Non-arthritic Hip Score: translation, cultural adaptation and validation of the Italian version

BACKGROUND: The aim of the study was to translate the Non-arthritic Hip Score (NAHS) questionnaire into the Italian language, to adapt it into the Italian culture and to validate it. METHODS: Translation and cultural adaptation were performed following international guidelines. To assess the reliability of the tool, internal consistency and test-retest reliability were evaluated through Cronbach's alpha and intraclass correlation coefficient (ICC) respectively. Validity was evaluated by Pearson's correlation coefficient between the NAHS, the Lequesne Index of Severity for Osteoarthritis of the Hip (LISOH) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC), that were administered together. These three questionnaires were applied to a population of 64 individuals aged between 19 and 82 years with generic hip injures or diseases. RESULTS: The items of the original version of NAHS are similar or equal to the items of the Italian version of NAHS. Cronbach's alpha was 0.614 (Pain); 0.821 (Symptom); 0.877 (Function); 0.896 (Activity). ICC for total score was 0.905. The correlation with the WOMAC was 0.850 (P<0.01) and with the LISOH was 0.738 (P<0.01). CONCLUSIONS: The NAHS showed positive results for reliability and validity so it was translated into Italian language and was cross-culturally adapted to Italian culture. This questionnaire is a good instrument in clinical practice and scientific research for the evaluation of young and active individuals affected by hip injures or diseases.