Ceftriaxone versus cefazolin plus gentamicin for antibiotic prophylaxis in Gustilo-Anderson type III open lower extremity fractures.

OBJECTIVES

To compare fracture related infection (FRI) rates and outcomes between ceftriaxone (CTX) and cefazolin plus gentamicin (C+G) for antibiotic prophylaxis in Gustilo-Anderson (GA) type III open lower extremity fractures.

METHODS

Design

Retrospective cohort study.

SETTING

Single, academic level one trauma center.

PATIENT SELECTION CRITERIA: Included were patients age 18-89 years with GA type III open lower extremity fractures (AO/OTA 32,33,41,42,43,4F3, 44) from 2013 to 2024 with at least 6 weeks follow-up.

OUTCOME MEASUREMENTS AND COMPARISONS: The primary outcome was FRI. Secondary outcomes included acute kidney injury (AKI), nonunion, and other complications. Cox proportional hazards models and multivariable logistic regression adjusted for confounding variables.

RESULTS

Of 3,334 lower extremity fractures reviewed, 307 met inclusion criteria: 229 C+G and 78 CTX. Mean age (40.4 [range 18-88] vs 41.2 [range 18-81] years, p=0.7) and sex (75.1% vs 64.1% male, p=0.084) were similar between the C+G and CTX cohorts. Mean follow-up was 23.8 months (C+G) and 14.0 months (CTX) (P=0.002). The C+G cohort had more tibial shaft fractures (34.1% vs 19.2%, P=0.014) and type IIIB injuries (19.7% vs 7.7%, P=0.014). On unadjusted analysis, there was no significant difference in FRI (18.3% vs 12.8%, P=0.343) or AKI (11.4% vs 12.8%, P=0.728) or organisms cultured. After adjusting for GA type, fracture location, time to debridement and time to antibiotics there remained no significant difference in FRI (HR=1.26, 95% CI: 0.59-2.68, P=0.545), AKI (OR=1.51, 95% CI: 0.62-3.49, P=0.349) or other complications between antibiotic regimens. Tibial shaft fractures trended towards higher risk of FRI compared to femur fractures (HR=2.15, P=0.052). GA type IIIB/C fractures (HR=3.05, p<0.001) and time to antibiotics of >60min (HR=2.56, p=0.003) were associated with higher odds of FRI.

CONCLUSIONS

Ceftriaxone monotherapy demonstrated similar rate of FRI and complications compared to cefazolin plus gentamicin for Gustilo-Anderson type III open lower extremity fractures. Severity of the open fracture and time to antibiotics were independently associated with higher infection risk regardless of antibiotic regimen.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.