TY - JOUR
T1 - Microdamage distribution in fatigue fractures of bone allografts following gamma-ray exposure
AU - Presbítero, Gerardo
AU - Hernandez-Rodríguez, Marco A.L.
AU - Contreras-Hernandez, Geo R.
AU - Vilchez, José Félix
AU - Susarrey, Orlando
AU - Gutiérrez, David
N1 - Publisher Copyright:
© 2018, Institute of Machine Design and Operation. All rights reserved.
PY - 2017
Y1 - 2017
N2 - Purpose: Although significant differences in bone properties have been extensively studied, results vary when bones are exported to gamma radiation of a range usually used for sterilization purposes (25–35 kGy). Hence, the aim of this work was the study of the mechanical properties and microdamage development of human bones used as allografts following gamma-ray exposure, followed by an extensive statistical analysis of microdamage effects in fatigue behaviour. Methods: Specimens of the cortical region of human femurs were exposed to 15–25 kGy and 26–30 kGy radiation levels, then they were subjected to compression fatigue tests until fracture. The fatigue life was determined in relation to the radiation level, and the evolution of microdamage was assessed using fluorescence microscopy in order to calculate characteristic lengths of microcracks. Results: Significant differences in fatigue life were detected (p < 0.05) between non-radiated (control) and radiated specimens, resulting in a drastic 89.2% fatigue life reduction of the 15–25 kGy group, and 95.3% in the 26–30 kGy group, compared to the reference. Microdamage analysis showed a considerable increase in microcrack lengths when bone was exposed to gamma radiation, which may indicate that bones used as allografts could fracture at some point when subjected to loading conditions in vivo. Conclusions: The results of our research indicate that even if a range of 15–25 kGy is suggested to sterilize bone allografts, such practice needs to be reconsidered. In addition, using Weibull distribution, this work describes the conditions in which microcracks grow towards the fracture of bones in relation to the decrease in their mechanical properties.
AB - Purpose: Although significant differences in bone properties have been extensively studied, results vary when bones are exported to gamma radiation of a range usually used for sterilization purposes (25–35 kGy). Hence, the aim of this work was the study of the mechanical properties and microdamage development of human bones used as allografts following gamma-ray exposure, followed by an extensive statistical analysis of microdamage effects in fatigue behaviour. Methods: Specimens of the cortical region of human femurs were exposed to 15–25 kGy and 26–30 kGy radiation levels, then they were subjected to compression fatigue tests until fracture. The fatigue life was determined in relation to the radiation level, and the evolution of microdamage was assessed using fluorescence microscopy in order to calculate characteristic lengths of microcracks. Results: Significant differences in fatigue life were detected (p < 0.05) between non-radiated (control) and radiated specimens, resulting in a drastic 89.2% fatigue life reduction of the 15–25 kGy group, and 95.3% in the 26–30 kGy group, compared to the reference. Microdamage analysis showed a considerable increase in microcrack lengths when bone was exposed to gamma radiation, which may indicate that bones used as allografts could fracture at some point when subjected to loading conditions in vivo. Conclusions: The results of our research indicate that even if a range of 15–25 kGy is suggested to sterilize bone allografts, such practice needs to be reconsidered. In addition, using Weibull distribution, this work describes the conditions in which microcracks grow towards the fracture of bones in relation to the decrease in their mechanical properties.
KW - Allografts
KW - Cortical bone
KW - Fatigue fracture
KW - Gamma radiation
KW - Microdamage
KW - Weibull distribution
UR - http://www.scopus.com/inward/record.url?scp=85041522933&partnerID=8YFLogxK
U2 - 10.5277/ABB-00824-2017-04
DO - 10.5277/ABB-00824-2017-04
M3 - Artículo
SN - 1509-409X
VL - 19
SP - 43
EP - 53
JO - Acta of Bioengineering and Biomechanics
JF - Acta of Bioengineering and Biomechanics
IS - 4
ER -