Spinal correction surgery improves asymmetrical trunk kinematics during gait in adolescent idiopathic scoliosis with thoracic major curve

Purpose: To clarify the effect of posterior correction and fusion surgery on the trunk–pelvic kinematics during gait in adolescent idiopathic scoliosis (AIS) patients with single thoracic major curve. Methods: Among preoperative AIS patients who planned correction surgery, 18 patients with Lenke type 1A or B were selected for this study. All patients were female. The patients’ trunk and pelvic kinematics during gait were measured three-dimensionally and dynamically using reflective markers, optoelectronic motion capture system. The gait analysis was performed before and 1–2 years after surgery. The trunk and pelvic symmetry during gait was evaluated at coronal, sagittal, and transverse planes between concave and convex sides. Results: The trunk and pelvic angles in sagittal and coronal planes were equivalent between concave and convex sides before and after surgery. Preoperatively, transverse trunk rotation angles were significantly deviated toward the concave (left) side during both static standing (4.3 ± 2.0°) and gait (8.8 ± 0.6°, p < 0.01). Preoperative transverse pelvic rotation angles were significantly deviated toward the convex side during static standing (4.0 ± 3.8°). However, pelvis displayed with symmetric rotational kinematics during gait. Postoperatively, the deviated transverse trunk rotation angle significantly decreased (1.6 ± 0.3°), and the transverse rotational kinematics of both trunk and pelvis improved to symmetric. Conclusions: Posterior correction and fusion surgery have improved preoperative asymmetric global rotational kinematics of trunk and pelvis in transverse plane to symmetric postoperatively in AIS patients with thoracic single major curve. Graphical abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.].