Is Outpatient Unicompartmental Knee Arthroplasty Safe to Perform at an Ambulatory Surgery Center? A Comparative Study of Early Post-Operative Complications

Background: Unicompartmental knee arthroplasty (UKA) lends itself to the outpatient surgical setting. Prior literature has established a low rate of readmission and post-operative complications when performed in a hospital outpatient setting (HOP). To our knowledge, there have been no studies comparing complications of UKA performed at an ambulatory surgery center (ASC) and those in a HOP. Methods: We retrospectively reviewed all patients who underwent outpatient UKA by a single surgeon from 2012 to 2016. In all 569 outpatient UKAs were performed: 288 in the ASC group and 281 in the HOP group. We compared the groups with regard to all complications within the first 90 days after surgery. Results: Thirty minor and major complications occurred within 90 days (5.3%). There was no difference in the overall complication rate between groups (ASC 12, 4.2%; HOP 18, 6.4%) (P = .26). Day of surgery admission occurred once in the HOP group (0.4%) and did not occur in the ASC group (P = .49). There was 1 visit to the emergency department (ED) < 24 hours from surgery in each group (ASC 0.3%, HOP 0.4%) (P = 1.0). ED visits occurred within 7 days in 3 ASC cases (1.0%) and 4 HOP cases (1.4%) (P = .72). Readmissions in the first 90 days occurred in 5 ASC cases (1.7%) and 8 HOP cases (2.8%) (P = .41). Conclusion: UKA at an ASC has a low early postoperative complication rate without increased risk of readmission or ED evaluation when compared to UKAs performed at a HOP. Published by Elsevier Inc.