Obtaining clean margins in patients who undergo surgical treatment for diabetic foot osteomyelitis (DFO) is recommended. We hypothesize that the rate of recurrence of the infection is not associated with positive margins, even when using a short-term duration of postoperative antibiotic treatment. We conducted a retrospective pilot study of patients who underwent surgery for DFO confirmed by histopathological analysis of the resected bone from August 1, 2020, to December 1, 2020. Bone samples were taken from the proximal margins to be studied by microbiology and histopathology. Twenty-five (89.3%) patients underwent conservative surgery, and 3 (10.7%) patients underwent a minor amputation. After surgery, the antibiotics were stopped in 19 (67.9%) patients and continued in 9 (32.1%) patients for a median period of 4 days. The microbiology of the bone margins was positive in 20 (71.4%) cases, but the histopathology of the bone margins was positive in just 7 (25%) cases. Recurrence of the infection was detected in 3 (10.7%) patients. Seventeen (68%) patients with microbiological-positive margins did not have a recurrence of infection, while 3 (100%) patients had a recurrence of infection (P = .53). Six (24%) patients among those with histopathological-positive margins did not have a recurrence of infection, and1 (33.3%) patient had a recurrence of infection (P = 1). The recurrence of infection was low and always detected in soft tissues, including the cases with a histopathological-positive bone margin. Postoperative antibiotics were administered for a short period of time and not based on the analysis of bone margins.

In patients with diabetic foot osteomyelitis (DFO) who underwent surgical debridement, we investigated whether a short (3 weeks) duration compared with a long (6 weeks) duration of systemic antibiotic treatment is associated with noninferior results for clinical remission and adverse events (AEs).
In this prospective, randomized, noninferiority pilot trial, we randomized (allocation 1:1) patients with DFO after surgical debridement to either a 3-week or a 6-week course of antibiotic therapy. The minimal duration of follow-up after the end of therapy was 2 months. We compared outcomes using Cox regression and noninferiority analyses (25% margin, power 80%).
Among 93 enrolled patients (18% females; median age 65 years), 44 were randomized to the 3-week arm and 49 to the 6-week arm. The median number of surgical debridements was 1 (range, 0-2 interventions). In the intention-to-treat (ITT) population, remission occurred in 37 (84%) of the patients in the 3-week arm compared with 36 (73%) in the 6-week arm (P = .21). The number of AEs was similar in the 2 study arms (17/44 vs 16/49; P = .51), as were the remission incidences in the per-protocol (PP) population (33/39 vs 32/43; P = .26). In multivariate analysis, treatment with the shorter antibiotic course was not significantly associated with remission (ITT population: hazard ratio [HR], 1.1 [95% confidence interval {CI}, .6-1.7]; PP population: HR, 0.8 [95% CI: .5-1.4]).
In this randomized controlled pilot trial, a postdebridement systemic antibiotic therapy course for DFO of 3 weeks gave similar (and statistically noninferior) incidences of remission and AE to a course of 6 weeks.
NCT03615807; BASEC 2016-01008 (Switzerland).

Transcutaneous bone biopsy (TCB) is the gold standard for taking microbiological specimens in diabetic foot osteomyelitis (DFO), but this technique is not widely used in diabetic foot care centers. We aimed to evaluate the reliability of per-wound bone biopsy (PWB) cultures by comparing them with concomitant TCB cultures obtained through healthy skin. This is a prospective monocentric study including patients seen in consultation for clinical and radiological diabetic foot osteomyelitis with positive probe-bone tests between April 2015 and May 2018. Two bone biopsies were performed on each consenting patient: TCB through a cutaneous incision in healthy skin, and PWB, after careful debridement of the wound. A total of 46 paired cultures were available from 43 eligible patients. Overall, 16 (42%) of the PWB and TCB pairs had identical culture results, but the TCB cultures were sterile in 8 (17%) cases. For 38 paired cultures with positive TCB, the correlation between PWB results and TCB results was 58.4%. PWB revealed all microorganisms found in the transcutaneous specimen in 26/38 samples (68.5%). In patients with DFO, the culture results of specimens taken by per-wound biopsies did not correlate well with those obtained by TCB. PWB should be reserved for cases where the transcutaneous biopsy is sterile or not feasible.