Translation, cross-cultural adaptation, reliability, validity, and responsiveness of the Brazilian Portuguese version of the Knee Injury and Osteoarthritis Outcome Score for Children (KOOS-Child) in children and adolescents with knee injuries.

Marques, Sarah Caroline de Sousa; de Aquino, Cecília Ferreira; de Castro, David Bruno Braga; Pereira, Marina Gonçalves; Silva, Sabrina de Sousa; Almeida, Gabriel Peixoto Leão · Disabil Rehabil · 2026

cross_sectional · Level IV

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Abstract

To translate, culturally adapt, and evaluate the reliability, validity, and responsiveness of the Brazilian Portuguese version of the Knee Injury and Osteoarthritis Outcome Score for Children (KOOS-Child-Br) in children and adolescents with knee injuries. This is a clinical measurement study. Cross-cultural adaptation was assessed <i>via</i> cognitive debriefing. Test-retest reliability was evaluated using the intraclass correlation coefficient (ICC<sub>2,1</sub>). Internal consistency was assessed using Cronbach's alpha. Construct validity was assessed by correlations between KOOS-Child-Br subscales and the Pediatric Quality of Life Inventory (PedsQL<sup>™</sup>), and between the pain subscale and the Numerical Pain Rating Scale (NPRS). Responsiveness was evaluated through correlations with the Global Perceived Effect Scale (GPES) and effect size. 135 participants were evaluated. KOOS-Child-Br subscales showed excellent test-retest reliability (ICC<sub>2,1</sub> = 0.84-0.91) and adequate internal consistency (<i>α</i> = 0.77-0.93). KOOS-Child-Br showed moderate to good correlation with the PedsQL<sup>™</sup> (<i>r</i> = 0.65-0.82), moderate correlation between the pain subscale and the NPRS (r = -0.66), moderate to high effect size (0.60-0.84) and an adequate correlation with the GPES (rho = 0.35-0.56). KOOS-Child-Br is reliable, valid and responsive in children and adolescents with knee injuries.