Quantifying success after total shoulder arthroplasty: the substantial clinical benefit

Substantial clinical benefit, responsiveness, and sensitivity to change of three common outcome measures following shoulder arthroplasty

“…Werner et al 24 subtracted the mean change of ASES score of those reporting "no change" and "somewhat dissatisfied" from the mean change of ASES score of those who had reported "very satisfied" and measured the SCB associated with the overall satisfaction with surgery (SCB = 37.4), ability to do housework/yardwork (SCB = 21.6), and recreational activities (SCB = 19.2) at 2 years post arthroplasty. Simovitch et al 19 calculated the SCB as the mean difference between the unchanged group "no change/worse" and the changed group "much better" and reported SCB values of 31.5 and 19.1 for substantial overall satisfaction in the ASES and CMS, respectively, at the minimum of 2 years. The results of the SCB values of the ASES by the previous studies are more consistent with our findings at 6 months.…”

“…The lowest SCB change reported in the literature is 19 points for the CMS. 19 By choosing an estimated standard deviation of 10 and a small effect size of 0.2, 39 using the below formula for one group (paired t-test), a minimum of 43 patients with complete data (N ={(Za–Zb)SD/d} 2 where a = 0.05, Za = 1.65, b = 0.20, Zb = 0.84, SD = 2, d = 0.2 × 19 = 3.8, N ={(1.65 + 0.84) 10/3.8} 2 = 43) is required to detect substantial change over time. Descriptive analyses of patient characteristics and initial outcome measure summary scores of a convenient sample were performed and compared between 6 months and 2 years.…”

“…Utilizing the SCB metric values after shoulder arthroplasty helps to identify the denominator of a cost-to-benefit ratio for the appropriateness of performing a costly surgery. 19 Patient-oriented outcome measures such as the American Shoulder and Elbow Surgery (ASES) score, 20 the relative Constant Murley Score (CMS), 21 and the Western Ontario Osteoarthritis of the Shoulder (WOOS) index 22 are frequently used to assess clinical outcome following shoulder arthroplasty. The ASES and CMS have shown good psychometric properties in this population with a significant body of knowledge on their MCID.…”

“…Utilizing the SCB metric values after shoulder arthroplasty helps to identify the denominator of a cost-to-benefit ratio for the appropriateness of performing a costly surgery. 19 …”

Editorial Commentary: The Alphabet Soup of Understanding Clinical Shoulder Research: MCID (Minimal Clinically Important Difference), PASS (Patient Acceptable Symptomatic State), SCB (Substantial Clinical Benefit), and Now . . . MOI (Maximal Outcome Improvement)

“…3 Substantial clinical benefit (SCB) is a similar concept to the MCID except the difference in change scores is between no change and substantial change on an anchor question instead of the difference between no change and minimal change, which is used for the MCID. 4 The maximal outcome improvement (MOI) is a threshold for an outcome measure normalized to the maximal possible improvement for each patient beyond which a patient is considered to have achieved a satisfactory result. 5 So, what are the upsides and downsides of each metric?…”