Mechanical Characterization of Bone: State of the Art in Experimental Approaches—What Types of Experiments Do People Do and How Does One Interpret the Results?

Abstract

Quasi-static tests are the most commonly used for determining the resistance to structural failure by a single load at the organ (whole bone) level. The resistance to crack initiation or growth by fracture toughness testing and fatigue loading offers additional and more direct characterization of tissue material properties. Non-traditional indentation techniques and in situ testing are being increasingly used to probe the material properties of bone ultrastructure. Destructive ex vivo testing or clinical surrogate measures are considered to be the gold standard for estimating fracture risk. The type of mechanical test used for a particular investigation depends on the length scale of interest, where the outcome variables are influenced by the interrelationship between bone structure and composition. Advancement in the sensitivity of mechanical characterization techniques to detect changes in bone at the levels subjected to modifications by aging, disease, and/or pharmaceutical treatment is required. As such, a number of techniques are now available to aid our understanding of the factors that contribute to fracture risk.

Short‐term caloric restriction induced bone loss in both axial and appendicular bones by increasing adiponectin

“…The three-point bending test characterizes the extrinsic mechanical properties of cortical bone. 27 So, it is reasonable to suggest that cortical bone may be impaired, although we do not have the other parameters due to technical problems. And the result of compression testing is primarily affected by apparent density, BV/TV, and the size and distribution of trabecular struts.…”

“…And the result of compression testing is primarily affected by apparent density, BV/TV, and the size and distribution of trabecular struts. 27 Decreased mechanical results can be explained by the damaged microstructure of vertebral bodies. In addition, a previous study showed a correlation between bone mechanical properties and composition parameters.…”

In Vivo Assessment of Cortical Bone Fragility

“…FP (Type 1) errors drive up cost by administering preventive care to patients who do not need it; and FN (Type 2) errors drive up cost by withholding preventive care from patients who do need it and then require treatment for fracture repair. Increasing attention to these disappointing observations [11,12] has led to widening agreement that "new methods for assessing bone health are required, beyond characterization of mineral density" [4,13]. We suggest that FPR and FNR be the metrics by which such new methods are judged.…”

“…Because CBMT is a whole bone test, its measurements reflect the sum total of all factors operating at all hierarchical levels of the ulna, from whole bone geometry to tissue material properties and composition, porosity, microarchitecture, and nanoscale collagen cross-linking and protein-mineral bonding [4]. Thus, CBMT captures the influences of bone quality as well as bone quantity on the ulna's load-bearing capacity, however, that may have been affected by genetics, modeling, remodeling, nutrition, activity, aging, disease, pharmacological intervention, etc.…”

Bone Density Micro-CT Assessment during Embedding of the Innovative Multi-Spiked Connecting Scaffold in Periarticular Bone to Elaborate a Validated Numerical Model for Designing Biomimetic Fixation of Resurfacing Endoprostheses

“…Huang et al [21] used finite element analysis and computer tomography imaging to investigate bone stresses surrounding a dental implant; Du et al [22] placed dental implants in a human cadaver mandible, and then detailed the geometry of trabecular structures and implants with micro-CT imaging, and subsequently, the stress and strain distributions in the bone under implant loading were computed and compared with prior experimental discoveries. The advantage of micro-CT imaging is that it does not damage a bone sample, and therefore changes in bone structure can be accurately examined [23,24].…”