Residual osteomyelitis at the resection margin after conservative surgery is not associated with the recurrence of diabetic foot infection and may successfully be treated without postoperative antibiotic therapy.

Abstract

We hypothesize that microbiology- and pathology-confirmed positive bone margins after the resection of diabetes-related foot osteomyelitis are associated with worse outcomes. We conducted a prospective study consisting of a cohort of 93 patients with diabetes-related foot osteomyelitis (histopathology confirmed) who underwent bone resection and where an additional bone biopsy was taken at the resection margin. The primary outcome was the recurrence of the infection. Pathology-confirmed positive margins were detected in 62 cases (66.7%), microbiology-confirmed positive margins were detected in 75 cases (80.6%) and recurrence was detected in 19 patients (20.4%). Chi-squared test failed to show the presence of an association between the recurrence of the infection with pathology-confirmed positive margins (p = 0.82), with microbiology-confirmed positive margins, (p = 0.34) and with the use of postoperative antibiotics (p = 0.70). Healing in patients with pathology-confirmed positive margins was achieved in a median of 12 weeks (95% CI 9.2-18) and those with pathology-confirmed negative margins in 14.9 weeks (95% CI 10.2-21.9), Log-rank test, p = 0.74. Thirty-four patients out of 61 available for follow-up (55.7%) with pathology-confirmed positive margins were treated without postoperative antibiotics. In that group, Chi-squared test failed to show the presence of an association between the recurrence of the infection with the use of postoperative antibiotics (p = 0.47). A positive margin was neither associated with the recurrence of the infection nor with the time to healing. More than half of patients with pathology-confirmed positive margins were treated without postoperative antibiotics and this approach was not associated with the recurrence of the infection.