Surgical Infection Prevention: Antibiotic Given Within One Hour of Surgery
Having an antibiotic circulating in your blood during surgery has proven to be a key factor in preventing post-operative infections.

Surgical Infections: Antibiotic Stopped Less Than 24 Hours After Surgery
Recent studies indicate that administering antibiotics beyond 24 hours does not provide an added benefit. Though continuing antibiotics beyond 24 hours does not harm the patient, studies indicate that it will not further reduce the rate of post-operative infections.