Infection Rate and Antibiotic Administration for Urban Low-Energy Gunshot Wounds at an Academic Level 1 Trauma Center.

Introduction: The purpose of this study was to review rates of infection after civilian ballistic fractures and assess the effect of early antibiotic administration (EAA) on infection rates.

Methods: This was a retrospective cohort study done at an urban Level 1 Trauma Center. Patients ages 16 years and older with ballistic orthopaedic extremity injuries between May 2018 and December 2020 were enrolled. A total of 827 ballistic fractures were identified, and 371 fractures were analyzed after exclusions. The primary outcome measure was the incidence of infection within 90 days postinjury, correlated with the timing of antibiotic administration.

Results: Seventy percent of the extremity injuries received EAA (<3 hours of hospital admission) and 30% did not. Infections occurred in 6.9% of patients with EAA and in 7.3% of those without. We found no notable association between EAA and infection on multivariate logistic regression (odds ratio [OR] 1, 95% Confidence Interval [CI] 0.4 to 2.4, P = 0.99). Compartment syndrome (OR 5.4, 95% CI 1.1 to 26.4, P = 0.04) and surgical treatment of fracture (OR 12.9 95% CI 1.7 to 97.9, P = 0.01) were independently associated with higher odds of infection. We found no notable association between vascular injury or visceral injury and infection. Lower extremity fracture location was markedly associated with infection on multivariate logistic regression (OR 2.8; 95% CI 1 to 7.8; P = 0.05) when compared with upper extremity, hand, and foot locations. The highest infection rate was observed in tibial shaft fractures at 22%.

Conclusions: Early antibiotic treatment did not markedly reduce infection odds in civilian low-energy ballistic fractures. The study underscores the need for context-specific, evidence-based treatment strategies.

Level of evidence: III (retrospective cohort study).