Establishing clinically significant outcome thresholds for the Single Assessment Numeric Evaluation 2 years following total shoulder arthroplasty

Abstract

Background: Single Assessment Numerical Evaluation (SANE) is a simple, time-efficient patient-reported outcome measure (PROM) used to assess postoperative shoulder function. Clinically significant outcome values and ability to correlate with longer legacy PROM scores at 2 years following shoulder arthroplasty are unknown.

Methods: A retrospective analysis was performed using SANE, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Constant scores that were collected at a minimum 2-year follow-up. A total of 153 patients who underwent anatomic total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (RTSA) were included. A distribution-based method was used to determine the minimal clinically important difference (MCID). An anchor-based method was used to determine substantial clinical benefit (SCB). The following anchor question was collected alongside the PROMs and graded on a 15-point Likert-type scale to establish the SCB: "Since your surgery, has there been any change in the pain in your shoulder?" Linear regression was used to assess correlations between PROMs.

Results: SANE showed moderate correlation with ASES (R² = 0.493) and Constant (R² = 0.586) scores (P < .001). The MCID value was 14.9, and the SCB absolute value was 80.4 (area under the curve = 0.663) for SANE. Multivariate logistic regression demonstrated that patients undergoing RTSA were less likely to achieve SCB on all 3 outcome measures (P < .02).

Conclusions: This study establishes concurrent construct validity for SANE and suggests that it is a valid metric to assess the MCID and SCB at 2 years following anatomic TSA and RTSA. SANE demonstrated moderate correlations with ASES and Constant scores. Patients undergoing RTSA demonstrated a lower propensity to achieve SCB at 2 years postoperatively compared with anatomic TSA.

Keywords: Clinical outcomes; Single Assessment Numeric Evaluation (SANE); minimal clinically important difference (MCID); patient-reported outcome instrument validation; substantial clinical benefit (SCB); total shoulder arthroplasty.