Histopathologic characteristics of bone infection complicating foot ulcers in diabetic patients.

BACKGROUND: A universally accepted histopathologic classification of diabetic foot osteomyelitis does not currently exist. We sought to evaluate the histopathologic characteristics of bone infection found in the feet of diabetic patients and to analyze the clinical variables related to each type of bone infection.
METHODS: We conducted an observational prospective study of 165 diabetic patients with foot ulcers who underwent surgery for bone infection. Samples for microbiological and histopathologic analyses were collected in the operating room under sterile conditions.
RESULTS: We found four histopathologic types of osteomyelitis: acute osteomyelitis (n = 46; 27.9%), chronic osteomyelitis (n = 73; 44.2%), chronic acute osteomyelitis (n = 14; 8.5%), and fibrosis (n =32; 19.4%). The mean ± SD time between the initial detection of ulcer and surgery was 15.4 ± 23 weeks for acute osteomyelitis, 28.6 ± 22.4 weeks for chronic osteomyelitis, 35 ± 31.3 weeks for chronic acute osteomyelitis, and 27.5 ± 27.3 weeks for the fibrosis stage (analysis of variance: P = .03). Bacteria were isolated and identified in 40 of 46 patients (87.0%) with acute osteomyelitis, 61 of 73 (83.5%) with chronic osteomyelitis, 11 of 14 (78.6%) with chronic acute osteomyelitis, and 25 of 32 (78.1%) with fibrosis.
CONCLUSIONS: Histopathologic categorization of bone infections in the feet of diabetic patients should include four groups: acute, chronic, chronic acute, and fibrosis. We suggest that new studies should identify cases of fibrosis to allow comparison with the present results.