Safety and Cost-Effectiveness of Outpatient Unicompartmental Knee Arthroplasty in the Ambulatory Surgery Center: A Matched Cohort Study.

Using an age- and comorbidity-matched cohort, we compared patients who underwent unicompartmental knee arthroplasty in an ambulatory surgery center with those who underwent the procedure in a traditional hospital inpatient setting. Postoperatively, the ambulatory surgery center cohort had fewer major complications than the inpatient cohort. No ambulatory surgery center patients required acute hospital admission and none had major complications. Four major complications occurred in the inpatient cohort. There was no difference in complication rates. Our results suggest that outpatient unicompartmental knee arthroplasty in a freestanding ambulatory surgery center is a safe and reasonable alternative to the traditional inpatient hospital setting.