Assessment of the Relationship between Pelvic Tilt and the Sacro-Femoral-Pubic Angle in Middle-Aged and Elderly Asian Individuals

STUDY DESIGN: Cross-sectional study. PURPOSE: The purpose of this study was to evaluate the correlation between pelvic tilt (PT) and the sacro-femoral-pubic (SFP) angle, which is easier to identify than PT, in middle-aged and elderly Asian subjects from the general population. OVERVIEW OF LITERATURE: Measuring PT is important in the diagnosis and treatment of adult spinal deformity. However, identifying femoral heads, which are necessary to determine PT, using sagittal radiographs is often difficult. METHODS: Standing coronal and sagittal pelvic radiographs of individuals aged more than 50 years were taken during a local medical examination. The subjects were divided into female, male, and total groups at the time of evaluation. Linear regression analysis was performed to investigate the relationship between PT and the SFP angle, which were obtained from the X-rays. RESULTS: The present study included 291 subjects. There were no statistically significant differences between the left and right SFP angles, and there was gender difference regarding the SFP angle. However, a gender difference was observed regarding PT. The correlation between PT and the SFP angle was substantiated in each group. Pearson's correlation coefficients between PT and the SFP angle in the total, female, and male groups were 0.696, 0.853, and 0.619, respectively. In the linear regression analysis, PT was calculated as follows: PT=60.1−0.77×(SFP angle) in the total group, PT=62.8−0.80×(SFP angle) in the female group, and PT=51.5−0.64×(SFP angle) in the male group. CONCLUSIONS: A significant correlation between PT and the SFP angle was observed in middle-aged and elderly Asian subjects from the general population.