Asymmetrical gait in adolescents with idiopathic scoliosis

Abstract

Purpose: This study investigated side-to-side gait asymmetry in subjects with adolescent idiopathic scoliosis.

Methods: There were 20 adolescents with idiopathic scoliosis and 20 age-matched control subjects, who participated in the study. To minimize confounding effects, we recruited patients with similar spinal curvature for the scoliosis group, and all participants are right hand dominant. The participants were instructed to ambulate on a 10 m walkway while barefoot. There were two force plates in the middle of the walkway. The ground reaction force (GRF) and angular displacements of six segments (foot, shank, thigh, pelvis, trunk, and head) were measured during one gait cycle based on the right and left lower extremities. To remove the positional information in the kinematic data, the derivative of angular displacement in each segment was calculated. To evaluate the side-to-side gait symmetry, we calculated the cross-correlation of each bilateral gait parameter.

Results: In the kinematics, the scoliosis group demonstrated asymmetrical gait in the frontal and transverse planes compared to the control group. In the GRF data, the scoliosis group demonstrated asymmetrical gait in the medial-lateral (M/L) direction compared to the control group.

Conclusions: These results indicated that the scoliosis group produced an asymmetrical rotation pattern of the segments bilaterally in the frontal and transverse planes, resulting in asymmetrical GRF patterns in the M/L direction. This asymmetrical gait may be produced by changes in global postural control during gait and not simply by changes in control of only one or two specific segments.

Figures

Fig. 1

Illustration of one gait cycle for the right leg (a–c) and for the left leg (b–d). The angular displacements of the segments were calculated based on these gait cycles. The experimenter controlled the start position so that each subject always touched the first force platform with his/her right heel and the second force platform with his/her left heel

Fig. 2

Definition of angular displacement of the segments in the sagittal plane. θft = angular displacement of the foot (foot rotation relative to the ankle), θsh = angular displacement of the shank (shank rotation relative to the knee), θth = angular displacement of the thigh (thigh rotation relative to the hip), θpe = angular displacement of the pelvis (pelvic rotation relative to the global coordinate at the hip), θtr = angular displacement of the trunk (trunk rotation relative to the sacrum), and θhd = angular displacement of the head (head rotation relative to the first thoracic spine level)