WOUND INFECTIONS FOLLOWING IMPLANT REMOVAL BELOW THE LEVEL OF THE KNEE: THE INFLUENCE OF 2G PROPHYLACTIC CEFAZOLIN

Aim Elective implant removal (IR) after fracture fixation is one of the most common procedures within the orthopaedic/trauma surgery. The rate of surgical site infections (SSI) in this procedure is high, especially below the level of the knee. Antibiotic prophylaxis is not always routinely prescribed, even though it has proved to lower SSI rates in other orthopaedic/trauma surgical procedures. The aim of this study was to determine whether a single prophylactic dose of 2g intravenous cefazolin reduces the incidence of SSIs following elective implant removal below the knee. Methods This was a national double-blind multicenter randomized controlled trial. A total of 18 academic and teaching hospitals participated in the study. Patients aged between 18 and 75 years who were scheduled for IR following fracture surgery of the patella, lower leg, ankle or foot were included. Exclusion criteria were: re-implanting osteosynthetic material, active wound infection, peripheral vascular disease, active antibiotic treatment, severe beta-lactam antibiotic allergy, severe kidney insufficiency, pregnancy and immunosuppressant use. Patients were randomly assigned 1:1 to receive either 2g prophylactic cefazolin or a placebo (10cc 0.9% NaCl) within 60 minutes before implant removal surgery below the level of the knee. The primary outcome was SSI within 90 days, as defined by the criteria used in the latest Center of Disease Control (CDC) guideline for the prevention of SSI. The aim was to include at least 696 patients in order to achieve 80% power. Results A total of 711 patients were included in the intention-to-treat analysis. Median age was 46.9 years [IQR 31.9-58.2] and 58.9% were female. In total, 75 patients developed an SSI, resulting in an overall infection rate of 10.5%. No significant differences in infection rates were observed between the cefazolin group and the placebo group (11.3% vs. 9.8%, p = 0.500). Further analysis revealed no significant differences in the rates of superficial or deep infections between the two groups (superficial: 10.2% vs. 8.4%, p = 0.403; deep: 1.1% vs. 1.4%, p = 0.753). Conclusions These findings suggest that routine prophylactic administration of 2g intravenous cefazolin is not effective in reducing SSIs following the removal of osteosynthesis material below the knee. This study was funded by ZonMw – The Netherlands Organisation for Health Research and Development grant GGG 848018013