Cross-cultural adaptation and validation of the Ankle Osteoarthritis Scale for use in French-speaking populations

Background The Ankle Osteoarthritis Scale (AOS) is a self-administered score specific for ankle osteoarthritis (OA) with excellent reliability and strong construct and criterion validity. Many recent randomized multicentre trials have used the AOS, and the involvement of the French-speaking population is limited by the absence of a French version. Our goal was to develop a French version and validate the psychometric properties to assure equivalence to the original English version. Methods Translation was performed according to American Association of Orthopaedic Surgeons (AAOS) 2000 guidelines for cross-cultural adaptation. Similar to the validation process of the English AOS, we evaluated the psychometric properties of the French version (AOS-Fr): criterion validity (AOS-Fr v. Western Ontario and McMaster Universities Arthritis Index [WOMAC] and SF-36 scores), construct validity (AOS-Fr correlation to single heel-lift test), and reliability (AOS-Fr test-retest). Sixty healthy individuals tested a prefinal version of the AOS-Fr for comprehension, leading to modifications and a final version that was approved by C. Saltzman, author of the AOS. We then recruited patients with ankle OA for evaluation of the AOS-Fr psychometric properties. Results Twenty-eight patients with ankle OA participated in the evaluation. The AOS-Fr showed strong criterion validity (AOS:WOMAC r = 0.709 and AOS:SF-36 r = -0.654) and construct validity (r = 0.664) and proved to be reliable (test-retest intraclass correlation coefficient = 0.922). Conclusion The AOS-Fr is a reliable and valid score equivalent to the English version in terms of psychometric properties, thus is available for use in multicentre trials.