Did the centers for medicare & medicaid services’ 2018 policy change removing total knee arthroplasty from the inpatient-only list affect overall patient outcomes in the medicare population?

Background: The 2018 Centers for Medicare & Medicaid Services (CMS) removal of total knee arthroplasty (TKA) from the Inpatient-Only (IPO) list was accompanied by confusion, lack of central guidance on patient selection criteria, payor misinterpretation of the updated policy, and altered payor incentives. The purpose of this study was to assess how the CMS policy change affected overall patient outcomes in the Medicare population after TKA. Methods: Using the ACS-NSQIP database, patients 65 years and older who underwent primary, elective, unilateral TKA without any significant medical comorbidity were included. Complication rates before (2014-2017) and after (2018-2019) CMS removal of TKA from the IPO list were compared using interrupted time series analysis to gauge the impact of the policy shift. Results: A total 185,294 TKA cases were included in the analysis. Following the CMS removal of TKA from the IPO list in 2018, there were significant decreases in rates of any adverse event (RR 0.90, 95% CI 0.83-0.98, P=0.02), any minor adverse event (RR 0.84, 95% CI 0.73-0.97, P=0.02), and thromboembolic events (RR 0.76, 95% CI 0.64-0.89, P<0.001) significantly decreased There were no significant changes in rates of readmission (RR 0.95, 95% CI 0.87-1.05, P=0.31), reoperation (RR 0.92, 95% CI 0.78-1.09, P=0.33), or any major adverse event (RR 0.92, 95% CI 0.83-1.01, P=0.07). Conclusions: Though the CMS removal of TKA from the IPO list in 2018 was accompanied by the emergence of key new issues, the policy change did not adversely affect 30-day postoperative outcomes in the Medicare TKA patient population. Level of Evidence: Level IV—retrospective cohort study.