Preoperative predictors of spacer retention and mortality in two-stage revision for infected total hip arthroplasties: a single-center experience of 90 patients

BACKGROUND: Although two-stage revision arthroplasty achieves favorable infection control rates, a substantial proportion of patients experience spacer retention or short-term mortality. Therefore, the goal of this study was to identify preoperative risk factors associated with spacer retention and mortality during a two-stage approach. METHODS: This single-center retrospective cohort study included a consecutive series of 90 chronic periprosthetic joint infections (PJI) of the hip treated with a two-stage revision between August 2017 and December 2021. Associations between potential risk factors and outcomes were analyzed using correlation analyses, and the effect size was quantified by Spearman's rho (r). Mortality rates were estimated using the Kaplan-Meier method and compared with the log-rank test. RESULTS: After a mean follow-up of 48 months (range 24 to 73), 19 patients (21%) did not undergo reimplantation, 23 patients (25.5%) had died, and two patients (2%) were lost to follow-up. Successful reimplantation was significantly associated with implantation of an articulating hip spacer (r = 0.57) and favorable periarticular soft tissue conditions (r = 0.25). Mortality was significantly correlated with a higher comorbidity burden (ASA ≥ 3; r = 0.36) and advanced age (≥ 80 years; r = 0.22). CONCLUSION: This study identified three simple, yet powerful prognostic markers of spacer retention and mortality. Implantation of an articulating hip spacer emerged as the strongest positive predictor of successful reimplantation, although it likely functions, at least in part, as a surrogate marker for favorable local bone and soft-tissue conditions. In contrast, advanced age and a high comorbidity burden were the strongest predictors of short-term mortality. These readily assessable prognostic markers may facilitate the identification of patients at the highest risk of not completing a two-stage approach or dying shortly after.