Impact of adherence to local antibiotic prophylaxis guidelines on infection outcome after total hip or knee arthroplasty

Background National guidelines exist regarding preoperative antibiotic treatment for the prevention of surgical site infection (SSI); however, there are no published studies showing rates of compliance with them. Aim To establish compliance with national guidelines within our institution, and the impact of adherence, on SSI rate. Methods This was a retrospective observational study of 1019 patients undergoing hip or knee arthroplasty. Procedures were conducted at three metropolitan hospitals in Melbourne, Australia, throughout a 2.5-year period. Antibiotic prophylaxis recommendations were taken from the Australian Therapeutic Guidelines. Findings Of the procedures included, 61.3% adhered to prophylaxis guidelines, 38.7% did not. The total SSI rate was 2.7%; with an infection rate of 1.7% in those adherent to antibiotic guidelines, compared with a rate of 5.0% if non-adherent (P < 0.01). Overall, 98.4% of patients received a dedicated prophylactic antibiotic dose as per guidelines. Of the procedures, 1.7% lasted >4 h with re-dosing being poorly adhered to (23.5% of procedures). In patients weighing >80 kg (49.5% of surgeries), guideline-concordant dosing occurred in only 58.7% of cases. For patients >80 kg without guideline-concordant dosing, the SSI rate was 6.6% and the odds ratio of SSI was 3.89 (confidence interval: 1.17–7.84; P = 0.01). Conclusion Non-adherence to guidelines increased the risk of SSI in patients undergoing total knee and hip arthroplasty. Dosing adjustment recommendations of prophylaxis for patients weighing >80 kg was poorly adhered to, and these patients were subsequently at higher risk of infection.