Cefazolin and an aminoglycoside compared with cefazolin alone for the antimicrobial prophylaxis of type III open orthopedic fractures

CONTEXT: Uncertainty of antibiotic prophylaxis of type III open orthopedic fractures still exists. Controversy remains as using cefazolin as a single agent or the addition of an aminoglycoside for broader coverage to prevent infection. AIMS: The aim of the study was to determine if the combination of cefazolin and an aminoglycoside reduced infections compared with cefazolin alone. SUBJECTS AND METHODS: This was a retrospective study inclusive of patients with type III open fracture admitted between January 1, 2010, and August 31, 2014 at a level 1 trauma center, who were prophylactically treated with cefazolin alone or cefazolin and an aminoglycoside. STATISTICAL ANALYSIS USED: All analyses were performed using Microsoft Excel 2010. Chi-square or Fisher's exact tests were used for categorical data and Wilcoxon rank-sum test for skewed continuous data. Logistic regression analysis was performed on all confounding variables with P < 0.1. RESULTS: A significantly higher percentage in the combination group developed infection (6/15 [40%] vs. 8/53 [15.1%], P = 0.035). There was a trend toward a higher odds of infection in the combination group (odds ratio: 2.99, 95% confidence interval: 0.79–11.33, P = 0.107). Infection rates due to multidrug-resistant bacteria were statistically higher with the combination group (3/15 [20%] vs. 1/53 [1.9%], P = 0.046). There were no statistically significant differences in 30-day mortality, 1-year readmission rates due to fracture complication, or length of hospital stay. CONCLUSIONS: The results suggest that the addition of an aminoglycoside to cefazolin may not be necessary to prevent infection.