Influence of osteomyelitis location in the foot of diabetic patients with transtibial amputation.

Background: To evaluate the prevalence of osteomyelitis in different areas of the foot and the possible correlation between localization and outcome of major amputation.
Methods: From January 2008 to December 2010, a total of 350 diabetic patients were admitted to our diabetic foot unit for the surgical treatment of osteomyelitis. Osteomyelitis was diagnosed when both the probe-to-bone maneuver and plain radiography were positive. In all of these patients, osteomyelitis was confirmed by histological examination.
Results: Osteomyelitis was localized to the forefoot in 300 (85.7%) patients, to the midfoot in 27 (7.7%) patients, and to the hindfoot in the remaining 23 (6.75) patients. On average, foot lesions had developed 6.6 ± 5.6 months before admission to our unit. Transtibial amputation was performed in 1 (0.33%) patient with forefoot osteomyelitis, in 5 (18.5%) patients with midfoot osteomyelitis, and in 12 (52.2%) patients with osteomyelitis of the heel (χ(2) = 128.4, P < .001). Multivariate analysis showed the independent role that osteomyelitis in the heel region had in major amputation outcome (odds ratio 15.3; P < .001; confidence interval, 17.4-5336.0), dialysis treatment (odds ratio 6.3; P = .012; confidence interval, 2.5-1667.2), and leukocyte count greater than 10(3) mm(3) (odds ratio 2.25; P = .036; confidence interval, 1.1-76.6).
Conclusions: We found a higher rate of transtibial amputation when osteomyelitis involved the heel instead of the midfoot or forefoot in diabetic patients.
Level of Evidence: Level III, retrospective comparative series.