“…For the selection of activities, an expert group in the field of OA (i.e., physical therapists, a rehabilitation physician, an orthopedic surgeon, a rheumatologist, [human movement] scientists, and patient research partners) used the following sources: the ICF core set for hip and knee OA (18), items in existing self-reported questionnaires (19,20), performance-based tests (21,22), and self-reported activity limitations (by using the Patient-Specific Complaints Questionnaire) (23) collected from 400 patients in the Amsterdam Osteoarthritis (AMS-OA) cohort in an outpatient center for rehabilitation and rheumatology (Reade, Amsterdam, The Netherlands) (24).…”