Postoperative infection rates in foot and ankle surgery: a comparison of patients with and without diabetes mellitus.

BACKGROUND Patients with diabetes mellitus may be at increased risk for infection following foot and ankle surgery. This study aimed to determine whether patients with a diagnosis of diabetes mellitus have an increased rate of infection following foot and ankle surgery compared with a cohort of patients without diabetes. Furthermore, our study sought to demonstrate whether patients with complicated diabetes are at greater risk of postoperative wound infection than are patients with uncomplicated diabetes or patients without diabetes. METHODS We conducted a retrospective review of the charts of 1000 patients who had orthopaedic foot and ankle surgery. The following data were extracted: patient age, sex, history of diabetes mellitus, development of postoperative infection, severity of infection, inpatient or outpatient surgery, use of internal or external fixation, tobacco use, history of organ transplantation, history of rheumatoid arthritis, length of surgery, follow-up time in weeks, and comorbid conditions. RESULTS The overall infection rate in this study was 4.8%. Fifty-two percent of all infections occurred in our diabetic study group, which represented only 19% of the patient population. Postoperative infections occurred in significantly more persons with diabetes (13.2%) than in those without diabetes (2.8%). Diabetic patients were five times more likely to experience a severe infection requiring hospitalization compared with patients without diabetes. After removing the patients with neuropathy from the analysis, there was no longer a significant association between diabetes and infection. The presence of complicated diabetes increased the risk of postoperative infection by a factor of ten compared with the risk for patients without diabetes and by a factor of six compared with the risk for patients with uncomplicated diabetes. We did not identify a significantly increased risk of infection in patients with uncomplicated diabetes compared with that in patients without diabetes. CONCLUSIONS Patients with diabetes mellitus are at increased risk of severe infection compared with those without diabetes. Patients with uncomplicated diabetes did not have an increased risk of postoperative infection compared with patients without diabetes, whereas patients with complicated diabetes had a significantly higher rate of postoperative infection.