Cross-Cultural Validation of Urdu Version KOOS in Indian Population with Primary Knee Osteoarthritis.

Purpose: The primary aim of this study was to translate a self-reported questionnaire (KOOS) from English to Urdu and then to see its internal consistency, agreement, test-retest reliability, and validity among primary OA knee patients.

Methodology: First, KOOS questionnaire was translated from English language to Urdu through standardized cross-cultural protocol. This translated version of KOOS was administered to 111 radiographically diagnosed primary OA knee patients at two times with 48-hour interval in-between. Cronbach's alpha, floor and ceiling effect, intraclass correlation coefficient (ICC), absolute agreement %, and Spearman correlation were used to fulfill our objectives.

Results: Average time to administer this questionnaire was 20 minutes. There was good internal consistency with Cronbach's alpha ranging from 0.7246 to 0.9139. The absolute agreement of each item between two tests ranged from 81.08% to 98.20%. Test-retest reliability was excellent ("r" ranged from 0.9673 to 0.9782). There was no ceiling effect; however less than 4% floor effect was seen in two subscales. There was significant difference that existed between different X-ray grades in all subscales meaning good content validity for disease prognosis.

Conclusion: The present results show that KOOS Urdu version is a reliable and valid measure for primary OA knee patients.