Questionnaire for usability evaluation of orthopaedic shoes: construction and reliability in patients with degenerative disorders of the foot

Objective: To develop a self-report questionnaire for patients with degenerative disorders of the foot to evaluate the usability of their orthopaedic shoes, and to assess the reproducibility and responsiveness of the instrument. Design: Development of the Questionnaire for Usability Evaluation of orthopaedic shoes was based on a literature search, structured expert interviews and a ranking procedure. A cross-sectional study was carried out to determine the reproducibility and internal consistency of the questionnaire. Setting and subjects: The study population comprised 15 patients with degenerative disorders of the foot, who had worn their orthopaedic shoes for at least 3 years and 15 patients with degenerative disorders of the foot, who had never worn orthopaedic shoes, but would receive them within 1 month. Results: Within the questionnaire 4 effectiveness items (pain, instability, callus, wounds), 1 efficiency item (putting on and taking off shoes) and 7 satisfaction items (pinch, slip, weight of shoes, cold feet, perspiration, maintenance, cosmetic appearance) were developed. All items in the questionnaire met the test-retest criteria. The smallest real difference ranged from 0.23 to 3.82 cm on a Visual Analogue Scale (10 cm). Cronbach's alpha's for the domains of pain and instability ranged from 0.70 to 0.92. Conclusion: The Questionnaire for Usability Evaluation should provide a good rationale to assess the usability of orthopaedic shoes and can be considered reliable.