Reliability, validity and responsiveness of the German Manchester-Oxford Foot Questionnaire (MOXFQ) in patients with foot or ankle surgery

Background: Patient-reported outcome measures are a critical tool in evaluating the efficacy of orthopaedic procedures. The intention of this study was to develop and culturally adapt a German version of the Manchester-Oxford Foot Questionnaire (MOXFQ) and to evaluate reliability, validity and responsiveness. Methods: According to guidelines forward and backward translation has been performed. The German MOXFQ was investigated in 177 consecutive patients before and 6 months after foot or ankle surgery. All patients completed MOXFQ, Foot and Ankle Outcome Score (FAOS), Short form 36 and numeric scales for pain and disability (NRS). Test-Retest reliability, internal consistency, floor and ceiling effects, construct validity and minimal important change were analyzed. Results: The German MOXFQ demonstrated excellent test-retest reliability with ICC values > 0.9 Cronbach's alpha (alpha) values demonstrated strong internal consistency. No floor or ceiling effects were observed. As hypothesized MOXFQ subscales correlated strongly with corresponding FAOS and SF-36 domains. All subscales showed excellent (ES/SRM > 0.8) responsiveness between preoperative assessment and postoperative follow-up. Conclusions: The German version of the MOXFQ demonstrated good psychometric properties. It proofed to be a valid and reliable instrument for use in foot and ankle patients. (C) 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved