Comparison of Complication Rates and Surgical Costs for Total Ankle Replacements Performed in the Outpatient vs Inpatient Setting

Abstract

Introduction/Purpose: Increasing data has highlighted the safety and cost-effectiveness of outpatient hip, knee, and shoulder arthroplasty. However, limited evidence – mainly small, single institution case series – has explored complication rates and costs between outpatient and inpatient total ankle arthroplasty (TAA) surgeries. Methods: Utilizing Medicare claims from 2016 to 2019, we retrospectively identified patients ≥65 years of age who underwent TAA based on CPT coding. Patients on Medicare HMO, under age 65, and dual-eligible patients were excluded. Within this dataset, we compared surgeries performed in the outpatient versus inpatient setting. We compared groups based on readmission, all-complication, and infection rates within 1-year of TAA using logistic regressions controlling for age, sex, race, and comorbidity. To help mitigate bias, we also performed a propensity matched model with the same variables. Data were reported as percentage point (PPT) differences (95% CI) between groups, with a positive number indicating higher complication rates and costs among patients treated in the inpatient setting. Results: In total, 8,281 total ankle arthroplasty cases were identified (outpatient: 5,524 and inpatient: 2,757. Compared to inpatient cases, outpatient TAA surgeries were performed on younger, healthier (as assessed by Charlson Comorbidity Index (CCI) scores) patients who were more likely to be female (p < 0.001). In logistic regression analyses, outpatient TAA cases had lower readmission, all-complication, infection, mortality, and device-associated complication rates (p < 0.001) as compared to inpatient surgeries. Further, outpatient surgeries had sizable cost reductions compared to inpatient surgeries (p < 0.001). Conclusion: TAA performed in the outpatient setting appears to have less complications and decreased cost compared to inpatient procedures – though inpatient surgeries were presumably riskier as they were performed on older patients with increased co-morbidities. When clinically appropriate, though, TAA as an outpatient procedure appears to provide substantial reductions in cost with notable reductions in surgical risk.