BACKGROUND: The number of revision total knee arthroplasty (TKA) procedures continues to rise. Both advanced chronological age and comorbidity burden are associated with poor surgical outcomes. However, the question remains whether these two factors have a synergistic effect. Does a patient with advanced age and notable comorbidity burden carry an exponentially increased risk of complications after revision TKA? This study aims to investigate the effect of chronological age on various Charlson-Deyo Comorbidity Index (CDI) categories among revision TKA patients. METHODS: A total of 144,402 patients who underwent elective revision TKA between 2006 and 2022 were identified from the Premier Healthcare Database. The primary outcome was the effect of chronological age on surgical outcomes following revision TKA, while stratified by the CDI. The analyzed postoperative complications in this study included postoperative cardiac complications, pneumonia, acute kidney injury, infections, central nervous system complications, and intensive care unit admissions. Spearman rank correlation coefficients and logistic regression models were used for analysis. Age was evaluated as both a continuous variable and categorical variable (<
80 years versus 80+ years). RESULTS: Both CDI and chronological age were associated with worse outcomes, with odds ratio (OR) 1.358 to 1.829 and OR 1.015 to 1.070, respectively, across these outcomes of interest. Patients aged 80 years and older had a markedly higher risk of postoperative complications across all CDI categories (OR 1.698 to 3.695) compared with patients younger than 80 years of age. The effect of chronological age on surgical outcomes does not vary under different CDI categories as chronological age presented similar patterns of OR trends on complications. CONCLUSION: Chronological age and CDI were independent risk factors for postoperative complications in patients after revision TKA. Chronological age and CDI did not exhibit a synergistic effect on outcomes after revision TKA as the trends of impact from chronological age on outcome remained similar across different CDI categories.