Determinants of pain, disability, health-related quality of life and physical performance in patients with knee osteoarthritis awaiting total joint arthroplasty

Purpose: In patients suffering from knee osteoarthritis awaiting knee arthroplasty, to measure associations between several selected determinants and pain, disability, health-related quality of life and physical performance. Material and methods: Validated self-reported measures were collected: (1) Western Ontario and McMaster Universities Osteoarthritis Index, (2) Lower Extremity Functional Scale (LEFS) and (3) Short-Form 36 (SF-36). Physical performance was also assessed with four validated performance tests. Demographic, socioeconomic, psychosocial and clinical characteristics of the participants were also measured. Multivariate regression analyses were used to evaluate potential associations. Results: Higher fear-avoidance beliefs, greater comorbidities, psychological distress and use of a walking aid were significantly associated with worse pain, function or HRQOL (p < 0.05) and explained 12%-35% of the variances of the self-reported measure scores. Pretest pain and change in pain during posttest, greater comorbidities, psychological distress and use of a walking aid were significantly associated with worse performance on the physical tests (p < 0.05) and explained 41%-59% of the variances of the different physical tests results. Conclusions: Several determinants were significantly associated with worse pain, disability, health-related quality of life or physical performance. Several of these associations may be considered clinically important, including psychosocial determinants in relation to self-reported measures, but to physical performance as well.