Testing for loss of protective sensation in patients with foot ulceration: A cross-sectional study

Current recommendations for the prevention of foot ulceration and amputation include screening at-risk individuals by testing for loss of protective sensation at eight sites using 10-g (5.07) nylon monofilaments. Yet measurement of the cutaneous pressure threshold to differentiate one-point from two-point static touch stimuli may allow identification of these at-risk individuals earlier in the clinical course of diabetic neuropathy. The present study tested this hypothesis using a prospective, cross-sectional, multicenter design that included sensibility testing of 496 patients with diabetic neuropathy, 17 of whom had a history of ulceration or amputation. Considering the cutaneous pressure threshold of the 5.07 Semmes-Weinstein nylon monofilament to be equivalent to the 95 g/mm² one-point static touch measured using the Pressure-Specified Sensory Device (Sensory Management Services LLC, Baltimore, Maryland), only 3 of these 17 patients with a history of foot ulceration or amputation would have been identified using the Semmes-Weinstein nylon monofilament screening technique. In contrast, using the Pressure-Specified Sensory Device, all 17 patients were identified as having abnormal sensibility, defined as greater than the 99% confidence limit for age, for two-point static touch on the hallux pulp. We conclude that patients at risk for foot ulceration can best be identified by actual measurement of the cutaneous sensibility of the hallux pulp.