Are fear of movement, self-efficacy beliefs and fear of falling associated with levels of disability in people with osteoarthritis of the knee? A cross sectional study.

Introduction: Osteoarthritis of the knee (OAK) can result in significant disability and previous authors have suggested that cognitive and falls-related factors may be significant determinants of function. However, no previous studies have considered the relative influence of these factors when the effects of symptoms related to OAK are also considered. Additionally, it is plausible that falls-related factors exert a greater influence in patients who have previously fallen.

Methods: Fifty-eight patients were recruited from an outpatient physiotherapy department. They completed measures of physical function, pain, stiffness, physical symptoms, fear avoidance, perceived consequences of falling, fear of falling and self-efficacy beliefs. Variables exhibiting significant correlations with disability were entered into a regression model. β Values were also calculated for the final model to allow the relative contribution of each variable to be established when all variables were considered. Sub-analysis was then performed using only data from patients who had previously fallen, to establish whether cognitive and falls-related factors exerted a stronger influence in this group.

Results: Pain, stiffness and joint symptoms significantly explained 75% of the variance in disability. The cognitive and falls-related variables did not significantly explain any additional variance. Only pain and stiffness exhibited significant β values in the final model. Similar findings were observed in the sub-analysis with the participants who had previously fallen, with only pain and stiffness explaining significant variance (77%) or exhibiting significant β values.

Discussion: The current findings suggested that cognitive and falls-related factors are not significantly related to disability in patients with OAK. By contrast, pain and stiffness were strongly associated with disability. This suggests that targeting cognitive and falls-related factors is unlikely significantly to improve outcome in these patients.