Outcomes of Medicare Outpatient Total Knee Arthroplasty at an Ambulatory Surgery Center

Background: Total knee arthroplasty (TKA) was removed from the “inpatient only” list for Medicare Beneficiaries in 2018. As a result, outpatient TKA’s have been performed at ambulatory surgery centers (ASC) more frequently. This study aims to evaluate outcomes of medicare patients who underwent outpatient TKA at an ASC. Methods: We conducted a retrospective cohort review of medicare patients who underwent TKA at an ASC between January 1st, 2020 and June 30th, 2020 performed by six orthopedic surgeons. Results: Thirty-six patients were identified who underwent primary TKA. There was a mean age of 72.4 and body mass index of 30.9. The mean preoperative range of motion was -6.7 degrees of extension and 114.8 degrees of flexion, two and six week post operative extension of -3.8 degrees and flexion of 104 degrees and -2.7 degrees and 114.6 degrees respectively. Preoperative physical and mental patient reported outcomes measurement and information system scores were 43.2 and 53.4 respectively and 49.4 and 53.1 post operatively. Preoperative patient reported outcomes measure with the knee injury and osteoarthritis outcome score was 48.4 and 72.8 post operatively. There were two patients (5.5%) with complications of arthrofibrosis that required manipulation under anesthesia. Total recovery time and time within the ASC were on average 200 minutes and 398.6 minutes respectively. Conclusion: Without adverse events within the first six months, this study suggests that outpatient TKA can be safely performed in medicare patients at an ASC.