Background: We developed and validated a five-item self-report questionnaire for assessing disability as defined by the International Classification of Functioning, Disability, and Health conceptual model in patients with hip osteoarthritis (OA).
Material and methods: The psychometric properties of the new score (Schulthess hip score, SHS) were examined in 105 consecutive patients (mean age 63 years; 48 women) undergoing total hip arthroplasty (THA).
Results: The completion rate (97%) and reproducibility (intraclass correlation coefficient 0.90) of the SHS were excellent. Exploratory factor analysis indicated that all items that loaded on one factor only that accounted for 69.4% of the total variance. Cronbach's alpha was 0.88. Evidence of validity was provided by moderate to high correlations (r=-0.37-0.78) with the scores of traditionally used self-reported outcome measures. The SHS was very responsive, with an effect size of 2.15 and a standardized response mean of 1.74 for changes recorded 6 months after THA.
Conclusion: These results provide evidence to support use of the SHS for assessing disability in patients with hip OA.