater than or equal to 10 kg cm(-2). Calluses and previous ulcers were documented and classifie d. All ulcers occurring prior to and during the study were recorded, r e-examination was 15.4 (range 10-22) months from baseline. Seven ulcer s (6 patients) occurred during the study. Pressures were higher in the ulcer than non-ulcer sub-group (p = 0.04) with a relative risk of dev eloping an ulcer of 4.7 for an area of elevated plantar pressure. This compares with a relative risk of 11.0 for an ulcer developing under a n area of callus, and a relative risk of 56.8 for an ulcer developing on a site of previous ulceration. This study confirms that a history o f previous ulceration is the highest risk factor for ulceration and de monstrates, for the first time, that the presence of plantar callus is highly predictive of subsequent ulceration. Careful history taking an d examination of the foot to detect the presence of callus require no special training or equipment and callus should be recognized as a 'hi gh risk' factor for foot ulceration.