How to Select Patients for Same-Day Discharge After Elective Primary Total Hip Arthroplasty: A Nationwide Analysis (2020-2022)

Same-day discharge (SDD) after elective primary total hip arthroplasty (THA) is expanding, yet contemporary national determinants and simple adjusted eligibility tools remain unclear. We examined factors associated with SDD in a short-stay cohort and evaluated a parsimonious postoperative day-0 (POD0) score. We conducted a retrospective cohort study using the Nationwide Readmissions Database (2020-2022). Elective primary THA cases were identified using ICD-10-PCS codes and linked within calendar year. We excluded COVID-19 diagnoses, age <18 years, traumatic indications, and non-elective admissions; analyses were restricted to procedures performed on hospital day 0 with length of stay (LOS) 0-1 days. The primary outcome was SDD (LOS 0) versus overnight stay (LOS 1). A 5-point POD0 score assigned one point each for age <65 years and absence of obesity, chronic anemia, major organ disease, and major cardio-neurovascular disease. Multivariable logistic regression adjusted for demographics, socioeconomic status, payer, hospital location, year, and robotic assistance. Among 211,794 patients, SDD occurred in 18,330 (8.7%). SDD was more frequent in higher-income ZIP codes and metropolitan hospitals (p<0.001). Ninety-day readmission was lower after SDD (3.6% vs 4.9%, p<0.001). SDD increased stepwise across POD0 scores (4.8% at 0 to 12.3% at 5; p<0.001). The score independently predicted SDD (aOR 1.36 per point, 95% CI 1.32-1.39); robotic-assisted THA was associated with lower odds (aOR 0.63, 95% CI 0.58-0.69). In a contemporary national short-stay THA cohort, SDD was uncommon and influenced by clinical and socioeconomic factors. A simple POD0 score showed graded, independent association with SDD.