Objective: To investigate the adaptive pattern of pelvic alignment and to determine the correlations between pelvic alignment and Angle of Trunk Rotation (ATR) of each curve type in individuals with Adolescent Idiopathic Scoliosis (AIS).
Material and Method: This cross-sectional study of 31 AIS subjects was divided according to single or double curve patterns. Demographic data and ATR were collected. Five-view photos were shot before using Scion Image Software to
calculate pelvic alignment. Independent t-test was used to compare pelvic alignment between groups. Pearson’s correlation
coefficient was used to identify the correlation between pelvic alignment and ATR.
Results: The subjects with single and double curves, showed significant difference in the right sagittal and transverse planes
(p = 0.021). The double-curve group showed significant negative correlation of anterior-pelvic-obliquity and ATR (p =
0.037), significant positive correlations of left-pelvic-tilt and ATR (p = 0.021), and right-pelvic-tilt and ATR (p = 0.005). The
major-curve group showed significant negative correlation of anterior-pelvic-obliquity and ATR (p = 0.014), significant
positive correlation of right-pelvic-tilt and ATR (p = 0.021), and top-pelvic-rotation and ATR (p = 0.032). The near-pelviscurve
group showed only significant negative correlation of anterior-pelvic-obliquity and ATR (p = 0.032).
Conclusion: Both AIS groups showed different pelvic tilt and rotation. ATR showed the correlation with pelvic tilt and obliquity in double-curve group only. A larger curve influenced the pelvic-spinal rotation relationship more than the nearpelvic-curve. Thus, awareness of pelvic alignment in AIS assessment and treatment is recommended.

Keywords: Idiopathic scoliosis, Pelvic alignment, Trunk rotation, Single curve, Double curve