Racial differences in whole-body sagittal alignment between Asians and Caucasians based on international multicenter data.

Purpose: To examine inherent differences adjusted for age and clinical score in whole-body sagittal (WBS) alignment involving the lower extremities between Asians and Caucasians, and to determine the relationship between age and WBS parameters by race and sex.

Methods: A total of 317 individuals consisting of 206 Asians and 111 Caucasians participated. WBS parameters including C2-7 lordotic angle, lower lumbar lordosis (lower LL, L4-S), pelvic incidence (PI), pelvic thickness, knee flexion (KF), sagittal vertical axis (SVA), and T1 pelvic angle (TPA) were evaluated radiologically. Propensity score-matching adjustments for age and the Oswestry Disability Index scores for comparative analysis between the two race cohorts and correlation analysis between age and WBS parameters for all subjects by race and sex were conducted.

Results: The comparative analysis included 136 subjects (age: Asians 41.1 ± 13.5, Caucasians 42.3 ± 16.2 years, p = 0.936). Racial differences in WBS parameters were observed in C2-7 lordotic angle (-1.8 ± 12.3 vs. 6.3 ± 12.2 degrees, p = 0.001), and lower LL (34.0 ± 6.6 vs. 38.0 ± 6.1 degrees, p < .001). In correlation analysis with age, moderate or more significant correlations with age were found in KF for all groups, and in SVA and TPA for females of both racial groups. Age-related changes in pelvic parameters of PI and pelvic thickness were more significant in Caucasian females.

Conclusion: Analysis of the correlation between age and WBS parameters suggested that age-related WBS changes vary between races and should be considered during corrective spinal surgery.