JAMA
Intrawound tobramycin add-on falls short in tibial fractures
Clinical Takeaway: For high‑risk periarticular tibial fractures treated with plate and screw fixation, intrawound vancomycin alone performed as well as vancomycin plus tobramycin; routine addition of tobramycin is not supported.
Deep surgical site infections occurred in about 7% of patients within 6 months despite local antibiotic prophylaxis, underscoring the need for evidence‑based approaches.
In the TOBRA randomized trial, investigators evaluated whether adding intrawound tobramycin powder to standard vancomycin powder could further reduce deep surgical site infections after surgery for periarticular tibial fractures. The open‑label, assessor‑masked study enrolled 1,528 adults across 39 US trauma centers and followed patients for 182 days after definitive fixation.
Deep infections requiring surgical intervention occurred in 7.4% of patients (51 of 753) receiving tobramycin plus vancomycin vs. 6.6% (47 of 775) with vancomycin alone—an absolute difference of 0.9%, with no statistically significant benefit for combination therapy. Hazard ratios clustered around unity, and posterior probability of superiority was about 30%. Rates of gram‑negative, gram‑positive, polymicrobial, and culture‑negative infections were similar between groups, as were superficial infections treated with antibiotics alone. Renal adverse events were rare (0.1% in each group).
“We specifically tested the common belief that adding an aminoglycoside like tobramycin would cut down gram‑negative infections,” said principal investigator Robert V. O’Toole, MD. “That simply didn’t bear out.” Notably, a subgroup of open fractures showed no benefit and a possible signal toward harm, warranting caution.
Source: O’Toole R, et al; Major Extremity Trauma Research Consortium (METRC). (2026, April 15). JAMA. Intrawound Tobramycin Plus Vancomycin to Prevent Surgical Site Infection in Tibial Fractures: The TOBRA Randomized Clinical Trial