Reliability, validity, and responsiveness of a modified International Knee Documentation Committee Subjective Knee Form (Pedi-IKDC) in children with knee disorders.
BACKGROUND
The International Knee Documentation Committee (IKDC) Subjective Knee Form is a knee-specific measure of symptoms, function, and sports activity. A modified IKDC Subjective Knee Form (pedi-IKDC) has been developed for use in children and adolescents. The purpose of this study was to determine the psychometric characteristics of the pedi-IKDC in children and adolescents with knee disorders.


OBJECTIVE
The pedi-IKDC is a reliable, valid, and responsive patient-administered outcome instrument in the pediatric population with knee disorders.


METHODS
Cohort study (diagnosis); Level of evidence, 2.


METHODS
Test-retest reliability, content validity, criterion validity, construct validity, and responsiveness to change were determined for the pedi-IKDC in patients aged 10 to 18 years with a variety of knee disorders. Test-retest reliability was measured in a group of 72 patients with a stable knee disorder. Validity was measured in a group of 589 patients with the Child Health Questionnaire to determine criterion validity. Responsiveness was measured in a group of 98 patients undergoing a variety of knee surgical procedures.


RESULTS
The overall pedi-IKDC had acceptable test-retest reliability (intraclass correlation coefficient, .91) and excellent internal consistency (Cronbach alpha, .91). The form also demonstrated acceptable floor (0%) and ceiling (6%) effects. There was acceptable criterion validity with significant (P < .01) correlation between the overall pedi-IKDC and 9 relevant domains of the Child Health Questionnaire. Construct validity was acceptable, with all 11 hypotheses demonstrating significance (P < .0001). Responsiveness to change was acceptable (effect size, 1.39; standardized response mean, 1.35).


CONCLUSIONS
The pedi-IKDC demonstrated overall acceptable psychometric performance for outcome assessment of children and adolescents with various disorders of the knee.
Department of Orthopaedic Surgery, Children’s Hospital Boston, Boston, Massachusetts 02115, USA. mininder.kocher@childrens.harvard.edu
Mininder S
MS
Kocher
Jeremy T
JT
Smith
Maura D
MD
Iversen
Katherine
K
Brustowicz
Olabode
O
Ogunwole
Jason
J
Andersen
Won Joon
WJ
Yoo
Eric D
ED
McFeely
Allen F
AF
Anderson
David
D
Zurakowski
D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires