Parenteral prophylactic antibiotics are now a routine part of most clean orthopaedic procedures since so many animal and clinical studies have shown a reduced infection rate with their use. First-generation cephalosporins are theoretically the preferred agents, and the pharmacokinetics of Cefazolin make it the drug of choice. It is imperative that an antibiotic be given on the induction of anesthesia or at least ten minutes before inflation of a tourniquet. Based on evidence in the current literature, 24 hours of postoperative coverage appears to be adequate.