Outpatient and Inpatient Unicompartmental Knee Arthroplasty Procedures Have Similar Short-Term Complication Profiles

Advances in surgical techniques and anesthesia have made performing unicompartmental knee arthroplasty (UKA) in the outpatient setting a possibility. The touted benefits of outpatient surgery include higher patient satisfaction and reduced costs. However, detailed information on the perioperative outcomes of outpatient compared with inpatient UKA in a large, national patient population in the United States has never been reported. The present study compares perioperative complications between outpatient and inpatient UKAs in the National Surgical Quality Improvement Program database.

Patients who underwent UKA were identified in the 2005-2015 National Surgical Quality Improvement Program database. Outpatient procedures were defined as those with length of hospital stay = 0 days, whereas inpatient procedures were defined as those with length of hospital stay = 1-4 days. Patients’ characteristics and comorbidities were compared between the two groups. Propensity score matched comparisons were performed for 30-day perioperative complications and readmissions between the two cohorts.

This study included 568 outpatient and 5312 inpatient UKA cases. After propensity matching to control potential confounding factors, statistical analysis revealed no significant difference in any perioperative complications or any postdischarge complications between the outpatient and inpatient cohorts. Notably, the rate of 30-day readmissions between the two cohorts was not statistically different.

Based on the perioperative outcome measures assessed in this study, outpatient UKA can be appropriately considered in carefully selected patients based on the lack of differences in rates of 30-day perioperative complications and readmissions between the outpatient and matched inpatient groups.