Cross-cultural adaptation and validation of the Italian version of the Western Ontario Rotator Cuff (WORC) index

: The aim of the study was to accomplish translation, cross-cultural adaptation and validation of the Western Ontario Rotator Cuff (WORC) Index questionnaire for its use in Italy. The WORC original version was translated and cross-culturally adapted into Italian. Subsequently, it was administered to a population of 60 patients suffering from rotator cuff disease to evaluate the validity and reliability of the Italian version. The content validity evaluated the correlation between questions and total score of each domain through Pearson's correlation coefficient. The construct validity was similarly assessed through Pearson's correlation coefficient by testing the correlation between the Italian WORC and the Italian version of the Disability of the Arm, Shoulder and Hand (DASH) questionnaire. Reliability was assessed using two methods: internal consistency by calculating the Cronbach's alpha coefficient for each domain; and test-retest by means of the intraclass correlation coefficient (ICC). The translation and cross-cultural adaptation of the Italian version did not reveal any major problems. No significant floor or ceiling effects were found. All the questions were linearly related to the concept expressed by the domain of belonging. Overall correlation with the DASH score was 0.75. Internal consistency was very high overall (α = 0.93) as well as reliability (overall ICC = 0.87). The Italian version of the WORC questionnaire is a valid and reproducible measuring instrument and can be considered a valid tool for the evaluation of the effectiveness of a treatment in terms of quality of life, in Italian patients affected by rotator cuff diseases.Level of evidence Diagnostic study, level II.