Scale development of the Osteoarthritis Conceptualisation Questionnaire: Phase 2 construct validity

An individual's knowledge, beliefs and/or expectations about their osteoarthritis can influence their engagement with physical activity and their treatment decisions surrounding recommended non-surgical management. Yet there is no widely accepted questionnaire to assess complex mental frameworks surrounding osteoarthritis. Therefore, this study aimed to develop an Osteoarthritis Conceptualisation Questionnaire (OACQ) to assess an individual's conceptual framework for osteoarthritis via psychometric evaluation of an established item-bank. The OACQ item-bank, co-developed with pain experts and people with lived experience of knee pain, was administered online to people with painful knee osteoarthritis. Psychometric evaluation was undertaken using factor and exploratory graph analyses to create a data-driven model of the OACQ which was then compared with the existing theoretical model (construct validity). Four hundred and fifty-four participants completed the survey (n=336 female; 64.52 ± 9.21 years). Psychometric evaluation resulted in the OACQ, consisting of 36 items across four domains: 'Expectations'; 'Context'; 'Physiology'; and 'Conceptual Change'. Data-driven models aligned with theoretical models, providing preliminary evidence of construct validity. The resultant OACQ could be used to assess osteoarthritis conceptualisations in people with painful knee osteoarthritis. Further research to evaluate scale and item functioning and test-retest reliability is warranted. PERSPECTIVE: Classical and innovative psychometric methods were utilised to develop a novel assessment of conceptualisations of osteoarthritis. The combined use of these methods provided a rigorous evaluation of construct validity. The OACQ may be useful for evaluating the effectiveness of pain science education interventions.