What is the KOOS-Child?

KOOS-Child is developed as an instrument to assess the patient’s opinion about their knee and associated problems.

KOOS-Child is intended to be used for knee injury that can result in post-traumatic osteoarthritis (OA); i.e. ACL (anterior cruciate ligament) injury, meniscus injury, chondral injury, etc.

The KOOS-Child preliminary version (LK 1.0) [1] was replaced by the final KOOS-Child version (LK 2.0) in October 2013 [2]. Data collected with the 1.0 version can be used to calculate KOOS-Child LK 2.0 scores, please see KOOS-Child scoring manual for instructions. Please note that there are TWO KOOS Child scoring files (excel) available, one for use when data was collected using the preliminary KOOS-Child questionnaire form (LK 1.0) and one for use when data was collected with the final KOOS-Child (LK 2.0) questionnaire form. When the scoring file for KOOS Child LK 1.0 is used the result is automatically converted to the LK 2.0 scores.

KOOS-Child is meant to be used over both short and long time intervals; to assess changes from week to week induced by treatment (medication, surgery, physical therapy) or over years due to the primary injury or post traumatic OA.

KOOS-Child can be used to assess groups and to monitor individuals.

KOOS-Child comprehensibility and content validity was ensured through cognitive interviews with 34 Swedish children aged 10-16 years with symptomatic knee injury. The KOOS was modified to the KOOS-Child version simultaneously in Swedish and English [1].

The psychometric properties (reliability, validity and responsiveness) of the preliminary version (LK. 1.0) of the KOOS-Child [1] have been evaluated in 115 children (7-16 years of age) with different knee disorders (overuse and acute knee injuries) [2]. When the submitted report is publically available, this information site will be updated with the key findings. The clinical validation study resulted in 9 items being removed. The final KOOS Child (LK. 2.0) consists of 39 items.

KOOS-Child (LK. 2.0) consists of 39 items divided in 5 subscales; Pain, other Symptoms (titled as “knee problems”), Difficulty during daily activities (ADL), Function in sport and play (Sport/Play) and Knee related Quality of Life (QOL). The last week is taken into consideration when answering the questions. Standardized answer options are given (5 Likert boxes) and each question gets a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale. The result can be plotted as an outcome profile.

KOOS-Child is patient-administered, the format is user friendly, and takes about 10-20 minutes for the child to fill out. The youngest patients (7-9 years of age) may need help by reading the questions, however they should be encouraged to answer the questionnaire by themselves without help.

KOOS-Child is self-explanatory and can be administered in the waiting room or used as a mailed survey.

KOOS-Child has been used in patients 7-16 years.

KOOS-Child is currently available in three versions, an American-English version, a Swedish version, and a Danish version.



1. Örtqvist M, Roos EM, Brostrom EW, Janarv P-M, Iversen MD. Development of the Knee Injury and Osteoarthritis Outcome Score for Children (KOOS-Child): Comprehensibility and Content Validity. Acta Orthop 2012;83:666-73.

2. Örtqvist M, Iversen MD, Janarv P-M, Brostrom EW, Roos EM. Psychometric properties of the Knee injury and Osteoarthritis Outcome Score for Children (KOOS-Child) in children with knee disorders. Submitted October 2013.