Preprint / Version 1

German Version of the Knee Injury and Osteoarthritis Outcome Score for Children (KOOS-Child)

Cross-Cultural Adaptation, Reliability, Internal Consistency and Validation in Children With Knee Problems


  • Conny Neuhaus University Basel
  • Carlo Camathias University of Basel
  • Marcus Mumme
  • Oliver Faude



questionnaire, youth, knee injuries, quality of life, QoL, physical activity, therapy


The Knee Injury Osteoarthritis Outcome Score for children (KOOS-Child) is a self-administered, valid and reliable questionnaire for children and adolescents with knee disorders. This study aimed to cross-culturally adapt and validate the German version of the KOOS-Child questionnaire and test the reliability in two groups of children, one treated conservatively and the other surgically. We conducted a forward-backward translation of the original questionnaire into the German language. Children and adolescents between 10 and 18 years of age with knee disorders were included. Two groups were compared: sample one consisted of 24 participants with knee pain (20.8% boys; mean age = 13.4y (standard deviation (SD) 1.8) treated conservatively. These participants completed the KOOS-Child questionnaire twice within two weeks to assess test–retest reliability. The second sample included 23 subjects (21.7% boys; mean age = 15.3y (SD 1.9)) treated surgically due to a knee disorder. They completed the questionnaire before surgery and six months post-operatively. Test–retest reliability and internal consistency were assessed using Spearman’s rank correlation and Cronbach’s alpha. All subscales showed a good to excellent internal consistency at both measurement points in both groups (conservatively treated group: a = .88–.95; surgery group a = .80–.91), with the exception of the subscale knee problems (conservatively treated: a = .60 and .52; surgery: α = 0.77 and 0.66). Test–retest reliability was between r = .85 and .94. The predominantly good to excellent internal consistency and the high test–retest reliability justifies the use of the German adaptation of the KOOS-Child questionnaire as a reliable multidimensional instrument for measuring health status and therapeutic effects in adolescents’ knee disorders.

Author Biographies

Carlo Camathias, University of Basel


Marcus Mumme


Oliver Faude

PD Dr.


Additional Files