Effectiveness of Extended Intravenous Antibiotic Prophylaxis in Preventing Periprosthetic Joint Infection After Total Knee and Hip Arthroplasty: An Analysis of a Japanese Nationwide Database.

Background: Although major international guidelines recommend discontinuing antibiotic prophylaxis within 24 hours after total joint arthroplasty, recent studies have suggested potential benefits of extended administration. The aim of this study was to evaluate the effectiveness of extended intravenous antibiotic prophylaxis in preventing periprosthetic joint infection (PJI). Methods: The Japanese Diagnosis Procedure Combination database was used to identify adults who underwent primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) from April 2014 to March 2024. Based on the duration of postoperative intravenous antibiotic prophylaxis, patients were divided into the standard intravenous antibiotic prophylaxis (0-1 day) and extended intravenous antibiotic prophylaxis (2-3 days) groups. Patients who received any oral antibiotic prophylaxis during the intravenous prophylactic period were excluded. The outcome was PJI within 90 and 365 days after surgery, defined as surgical site infection requiring surgical intervention. Propensity score matching and subgroup analyses in high-risk patients were conducted (e.g., obesity, smoking, diabetes mellitus with chronic complications, kidney disease, hepatic disease, autoimmune disease, and oral corticosteroid use). Results: Among 506,710 eligible patients (244,156 TKA and 262,554 THA), the 90-day PJI incidence was 0.34% in TKA and 0.37% in THA. In propensity score-matched analysis, extended intravenous antibiotic prophylaxis was associated with a small reduction in 90-day PJI after TKA, with a risk difference (RD) of -0.07% (95% confidence interval [CI], -0.12% to -0.01%) and a corresponding risk ratio (RR) of 0.83 (95% CI, 0.72-0.96). In high-risk TKA patients, a stronger association was observed (RD, -0.13% [95% CI, -0.25% to -0.01%]; RR, 0.78 [95% CI, 0.63-0.98]). Similar findings were observed for 365-day PJI after TKA. No clear association was observed in THA, either in the overall cohort or in the high-risk subgroup. Conclusions: Extended intravenous antibiotic prophylaxis was associated with a marginal reduction in PJI within 90 and 365 days after TKA, with a greater effect in high-risk TKA patients. While routine extension is not supported for all patients, it may be considered in selected high-risk TKA cases. Level of Evidence: Therapeutic Level Ⅲ. See Instructions for Authors for a complete description of levels of evidence.