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).
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).
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.
These results provide evidence to support use of the SHS for assessing disability in patients with hip OA.