Validity of five foot and ankle specific electronic patient-reported outcome (ePRO) instruments in patients undergoing elective orthopedic foot or ankle surgery.

BACKGROUND: Patient-reported outcomes (PROs) are widely accepted measures for evaluating outcomes of surgical interventions. As patient-reported information is stored in electronic health records, it is essential that there are valid electronic PRO (ePRO) instruments available for clinicians and researchers. The aim of this study was to evaluate the validity of electronic versions of five widely used foot and ankle specific PRO instruments. METHODS: Altogether 111 consecutive elective foot/ankle surgery patients were invited face-to-face to participate in this study. Patients completed electronic versions of the Foot and Ankle Ability Measure (FAAM), the Foot and Ankle Outcome Score (FAOS), the modified Lower Extremity Function Scale (LEFS), the Manchester-Oxford Foot Questionnaire (MOXFQ), and the Visual Analogue Scale Foot and Ankle (VAS-FA) on the day of elective foot and/or ankle surgery. Construct validity, coverage, and targeting of the scales were assessed. RESULTS: Based on general and predefined thresholds, construct validity, coverage, and targeting of the ePRO versions of the FAAM, the FAOS, the MOXFQ, and the VAS-FA were acceptable. Major issues arose with score distribution and convergent validity of the modified LEFS instrument. CONCLUSIONS: The ePRO versions of the FAAM, the FAOS, the MOXFQ, and the VAS-FA provide valid scores for foot and ankle patients. However, our findings do not support the use of the modified LEFS as an electronic outcome measure for patients with orthopedic foot and/or ankle pathologies.

Structural validity of the Finnish Manchester-Oxford Foot Questionnaire (MOXFQ) using the Rasch model.

BACKGROUND: The 16-item patient-reported Manchester-Oxford Foot Questionnaire (MOXFQ) with subscales of pain, social interactions, and walking/standing has been claimed for strongest scientific evidence in measuring foot and ankle complaints. This study tests the validity of the Finnish MOXFQ for orthopaedic foot and ankle population using the Rasch analysis. METHODS: We translated the MOXFQ into Finnish and used that translation in our study. MOXFQ scores were obtained from 183 patients. Response category distribution, item fit, coverage, targeting, item dependency, ability to measure latent trait (unidimensionality), internal consistency (Cronbach's alpha), and person separation index (PSI) were analyzed. RESULTS: Fifteen of the items had ordered response categories and/or sufficient fit statistics. The subscales provided coverage and targeting. Some residual correlation was noted. Removing one item in the pain subscale led to a unidimensional structure. Alphas and PSIs ranged between 0.68-0.90 and 0.67-0.92, respectively. CONCLUSIONS: Despite some infractions of the Rasch model, the instrument functioned well. The subscales of the MOXFQ are meaningful for assessing patient-reported complaints and outcomes in orthopaedic foot and ankle population.