Influence of loading condition and anatomical location on human cortical bone linear micro-cracks

• Published in: Journal of biomechanics Vol. 85; no. 4; pp. 59 - 66
• Main Authors: Gauthier, Rémy, Langer, Max, Follet, Hélène, Olivier, Cécile, Gouttenoire, Pierre-Jean, Helfen, Lukas, Rongiéras, Frédéric, Mitton, David, Peyrin, Françoise
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 06-03-2019; Elsevier Limited; Elsevier
• Subjects: Accidental Falls; Aged; Biomechanics; Computed tomography; Cortical bone; Cortical Bone - diagnostic imaging; Cortical Bone - pathology; Crack initiation; Crack propagation; Diaphyses - diagnostic imaging; Diaphyses - pathology; Engineering Sciences; Female; Femur; Femur - diagnostic imaging; Femur Neck - diagnostic imaging; Fracture mechanics; Fracture toughness; Fractures; Fractures, Bone - diagnostic imaging; Human cortical bone; Humans; Inter-site; Mechanical loading; Mechanical properties; Mechanics; Medical imaging; Micro-cracks; Microcracks; Middle Aged; Morphology; Neck; Pressure; Propagation; Radius - diagnostic imaging; Strain rate; Studies; Synchrotron radiation; Tomography, X-Ray Computed; Toughening; X-Ray Microtomography; Micro-cracks; Computed tomography; Synchrotron radiation; Inter-site; Human cortical bone; Strain rate
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2019.01.008

Human cortical bone fracture toughness depends on the anatomical locations under quasi-static loading. Recent results also showed that under fall-like loading, cortical bone fracture toughness is similar at different anatomical locations in the same donor. While cortical bone toughening mechanisms are known to be dependent on the tissue architecture under quasi-static loading, the fracture mechanisms during a fall are less studied. In the current study, the structural parameters of eight paired femoral diaphyses, femoral necks and radial diaphyses were mechanically tested under quasi-static and fall-like loading conditions (female donors, 70 ± 14 y.o., [50–91 y.o.]). Synchrotron radiation micro-CT imaging was used to quantify the amount of micro-cracks formed during loading. The volume fraction of these micro-cracks was significantly higher within the specimens loaded under a quasi-static condition than under a loading representative of a fall. Under fall-like loading, there was no difference in crack volume fraction between the different paired anatomical locations. This result shows that the micro-cracking toughening mechanism depends both on the anatomical location and on the loading condition.