[Modified Western Ontario and McMaster University Osteoarthritis Index Scale used in patients with knee osteoarthritis].

ABSTRACT

Objective: To modify Western Ontario and McMaster University Osteoarthritis Index (WOMAC) for more accurate evaluation of patients with knee osteoarthritis in China,and its reliability and validity were measured. Methods: The WOMAC was modified through reviewing relevant literatures and practical survey.Total of 120 patients were enrolled in this study. The subjects completed the WOMAC,the modified WOMAC and Medical Outcomes Study 36-item Short Form(SF-36), and 113 of the questionnaires were valid for analysis [27 males (23.9%), 86 females (76.1%), aged (59±10) years]. Intraclass correlation coefficient and Cronbach α reliability coefficient were used to analyze the modified WOMAC's reliability; exploratory factor analysis was adopted to analyze the validity of WOMAC and the modified WOMAC; Spearman rank correlation coefficient was used to make a correlation analysis among SF-36, WOMAC and the modified WOMAC. Results: For the four dimensions pain, stiffness, function and life quality in the modified WOMAC, the intraclass correlation coefficient values were 0.861-0.910 and Cronbach α values were 0.751-0.936. In the content validity analysis, the number of extracted common factors for the four dimensions pain,stiffness,function and life quality in the modified WOMAC were 1,1,2 and 1 respectively. The total variance interpretation rate was 65.684%, 84.367%, 67.252% and 67.572%, respectively. In the construct validity analysis, 4 common factors were extracted for WOMAC and the modified WOMAC respectively. The total variance interpretation rate was 70.100% and 67.213%, respectively. Both WOMAC and the modified WOMAC had a significant correlation with SF-36. Conclusion: The modified WOMAC is more suitable for Chinese living habits, but it still needs to be further evaluated with larger samples.