Bone Abstracts

While a strong emphasis has been put on the characteristics of trabecular bone due to its’ high metabolic rate, the human skeleton actually consists of ~80% cortical bone. Furthermore, the cortical bone supports a major proportion of the mechanical load (i.e. upto 96%) at common fracture sites, such as the base of the femoral neck and the intertrochanteric region. In these regions of the hip, large compressive stresses concentrate during walking as well as during falls and may result in bone fracture. Bone’s ability to resist fracture originates from the quality of the trabecular and cortical compartments. Bone quality encompasses many aspects of the bone’s state including the multi-length-scale composition, mass, architecture, microdamage, bone turnover and osteocytic mechanosensitivity. When aspects of the bone quality are altered due to disease-specific disorders, the risk of fracture may be attributed to changes in bone quality endangering the bone’s normal organization and is particularly relevant in cases with diseased bone and its subsequent treatment. Here, our data shows how osseous and cellular characteristics of the cortical compartment vary with age, disease and treatment strategies (e.g. osteoporosis, vitamin D-deficiency, Paget’s disease of bone, bisphosphonate treatment, total hip replacement, etc.) and may influence the risk of bone fracture. To assess changes in bone quality across bone’s hierarchical structure, a combination of techniques was carried out at the nano- to micron-level including 2D histomorphometry, 3D-microcomputed tomography, scanning electron microscopy/backscattered electron microscopy, Raman spectroscopy, Fourier transform infrared microscopy, micro-mechanical and materials testing. In this presentation, summarized findings emphasize how the structure of mineralized bone including the underlying osteocytic network, bone’s composition, as well as the mineral and collagen distribution may influence changes in the bone quality framework and the risk of fracture in a cohort of subjects suffering from skeletal aging, major bone diseases and/or pharmacologic treatment.