Reproducibility of the Dutch version of the Western Ontario rotator cuff Index

Background: The Western Ontario Rotator Cuff Index (WORC) is a disease-specific shoulder questionnaire, originally developed at the University of Western Ontario, to measure quality of life in patients with rotator cuff disease (RCD). The aim of the present study was to cross-culturally adapt the WORC for use in the Netherlands and to evaluate the reproducibility in patients with RCD.

Materials and methods: The WORC was translated into Dutch according to leading guidelines in the literature, and 52 patients with RCD completed the questionnaire twice within 2 weeks. The Cronbachs α and the intraclass correlation coefficient (ICC) were calculated, Bland-Altman analysis was applied, and the smallest detectable change (SDC) and reliable change index (RCI) were determined.

Results: The Cronbachs α ranged from 0.91 to 0.97 for the total WORC score and for the 5 domains. High ICCs were found for the WORC total score (0.94) and for the separate domains (range, 0.85-0.91). Bland-Altman analyses showed no systematic differences between assessments. SDC was 355.7 for the total WORC score, varying from 80.4 to 148.0 for the domains, resulting in RCIs of 16.9% for the total WORC score and 24.7% to 30.2% for the domains.

Conclusions: The results of the present study suggest good reproducibility of the Dutch version of the WORC in Dutch-speaking patients with RCD. Additional research on the validation of the Dutch version of the WORC is required in the near future.