Delay of Antibiotic Administration Greater than 2 Hours Predicts Surgical Site Infection in Open Fractures.

AIMS: Antibiotic administration, severity of injury, and debridement are associated with surgical site infection (SSI) after internal fixation of open fractures. We sought to validate a time-dependent treatment effect of antibiotic administration.

PATIENTS: Consecutive open fracture patients at a level 1 trauma center with minimum 30-day follow-up were identified from an orthopaedic registry from 2013-2017.

METHODS: The primary endpoint was SSI within 90 days. A threshold time to antibiotic administration associated with SSI was ascertained by receiver-operator analysis. A Cox proportional hazards model adjusted for age, smoking, and drug use determined the treatment effect of antibiotic administration within the threshold period.

RESULTS: Ten percent of 230 patients developed a SSI. There was a trend for patients who did not develop an SSI to receive antibiotics earlier than those who did develop an SSI (61 minutes, IQR 33-107 vs 83 minutes, IQR 40-186), p=0.053). Intravenous antibiotic administration after 120 minutes of presentation of an open fracture to emergency department was significantly associated with a 2.4 increased hazard of surgical site infection (p=0.036) within 90 days.

CONCLUSION: Antibiotic administration greater than 120 minutes after ED presentation of an open fracture was associated with an increased risk of SSI.