A standardised outcome measure of pain, symptoms and physical function in patients with hip and groin disability due to femoro-acetabular impingement: cross-cultural adaptation and validation of the international Hip Outcome Tool (iHOT12) in Swedish

There is a lack of standardised outcome measures in Swedish for active, young and middle-aged patients with hip and groin disability. The purpose of this study was to adapt the English version of the international Hip Outcome Tool (iHOT12) patient-reported outcome instrument for use in Swedish patients and evaluate the adaptation according to the consensus-based standards for the selection of health status measurement instruments checklist. Cross-cultural adaptation was performed in several steps, including translation, back-translation, expert review and pre-testing. The final version was evaluated for reliability, validity and responsiveness in a clinical study of patients [median age 37 (range 15-75)], undergoing surgery for femoro-acetabular impingement. Cronbach's alpha was 0.89, and significant correlations were obtained with the Copenhagen Hip and Groin Outcome Score (Spearman's r 0.10-0.70; p < 0.05) and the EuroQol, EQ-5D average score (Spearman's r 0.27-0.56; p < 0.01). Test-retest reliability (intraclass correlation coefficient) ranged from 0.59 to 0.93 for the individual items. The smallest detectable change ranged from 17.1 to 44.9 at individual level and 3.6 to 9.4 at group level. Factor analysis revealed one factor of pain and symptoms and another factor of physical function. Effect sizes were generally medium or large. The Swedish version of the iHOT12 is a valid, reliable and responsive instrument that can be used both for research and in the clinical setting. Diagnostic study, Level I.