Gait Analysis Research Of Gait In Patients With Medial Knee Osteoarthritis

In current research about mechanism of knee osteoarthritis(KOA), study populations have typically been small and involve a range of OA stages, from early OA to severe OA. In addition, knee OA has been used as a generic inclusion criterion; that is, no distinction was made between patients with OA affecting the medial knee compartment and those in the lateral compartment. The purpose of this study was to investigate the biomechanics changes of the major joints of the lower extremity during walking in patients with medial compartment KOA of varied severity. We hypothesized that gait changes related to KOA of varied severity are associated with increased loads at the ankle, knee,and hip, and that most changes will occur in the frontal plane. The subjects were divided into three groups : 30 less severe KOA patients(LKOA), 30 more severe KOA patients(MKOA), and 30 matched controls(CON). A three-dimensional VICON motion analysis and KISTLER force plate system was used to determine kinematics and kinetics data of the lower limb during similar-speed walking. The results indicated that, the general gait pattern and the angle of knee flexion at heel strike differed between patients with KOA and matched control subjects,and all patients walked with greater hip flexion moments during terminal stance and greater maximum abduction moments at the knee and at the hip following heel strike, and maximum abduction moments of knee was greater in patients with LKOA than those with MKOA, patients with MKOA had significantly greater first peak adduction moments at the knee than LKOA and CON, and LKOA had lower second peak adduction moments at the knee than CON, patients with MKOA had significantly lower first and second peak adduction moments at the hip than CON, and all patients with KOA had smaller maximum inversion moments at the ankle in terminal-stance phases, and there were significantly differences in maximum ground reaction force and maximum power of all joints of lower extremity during stance phases among all 3 groups. The results of this study support our hypothesis. All changes in loading pattern of each joint of lower extremity is a possible strategy of gait compensation used by patients with KOA to reduced the mediolateral distance between the center of mass and the knee, thereby reducing the moment arm of the ground reaction force and supposedly reducing the knee adduction moment at a subsequent point during stance. This strategy appears to be successful only in patients with LKOA. Gait changes appear to be initiated before heel strike and this not only affects the load distribution between the medial and lateral compartments of the knee, but also leads to leads to increased axial loading rates at all joints of the lower extremity. More rapidly increasing joint forces may lead to a more rapid progression of existing OA and to initiation of OA at joints adjacent to the knee. The study demonstrated the biomechanics mechanism in changes of gait compensation, and provided a powerful evidences for related treatments of rehabilitation.