Assessing the Predictive Accuracy of Popular Comorbidity Indices in Total Ankle Arthroplasty Outcomes

BackgroundThis study aims to investigate the validity of the Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Index (ECI) as predictive tools for adverse outcomes following total ankle arthroplasty (TAA).MethodsThe Nationwide Readmissions Database (NRD) was queried from 2015 to 2020 to identify 29 705 patients undergoing primary TAA. Patients' comorbidity was measured via CCI and ECI scores, and patients who experienced adverse postoperative outcomes (any complication, readmission, mortality, extended length of stay (LOS), and adverse discharge) were identified.ResultsBoth the ECI and CCI comorbidity indices predicted mortality with excellent accuracy (Area under the Curve [AUC] = 0.88 for both). However, ECI outperformed CCI in predicting complications, extended LOS, and adverse discharge, although both had poor predictive capability for these outcomes.ConclusionThese findings indicate that while ECI and CCI are capable of predicting postoperative mortality following TAA, there is a need for alternative models that better predict other postoperative adverse outcomes.Level of Evidence:Level III; Retrospective cohort study.