Inpatient vs outpatient arthroplasty: A in-state database analysis of 90-day complications.

Introduction: An increase in the number of policy initiatives, such as alternative payment models, have prompted healthcare providers to examine health-care expenditures while seeking to improve quality of care. Performing total joint arthroplasty (TJA) in the outpatient setting is an attractive option in driving costs down and providing psychological benefits to patients. Concerns regarding the safety and effectiveness of same-day discharge protocols warrants further investigation, especially on the state level. Due to the lack of consensus, we aimed to compare: (1) risk factors for outpatient arthroplasty and (2) incidences of postoperative complications between inpatient vs outpatient arthroplasty using an in-state database. Methods: Patients who underwent total knee or hip arthroplasty between January 1, 2022 and December 31, 2022 were identified. Data was drawn from the Maryland State Inpatient Database (SID) and Maryland State Ambulatory Surgery and Services Database (SASD). A total of 7817 patients had TJA within this time. Patients were divided into inpatient arthroplasty (n = 1429) and outpatient arthroplasty (n = 6338). Demographic variables, medical comorbidities, and 90-day complication rates were compared between inpatient and outpatient procedures. Additional independent variables included: marital status, primary language, race, and median household income. A multivariate logistic regression analysis was performed to identify independent risk factors for complications following TJA after controlling for risk factors and patient comorbidities. Results: Arthroplasty in the outpatient setting were more likely to be married (61.3% vs. 51.2%, p < 0.001), white (75.5% vs. 60.9%, <0.001), speak English as primary language (98.7% vs. 88.6%, p < 0.001), and have lower rates of diabetes (4.8% vs. 9.7%, p < 0.001), chronic obstructive pulmonary disease (16.3% vs. 21.8%, p < 0.001), and obesity (30.0% vs. 45.2%, p < 0.001) compared to arthroplasty in the inpatient setting, respectively. There were lower incidences of acute kidney injury (0.2 vs. 0.8%, p < 0.001) and infection (0.3% vs. 1.1%, p < 0.001) in the outpatient cohort compared to the inpatient cohort, respectively. Inpatient arthroplasty (Odds Ratio (OR) 1.98, 95% CI 1.30-3.02, p = 0.002) and hypertension (OR 2.12, 95% CI 1.23-3.64, p = 0.007) were independent risk factors for total complications following TJA. Conclusion: Arthroplasty in the outpatient setting showed fewer complications than compared to patients in the inpatient setting. Although multiple factors should guide the decision for arthroplasty, outpatient arthroplasty may be a safe option for select, healthier patients without the increased burden of increased complications.