Short Course of Oral Antibiotic Treatment After Two-Stage Exchange Arthroplasty Appears to Decrease Early Reinfection

Background: Recent evidence has suggested a benefit to extended postoperative prophylactic oral antibiotics after two-stage exchange arthroplasty for treatment of periprosthetic joint infections. We sought to determine reinfection rates with and without a short course of oral antibiotics after two-stage exchange procedures. Methods: A retrospective review identified patients undergoing two-stage exchange arthroplasty for periprosthetic joint infection of the hip or knee. Patients were excluded if they failed a prior two-stage exchange, had positive cultures at reimplantation, prolonged intravenous antibiotics postoperatively, and/or life-long suppression. This resulted in 444 reimplantations (210 hips and 234 knees). Patients were divided into three cohorts based on the duration of oral antibiotics after reimplantation: no antibiotics (102), ≤2 weeks (266), or >2 weeks (76). The primary endpoint was reinfection within 1 year of reimplantation. Results: Within 1 year of reimplantation, there were 34 reinfections. In the no-antibiotic, ≤ 2-week, and >2-week cohorts the reinfection rates were 14.1, 7.0, and 6.4%, respectively. Multivariate Cox regression showed a reduced reinfection rate in the ≤2-week cohort relative to no antibiotics (hazard ratio [HR]: 0.38, P = .01). While the smaller cohort with >2 weeks of antibiotics did not significantly reduce the reinfection rate (HR: 0.41, P = .12), when combined with the ≤2-week cohort, use of oral antibiotics had an overall reduction of the reinfection rate (HR: 0.39, P = .01). Conclusions: These data support the hypothesis that a short course of oral antibiotics after reimplantation decreases the 1-year reinfection rate. Future randomized studies should seek to examine the efficacy of different durations of oral antibiotics to reduce reinfection. Level of Evidence: Prognostic Level IV.