Benefits and Adverse Events Associated With Extended Antibiotic Use for One Year Following Periprosthetic Joint Infection in Total Knee Arthroplasty: A Prospective Cohort Analysis.

Background: Periprosthetic joint infections (PJIs) are common and serious complications following knee and hip arthroplasty. Our previous retrospective study suggested extended antibiotics following debridement, antibiotics, and implant retention (DAIR) decreased failure rates and were not associated with increased adverse events (AEs) as compared to a standard 6 weeks of antibiotic therapy. Further, extended antibiotics beyond one year did not provide additional benefits. These observations were tested in this prospective cohort study.

Methods: A prospective cohort of patients who underwent DAIR for total knee arthroplasty PJI and received primary antibiotics were compared to patients who received primary antibiotics combined with extended antibiotics for one year. Participants had a minimum of 2-year follow-up after the final dose of antibiotics.

Results: A prospective cohort of 79 patients was followed, where 39 participants (52.7%) received primary antibiotics and 35 participants (47.3%) received both primary and extended antibiotics following DAIR. Multivariable time-to-event analyses revealed that extended antibiotic use was an independent predictor of treatment success. Infection-free survival differed significantly between the two treatment regimens, as the hazard of PJI failure was significantly lower for extended antibiotics as compared to primary antibiotics alone (adjusted hazard ratio [HR] = 0.46 [0.24 to 0.87], P = 0.017). The AE rates did not significantly differ between patients treated with primary antibiotics only versus primary combined with extended antibiotics.

Conclusions: This prospective cohort study supports our previous observations that extended antibiotics for one year were associated with lower failure rates as compared to primary antibiotics alone. Extended antibiotics after primary antibiotics were not found to be associated with increased AEs as compared to only primary antibiotics.