Postoperative Oral Antibiotics Continue to Increase in Prevalence Without Associated Improvements in One-Year...

In an effort to reduce periprosthetic joint infections (PJIs) following total hip arthroplasty (THA) and total knee arthroplasty (TKA), extended oral antibiotic prophylaxis has gained national popularity. Given conflicting literature on the topic, the aim of this study was to determine if prescription of oral antibiotics at the time of primary arthroplasty was associated with a reduced risk of PJI at one year.

All patients who underwent primary THA or TKA from January 1, 2016, to November 1, 2024, were included from a large national database. Patients who received at least 48 hours of postoperative oral cefadroxil or cephalexin were matched 1:5 to those who did not receive postoperative antibiotics using propensity scores based on age, sex, body mass index, diabetes, chronic kidney disease, discharge disposition, and procedure type. The primary outcome was PJI within one year postoperatively. A total of 170,016 patients were included, and 28,336 (16.7%) received postoperative antibiotics.

The 1-year PJI rate was higher among patients prescribed antibiotics than those who were not (2.3 versus 1.1%, P < 0.001). After adjusting for risk factors, antibiotic prescription remained associated with an increased odds of PJI (odds ratio (OR) 2.02, 95% confidence interval (CI) 1.85 to 2.22). This was observed for low-risk patients (OR 2.75, 95% CI 2.24 to 3.37), but not high-risk patients (OR 1.40, 95% CI 0.94 to 2.10). When stratified by procedure, antibiotic use was associated with higher infection rates after TKA (2.5 versus 1.0%; OR 2.62, 95% CI 2.27 to 3.03) and after THA (2.0 versus 1.3%; OR 1.43, 95% CI 1.23 to 1.67).

Extended postoperative oral antibiotics after primary THA and TKA have become increasingly common. However, this database study showed no reduction in 1-year PJI rates or risk among those who received them, despite accounting for key risk factors.