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 (α) 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.