The Biomechanics Research Of Lower Extremity During Support Phase In Individual With Knee Osteoarthritis

Backgrounds: Osteoarthritis(OA), the most common form of arthritis, affects an increasing proportion of the population, with the knee being the most commonly affected joint in the lower limb. Knee OA has been shown to affect gait patterns, increases the risk of falls and reduces the quality of life in the elderly as a result of altered joint kinematics and loading patterns, as well as balance control. This study would be based on a few results about mechanical factors of knee osteoarthritis in the sagittal plane. Using traditional kinematic and kinetic test methods with intersegmental dynamics analysis method to understand and investigate the sagittal plane biomechanics of lower extremity during the support phase in the elderly patients with knee osteoarthritis. We could get biomechanics sensitive index of evaluating knee osteoarthritis gait, and then supplies biomechanics theoretical basis for the prevention and rehabilitation of knee osteoarthritis.Methods: A 16-camera motion analysis system and two Kistler force platforms were used to measure kinematic and kinetic data in 13 OA subjects’(65.9±4.1years,58.1±8.6kg) and 13 HO subjects’(63.4±2.3years,55.4±5.8kg) walking. On the basis of conventional kinematic and kinetic analysis, we would build the intersegmental model of lower extremity joints. Then combined with the intersegmental dynamic to analysis the relationship between active muscle torque and passive torques in two different groups. All variables characterizing sagittal-plane joint function were compared between the two groups using Independent-Samples T test. The level of significance for the T test was set at α=0.05.Results:1. The stride length(P<0.05)and speed of walking(P<0.05)in OA subjects are less than those in HO subjects.2. During the heel-strike portion and terminal portion of the stance phase, there are significant differences in the angle of left knee between two groups(P hs<0.05;Pts<0.05). Besides, knee extensor muscle torque of heel-strike(KFMhs)in OA group are less than that in healthy controls(P<0.05).Conclusion: The change of extensor and flexor muscles’ activity in lower extremity induced by knee osteoarthritis will alter the peak angle of knee and knee muscle torque in different portions of stance phase. So these variables could be considered to be effective diagnostic targets in biomechanics.