Evaluating the Association of Surgical Setting with Costs and Complications in Ankle Arthrodesis: Medicare Claims Analysis

Background: Ankle arthrodesis (AA) remains a reliable surgical treatment option for end-stage ankle arthritis in appropriately selected patients. Although traditionally performed in an inpatient (IP) setting, interest in these surgeries being done as an outpatient (OP) and ambulatory surgery center (ASC) settings has increased. We compared costs and post-operative complication rates for AA performed across these settings. Methods: Using Medicare fee-for-service claims (2016-2021), we retrospectively identified patients ≥65 years of age who underwent AA. Using subsequent inpatient and Part B (provider) claims, we evaluated postoperative complications within 1 year, defined by International Classification of Diseases, Tenth Revision ( ICD-10 ) codes, including infection, thromboembolic events, and device-related issues. We also evaluated total episode and post-acute care costs within 90 days. We tested for differences in perioperative safety indicators and costs through multivariate regressions, controlling for age, sex, race, and Charlson Comorbidity Index (CCI), dementia, and the involvement of a surgical assistant. A propensity-matched analysis was performed to minimize selection by indication bias. Results: We included 7104 initial AA cases across surgical settings: 262 (3.7%) in ASC, 3047 (42.9%) in OP, and 3795 (53.4%) in IP. Compared with IP cases, OP and ASC surgeries were performed in younger, healthier (as assessed by CCI) patients and more frequently in male patients ( P < .001). In multivariate analyses, IP cases had the highest infection rates (+7.2 percentage points compared with ASC, P = .001; +4.2 percentage points compared to OP, P = .016) and the highest 90-day total episode costs of $19 817 (95% CI: $18 137 to $21 497). Propensity-matched analyses were consistent with multivariable results, confirming the same directional associations but with modestly larger effect sizes. Conclusion: AA performed in ASC settings was associated with lower complication rates and substantially lower episode-of-care costs compared with IP and OP settings in this Medicare fee-for-service population, particularly among appropriately selected patients. Level of Evidence: Level III, retrospective comparative study.