Cross-cultural adaptation, reliability, and validity of the Italian version of the Western Ontario Rotator Cuff (WORC) Index in subjects with rotator cuff diseases.

PURPOSE: The Western Ontario Rotator Cuff (WORC) Index is a disease-specific, recommended tool to investigate the quality of life in subjects with rotator cuff (RC) disorders and tears. The purpose of this study was to deeply assess the psychometric properties of the WORC Index in patients with RC disorders and repair.

METHODS

The WORC Index was translated and cross-culturally adapted into Italian according to international guidelines and administered to 149 subjects with RC disorders or repair. Subjects completed the WORC Index, the American Shoulder and Elbow Surgeon Standardized Shoulder Assessment Form (ASES), the Short-Form Health Survey 36 (SF-36), and the Numerical Pain Rating Scale (NPRS). Confirmatory Factor Analysis (CFA) was run to investigate the structural validity. Internal consistency (Cronbach's alpha), test-retest reliability (Intraclass Correlation coefficient [ICC]), measurement error (Standard Error of Measurement [SEM], Minimum Detectable Change [MDC95]), and construct validity (a-priori hypothesis testing with the correlation with the other outcome measures) were also assessed.

RESULTS

After addressing local item dependency, the final CFA confirmed a five-subscale structure (RMSEA = 0.059; SRMSR = 0.04; CFI = 0.969; TLI = 0.958). Cronbach's alpha ranged from 0.843 to 0.933. The test-retest reliability was excellent (ICC ranged from 0.873 to 0.929). SEM ranged from 6.1 to 9.9 points, and MCD95 varied from 17 to 27.4 points. Construct validity was considered satisfactory for all subscales.

CONCLUSION

The Italian version of the WORC Index demonstrated validity and reliability in assessing subjects with RC disorders and repair. It is recommended for use in clinical practice and research.