Outcomes following total hip arthroplasty (THA) and total knee arthroplasty (TKA) with a short length of hospital stay have been reported; however, most studies have not accounted for an inherent patient selection bias and discharge disposition. The purpose of this study was to utilize a propensity score to match and compare the outcomes of patients undergoing THA or TKA with short and longer lengths of stay with a discharge directly home.
An administrative database from Ontario, Canada, which has a single-payer health-care system, was retrospectively reviewed to identify patients who underwent THA or TKA from 2008 to 2016. Patients were subsequently stratified into 2 groups based on their length of stay: short length of stay (≤2 days; thereafter referred to as short stay) and longer length of stay (>2 days; thereafter referred to as longer stay). Using a propensity score, patients who underwent short-stay THA or TKA were matched to patients who underwent longer-stay THA or TKA. Matching was based on 15 demographic, medical, and surgical factors. Our primary outcomes included postoperative complications, health-care utilization (readmission and emergency department presentation), and health-care costs.
Overall, 89,656 TKAs (14,645 short stays and 75,011 longer stays) and 52,610 THAs (9,426 short stays and 43,184 longer stays) were included in this study. Patients who underwent short-stay THA or TKA were significantly more likely (p < 0.05) to be younger, male, healthier, and from a higher socioeconomic status and to have undergone the procedure with a higher-volume surgeon. Over 95% of short-stay cases were successfully matched to longer-stay cases, and we found no significant difference in complications, health-care utilization, and costs between patients on the basis of the length of stay.
Patients undergoing short-stay THA or TKA with a discharge home were more likely to be younger, healthy, male patients from a higher socioeconomic status. Higher-volume surgeons are also more likely to perform short-stay THA or TKA. These characteristics confirm the previously held belief that a selection bias exists when comparing cohorts based on time to discharge. When comparing matched cohorts of patients who underwent short-stay and longer-stay THA or TKA, we observed no difference in outcomes, suggesting that a short stay with a discharge home in the appropriately selected patient is safe following THA or TKA.
Level of Evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.