815. Short-Course vs. Extended-Course Perioperative Antibiotic Prophylaxis in Patients Receiving Unilateral Primary Total Knee Arthroplasty

Abstract

Abstract Background International guidelines recommend up to 24 hours of perioperative antibiotic prophylaxis (AP) in joint replacement procedures. However, some observational studies support AP beyond 24 hours for the prevention of surgical site infections (SSI) and prosthetic joint infections (PJI), and this practice is also observed in our institution. This study aims to evaluate the incidence of SSI and PJI in patients receiving short- vs extended-course AP after unilateral primary total knee arthroplasty (TKA) at our center. Methods This was a retrospective cohort study of patients who underwent elective unilateral primary TKA from October to December 2019 at Singapore General Hospital. Patients were excluded if they received antibiotics for reasons other than post-operative AP or underwent other procedures in addition to unilateral primary TKA. Data was collected from electronic medical records and patients who received a short-course of AP (≤24 hours) were compared with patients who received an extended-course of AP. Primary outcomes were 30-day SSI and 30-day PJI rates. Secondary outcome was the impact of duration of AP on length of stay. Statistical analysis was performed using SPSS software version 20. Results There were 394 patients included in the study. 247 received short-course and 147 received extended-course AP. There were no differences in demographics (Table 1). Amongst those who received extended-course AP, median duration was 7 (IQR 4, 8) days, during which 119 (81.0%) patients switched from intravenous to oral route of antibiotics. Between the short- and extended-course arms, there were no differences observed in 30-day SSI (6.9% vs 6.1%, p=0.769) or PJI rates (0.4% vs 0.7%, p=0.999). However, extended-course AP was associated with a longer median length of stay (4 [IQR 3, 6] vs 5 [IQR 4, 7] days, p=0.001). In a subgroup analysis of 106 diabetic patients, there were no differences in 30-day SSI rates (12.3% vs 9.8%, p=0.763) and 30-day PJI rates (0% vs 2.4%, p=0.387) between both groups. Conclusion In this single center study, short-course AP in elective TKA was safe and effective. Extending AP did not reduce SSI or PJI rates, even in diabetic patients. In addition, extending AP was associated with increased length of stay, which translates to higher healthcare costs. Disclosures All Authors: No reported disclosures