The aim of this study was to investigate the content validity including item reduction, construct validity and internal consistency of the existing 16-item Knee Osteoarthritis Patient Education Questionnaire. Former research had indicated that a reduction of items was necessary. Participants were patients with severe knee osteoarthritis who, prior to undergoing a knee replacement operation, participated routinely in a preoperative educational intervention.
A mixed method design was used. The first step was directed at the reduction in the number of items on the 16-item Knee Osteoarthritis Patient Education Questionnaire. Based on a priori hypotheses, this was followed by a cross-sectional validation study, performed to compare the resulting 7-item Knee Replacement Patient Education Questionnaire to a patient-testing Interview Protocol that was tailored to the same patient educational material. Additionally, the revised questionnaire was correlated with both the Short Test of Functional Health Literacy and the Mini-Mental State Examination score.
A relatively high internal consistency was found for the 7-item Knee Replacement Patient Education Questionnaire, with a Cronbach's alpha of 0.84 (SE: 0.036). Explanatory factor analysis showed no evidence against a one-factor model, with the first and second eigenvalues being 3.8 and 0.31, respectively. Bayesian Estimation of the correlation between the 7-item Knee Replacement Patient Education Questionnaire and the Interview Protocol was 0.78 (mode) (95% HPD 0.58-0.89).
The 7-item Knee Replacement Patient Education Questionnaire shows good psychometric properties and could provide valuable support to health professionals. It can provide valid feedback on how patients waiting for a knee replacement operation experience an applied patient education intervention. Further investigation is needed to assess the applicability of the 7-item Knee Replacement Patient Education Questionnaire to larger samples in different hospitals and countries.