Towards patient‐specific material modeling of trabecular bone post‐yield behavior

Abstract

Bone diseases such as osteoporosis are one of the main causes of bone fracture and often result in hospitalization and long recovery periods. Researchers are aiming to develop new tools that consider the multiple determinants acting at the different scales of bone, and which can be used to clinically estimate patient-specific fracture risk and also assess the efficacy of new therapies. The main step towards this goal is a deep understanding of the bone organ, and is achieved by modeling the complexity of the structure and the high variability of the mechanical outcome. This review uses a hierarchical approach to evaluate bone mechanics at the macroscale, microscale, and nanoscale levels and the interactions between scales. The first section analyzes the experimental evidence of bone mechanics in the elastic and inelastic regions, microdamage generation, and post-yield toughening mechanisms from the organ level to the ultrastructural level. On the basis of these observations, the second section provides an overview of the constitutive models available to describe bone mechanics and predict patient-specific outcomes. Overall, the role of the hierarchical structure of bone and the interplay between each level is highlighted, and their effect is evaluated in terms of modeling biological variability and patient specificity.

Nanostructure and elastic modulus of single trabecula in bovine cancellous bone

“…The mechanical properties of a single trabecula that constitutes trabecular networks and their nanostructure composed of hydroxyapatite (HAp) crystals and collagen fibrils are important factors in determining the mechanical properties of the cancellous bone. However, only a few 5/44 studies have performed mechanical tests of a single trabecula because the mechanical tests of such small specimens are challenging, as reviewed by Carretta et al (2013a) and Lucchinetti et al (2000). Furthermore, the nanostructural effects on the mechanical properties of a single trabecula have not been investigated and elucidated, although various studies have been conducted on multiscale mechanical characterization in the cortical bone (e.g., Barkaoui et al, 2014;Tadano and Giri, 2011;Feng and Jasiuk, 2011;Gibson et al, 2006;Hoc et al, 2006).…”

From Sméagol to Gollum: Mechanical Stress and Bone Remodelling

“…pattern is yet to be discovered, although having a pattern in concentric fashion may provide substantial strength due to the alternating orientation of collagen fibrils [12]. In addition to trabeculae, the multiple bone packets are oriented parallel to the mutual line of stress but can realign their orientation of fibres if direction of stress alters accordingly [5]. Hence, as new bone is being formed, mechanical stress improves bone strength by influencing alignment of fibrils.…”

“…The mechanical aptitude of the bone's quality is reliant on material conformation of the bone's composite; geometry and architecture of the bone's network; and remodelling process repairing microdamage. These characteristics are influenced by external aspects like adaptation to the load itself and internal aspects like disease or aging [5].…”

“…Trabecular bone exhibits elastic properties due to its intriguing morphological arrangement [5] but can withstand stress according to the alignment of fibre matrix [1]. The stiffness of bone correlates rather well to tissue mineralization according to compression and bending tests conducted on cortical bone [6] and in fact cortical bone can withstand stress in compression better than in tension [1].…”

Micro-cantilever bending for elastic modulus measurements of a single trabecula in cancellous bone

“…Accordingly, small bone specimens such as 50 a single trabecula must be investigated to understand the impact of aging, osteoporosis, 51 and/or medicines on the risk of cancellous bone fractures. However, few studies have 52 performed mechanical tests on such specimens (Carretta et al, 2013a;Lucchinetti et al, 53 2000) because such studies remain technically challenging.…”