Three-dimensional distribution of bone density in the proximal humerus

Bone quality of the proximal humerus is important for the surgical treatment of proximal humeral fractures and rotator cuff tears. However, very few studies have evaluated the a real bone mineral density (BMD) of the proximal humerus. The aim of this study was to analyze the volumetric BMD (vBMD) using peripheral-quantitative-computed-tomography. Total, trabecular and cortical vBMD were determined separately for the proximal and distal half of the humeral head, the surgical neck and seven specific regions of interest. The greater tuberosity (GT) was divided into three regions, and the lesser tuberosity (LT) and articular surface (AS) were each divided into two regions. The proximal head showed a significantly higher trabecular (+46%) and cortical vBMD (+15%) than the distal one. The mean trabecular vBMD of AS was significantly higher (+80%), and the cortical vBMD was significantly lower (-11%) than that of the tuberosities. In the proximal half of GT, trabecular vBMD was higher in the posterior than in the middle and anterior regions. Cortical vBMD was higher in middle region than in the anterior and posterior ones. In the distal half of GT, trabecular vBMD was significantly higher in the posterior than in the middle region, and cortical vBMD was significantly higher in the anterior than in the middle region. In the proximal half of AS, trabecular vBMD was significantly higher in the posterior region than in the anterior one. These results point to bone sites that may provide stronger fixation for implants, reduce the risk of implant loosening, and therefore improve patient outcome.