RESUMO
Disability resulting from knee osteoarthritis (OA) is determined by physiological and functional variables though the interactions between the variables remain unclear and deserve further study. This study's major objective was to explore the relationship between pain, body mass index (BMI), balance, self-report function, and physical function in a cohort who had both unilateral and bilateral knee OA. Fifty-two patients (46 female, 6 male) ranging from 31 to 80 years of age (mean ± SD: 59.0 ± 9.8 years) with radiograph-confirmed OA of the knees participated in this study. Participants' pain intensity, self-reported function, dynamic balance, and physical function performance were measured by using box numerical scale, OA Index of Lequesne, functional reach test, and both stair climbing and timed up-and-go (TUG) tests, respectively. Associations between age, BMI, pain, balance, self-reported function, and physical function performance were explored by univariate and multivariate analyses at α = 0.05. Significant direct correlations were found between physical function performance and self-reported function (r = 0.56, r = 0.01) and age (r = 0.55, p = 0.01) and between self-reported function and age (r = 0.40, p = 0.01) in the cohort with bilateral knee OA. Significant inverse correlation was observed between age and balance (r = -0.58, p = 0.01) in participants with unilateral knee OA. In the regression model for all participants, self-reported function and age accounted for 27.0% of the variance in stair climbing test and 29.0% of the variance in the TUG test. Self-reported function and age are significant predictors of physical function in individuals with knee OA.