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

PURPOSE The purpose of this study was to examine reported MCID and PASS values for PROMs following shoulder instability surgery and assess variability in published values depending on the surgery performed. Secondarily, our 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 usage in studies on shoulder instability surgery. METHODS A systematic review of MCID and PASS values following 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 utilization MCID or PASS for patient reported outcome measures (PROMS) following Latarjet, Bankart, Remplissage approaches for shoulder instability surgery. Extracted data included study population characteristics, intervention characteristics, and outcomes of interest. Continuous data were described using median and range. Categorical variables, including PROMs reported and MCID/PASS methods, were described using percentages. As MCID is a patient-level metric and not a group-level metric, the authors validated that all included studies reported proportions (%) of subjects that 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 utilized outcome threshold which 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 (ASES) (range 5.65-9.6 for distribution MCID, 8.5 anchor MCID, 86 anchor PASS); Single Assessment Numeric Evaluation (SANE) (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 (WOSI) (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 (SCB) or maximal outcome improvement (MOI). CONCLUSION 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. While MCID has been the most frequently reported metric, there is considerable inter-study 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, since they allow us to know what is a clinically significant improvement for the patient.