Knee Injury and Osteoarthritis Outcome Score for Children

Last Updated

March 16, 2021

Purpose

The Knee Injury and Osteoarthritis Outcome Score for Children (KOOS-Child) is a 48-item instrument designed to assess the patient’s opinion about their knee after a knee injury that can result in post-traumatic osteoarthritis. The KOOS-Child 2.1, updated in October of 2015, consists of 39 items.

Link to Instrument

Instrument Details

Acronym KOOS-Child

Area of Assessment

Activities of Daily Living
Pain
Quality of Life

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil

Cost

Free

CDE Status

Not a CDE -- last searched 10/2/2024

Pediatric Disorders

39 items (KOOS-Child 2.1); 48 items (KOOS-Child 1.0)
5 subscales: pain, symptoms, activities of daily living, function in sports and play, and knee-related quality of life
Each question gets a score of 0-4
A normalized score is calculated for each subscale: 0 indicating extreme symptoms and 100 indicating no symptoms
Maximum score = 100 per subscale

Number of Items

39 items (KOOS-Child 2.1); 48 items (KOOS-Child 1.0)

Pen
Paper
Access to Questionnaire

10-20 minutes

Required Training

No Training

Required Training Description

No training is required. The KOOS-Child is self-explanatory and can be administered in the waiting room or used as a mailed survey.

Child

6 - 12

years

Adolescent

13 - 17

years

Instrument Reviewers

Alyssa Varsalona, SPT, CSCS

Le’Shaunda Jones, SPT

Kurtis Kepfer, SPT

Melisa Smith, PT, DPT

Jennifer Wiley, PT, DHS, DPT

Body Part

Lower Extremity

ICF Domain

Body Function
Activity

Measurement Domain

General Health

Professional Association Recommendation

None found -- last searched 10/2/2024

Considerations

The KOOS-Child is available in several languages. It has been validated in Danish, English, Finnish, Greek, Norwegian, Persion, Spanish, and Swedish. All versions are available on the KOOS Website (http://www.koos.nu).
An adult version (KOOS) is also available

Standard Error of Measurement (SEM)

Children with Knee Disorders: (Ortqvist et al., 2014; n = 115; mean age = 13.0 (1.9) years)

SEM for pain subscale (n = 72): 5.69
SEM for symptoms subscale (n = 72): 8.14
SEM for ADL subscale (n = 72): 5.28
SEM for sports/play subscale (n = 70): 8.02
SEM for QoL subscale (n = 70): 7.59

Children with Stable Knee Conditions: (Van der Velden et al., 2019; n = 100; mean age = 15.0)

SEM for symptoms subscale (n = 59): 10.2
SEM for pain subscale (n = 59): 9.9
SEM for ADL subscale (n = 59): 8.9
SEM for sports/play subscale (n = 59): 16.9
SEM for QoL subscale: (n = 59): 10.5

Minimal Detectable Change (MDC)

Children with Knee Disorders: (Ortqvist et al., 2014)

MDC for individuals on pain subscale: 15.78
MDC for individuals on symptoms subscale: 22.56
MDC for individuals on ADL subscale: 14.64
MDC for individuals on sports/play subscale: 22.22
MDC for individuals on QOL subscale: 21.03
MDC for group on pain subscale: 1.86
MDC for group on symptoms subscale: 2.66
MDC for group on ADL subscale: 1.73
MDC for group on sports/play subscale: 2.66
MDC for group on QOL subscale: 2.51

Children with Stable Knee Conditions: (Van der Velden et al., 2019)

MDC for symptoms subscale: 28.4
MDC for pain subscale: 27.3
MDC for ADL subscale: 24.7
MDC for sport/play subscale: 46.9
MDC for QoL subscale: 29.2

Normative Data

Healthy Individuals Aged 8-17: (Baldwin, 2017; n = 166, male = 84)

Gender-specific Reference Data for KOOS-Child (8-17 years)

Mean

Standard Dev.

