Age-related change and gender differences in pelvic morphology of healthy children.

BACKGROUND: An increasing number of studies about the hip joint morphology with childhood-specific hip diseases have been reported. But there have been few reports on pelvic morphology of healthy children. The purpose of this study was to assess the pelvic morphology of healthy children in detail and clarify the age-related change and gender difference of it.

METHODS: We retrospectively assessed the pelvic morphology of 97 healthy children (3-18 years old) using their pelvic computed tomography (CT) data. Superior iliac angle (SIA), inferior iliac angle (IIA), and ischiopubic angle (IPA) as the parameters of pelvic winging, and acetabular anteversion and anterior acetabular sector angle (AASA), posterior acetabular sector angle (PASA), superior acetabular sector angle (SASA) as the parameters of acetabular coverage, are measured. Pearson's correlation coefficient was used for examining the correlation between the each measurement and the age of cases. Multiple linear regression analysis was performed to investigate the possibility of association of age and sex with each measurement.

RESULTS: In female, it was found that IIA, AASA, PASA, SASA were significantly correlated with the age of the cases. And in male, SIA, IIA, IPA, AASA, PASA were significantly correlated with the age. Multiple linear regression analysis revealed the significant difference of the distribution between males and females was observed in IIA, IPA, AVcen, PASA, and these measurements were lager for female.

CONCLUSIONS: In this study, we revealed the age-related change and gender difference of the pelvic morphology of healthy children, and this could be useful information in evaluating the hip with what appears to be an abnormal acetabular anteversion and acetabular inclination in the patients with childhood specific hip disease. Additionally, it will also help us to make operation plans pertaining to the hip.