Three etiological factors–ischemia, peripheral neuropathy, and infection–underlie the development of gangrene of the feet in diabetics. The emphasis on each factor varies from patient to patient. A clinical classification based on the temperature of the foot divides patients with gangrene of the feet into three groups that occur with equal frequency: (1) necrosis in a cold foot, (2) necrosis in a hot foot, and (3) necrosis in a warm foot. In the first group, a major amputation is the inevitable result. Local excision and preservation of part of the foot is possible in all patients in the second group. It is worth attempting a local excision in the third group, as healing will occur in half the cases.
Williams HTG, Hutchinson KJ, Brown GD. Gangrene of the Feet in Diabetics. Arch Surg. 1974;108(4):609-611. doi:10.1001/archsurg.1974.01350280209035