Antimicrobial Prophylaxis in Orthopaedic Surgery

Research in antimicrobial prophylaxis started in the 70’s when Miles and Burke [23] established that the efficacy of antibiotics in reducing the wound size after subcutaneous bacterial inoculation in a guinea pig model was associated with its administration during surgery or few hours after wound closing. By delaying the administration of antibiotics by only 3 or 4 hours, the resulting lesions were identical in size to those of animals not receiving antibiotic prophylaxis. Afterwards, this concept was confirmed in a large study including surgical procedures performed in 2847 patients [6]. Patients receiving antibiotics between 24 h and 2 h before surgery or 3 h after finishing surgery had an infection rate over 3%. The lower infection rate (0.6%) was observed among those patients who received the antibiotic just prior to the intervention. Once the precise moment for the administration was established, many other studies were conducted to identify the best antibiotic for different types of surgery and its optimal duration. The information from these studies could be summarized as follows: 1) the antibiotic chosen should cover the main contaminant flora present in the skin or mucosa disrupted by incision, 2) it is necessary to achieve high antibiotic concentrations during surgery, therefore, the best moment for antibiotic infusion is 15–30 minutes by intravenous route before starting surgery and 3) the administration of one preoperative dose of antibiotic is probably sufficient. The third point is still controversial and many international guidelines maintain an antibiotic prophylaxis during 24 h after surgery.