Time to Reimplantation: Waiting Longer May Increase the Risk of Subsequent Failure.

Abstract

To date, few studies in the orthopaedic literature have evaluated the association between the time from resection arthroplasty to reimplantation and subsequent outcomes following completion of a two-stage exchange. The purpose of this study was to evaluate the impact of time to reimplantation on the risk of failure in two-stage exchange patients. This retrospective study identified 576 patients who had chronic periprosthetic joint infection (PJI) of the knee who underwent two-stage exchange arthroplasty. A PJI was defined using the 2013 Musculoskeletal Infection Society (MSIS) criteria. Patients who had a time to reimplantation greater than 180 days from resection arthroplasty (n = 76) and those who underwent spacer exchange were excluded (n = 49). Treatment failure was defined as any reoperation for infection or PJI-related mortality. Multivariate regression analyses were performed to identify predictors of failure. There were 451 patients who had a mean follow-up time of 5.8 ± 3.6 years included. Of these, 71 (15.7%) patients experienced failure and 380 (84.3%) experienced success. Using multivariate regression analyses, we found that there was a 22% increase in the risk of failure for every 10-day increase in time to reimplantation. Furthermore, when stratifying the cohort into tertiles based on their interstage duration (less than 76, 76 to 100, and ≥ 100 days), there was no difference in baseline health status or infecting organism between the three groups (all P > 0.05). After controlling for co-variates, regression analyses demonstrated that a time to reimplantation of less than 76 days (OR [odds ratio] 0.23 [95% CI [confidence interval]: 0.05 to 0.75]; P = 0.031) was an independent predictor of treatment success. We found that prolonging time to reimplantation is associated with an increased risk of treatment failure after completion of a two-stage procedure. Furthermore, patients who had an interstage duration of less than 76 days were more than three times more likely to experience a successful two-stage.