Evaluating the Duration of Prophylactic Post-Operative Antibiotic Agents after Open Reduction Internal Fixation for...

The importance of timely pre-operative antibiotic agents for effective surgical prophylaxis has been established but the optimal duration of antimicrobial coverage post-operatively has not yet been defined clearly. The purpose of this study was to determine if prophylactic post- operative cefazolin for 23 hours decreases the risk of surgical site infection (SSI) after open reduction internal fixation (ORIF) of closed extremity fractures.

After Institutional Reviews Board approval, patients undergoing ORIF of closed extremity fractures who had a planned post-operative stay of at least 23 hours were randomly assigned to either receive 23 hours of cefazolin or a placebo. Both groups received weight-based pre-operative cefazolin and intra-operative re-dosing at three-hour intervals until surgery completion. The primary end point was infection. Patients were followed clinically until bony union. Published risk factors were accumulated as a risk score to help determine risk of SSI.

A total of 227 patients were randomized to either receive post-operative cefazolin or placebo and 160 patients completed clinical follow-up to bony union. There were 83 patients in the cefazolin group and 77 in the placebo group. Surgical site infections occurred in a total of 15 patients (9.4%) in this trial without any differences between the cefazolin and placebo groups. Patients with diabetes mellitus were 4.33 times more likely to develop an SSI (95% confidence interval [CI], 1.30-14.38; p = 0.02). Patients with a risk score of two or more were 3.14 times more likely to develop an infection (95% CI, 1.02-9.68; p < 0.05).

Although not statistically significant, in a randomized double-blinded placebo-controlled trial, patients who were treated with a 23-hour post-operative regimen of antibiotics after ORIF were less likely to develop SSIs. Patients with diabetes mellitus and those with a risk score of two or greater were more likely to develop an SSI.