Responsiveness of patient-reported outcomes in shoulder arthroplasty: what are we actually measuring?

The purpose of this study was to determine the prevalence and responsiveness of common patient-reported outcome (PRO) tools in patients undergoing primary total shoulder arthroplasty (TSA) for glenohumeral arthritis.

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of anatomic and reverse TSA studies from PubMed, SportDiscus, Cochrane, and CINAHL was performed. Studies on primary TSA for glenohumeral arthritis that reported at least 1 PRO tool were included in the final analysis. A subgroup analysis of studies that reported preoperative and postoperative PRO scores with at least 2-year follow-up data was evaluated to compare the responsiveness between the different PRO instruments.

After full-text review of 490 articles, 74 articles met all inclusion criteria and were included in the final analysis. Anatomic TSA was evaluated in 35 studies, reverse TSA in 32 studies, and both anatomic and reverse in 7 studies. There were a total of 7624 patients, and 25 different PRO tools were used. The most commonly reported PRO tools were the American Shoulder and Elbow Surgeons (44 studies), Constant (42 studies), the visual analog scale for pain (23 studies), and the Simple Shoulder Test (17 studies). A median of 3.0 PRO instruments were used in each study. All instruments had large effect sizes. The University of California at Los Angeles (UCLA) score was found to be the most responsive instrument, and the Single Assessment Numeric Evaluation score was least responsive. The American Shoulder and Elbow Surgeons score was the most responsive instrument that required only patient-reported data.

Overall, the UCLA score was found to be the most responsive followed by the Adjusted Constant. However, both the UCLA and Adjusted Constant scores require strength and range of motion assessment that may limit their widespread clinical use. The increased responsiveness of these measures, which include objective clinical testing, speaks to the predicted increases in strength and range of motion after shoulder arthroplasty. Of the measures that can be administered without in-person clinical evaluation, the American Shoulder and Elbow Surgeons score and Western Ontario Osteoarthritis of the Shoulder index were the most responsive.