Gait Asymmetry in Arm Swing and Foot Progression Angle of Knee Osteoarthritis.

Background: Knee pain, proprioceptive deficits, and muscle weakness brought about by articular degeneration in knee osteoarthritis (OA) can cause postural instability and gait asymmetry. Arm swing plays a major role in balance control during human walking. However, few studies have examined the arm movement and gait stability in knee OA. Therefore, the purpose of this study is to investigate the gait asymmetry in upper and lower limb movement and to understand the overall movement pattern during walking in people with knee osteoarthritis. Methods: Thirty-five people with knee OA and twenty-four age-matched controls were enrolled in this study. The arm swing amplitude, gait biomechanics, and spatiotemporal parameters during walking were measured using a Vicon motion capture system incorporating two AMTI force plates. The differences between the knee OA and control groups were analyzed using independent t-tests. Results: The knee OA patients walked with a slower, smaller step and lower arm swing amplitude. The asymmetries of step time, foot progression angle, and total arm swing amplitude were significantly greater in the knee OA group than in the controls (p < 0.05). There was no significant difference in the mean value of step width and the foot progression angle and the asymmetry of step length and the knee adduction moment between the groups. Conclusions: This study demonstrates that the pathological changes in the lower limbs in knee OA are intrinsically reflected in the upper limbs through diagonal coordination. Asymmetry of arm swing and foot progression angle may be key for understanding OA-related instability.