High Variability in Standardized Outcome Thresholds of Clinically Important Changes in Shoulder Instability Surgery: A Systematic Review

Purpose: To examine reported minimal clinically important difference (MCID) and patient-acceptable satisfactory state (PASS) values for patient-reported outcome measures (PROMs) after shoulder instability surgery and assess variability in published values depending on the surgery performed. Our secondary aims were to describe the methods used to derive MCID and PASS values in the published literature, including anchor-based, distribution-based, or other approaches, and to assess the frequency of MCID and PASS use in studies on shoulder instability surgery. Methods: A systematic review of MCID and PASS values after Bankart, Latarjet, and Remplissage procedures was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The Embase, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were queried from 1985 to 2023. Inclusion criteria included studies written in English and studies reporting use of MCID or PASS for patient-reported outcome measures (PROMS) after Latarjet, Bankart, and Remplissage approaches for shoulder instability surgery. Extracted data included study population characteristics, intervention characteristics, and outcomes of interest. Continuous data were described using medians and ranges. Categorical variables, including PROMs and MCID/PASS methods, were described using percentages. Because MCID is a patient-level rather than a group-level metric, the authors confirmed that all included studies reported proportions (%) of subjects who met or exceeded the MCID. Results: A total of 174 records were screened, and 8 studies were included in this review. MCID was the most widely used outcome threshold and was reported in all 8 studies, with only 2 studies reporting both the MCID and the PASS. The most widely studied PROMs were the American Shoulder and Elbow Surgeons (range 5.65-9.6 for distribution MCID, 8.5 anchor MCID, 86 anchor PASS); Single Assessment Numeric Evaluation (range 11.4-12.4 distribution MCID, 82.5-87.5 anchor PASS); visual analog scale (VAS) (range 1.1-1.7 distribution MCID, 1.5-2.5 PASS); Western Ontario Shoulder Instability Index (range 60.7-254.9 distribution MCID, 126.43 anchor MCID, 571-619.5 anchor PASS); and Rowe scores (range 5.6-8.4 distribution MCID, 9.7 anchor MCID). Notably, no studies reported on substantial clinical benefit or maximal outcome improvement. Conclusions: Despite the wide array of available PROMs for assessing shoulder instability surgery outcomes, the availability of clinically significant outcome thresholds such as MCID and PASS remains relatively limited. Although MCID has been the most frequently reported metric, there is considerable interstudy variability observed in their values. Clinical Relevance: Knowing the outcome thresholds such as MCID and PASS of the PROMs frequently used to evaluate the results of glenohumeral stabilization surgery is fundamental because they allow us to know what is a clinically significant improvement for the patient.