Objective Little is known regarding the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) with regard to the Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Lysholm score, and Short Form 12 (SF-12) score of patients who undergo osteochondral allograft transplantation (OCA). We aimed to determine the MCID and SCB associated with those patient-reported outcome measures (PROMs) after OCA. Design We analyzed the data of 86 consecutive patients who underwent OCA and who completed satisfaction surveys at a minimum of 1 year postoperatively and had at least one repeated PROM. MCID was determined using an anchor-based method: the optimal cutoff point for receiver operative characteristic (ROC) curves. If an anchor-based method was inapplicable, distribution-based methods were employed. SCB was determined using ROC curve analysis. Results Based on the ROC curve analysis, MCID was 16.7 for KOOS pain, 25 for KOOS sports/recreation, and 9.8 for IKDC. SCB was 27.7 for KOOS pain, 10.7 for KOOS symptom, 30 for KOOS sports/recreation, 31.3 for KOOS quality of life, 26.9 for IKDC, 25 for Lysholm, and 12.1 for SF-12 physical component summary. No significant association was noted between SCB achievement and the baseline patient factors and baseline PROMs. Conclusion We demonstrated the MCIDs and SCBs of several PROMs in patients undergoing OCA. These results will aid the interpretation of the effect of treatment and clinical trial settings. Moreover, the SCBs will help surgeons in the counseling of patients, where patients expect optimal results rather than minimal improvement.

Objective We sought to determine the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) associated with the Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Lysholm, and Short Form-12 (SF-12) after autologous chondrocyte implantation (ACI). Design Ninety-two patients with satisfaction surveys at a minimum of 2 years postoperatively and at least 1 repeated patient-reported outcome measure (PROM) were analysed. The MCID was determined using 4 anchor-based methods: average change, mean change, minimally detectable change, and the optimal cutoff point for receiver operating characteristic (ROC) curves. If an anchor-based method was not applicable, standard deviation-based and effect size-based estimates were used. SCB was determined using ROC curve analysis. Results The 4 anchor-based methods provided a range of MCID values for each PROM (11-18.8 for the KOOS pain, 9.2-17.3 for the KOOS activities of daily living, 12.5-18.6 for the KOOS sport/recreation, 12.8-19.6 for the KOOS quality of life, 10.8-16.4 for the IKDC, and 6.2-8.2 for the SF-12 physical component summary). Using the 2 distribution-based methods, the following MCID value ranges were obtained: KOOS symptom, 3.6 to 8.4; the Lysholm, 4.2 to 10.5; and the SF-12 mental component summary, 1.9 to 4.6. SCB was 30 for the KOOS sport/recreation and 34.4 for the IKDC, which most accurately predict substantial improvement. No significant association was noted between SCB achievement and the baseline PROMs. Conclusion The MCID and SCB determined in our study will allow interpretation of the effects of treatment in clinical practice and trials. Given the varied MCID values in this study, standardisation of the most appropriate calculation methods is warranted.