Median

Min;Max

Pain

Male

Female

95.7

92.2

10.7

14.0

100

44;100

28;100

Symptoms

Male

Female

95.8

93.1

8.3

11.4

100

57;100

43;100

ADL

Male

Female

99.1

96.4

3.4

7.6

100

75;100

52;100

Sport/play

Male

Female

97.8

93.2

5.8

13.7

100

71;100

43;100

QoL

Male

Female

97.3

94.4

7.2

13.7

100

54;100

13;100

Test/Retest Reliability

Children with Knee Disorders: (Ortqvist, 2014)

Excellent test-retest reliability for pain subscale (ICC = 0.87)
Excellent test-retest reliability for ADL subscale (ICC = 0.85)
Excellent test-retest reliability for sports/play subscale (ICC = 0.91)
Excellent test-retest reliability for QoL subscale (ICC = 0.85)
Adequate test-retest reliability for symptoms subscale (ICC = 0.78)

Children with Stable Knee Conditions: (Van der Velden, 2019)

Excellent test-retest reliability for symptoms subscale (ICC = 0.9)
Excellent test-retest reliability for pain subscale (ICC = 0.9)
Excellent test-retest reliability for ADL subscale (ICC = 0.9)
Excellent test-retest reliability for sports/play subscale (ICC = 0.8)
Excellent test-retest reliability for QoL subscale (ICC = 0.9)

Internal Consistency

Children with Knee Pathology: (Moutzouri et al, 2021; n = 59; male = 29; mean age: 11 (1.8) years; age range = 8-14; inclusion criteria: Greek as native language, able to understand/complete questionnaires, referred with confirmed knee pathology symptoms; Greek translation of KOOS-Child)

Excellent internal consistency for all KOOS-Child subscales (Cronbach’s alpha all > 0.8)

Internal consistency for KOOS-Child subscales (n = 59)

Subscale	Cronbach’s alpha
Pain	0.92
Symptoms	0.81
ADL	0.96
Sport-play	0.94
QoL	0.93

Patients with Knee Pain: (Rioux Trottier et al, 2018; n = 99 (21 in control group and 78 in knee injury group; inclusion criteria: age range = 8-16; French as native language; signed consent form; knee injury group: knee pathology diagnosed by an orthopedic surgeon; control group: no past or present lower extremity problems; French translation of KOOS-Child)

Poor to Excellent internal consistency (Cronbach’s alpha) by KOOS-Child subscale for Control and Knee Pain groups

Internal consistency for KOOS-Child subscales and total score for subject groups

Subscale	Cronbach’s alpha-Control (n = 21)	Cronbach’s alpha-Knee Pain (n = 78)
Symptoms	0.572; missing = 1	0.622; missing = 5
Pain	0.943; missing = 0	0.873; missing = 6
ADL	0.856; missing = 0	0.948; missing = 7
Sports	0.898; missing = 0	0.906; missing = 11
Quality of life	0.547; missing = 0	0.739; missing = 2
Total score	0.953; missing = 1	0.959; missing = 19

Construct Validity

Convergent validity:

Children with Knee Pathology: (Moutzouri et al, 2021; Greek translation of KOOS-Child)

Poor to Excellent convergent validity between KOOS-Child and KIDSCREEN subscales

Correlations between KOOS-Child and KIDSCREEN subscales

	KIDSCREEN Subscales
KOOS-Child Subscales	Physical activities/health	General Feeling	Parents/Free Time	Friends	School
Pain	0.6	0.5	-	-	0.4
Symptoms	0.7	0.3	-	-	0.5
ADL	0.5	0.4	0.4	0.3	0.3
Sport-play	0.5	0.4	-	0.4	0.3
QoL	0.5	0.6	0.5	0.4	0.4

