Cross-Cultural Adaptation and Validation of the Ilokano Knee Injury and Osteoarthritis Outcome Score (KOOS) among Ilokanos with Knee Osteoarthritis

Aim: To translate, cross-culturally adapt and evaluate the validity and reliability of the Ilokano-KOOS to patients with knee osteoarthritis in Ilocos Norte. Methods: A quantitative non-experimental methodological research design was used in the study. The Ilokano-KOOS was developed according to the standard cross-cultural adaptation guidelines. KOOS data were obtained in patients with knee osteoarthritis. Reliability was tested using the intraclass correlation coefficient (ICC). Internal consistency was assessed using Cronbach's alpha. Construct validity was evaluated by quantifying the correlation between the Ilokano-KOOS and original-KOOS with Pearson's correlation coefficients. Results: No major difficulties were encountered during the translation and pre-testing stages. All five domains of the Ilokano-KOOS have demonstrated a good test-retest reliability between two assessment points: 0.77- 0.97 (95% of CI). For all domains, the internal consistency was determined to be good (α = 0.770- 0.969). Construct validity of all domains showed a good to an excellent correlation which ranged from 0.969-0. 996. Conclusion and Implications: The Ilokano-KOOS is a valid, reliable, relevant instrument with good psychometric properties. Results of the study suggest its use in physical therapy to assess the functional disabilities of Ilokano patients with knee osteoarthritis and to provide instructions for future interventions.