Reliability and validity of Knee Injury and Osteoarthritis Outcome Score (KOOS) in Iranian Population

Objectives: The purpose of present study was the investigation of reliability and validity of the knee injury and osteoarthritis outcome score in the Iranian population. Methods: The method of the present study was non-experimental and methodological. The statistical population of the present study was patients with osteoarthritis of the knee. Patients with osteoarthritis of the knee referred to the Akhtar Center were selected from 127 people by available sampling for sample adequacy. In data analysis, Cronbach's alpha test to determine internal agreement, test-retest method to determine stability in reliability, item impact method to determine face validity, CVI and CVR indicators to determine content validity, and to determine structural validity two convergent and divergent validities as well as confirmatory factor analysis were used. Results: The results showed that if the fourth question "symptoms" is removed, the questionnaire has acceptable reliability and validity. Conclusion: The analysis of the findings indicated that the Persian version of the questionnaire (KOOS) was a reliable tool for assessing the health status and impact of various treatments on patients with osteoarthritis in the country, which had high validity and reliability.