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Age‐related factors affecting the postyield energy dissipation of human cortical bone
Author(s) -
Nyman Jeffry S.,
Roy Anuradha,
Tyler Jerrod H.,
Acuna Rae L.,
Gayle Heather J.,
Wang Xiaodu
Publication year - 2007
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20337
Subject(s) - pentosidine , dissipation , cortical bone , elastic energy , stiffness , materials science , composite material , ultimate tensile strength , chemistry , biomedical engineering , anatomy , medicine , biochemistry , physics , receptor , quantum mechanics , glycation , thermodynamics
The risk of bone fracture depends in part on tissue quality, not just the size and mass. This study assessed the postyield energy dissipation of cortical bone in tension as a function of age and composition. Specimens were prepared from tibiae of human cadavers in which male and female donors were divided into two age groups: middle aged (51 to 56 years, n = 9) and elderly (72 to 90 years, n = 8). By loading, unloading, and reloading a specimen with rest periods inserted in between, tensile properties at incremental strain levels were assessed. In addition, postyield toughness was estimated and partitioned as plastic strain energy related to permanent deformation, released elastic strain energy related to stiffness loss, and hysteresis energy related to viscous behavior. Porosity, mineral and collagen content, and collagen crosslinks of each specimen were also measured to determine the micro‐ and ultrastructural properties of the tissue. Age affected all the energy terms plus strength but not elastic stiffness. The postyield energy terms were correlated with porosity, pentosidine (a marker of nonenzymatic crosslinks), and collagen content, all of which varied significantly with age. General linear models suggested that pentosidine concentration and collagen content provided the best explanation of the age‐related decrease in the postyield energy dissipation. Among them, pentosidine concentration had the greatest contribution to plastic strain energy and was the best explanatory variable of damage accumulation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:646–655, 2007