RELIABILITY AND RESPONSIVENESS OF THE DANISH MODIFIED INTERNATIONAL KNEE DOCUMENTATION COMMITTEE SUBJECTIVE KNEE FORM FOR CHILDREN WITH KNEE DISORDERS

IntroductionThe modified international Knee Documentation Committee Subjective Knee Form (Pedi-IKDC) is a widely used patient-reported tool applicable for children with knee disorders ranging on a scale from 0-100. We aimed to translate the Pedi-IKDC Subjective Knee Form into Danish, and furthermore to assess its reliability and responsiveness.Material and MethodsThe Pedi-IKDC Subjective Knee Form was translated to Danish according to international guidelines. Reliability was assessed with Bland Altman plots, standard error of measurement (SEM), Minimal Detectable Change (MDC) and the Intra-class Correlation Coefficient (ICC). Responsiveness was assessed by calculating the Standardised Response Mean (SRM) and the correlation between the form and the Global Rating Scale (GRS). Furthermore, area under the receiver operating characteristics (ROC) curve (AUC) was calculated using the external anchor GRS. Reliability and responsiveness were assessed in 50 children (median 15 years) referred to hospital due to different knee disorders. ResultsThe SEM was 4.2 points and the MDC was 11.5 points. The ICC was 0.91 (0.9-1.0). The change score of the Pedi-IKDC Subjective Knee form was correlated to the external anchor GRS with a Spearmen´s Rho of 0.45 (p=0.001). The value of the AUC was 0.7 (0.5, 0.9).ConclusionsAcceptable test-retest agreement was found at group level, but at the individual level the MDC was high. Thus, considerable changes are needed to detect true change at individual level. The form showed adequate responsiveness and is suitable for assessing improvement or deterioration in children with knee disorders.