The variability of minimum clinically important difference, substantial clinical benefit, and patient acceptable symptom state thresholds for Patient-Reported Outcome Measures in the anatomic total shoulder arthroplasty literature: a systematic review.

BACKGROUND

Anatomic total shoulder arthroplasty (aTSA) is a technique commonly utilized to address degenerative pathologies of the glenohumeral joint. Utilization of patient-reported outcome measures (PROMs) has led to increased reliance on the minimum clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) thresholds to assess efficacy of aTSA.

METHODS

PubMed, Embase, MEDLINE, Cochrane Library, and Google Scholar were queried for articles from January 1, 2000, March 31, 2023, reporting MCID, SCB, or PASS values for PROMs following aTSA. Patient demographics, study characteristics, MCID/SCB/PASS thresholds, and threshold calculation methods utilized were extracted.

RESULTS

Across the 30 studies comprising 11,482 patients who underwent aTSA, there were 13 unique PROMs reported. The most common were the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test, the Constant-Murley Shoulder Outcome Score, the University of California at Los Angeles Shoulder Score, the Shoulder Pain and Disability Index score, and the Visual Analog Scale. Of 30 studies, 25 (83%) reported MCID thresholds, 15 (50%) reported SCB, and 6 (20%) reported PASS. Of 30 studies, 20 (67%) studies reference a previous study when reporting MCID, SCB, or PASS values. Five (17%) used an anchor-based method to calculate threshold values, 1 (3%) used a distribution-based method, and 4 (13%) used both anchor and distribution methods. There were 46 newly calculated MCID (29) and SCB (17) threshold values. A variety of approaches were employed for threshold calculation, with anchor (difference in change) being the most common (52.9%). Notably, 83.3% of MCID thresholds had variability >50% of the most commonly referenced values and 33.3% of SCB calculated thresholds are >25% of the most commonly referenced values reported for the 6 most commonly utilized PROMs (American Shoulder and Elbow Surgeons, Simple Shoulder Test, Constant-Murley Shoulder Outcome Score, University of California at Los Angeles Shoulder Score, Shoulder Pain and Disability Index, and Visual Analog Scale).

CONCLUSION

The calculation methods and reported MCID, SCB, and PASS thresholds in the aTSA literature demonstrate variability, especially for the most commonly utilized PROMs. Standardizing calculation and utilization of MCID, SCB, and PASS thresholds for aTSA will ensure clinicians may more effectively assess patient outcomes.