Evaluation of the “Minimal Clinically Important Difference” (MCID) of the KOOS, KSS and SF-12 scores after open-wedge high tibial osteotomy

Abstract

Purpose Defining a Minimal Clinically Important Difference (MCID) value for Patient-Reported Outcome Measures (PROMs) is crucial for determining the effectiveness of a procedure and calculating the sample size for trial planning. The purpose of this study was to determine the MCID of several PROMs (Knee injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS) and the SF-12) in patients who underwent medial opening-wedge High-Tibial Osteotomy (owHTO) with Patient-Specific Cutting Guides (PSCGs), using anchor-based methods. Methods Patients undergoing isolated medial owHTO with PSCGs between January 2013 and January 2017 were enrolled in this single-center, prospective, observational study. Three outcome scores were collected pre-operatively and at the 2 years follow-up evaluation: KOOS, KSS and SF-12. The MCIDs were calculated using anchor-based method: at 2 years postoperatively: "Compared with before surgery, how would you rate operated joint now?" The responses were recorded using a five-point scale. Patients who answered "about the same" or "somewhat worse" were classified into the no change group, while those who answered "somewhat better" were classified into the minimal change group. A receiver operating characteristic (ROC) curve was used to define the cutoff point that best discriminated between the minimal change and no change groups for each PROMs Results 196 patients were included, 75 (somewhat better) and 24 patients (about the same and somewhat worse) were, respectively, assigned to the "no change" and "minimal change" groups. There was no significant difference between the two groups in terms of baseline characteristics and postoperative complications. At 24 months follow-up all the PROMs (KOOS, KSS and SF-12) were significantly better for the "minimal change" group compared to the "no change" group. MCID was 15.4 for KOOS pain, 15.1 for KOOS symptoms, 17 for KOOS ADL, 11.2 for KOOS sports/recreation, 16.5 for KOOS QQL, 3 for KSS symptoms, 5.6 for KSS activity, 7.2 for SF-12 physical component and 6.3 for PCS mental component. Conclusion This study determined the MCIDs of common used PROMs in patients undergoing owHTO. Level of evidence Prospective Cohort Study, Level II

The Minimal Clinically Important Difference (MCID) for the WOMAC and Factors Related to Achievement of the MCID After Medial Opening Wedge High Tibial Osteotomy for Knee Osteoarthritis

“…The anchorbased method includes ROC analysis, mean change method, and mean difference method. 13,14,19,29,40,46 ROC analysis is the most commonly used anchor-based method, 19,46 and the FDA recommended it as the most available method for determining the MCID ''within an individual analysis.'' 11 The mean change method determines the MCID through the absolute change in mean PROM scores from baseline to follow-up in patients who respond with ''somewhat better'' to anchor questions.…”

“…14,40 The mean difference method determines the MCID by using the difference in PROM scores between 2 transitional groups, for example, ''somewhat better'' and ''no change.'' 19 The mean difference method is the most appropriate method for comparing the study group and control group in a clinical trial. 29 In this study, the anchor-based method using an anchor question was applied to determine the patient-centered MCID 5,31 because this method used the patient's subjective response for improvement.…”

“…13,14,19,29,40,46 ROC analysis is the most commonly used anchor-based method, 19,46 and the FDA recommended it as the most available method for determining the MCID “within an individual analysis.” 11 The mean change method determines the MCID through the absolute change in mean PROM scores from baseline to follow-up in patients who respond with “somewhat better” to anchor questions. 14,40 The mean difference method determines the MCID by using the difference in PROM scores between 2 transitional groups, for example, “somewhat better” and “no change.” 19 The mean difference method is the most appropriate method for comparing the study group and control group in a clinical trial. 29 In this study, the anchor-based method using an anchor question was applied to determine the patient-centered MCID 5,31 because this method used the patient’s subjective response for improvement.…”

“…5,20 Many studies 3,4,6,13,14,29,32,40 have evaluated the MCID after total knee arthroplasty (TKA), 32 but few studies have evaluated the MCID after MOWHTO. 19 Improved understanding of the MCID and factors that predict surpassing the MCID threshold may have a significant effect on defining surgical outcomes and developing shared decision-making tools with patients. 5,32 Because clinical relevance is more important than mere statistical significance, the MCID should be used instead of PROMs alone.…”

The Formulation of Minimal Clinically Important Differences in the Quality of Life Instrument for Patients with Chronic Renal Failure (QLICD-CRF) Based on Combinations of Anchor-Based and Distribution-Based Methods

“…This information could be useful to improve patient satisfaction and the doctor-patient relationship. The current study primarily used a single anchor-based method to calculate the MCID of different scales; then, an ROC curve was used to identify the most effective scale [25][26][27][28][29] . A few studies have used multiple methods to calculate MCID.…”