Limitations in activities in patients with osteoarthritis of the hip or knee: The relationship with body functions, comorbidity and cognitive functioning

Purpose. To determine the relationship between body functions, comorbidity and cognitive functioning on the one side and limitations in activities on the other, in elderly patients with osteoarthritis (OA) of the hip or knee. Method. A cross-sectional cohort study was conducted in which 288 patients with hip or knee OA were included. Patients were recruited from rehabilitation centres and hospitals (Departments of Orthopedics, Rheumatology or Rehabilitation). Apart from demographic and clinical data, information about limitations in activities, body functions (pain, muscle strength, range of joint motion), comorbidity and cognitive functioning was collected by questionnaires and tests. Statistical analyses included univariate and stepwise multivariate regression analysis. Results. Self-reported limitations in activities (Western Ontario and McMaster Universities Osteoarthritis Index) were significantly associated with pain, muscle strength knee extension, range of motion (ROM) hip flexion and morbidity count. Performance-based limitations in activities (timed walking test) were significantly associated with ROM (knee flexion, hip flexion and knee extension), muscle strength hip abduction, pain, cognitive functioning and age. Conclusions. Self-reported limitations in activities in hip or knee OA are largely dependent on pain and to a lesser extent on range of joint motion, muscle strength and comorbidity. Performance-based limitations in activities are largely dependent on range of joint motion and muscle strength, and to a lesser extent on pain, cognitive functioning and other factors. These findings point to the role of body functions in limitations in activities in OA of the hip or knee. Although less important, comorbidity and cognitive functioning play a role as well.