Development and content validation of a questionnaire identifying patients' functional priorities and abilities after hip or knee arthroplasty

Background: To develop a self-report questionnaire evaluating functional priorities after hip or knee arthroplasty and evaluate patients' understanding of its items and conceptual relevance. Methods: A self-report questionnaire was first developed based on the International Classification of Functioning, Disability, and Health (ICF) core set for osteoarthritis (OA). In the second stage, two research physiotherapists thoroughly reviewed and refined the questionnaire, and another physiotherapist conducted cognitive think-aloud interviews with 18 patients to assess the face and content validity of the questionnaire. Results: All categories and corresponding activities of ICF core set for OA were used to develop the questionnaire. Several questionnaire issues were identified and addressed. Most challenges were related to comprehension, followed by item ordering and visual elements. Patients identified ambiguous wording which we subsequently simplified. Ten activities of the core set were excluded due to lack of face validity, two activities were added, and four activities were modified. Conclusion and implication: The findings suggest that the ICF core set for OA needs to be adjusted for patients undergoing hip or knee arthroplasty and highlight the feasibility of applying a modified core set to assess functional priorities after hip or knee arthroplasty.