Two-day versus three-day systemic antibiotic prophylaxis for Gustilo-Anderson type IIIA and IIIB open tibial fractures (PROACT): a randomised controlled trial.

BACKGROUND

The optimal duration of systemic antibiotic prophylaxis (SAP) for Gustilo-Anderson type IIIA and IIIB open tibial fractures remains uncertain. We compared 2-day versus 3-day prophylaxis in patients treated at a level I trauma centre.

METHODS

The Prophylactic Antibiotic Course in Open Tibial Fractures (PROACT) trial was a pragmatic, single-centre, single-blinded randomised controlled trial conducted in India. Adults (≥18 years) with Gustilo-Anderson type IIIA or IIIB open tibial fractures were randomly assigned (1:1) to receive 2 days or 3 days of intravenous cefuroxime and amikacin; metronidazole was added for farm-related contamination. Outcome assessors were masked, and all patients received standardised orthoplastic care. The primary outcome was 90-day surgical-site infection (SSI). Analyses were by intention to treat. The trial was prospectively registered with the Clinical Trials Registry of India (CTRI/2020/06/026083) and is closed to recruitment.

FINDINGS: Between July 1, 2020, and Dec 31, 2022, 241 patients were assessed for eligibility, and 204 were randomly assigned to 2-day (n = 104) or 3-day (n = 100) prophylaxis; all were included in the primary analysis. SSI within 90 days occurred in 15 of 104 patients (14%) and 18 of 100 patients (18%), respectively (risk difference -3.6%, 95% CI -14.0 to 7.0; p = 0.60). Time-to-event analysis showed no statistically significant difference between groups (hazard ratio 1.22, 95% CI 0.60-2.46). Unplanned reoperation within 12 months occurred in 24 of 104 patients (23%) and 19 of 100 patients (19%). One patient in each group underwent secondary amputation due to flap failure. No treatment-related deaths were reported.

INTERPRETATION: Among adults with severe open tibial fractures managed with contemporary orthoplastic care, 2-day compared with 3-day SAP was not associated with a statistically significant difference in SSI. However, clinically meaningful benefit or harm cannot be excluded because of the limited sample size and imprecise estimates. Larger multicentre studies are warranted to confirm these findings.

FUNDING: This study received no external funding.