A matched-cohort study comparing outpatient total knee arthroplasty in an ambulatory surgery center with inpatient total knee arthroplasty in a hospital

Abstract

Background: The authors compared a matched cohort of outpatient total knee arthroplasties (TKA) performed in a free-standing ambulatory surgery center (ASC) with those performed in a standard inpatient hospital setting to determine the safety, efficacy, and expense associated with both locations. Methods: Retrospective review identified 82 patients who had TKA, 41 at an ASC and 41 in an inpatient hospital. The cohorts were matched according to age and American Society of Anesthesiologists (ASA) physical status classification. Results: There were no statistically significant differences in age, gender, body mass index, or ASA scores. There were no readmissions or major complications, including deep infection, periprosthetic fracture, or venous thromboembolism, in either cohort. Minor wound issues occurred in four (9.8%) hospital patients and one (2.4%) ASC patient. All ASC patients were discharged the day of surgery without an overnight stay. The average length of stay for the hospital group was 2.5 days. The average total facility charge for ASC patients was $26,800.00 compared to the national average of $31,124. Conclusions: No significant differences were noted between TKA performed in an ASC and a hospital for major complications or hospital readmissions at 90 days. The average length of stay in the hospital was 2.5 days, however, which might indicate a higher cost than day surgery. Although not statistically significant, the ASC cohort had fewer minor complications than the inpatient cohort. In select patients TKA performed outpatient in an ASC appears to be as effective and safe as that performed in a hospital, with the caveat that some patients may not be candidates. Careful patient selection, preoperative screening and counseling, and the use of multimodal pain regimens are critical to minimizing complications and reducing costs. Level of Evidence: Level III.