Radiographic Evaluation of Soft-Tissue Necrosis in Diabetics

Abstract

The evaluation and classification of ischemic and nonischemic soft-tissue necrosis in the diabetic is of utmost clinical importance. Due to combinations of various factors such as neuropathy, arteriosclerotic occlusion, and infection, the clinical manifestations of soft-tissue necrosis in diabetics are varied, and identification of the predominant component may be difficult. The roentgen appearance of the bones of the foot is of prime importance in assessing the vascular supply to the limb, because osseous resorption, no matter what the cause, can occur only in the presence of an adequate circulation (8). In the presence of soft-tissue necrosis, the absence of resorptive changes is indicative of ischemic disease (6). Methods and Materials Radiographs of the feet of 32 diabetic patients with soft-tissue necrosis were reviewed. With the resorptive osseous changes utilized as a differentiating factor, the patients were placed into categories of ischemic and nonischemic necrosis. The osseous changes in the foot involved by soft-tissue necrosis of the nonischemic variety are of two types (Fig. 1, A and B). One is a mottled or patchy demineralization involving, in some cases, almost all of the osseous structures. These changes are quite similar in appearance to those of Sudeck's atrophy. The second is a localized form in which resorptive changes are characteristically located, initially, in the periarticular bone, although the process may progress to include almost the entire shaft. The heads of the metatarsals and the metatarsophalangeal joints are most commonly involved. Classification was done without benefit of clinical history or examination, these findings being obtained and compared afterwards. All cases lacking adequate follow-up were discarded for trie purpose of this study. Additional examinations such as peripheral arteriography, when available, were included in the tabulation. Case Reports Case I: E. B., a 38-year-o1d white female, was admitted for gangrene of the left third toe which had been present for one year. She had been hospitalized previously with cellulitis and gangrene, but surgery had not been performed since the area was not well demarcated. She had been diabetic for thirty-two years and suffered from far-advanced diabetic retinopathy, nephropathy, and neuropathy. Physical examination revealed total blindness in the right eye and retinitis proliferans in the left. The gangrene of the left middle toe was well demarcated at the base of the proximal phalanx, and the remainder of the left foot was mildly edematous, reddened, and nontender. A poorly defined gangrenous area was noted on the right great toe. Dorsalis pedis and posterior tibial pulses were palpable bilaterally, but decreased. Laboratory studies showed anemia (hemoglobin 9.1 g per 100 ml), hypoproteinemia (albumin 1.8, globulin 2.9 g per 100 ml), and poor renal function (creatinine 2.6). Blood sugars varied from 50 to 270 mg per 100 ml.