Antimicrobial prophylaxis in open lower extremity fractures

CLINICAL QUESTION: Based on the grade of open fracture, which antibiotic should be selected for antimicrobial prophylaxis, and what is the optimal timing and duration of administration? RESULTS: For Grade I and II open fractures, a first-generation cephalosporin (eg, cefazolin) should be administered within 3 hours of initial injury and be continued for 24 hours after initial injury. Grade III open fractures require coverage with an aminoglycoside in addition to a first-generation cephalosporin within 3 hours of initial injury, and antibiotics should be continued for 48–72 hours after initial injury but no more than 24 hours after wound closure. If a fracture is at risk of contamination with clostridium species, such as a farm-related injury, penicillin should be added to the antibiotic regimen. IMPLEMENTATION: Pitfalls to avoid when using antibiotics for infection prophylaxis in open fractures include utilizing cultures immediately postinjury to direct choice of agent for antimicrobial prophylaxis, because infecting pathogens do not typically correlate to pathogens initially cultured after injury; failure to consider patients’ medication allergy history or reconcile allergy records; and failure to obtain a thorough history to determine injury exposure (eg, farm, water).