Psychological Factors Associated with Functional Disability in Patients with Hip and Knee Osteoarthritis.

Several studies have shown an association between psychosocial variables and functional capacity in chronic pain processes such as osteoarthritis. The aim of this study was to test a structural equations model that shows the predictive weight of certain variables such as catastrophizing, self-efficacy and kinesiophobia on functional pain and WOMAC subscales scores of pain and physical function of older patients diagnosed with hip and knee osteoarthritis. We also assessed the specific weight of age in terms of the factors. The study was conducted on a sample of 170 patients (142 women and 28 men mean age, 74.44 years range, 50-96 years). The main variables evaluated were WOMAC subscales scores of pain and physical function, self-efficacy, catastrophizing and kinesiophobia. To assess these variables, we used the Spanish validated version of the Western Ontario and McMaster Universities questionnaire, the Chronic Pain Self-Efficacy Scale, the Pain Catastrophizing Scale and the Tampa Scale for Kinesiophobia, respectively. We tested a structural equations model (IBM SPSS Amos version 22). The results showed the predominant predictive weight (both direct and indirect) of catastrophizing while simultaneously ruling out the relevance of age as a predictor of WOMAC subscales scores of pain and physical function. This study provides data of interest on the explanatory mechanisms that underlie the direct and inverse relationships between the studied psychological variables.