No Benefit to Using 2 Antibiotic Powders During Surgery for Complex Leg Fracture
A large multicenter clinical trial has found that application of 2 antibiotic powders — vancomycin and tobramycin — directly into the surgical wound during surgery for high-risk tibia fractures did not reduce deep surgical site infections compared with application of vancomycin powder alone.
Results of the trial were published online ahead of print by the Journal of the American Medical Association.
Study Methods and Findings
In the study, 1660 patients were randomly assigned to have their surgical incision treated with:
- 1.2 grams of intrawound tobramycin powder plus 1.0 gram of intrawound vancomycin powder
- 1.0 gram of intrawound vancomycin powder alone
The patients underwent surgical repair of a periarticular tibial fractures (tibial plateau or pilon) between June 18, 2021, and December 12, 2024, at 39 trauma centers in the US.
Within 6 months of surgery, deep surgical site infections occurred in 7.4% of patients who received tobramycin plus vancomycin, compared with 6.6% of patients who received vancomycin alone.
The research team also observed no advantage of the combination to prevent gram-negative bacterial infections, which are resistant to vancomycin.
“We specifically tested the common belief that adding an aminoglycoside like tobramycin would cut down gram-negative infections,” said principal investigator Robert O’Toole, MD, Professor of Orthopedics at the University of Maryland School of Medicine (UMSOM) and Chief of Orthopaedics at the R Adams Cowley Shock Trauma Center.
“That simply didn’t bear out. Vancomycin alone remains a solid option for reducing gram-positive infections, but our data do not support routinely adding tobramycin powder.”
Intrawound tobramycin powder has become more commonly used by orthopaedic surgeons over the past decade to reduce infections in patients undergoing surgery for a fracture. This trial demonstrated that tobramycin powder plus vancomycin powder did not reduce the risk of infection compared to vancomycin powder alone.
Higher Risk with Open Fractures?
In a subgroup analysis of patients with open fractures, the risk of infection was higher in those receiving tobramycin powder plus vancomycin powder compared with vancomycin alone. The researchers said the subgroup results should be interpreted cautiously due to smaller group of patients with open fractures.
“The findings should change surgeons’ practice to avoid the use of intrawound tobramycin powder in this population, as there is no evidence that it prevents infections and might be harmful in open fracture patients,” said study co-author Nathan O’Hara, PhD, MHA, Associate Professor of Orthopedics at UMSOM.
“Surgeons should not expect benefit from this combination approach in routine practice.”
Adverse events, including kidney issues and allergic reactions, were similar in both groups, with very low rates observed.
Source
O’Toole RV, O’Hara NN, Carlini AR, and the Major Extremity Trauma Research Consortius (METRC). Intrawound tobramycin plus vancomycin to prevent surgical site infection in tibial fractures: The TOBRA randomized clinical trial. JAMA. 2026 Apr 15:e264023. doi: 10.1001/jama.2026.4023. Online ahead of print.