Cross-cultural adaptation and validation of the 12-item short forms of the knee injury and osteoarthritis outcome score (KOOS-12) to Persian language.

Background: The aim of this study was to translate, culturally adapt, and validate the 12-item short form of the knee injury and osteoarthritis outcome score (KOOS-12) for use in the Persian language.

Methods: This study employed a cross-sectional design involving 105 participants with moderate to severe knee osteoarthritis (OA). The Persian version of the KOOS-12 was administered to assess its test-retest reliability, internal consistency, and construct validity. Test-retest reliability was evaluated using the intraclass correlation coefficient (ICC), with values above 0.75 indicating excellent reliability. Internal consistency was assessed using Cronbach's alpha, where values between 0.70 and 0.90 indicate good to excellent consistency. Construct validity was examined through Pearson correlation coefficients, comparing KOOS-12 scores with established measures such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), cincinnati knee rating system (CKRS), Oxford knee score (OKS), and knee society knee scoring system (KSS). Additionally, the standard error of measurement (SEM) and minimal detectable change (MDC) were calculated to provide insights into the measurement's precision and responsiveness, with SEM calculated as SD × √(1-R) and MDC as 1.96 × √2 × SEM.

Results: The Persian version of the KOOS-12 was administered to assess its construct validity, test-retest reliability, and internal consistency. Construct validity was evaluated through Pearson correlation coefficients, revealing strong correlations with the KOOS (r = 0.81), moderate correlation with the CKRS (r = 0.56), and strong negative correlation with the WOMAC (r = - 0.77), along with strong correlations with the OKS (r = 0.71) and the KSS (r = 0.73). Test-retest reliability was assessed using the ICC, with values above 0.75 indicating excellent reliability. Internal consistency was measured using Cronbach's alpha, where values between 0.70 and 0.90 indicate good to excellent consistency.

Conclusion: The analysis of the Persian KOOS-12 questionnaire confirms its excellent reliability, validity, and suitability for clinical use, supported by excellent internal consistency and excellent test-retest reliability. These findings underscore the importance of culturally adapted instruments and indicate the need for future research to evaluate the KOOS-12's responsiveness to clinical changes over time.