Background — 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.
Methods — 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.
Results — 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.
Conclusions — 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.