Reliability and validity of the Bangla version of the knee injury and osteoarthritis outcome score

Background: Patient self-assessed outcome scores for musculoskeletal conditions are limited in Bangladesh, especially for knee osteoarthritis. Therefore, a reliable outcome measure like the widely used knee injury and osteoarthritis outcome score (KOOS) for Bangladeshi population is necessary. The aim was to assess the validity and reliability of the Bangla version of KOOS. Methods: Following Beaton et al. forward-backwards method, an expert committee translated and adapted the original English version of KOOS with slight modifications for the Bangladeshi Bangla-speaking population. The psychometric testing assessed the questionnaire's reliability using internal consistency (Cronbach’s alpha) and test-retest reliability (Intraclass correlation coefficients). The questionnaire was compared to validated Bangla versions of the Short-Form 36 health survey (SF-36) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) to establish construct validity. Results: This study involved 150 patients with knee osteoarthritis. Bangla KOOS was found to have good internal consistency (0.77-0.88) and high test-retest reliability (0.86-0.99). Construct validity was established by comparing Bangla KOOS with the WOMAC and SF-36. The Bangla KOOS sub-scores showed negative correlations with WOMAC domains (ρ = −0.41 to −0.93) and positive correlations with SF-36 domains (ρ = 0.26 to 0.68). Conclusions: Findings showed that the Bangla KOOS is a reliable and valid measure for evaluating outcomes in Bangladeshi patients with knee osteoarthritis. It is a dependable and valid outcome measure tailored to the local language.