Finite element modelling
C M Langton, C F Njeh in The Physical Measurement of Bone, 2016
At the bone organ level, bone is considered as a continuous material with material properties that represent the average properties of a representative bone volume. At this level, two types of bone are distinguished: cortical bone and cancellous bone. The latter type is the porous type of bone which is often referred to as trabecular bone. In this chapter, however, the term cancellous bone is used when the continuum level properties of this type of bone are considered, whereas the term trabecular bone will be used when this type of bone is considered as a discontinuous porous structure. For cortical bone, a representative volume can be rather small (∼1 mm3). For cancellous bone regions, however, a representative volume must hold a large enough number of trabeculae in order to provide sufficiently averaged continuum quantities. It has been stated that a representative volume of cancellous bone should be at least five inter-trabecular lengths in size (approximately 3–5 mm) [26]. It is not possible to define meaningful continuum-level elastic properties for cancellous bone volumes smaller than this minimum size. A typical length scale associated with this level thus is of the size of a few millimetres.
Osteoporosis
Maria A. Fiatarone Singh, John Sutton Chair in Exercise, Nutrition, and the Older Woman, 2000
In one year approximately 40% of trabecular bone goes through this remodeling process, compared to 10% of cortical bone, despite the fact that we have about four times more cortical bone than trabecular bone. It is speculated that because trabecular bone is more fragile than cortical bone it may need to be replaced more frequently to repair microfractures in the trabecular network which have been sustained by normal loading, trauma, or pathologic processes. The spongy structure of trabecular bone also provides a greater surface area for the bone-removing osteoclasts to attach and begin breaking down bone cells. The fragility of trabecular bone is indicated by the preponderance of osteoporotic fractures at the wrist, spine and hip, which have greater amounts of trabecular bone than the mid-sections of the appendicular bones.
Osteoporotic os calcis fractures
Peter V. Giannoudis, Thomas A. Einhorn in Surgical and Medical Treatment of Osteoporosis, 2020
Trabecular bone is a metabolically active tissue that shows changes in composition with aging or loading, in keeping with Wolff's law (10). The age-related changes are similar to other anatomical sites such as the distal radius, proximal femur, and vertebrae (9). There are changes in mineral composition as well as microstructure, but the structural changes are the most striking. Rupprecht showed that based on direct histomorphometric data, the calcaneus undergoes age-related loss of bone throughout, but that it is most evident beneath the posterior facet of the subtalar joint (1). Interestingly, this study also showed a higher trabecular density under the posterior facet in males but similar densities elsewhere between the sexes. The maximal rate of bone loss in females occurred between the 20–40 years and the 40–60 years age brackets, whereas in males it was between the 40–60 years and 60–80 years age groups. Other studies have demonstrated similar findings, with Ensrud noting a significant loss in the calcaneus bone mineral density after the age of 75 years in both men and women (11), and Mitchell stating that calcaneus bone mineral density loss increases with advancing age in elderly women (12).
Effects of osthole on osteoporotic rats: a systematic review and meta-analysis
Published in Pharmaceutical Biology, 2022
Bin Wu, Xiu-Fang Zhu, Xiao-Qiang Yang, Wei-Yi Wang, Jian-Hua Lu
Bone strength depends on bone mass and bone quality (Fonseca et al. 2014). BMD measured by dual-energy X-ray absorptiometry is the standard for diagnosis of osteoporosis and for determining treatment (Curry et al. 2018). BMD refers to the amount of bone mass per unit volume or area, i.e., the amount of bone tissue and bone matrix, osteoporosis is characterized by low BMD (Eastell et al. 2016). Trabecular bone volume fraction reflects the bone mass; trabecular thickness and number reflect the variation in bone mass. Trabecular separation represents the structure of trabeculae and is closely related to bone mass. Bone biomechanical parameters are the most direct indicators of bone quality and are used to assess the bone strength (Díaz et al. 2016). The results of this meta-analysis suggest that osthole improves the above-mentioned parameters and has a therapeutic effect on osteoporotic rats.
Bone Turnover Markers and Bone Histomorphometry in Pubertal Rats with Intrauterine Growth Restriction
Published in Fetal and Pediatric Pathology, 2021
Kaiju Luo, Pingyang Chen, Mingfeng He, Yonghui Yang, Juncao Chen, Tao Wang
After removal the left femur was scanned using the little animal ZKKS-Sharp-MCT micro-CT system (Zhongke Kaisheng Medical Technology CO., Ltd, Guangzhou, China) with cone scanning and three-dimensional reconstruction. The scanning parameters were as follows: tube tension 60 KVp, power 40 w, turning angle 0.72, exposure time 2400 s, angle gain 0.4°, isotopism resolution 20 μm × 20 μm × 20 μm voxel. A standard phantom was scanned simultaneously to adjust the CT value. After complete reconstruction of the femurs, we examined reconstructive images and identified the region of interest (ROI) which was a 3.35 mm × 8 mm × 0.9 mm cuboidal region about 1 mm below the epiphyseal line. The ROI was reconstructed with 15 μm × 15 μm × 15 μm voxels to produce three dimensional images for quantitative measurement. Then we extracted image information using the mean threshold of the femurs in the control group (lowest 450), discarded the non-trabecular part and only retained the trabecular portion. The bone histomorphometry parameters were acquired by running the micro-CT system with Medproject 4.1. The quantitative bone histomorphometry parameters in our study were bone mass parameters including bone volume fraction (BVF), bone mineral content (BMC), bone mineral density (BMD) and trabecular microstructure parameters including trabecular number (Tb.N), trabecular separation (Tb.Sp), trabecular thickness (Tb.Th), and trabecular bone pattern factor (Tb.Pf).
Effect of metastatic lesion size and location on the load-bearing capacity of vertebrae using an optimized ash density-modulus equation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Sebastian Saldarriaga, Simon Jimenez Cataño, Asghar Rezaei, Hugo Giambini
The current study investigated the effect of lesion size and location within the vertebral body on fracture properties using the optimum coefficients obtained during the inverse QCT/FEA optimization process. Furthermore, these effects were evaluated for both sexes using subject-specific models. The larger effect in fracture properties was observed when the lesion was located in the center of the vertebra. The extent of reduction in the fracture load-bearing capacity of the vertebrae was significant at this location compared to the other regions. These results align well with previous research stating that a deterioration of the vertebral trabecular bone has a significant effect in fracture properties. Using axial rigidity analysis, Oppenheimer-Velez et al. (2018) showed trabecular bone to pose a significant and greater effect, about ∼70%, on the structural integrity of vertebrae as compared to cortical bone. Homminga et al. (2004, 2001) showed trabecular bone to carry about 50–70% of the total vertebral load. The current study also demonstrated a significant decrease in fracture loads on vertebrae presenting a lesion in the trabecular bone region, indicating trabecular bone to be at a higher risk of fracture.