Does Local Aqueous Tobramycin Injection Reduce Open Fracture-Related Infection Rates?

OBJECTIVES: To examine the effect of local aqueous tobramycin injection adjunct to perioperative intravenous (IV) antibiotic prophylaxis in reducing fracture-related infections (FRIs) following reduction and internal fixation of open fractures. METHODS: Design: Retrospective cohort studySetting: Single academic Level I trauma centerPatient Selection Criteria: Patients with open extremity fractures treated via reduction and internal fixation with (intervention group) or without (control group) 80 mg of local aqueous (2mg/mL) tobramycin injected during closure at the time of definitive fixation were identified from December 2018 to August 2021 based upon population-matched demographic and injury characteristics. Outcome Measures and Comparisons: The primary outcome was FRI within 6 months of definitive fixation. Secondary outcomes consisted of fracture nonunion and bacterial speciation. Differences in outcomes between the two groups were assessed and logistic regression models were created to assess the difference in infection rates between groups, with and without controlling for potential confounding variables, such as sex, fracture location, and Gustilo-Anderson classification. RESULTS: An analysis of 157 patients was performed with 78 patients in the intervention group and 79 patients in the control group. In the intervention group, 30 (38.5%) patients were female with mean age of 47.1 years. In the control group, 42 (53.2%) patients were female with mean age of 46.4 years. The FRI rate was 11.5% in the intervention group compared to 25.3% in the control group (p=0.026). After controlling for sex, Gustilo-Anderson classification, and fracture location, the difference in FRI rates between groups remained significantly different (p=0.014). CONCLUSIONS: Local aqueous tobramycin injection at the time of definitive internal fixation of open extremity fractures was associated with a significant reduction in fracture-related infection rates when administered as an adjunct to intravenous antibiotics, even after controlling for potential confounding variables.