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Kinematic and Kinetic Differences and Asymmetries in Gait in Children with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is characterized by a three-dimensional curve within the spine thus creating asymmetries within the trunk. In addition to modifying the trunk geometry, these structural asymmetries change the location of the center of mass. Gait patterns in people with AIS may possibly be altered on the basis of these structural changes. The purpose of this study was to identify differences in gait kinematics and kinetics as well as left-right symmetry as a function of the severity of adolescent idiopathic scoliosis. Forty-five girls divided into a control group, a mild-to-moderate AIS group and a severe AIS group participated in data collection. Gait analysis included bilateral kinematic and kinetic measurements. The maximal joint ranges of motion at the ankle, knee, hip and trunk-pelvis were analyzed. Maxima and minima in the antero-posterior, medio-lateral and vertical components of ground reaction force (GRF) were compared between the three groups as well as the median frequencies obtained from a frequency spectrum analysis of GRF. A symmetry index was computed between the primary curve side and the contralateral side for each kinematic and kinetic variable. Both AIS groups differed from controls in their range of motion at the ankle and at the knee but for the AIS group with severe curves, this was also observed at the hip. Both local maxima in the vertical component and the maximum of the antero-posterior component of the ground reaction force were decreased while the local minimum of the vertical component and the antero-posterior component of GRF increased in the severe AIS group compared to the control group. Higher median frequency contents in the antero-posterior and vertical component of ground reaction force were found in the AIS groups than in controls. No difference in asymmetry was found in any of the variables between all groups. These results seem to indicate that severe AIS participants have a more altered gait pattern than the mild-to-moderate AIS group. Findings from this study point toward greater changes in kinematics and kinetics during stance between all AIS groups and the control group.