Factors affecting balance in patients with knee osteoarthritis

Osteoarthritis is a slowly progressive degenerative joint disease characterized by damage to the joint cartilage and remodeling of the periarticular bone. OA is the most commonly seen joint disorder in older adults that causes functional impairment and pain. The knee is the most commonly affected weight-bearing joint and increased balance problems and fall risk are prevalent in patients with knee OA. The aim of this study was to investigate the factors affecting balance in patients with knee OA. For this purpose we examined the demographic, clinical and structural factors in patients with knee OA and explored their relationship with balance. One hundred, 45 years and older men and women who applied to outpatient clinics with knee pain and diagnosed with knee OA were included in this study. Three patients were excluded from the study due to lack of cooperation. Timed up and go test (TUG), 5 times sit and stand test (5xSST) were held to investigate dynamic balance and functional reach (FR) and one leg stance (OLS) tests were held to investigate the static balance. Also Berg Balance Scale (BBS) was used to explore balance. Knee muscle strength and proprioception were measured using a isokinetic dynamometer. WOMAC questionnaire was used for detecting pain intensity. Radiographic severity was assessed according to Kellgren–Lawrence grading system. Age, disease duration, height, weight, body mass index (BMI) were recorded. Correlation and multiple linear regreesion analysis were used to assess the associations. In the linear regression models knee muscle weakness, increased BMI, and older age were main determinants of TUG, 5xSST, OLS and BBS and contributed to 30-51 % of variance in these tests. Knee muscle weakness was the only determinant of FR test and explained 19% of the variance in this test. Knee pain, radiographic severity, propriocepcition, and disease duration did not have a significant association (p<0.05). Balance tests and BBS had significant correlations (r range: 0.31-0.68, p<0.05). In patients with knee OA knee muscle strength is the main determinant of balance together with BMI, and age. Improving muscle strength and weight loss seems to be the most important factors in rehabilitation of patients with knee OA to maintain balance and reduce fall.