Regional characteristics of cortical bone quality in the proximal humerus of postmenopausal women: a preliminary study

Abstract

Proximal humeral fractures represent the third most common fragility fracture treated in osteoporotic populations, after hip and distal radial fractures. The purpose of this study was to characterize the spatial variability in cortical geometry in the proximal humerus in postmenopausal women. The proximal humeri in 43 healthy postmenopausal women were imaged by computed tomography. Cortical bone mapping was applied to create color 3-dimensional thickness maps for each proximal humerus. Cortical parameters, including the cortical thickness (CTh), cortical mass surface density (CM), and endocortical trabecular density, were measured over the humeral head and metaphyseal region after 15 regions of interest (ROIs) were defined. In the humeral head region, significant differences in CTh and CM values were detected between the anterior, lateral, and posterior walls (P < .05). The highest CTh and CM were found in the anterior wall in each plane (P < .05). Regarding the endocortical trabecular density, no significant findings were noted in the 3 planes (P > .05). In the metaphyseal region, the cortical structure in the medial column had higher CTh and CM values in ROI 10 compared with the lateral column (P < .05). The highest CTh and CM values of compact bone were seen in ROI 10 of the medial column (ROIs 10-12) (P < .05). Our results showed significant regional variation of cortical bone in the humeral head region in postmenopausal women. Similar conditions were seen in the medial column in the metaphyseal region. This finding provides discriminatory information for stronger fixation of implants.