Determining the validity of the Outpatient Arthroplasty Risk Assessment (OARA) tool for identifying patients for safe same-day discharge after primary shoulder arthroplasty.

Abstract

Early discharge has been a target of cost-control efforts given the growing demand for joint replacement surgery. The Outpatient Arthroplasty Risk Assessment (OARA) score, a medically based risk-assessment score, has shown high predictive ability in achieving safe early discharge following outpatient lower-extremity arthroplasty using a score threshold initially set at ≤59 points but more recently adapted to ≤79 points. However, no study has been performed using the OARA tool for shoulder replacement, which has been shown to have lower associated medical risks than lower-extremity arthroplasty. The purpose of this study was to determine the OARA score threshold for same-day discharge (SDD) following shoulder arthroplasty and evaluate its effectiveness in selecting patients for SDD. We hypothesized that the OARA score threshold for shoulder arthroplasty would be higher than that for lower-extremity arthroplasty. We performed a retrospective review of 422 patients who underwent primary anatomic or reverse shoulder arthroplasty between April 2018 and October 2019 performed by a single surgeon. As standard practice, all patients were counseled preoperatively regarding SDD and given the choice to stay overnight. Medical history, length of stay, and 90-day readmissions were obtained from medical records. Analysis of variance testing and screening test characteristics compared the performance of the OARA score vs. the American Society of Anesthesiologists Physical Status (ASA-PS) class and a previously published OARA score threshold used to define a low risk of outpatient lower-extremity arthroplasty. A preoperative OARA score cutoff of ≤110 points demonstrated a sensitivity of 98.0% for identifying patients with SDD after shoulder arthroplasty, compared with 66.7% using the hip and knee OARA score threshold of ≤59 points (P < .0001) and 80.4% using ASA-PS class ≤ 2 (P = .008). OARA scores ≤ 110 points also showed a negative predictive value of 98.9% and a false-negative rate of 2.0% but remained incomprehensive with a specificity of 24.0% (P < .0001). Analysis of variance demonstrated that mean OARA scores increased significantly with length of stay (P = .001) compared with ASA-PS classes (P = .82). Patients with OARA scores ≤ 110 points were also 2.5 times less likely to have 90-day emergency department visits (P = .04) than those with OARA scores > 110 points. There was no difference in 30- and 90-day readmission rates for patients with OARA scores ≤ 59 points, OARA scores ≤ 110 points, and ASA-PS classes ≤2. Our study suggests that a preoperative OARA score threshold of ≤110 points is effective and conservative in screening patients for SDD following shoulder arthroplasty, with low rates of 90-day emergency department visits and readmissions. This threshold is a useful screening tool to identify patients who are not good candidates for SDD.