Preoperative psychometric properties of visual analog scale asessments for function, pain, and strength compared with legacy upper extremity outcome measures in glenohumeral osteoarthritis

Background: Patient-reported outcome measures (PROMs) are increasingly being used in orthopedic surgery; however, there is significant variability and burden associated with their administration. The visual analog scale (VAS) may represent an efficient, single-question method to establish functional baselines in a domain-specific manner for glenohumeral arthritis.

Methods: Single-question VAS measures assessing function, strength, and pain as a percentage of normal were administered alongside legacy PROMs in patients with primary glenohumeral arthritis in a preoperative setting between October 2015 and March 2017. PROM performance was assessed using Spearman correlation coefficients. Both absolute and relative floor and ceiling effects were examined.

Results: A total of 70 patients (age 66.09 ± 9.84 years, body mass index 28.8 ± 9.77, 57.1% male, 54.2% right-sided) were included. The VAS Pain instrument (r = 0.45-0.64) outperformed the VAS Function (r = 0.23-0.62) and VAS Strength (r = 0.21-0.65) in correlation to preoperative PROMs. The performance of VAS Pain was comparable to American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES; r = 0.47-0.84). None of the VAS instruments in our study demonstrated preoperative floor effects (7.1%-8.6%) or ceiling effects (0.0%-4.3%). The most efficient instruments were Single-Assessment Numerical Evaluation (SANE; 0.87 ± 0.41 minutes), Patient-Reported Outcome Measurement Information System Upper Extremity Computer Adaptive Test (PROMIS UE CAT; 1.27 ± 1.30 minutes), and the triad of VAS measures (1.51 ± 1.61 minutes).

Conclusion: VAS Pain outperformed VAS Strength and Function relative to legacy PROMs, while performing comparable to ASES. None of the VAS measures were susceptible to significant floor or ceiling effects preoperatively. The VAS instruments along with SANE and PROMIS UE were the most time-efficient measures. VAS instruments may have a role in establishing preoperative baselines in those with glenohumeral arthritis in a simple, efficient, and adoptable manner.