POSTOPERATIVE “PROPHYLACTIC” ORAL ANTIBIOTIC USE IS A MARKER FOR SUBSEQUENT INFECTION AFTER ASEPTIC REVISION TOTAL HIP ARTHROPLASTY

Introduction & Aim Postoperative prophylactic oral antibiotics (PPOA) are variably used after aseptic revision total hip arthroplasty (rTHA), despite limited evidence of benefit. This study examined PPOA's link to periprosthetic joint infection (PJI), healthcare use, and antibiotic-related adverse events. Methods A retrospective study using a national claims database from 2016 to 2023 identified patients undergoing aseptic rTHA, who were grouped by PPOA exposure. PPOA was defined as a minimum duration of seven days of antibiotics between seven and 14 days post-surgery; controls had less than two days. Propensity score matching (1: 2) using demographics, comorbidities, procedure type, and healthcare factors, resulting in 840 PPOA patients and 1,677 controls. The primary outcome was PJI at one year; secondary outcomes included healthcare resource utilization, re- revision, and adverse events. Multivariable logistic regression analysis was performed to adjust for potentially confounding variables and sensitivity analysis was performed to assess data robustness, excluding patients placed on early postoperative oral therapy for SSI, hematoma, UTI, and pneumonia. Results PPOA was associated with higher PJI rates at 90 days (2.1% vs 0.9%; OR 2.24, 95% CI 1.18–4.26; p = 0.018) and one year (2.9% vs 1.6%; OR 1.77, 95% CI 1.06–2.96; p = 0.039). PPOA was also associated with higher 30-day superficial SSI rates (6.7% vs 2.6%; OR 2.71; p < 0.001) and wound complication rates (3.3% vs 1.6%; OR 2.03, 95% CI 1.24–3.34; p = 0.006), but there was no difference in emergency department visits or readmissions. After excluding 198 patients with early postoperative infection or wound complications (e.g. SSI, hematoma, UTI, and pneumonia), PPOA remained associated with higher risk of recurrent infection at 90 days (aOR 2.09, p < 0.001), one year (aOR 1.86, p = 0.011), and two years (aOR 1.79, p = 0.002). Conclusions PPOA was not associated with reduced PJI, healthcare utilization, or re-revision. PPOA recipients had higher observed infection and wound complication rates, even after matching and sensitivity exclusions, likely reflecting unmeasured clinical risk rather than a causal effect of antibiotics. These findings do not support routine PPOA after aseptic rTHA and highlight the need to better define high-risk patients who may warrant selective antibiotic use.