Validation of the French version of the Non-Arthritic Hip Score (NAHS) in 113 hip arthroscopy procedures

Abstract

BackgroundThe Non-Arthritic Hip Score (NAHS) used to evaluate the hip in younger patients is a self-administered questionnaire with 20 items in four sections: pain, symptoms, function, and activities. Although used in France, no transcultural version had been validated. The objective of this study was to translate the NAHS into French then assess the validity, reliability, and sensitivity to change of the French-language version (NAHS-Fr) in younger patients with hip conditions other than osteoarthritis. HypothesisThe NAHS-Fr demonstrates good validity and reliability when used in younger French-speaking patients with hip pain. Material and methodsWe conducted a prospective observational study in 105 patients (62 males and 43 females) scheduled for surgery on one or both hips (113 hips in total) to treat cam-type femoro-acetabular impingement or labral lesions. Before and 6 months after surgery, each patient completed the NAHS-Fr and Western Ontario and McMaster Osteoarthritis Index (WOMAC). Statistical tests were done to evaluate validity, reliability, and sensitivity to change, as recommended by the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN). ResultsThe response rate was 100%, confirming that the NAHS-Fr was easy to use. The NAHS-Fr was both valid and reliable. No ceiling or floor effect was detected for the total NAHS-Fr score. All items had Cronbach alpha coefficients greater than 0.8, indicating good internal consistency. External consistency between the NAHS-Fr and WOMAC was negative (–0.676) due to inversely proportional score indexing. Before surgery, the NAHS-Fr and WOMAC scores were strongly and significantly correlated (p<0.0001). The effect size was greater than 0.8, indicating good sensitivity to the change induced by surgery. DiscussionThese results confirm the study hypothesis: the NAHS-Fr has the same good psychometric characteristics as does the original version and versions in other languages. The NAHS-Fr is useful for evaluating younger patients with non-osteoarthritic hip pain and can be used by French-speaking surgeons in everyday clinical practice. Level of evidenceIV, prospective observational non-comparative cohort study.