Note: p < 0.01 for all correlations

Poor to Excellent convergent validity between KOOS-Child and Kid-KINDL subscales

Correlations between KOOS-Child and Kid-KINDL subscales

	Kid-KINDL Subscales
KOOS-Child Subscales	Physical Health	General Feeling	Self	Family	Friends	School	Hospital/Disease
Pain	0.5	0.5	-	-	-	-	0.3 (ns)
Symptoms	0.6	0.5	-	-	-	-	0.4*
ADL	0.6	0.5	-	-	-	-	-
Sport-play	0.6	0.4	-0.6 (ns)	-	-	-	-
QoL	0.6	0.6	0.1 (ns)	0.2 (ns)	0.6*	0.3	0.3 (ns)

Note: All correlations significant at p < 0.01 except where noted: ns = not significant (p>0.05) and * = significant at p < 0.05

Children with Stable Knee Conditions: (Van der Velden, 2019)

Adequate to Excellent convergent validity between KOOS-Child and other scales

	KOOS Symptoms	KOOS Pain	KOOS ADL	KOOS Sport/play	KOOS QoL
Pedi-IKDC	0.69	0.84	0.83	0.80	0.76
Lysholm	0.70	0.71	0.66	0.56	0.57
NRS Pain	-0.44	-0.71	-0.62	-0.54	-0.52
EQ_5D	0.42	0.52	0.50	0.45	0.53

Patients with Knee Pain: (Rioux Trottier et al, 2018; French translation of KOOS-Child)

Poor correlation between KOOS-Child subscales and CHAQ grip subscales (pain = -0.023; symptom = 0.110; ADL = -0.102; sport/play = -0.091; QoL = 0.132)
Excellent correlation between KOOS-Child pain subscale and CHAQ pain subscale (-0.792)
Excellent correlation between KOOS-Child sport/play subscale and CHAQ run and play subscale (-0.809)
Excellent correlation between KOOS-Child ADL subscale and CHAQ walking subscale (-0.782)
Adequate correlation between KOOS-Child symptoms subscale and VAS (-0.507)
Excellent correlation between KOOS-Child pain, ADL, sport/play and QoL subscales and VAS (pain = -0.601; ADL = -0.646; sport/play = -0.604; QoL = -0.622)
Excellent correlation between KOOS-Child QoL subscale and EQ-5D-Y usual activities subscale (-0.788)

Content Validity

Children with Stable Knee Conditions: (Van der Velden, 2019)

Number of orthopedic surgeons and patients rating KOOS-Child subscales as relevant

Relevant items/total items (%)	Orthopedic surgeons (n = 18)	Patients (n = 18)
Symptoms	6/7 (86%)	7/7(100%)
Pain	7/8 (88%)	7/8 (88%)
ADL	7/11(64%)	9/11(82%)
Sport/play	7/7(100%)	7/7(100%)
QOL	5/6(83%)	6/6(100%)

“The KOOS-Child subscales were all found relevant by patients (all > 75%). The orthopedic surgeons rated the KOOS-Child subscales as relevant (all > 75%), except for the KOOS-Child ADL subscale (64%) (Van der Velden, et al., 2019, p. 4-5).”

Floor/Ceiling Effects

Patients with Knee Pain: (Rioux Trottier et al, 2018; French translation of KOOS-Child)

Excellent: no floor effects for KOOS-Child scales: Symptoms, Pain, and QoL
Adequate: floor effects of < 20% for ADL (1%) and Sport/Play (7.7%) scales
Adequate: ceiling effects of < 20% for KOOS-Child scales: Symptoms (13.4%), Pain (18.6%), and QoL (10.1%)
Poor: ceiling effects > 20% for ADL (21.2%) and Sport/Play (20.9%) scales

Children with Stable Knee Conditions: (Van der Velden, 2019)

