Evaluation of Validity, Reliability, and Feasibility of 3 Patient-Reported Foot and Ankle Outcome Measures

Abstract

BackgroundA wide range of patient-reported outcome measures have been developed to assess the impact of foot and ankle pathology on patients’ function. In this study, Manchester-Oxford Foot Questionnaire (MOXFQ), Foot and Ankle Ability Measure (FAAM), and Revised-Foot Function Index (R-FFI) scores were assessed independently of their developers for validity, reliability, item bias, acceptability, and feasibility. MethodsWe prospectively recruited 100 consecutive patients with a range of foot and ankle disorders over a 6-month period. Patients completed a set of 3 questionnaires at initial consultation. Patients were subsequently sent questionnaires in a random order with a prepaid envelope and asked to complete them with 2 to 14 days. To assess feasibility in routine clinical practice, the time taken to complete questionnaires was evaluated in a cohort of 65 patients. ResultsThe mean age of patients was 51.7 years (range 20 to 85). The majority were females (64 of 96). The internal consistency of all 3 questionnaires was high, suggesting good intercorrelation among the items of each questionnaire. The questionnaires were reproducible and valid. There was strong correlation between the total scores of all 3 questionnaires. There was no item bias on the overall scores by the assumed independent variables such as age, sex, site, and pathology. Form completion rates were 98% for MOXFQ, 89% for FAAM, and 75% for FFI. MOXFQ was the easiest to understand and complete. No significant difference was found in the time taken to complete each questionnaire. ConclusionAll 3 scores correlate with the level of function and have very good reproducibility. For routine use, the MOXFQ has good practical properties of patient acceptability, high item response rate, and ease of completion.