Incidence and Reasons for Direct Transfers Among Hip and Knee Arthroplasties Performed at Ambulatory Surgical Centers.

Background: As joint arthroplasty (JA) increasingly shifts to outpatient ambulatory surgical centers (ASCs) for same-day procedures, it is critical to identify appropriate candidates for this setting. This study reviews our institutional experience transitioning from hospital-based to stand-alone ASC surgery, examining causes of direct transfers to hospitals for complications occurring during hip and knee arthroplasties performed at ASCs. Methods: Prospectively collected arthroplasty procedure and adverse event data were reviewed to identify all direct transfers that occurred among hip and knee arthroplasties performed at ASCs between January 2012 and July 2025. A total of 32,564 JAs were performed during the study period, including 6379 at ASCs. The primary outcome was the number and cause of direct transfers from ASCs to a hospital. Results: There were 7 (0.1%) direct hospital transfers, all associated with systemic medical conditions including syncope, postoperative atrial fibrillation, hypotension, unstable oxygen saturation, hypotension with shortness of breath, and bradycardia and transient asystole following administration of regional anesthesia. Three patients were admitted to the hospital, with 2 requiring stays longer than 1 day. No patient deaths occurred as a result of these adverse events at the time of this study. Conclusions: Direct transfer to a hospital following JA was found to be exceedingly rare based on our institutional experience. All direct transfers resulted from medical complications that occurred prior to or after the arthroplasty procedure. These findings support the safety of performing primary JA in appropriately selected patients within the ASC setting, reinforcing the importance of careful preoperative screening.