Poor: ceiling effects were found for the KOOS-Child ADL, with 25% of the patients having the maximum score of > 95 (n = 53).
Adequate: ceiling effects of < 20% were found for the other KOOS-Child scales (n = 53): Symptoms (5%), Pain (5%), Sport/Play (2%), and QoL (1%)
Excellent: no floor effects found for KOOS-Child Symptoms, Pain, or ADL subscales
Adequate: floor effects of <20% for Sport/Play (18%) and QoL (1%) subscales

Children with Knee Pathology: (Moutzouri et al, 2021; Greek translation of KOOS-Child)

Excellent: no floor effects for Symptoms, Pain, ADL, Sport/Play, or QoL subscales
Adequate: ceiling effects of < 25% for Pain (22.0%), Sport/Play (15.1%) and QoL (15.1%) subscales
Poor: ceiling effects of > 25% for Symptoms (27.4%) and ADL (39.8%) subscales

Responsiveness

Children with Knee Pathology: (Moutzouri et al, 2021; Greek translation of KOOS-Child)

Moderate effect size for pain, symptom, and QoL subscales at 2 weeks
Small effect size at 2 weeks for ADL and sport/play subscales

Moderate to Large Effect Sizes for KOOS-Child Subscales from Baseline to 3 Months

KOOS-Child Subscale	Effect Sizes (baseline to 3 months)
Pain	1.1
Symptoms	0.6
ADL	0.8
Sport/play	1.2
QoL	1.4

Children with Stable Knee Conditions: (Van der Velden et al., 2019)

Responsiveness of the KOOS-Child subscales (n =71)

Effect Size	Symptoms	Pain	ADL	Sport/Play	QoL
No Change (n =22)	0.29	0.27	0.13	0.28	-0.07
Improvement (n =42)	0.84	1.26	0.83	1.57	1.24
Worsening (n = 7)	-0.44	-0.43	-0.75	-1.23	-0.83

Bibliography

Baldwin, J. N., McKay, M. J., et al. (2017). Self-reported knee pain and disability among healthy individuals: Reference data and factors associated with the knee injury and osteoarthritis outcome score (KOOS) and KOOS-child. Osteoarthritis and Cartilage, 25(8), 1282-1290. https://doi.org/10.1016/j.joca.2017.03.007

Moutzouri, M., Tsoumpos, P., et al. (2021). “Greek KOOS-child: A valid, disease specific, diagnostically accurate and responsive PROM in children with knee-related pathology”. Knee Surgery, Sports Traumatology, Arthroscopy, 29(6), 1841-1849. https://doi.org/10.1007/s00167-020-06237-5

Örtqvist, M., Iversen, M. D., et al. (2014). Psychometric properties of the knee injury and osteoarthritis outcome score for children (KOOS-child) in children with knee disorders. British Journal of Sports Medicine, 48(19), 1437-1446. https://doi.org/10.1136/bjsports-2013-093164

Rioux Trottier, E., Beauséjour, M., et al. (2018). Validation of the French version of the KOOS-child questionnaire. Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA, 27(7), 2361-2367. https://doi.org/10.1007/s00167-018-5302-y

Van der Velden, C. A., van der Steen, M. C., et al. (2019). Pedi-IKDC or KOOS-child: Which questionnaire should be used in children with knee disorders? BMC Musculoskeletal Disorders, 20(1) https://www.narcis.nl/publication/RecordID/oai:pure.tue.nl:publications%2F1a71cac7-aa34-4188-8e67-944918799245

Last Updated

Purpose

Link to Instrument

Area of Assessment

Assessment Type

Administration Mode

Cost

CDE Status

Number of Items

Required Training

Required Training Description

Instrument Reviewers

Body Part

ICF Domain

Measurement Domain

Professional Association Recommendation

Considerations

Standard Error of Measurement (SEM)

Minimal Detectable Change (MDC)

Normative Data

Test/Retest Reliability

Internal Consistency

Construct Validity

Content Validity

Floor/Ceiling Effects

Responsiveness

Bibliography

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