Bone Abstracts

Study aim: The general assumption that changes in bone microstructure and material properties at the iliac crest are representative of skeletal sites that are susceptible to osteoporotic fracture has not yet been addressed. Therefore, our study aim was to perform a comparative analysis of bone microarchitecture, accumulated microdamage and osteocyte morphology between the iliac crest, proximal femur and vertebral body.

Methods: Trabecular bone cores were obtained from the iliac crest, proximal femur (intertrochanteric region) and T12 vertebral body (central region) from seven postmenopausal female cadavers, aged 70–98 years (mean 79±9 years), with no history of disease/medication that may have affected bone turnover. All bone cores were micro-CT imaged for 3D microarchitecture, then divided lengthwise for histomorphometric assessment of microdamage and osteocyte morphology.

Results: BV/TV, Tb.N, and DA were lower for vertebral bone compared to iliac crest (P<0.05). Other architectural parameters were not different between sites. Microcrack, crack surface and diffuse damage density were higher in vertebral vs iliac crest and proximal femur bone (P<0.01). Crack lengths were similar between vertebral and femoral bone, with both sites higher vs iliac crest (P<0.05). Osteocyte, empty lacunar and total lacunar densities were not different between sites. Percent empty lacunae was increased in iliac crest vs femoral bone (P<0.05).

Conclusions: There is variability in trabecular bone microarchitecture, damage accumulation and osteocyte morphology between skeletal sites. Vertebral trabecular bone is typified by microarchitectural decay and microcrack and diffuse damage accumulation, suggesting that the vertebral body is structurally and functionally compromised in the aged postmenopausal skeleton.