Interim Spacer Exchange for Treatment of Periprosthetic Joint Infection: Almost Half the Patients Fail Subsequently.

Abstract Introduction Interim spacer exchange may be performed in patients undergoing two-stage exchange for periprosthetic joint infection (PJI). Several studies have demonstrated that interim spacer exchange is associated with poor outcomes. This study investigated the survivorship and risk factors for failure in patients with an interim spacer exchange. Methods Two institutional databases identified 182 patients who underwent spacer exchange from 2000-2017. Primary outcomes included progression to reimplantation, treatment success and mortality. Bivariate analysis was performed to evaluate risk factors associated with failure. Kaplan Meier curves using host and local grades were generated to evaluate for primary outcomes and differences in survivorship. Results The overall failure rate was 49% in patients with a spacer exchange. Most patients (60%) failed before two years. Higher comorbidity scores, elevated erythrocyte sedimentation rate (ESR) and non-White race were more prevalent in patients who failed. Negative cultures at the time of exchange were more prevalent in patients who did not fail. Failure rate was higher in immunocompromised conditions, and those who had revision prior to exchange. After considering clinically relevant variables, advanced host grade C was the single factor associated with treatment failure. While survivorship curves were not significantly different between extremity local grades, higher host grades were associated with treatment failure. Conclusion Almost one out of two patients with spacer exchange were found to fail the intended two-stage revision arthroplasty. Benefits of delivering additional antibiotic load with a new spacer should be balanced against poor outcomes in patients with the aforementioned risk factors.