Regional Distribution of Bone Mineral Density in the Pubic Symphysis: A Study of Sex and Age Differences

Background The subchondral bone (SCB) remodels in response to long-term mechanical loading, with mineralisation patterns reflecting chronic stress. Computed tomography osteoabsorptiometry (CT-OAM) enables non-invasive visualisation of these adaptations. While CT-OAM has been widely applied to several joints, its use in the pubic symphysis is limited. This study aimed to identify sex- and age-related differences in mineralisation patterns and quantify bone mineral density (BMD) distribution across the symphyseal surfaces. Methods CT scans from 85 individuals (51 males, 34 females; age range 18–97 years) were analysed, generating 170 symphyseal surfaces. Segmented three-dimensional reconstructions were processed into HU-based densitograms. Mineralisation was classified qualitatively into three patterns: diffuse across the surface (Pattern 1), ventral border with/without inferior apex involvement (Pattern 2), and dorsal border with/without inferior apex involvement (Pattern 3). Quantitatively, each surface was subdivided into six anatomical subregions, and mean HU values were compared by sex, side, and age. Results Across all specimens, Pattern 2 predominated (58%), with Pattern 2 most frequent in males (76%) and Pattern 3 in females (55%). High bilateral conformity (81%) was observed. Males exhibited significantly higher mean HU values than females (554 ± 180 HU vs. 374 ± 111 HU, p < 0.01), with greater BMD across all subregions. Region-specific analyses revealed highest mineralisation anteriorly and inferiorly in males, while females displayed increased posterior mineralisation. No significant correlation was found between overall BMD and age; however, females demonstrated a weak negative correlation in the ventral middle region (r = − 0.24, p < 0.05). Conclusion This study provides the first systematic CT-OAM analysis of pubic symphyseal SCB mineralisation. Findings highlight sex-specific patterns, with males demonstrating greater anterior and inferior mineralisation, and females exhibiting posterior dominance. Males also displayed higher overall BMD, reflecting greater chronic loading. These results deepen understanding of pelvic biomechanics and may inform future research on conditions such as osteitis pubis.