Reducing the radiation sterilization dose improves mechanical and biological quality while retaining sterility assurance levels of bone allografts

Huynh Nguyen, Cassady, Alan I., Bennett, Michael B., Gineyts, Evelyne, Wu, Andy, Morgan, David A. F. and Forwood, Mark R. (2013) Reducing the radiation sterilization dose improves mechanical and biological quality while retaining sterility assurance levels of bone allografts. Bone, 57 1: 194-200. doi:10.1016/j.bone.2013.07.036


Author Huynh Nguyen
Cassady, Alan I.
Bennett, Michael B.
Gineyts, Evelyne
Wu, Andy
Morgan, David A. F.
Forwood, Mark R.
Title Reducing the radiation sterilization dose improves mechanical and biological quality while retaining sterility assurance levels of bone allografts
Journal name Bone   Check publisher's open access policy
ISSN 8756-3282
1873-2763
Publication date 2013-11-01
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.bone.2013.07.036
Open Access Status
Volume 57
Issue 1
Start page 194
End page 200
Total pages 7
Place of publication Philadelphia, PA, United States
Publisher Elsevier
Language eng
Formatted abstract
Background: Bone allografts carry a risk of infection, so terminal sterilization by gamma irradiation at 25 kGy is recommended; but is deleterious to bone quality. Contemporary bone banking significantly reduces initial allograft bioburden, questioning the need to sterilize at 25 kGy.
Methods: We inoculated allograft bone with Staphylococcus epidermidis and Bacillus pumilus, then exposed them
to gamma irradiation at 0, 5, 10, 15, 20 and 25 kGy. Mechanical and biological properties of allografts were also
assessed. Our aimwas to determine an optimal dose that achieves sterility assurance whileminimizing deleterious
effects on allograft tissue.
Results: 20–25 kGy eliminated both organisms at concentrations from101 to 103 CFU, while 10–15 kGy sterilized bone samples to a bioburden concentration of 102 CFU. Irradiation did not generate pro-inflammatory bone surfaces, as evidenced bymacrophage activation, nor did it affect attachment or proliferation of osteoblasts. At doses ≥10 kGy, the toughness of cortical bone was reduced (P <0.05), and attachment and fusion of osteoclasts onto irradiated bone declined at 20 and 25 kGy (P < 0.05). There was no change in collagen cross-links, but a significant dose-response increase in denatured collagen (P < 0.05).
Conclusions: Ourmechanical and cell biological data converge on 15 kGy as a threshold for radiation sterilization of bone allografts. Between 5 and 15 kGy, bone banks can undertake validation that provides allografts with an acceptable sterility assurance level, improving their strength and biocompatibility significantly.
Clinical relevance: The application of radiation sterilization doses between 5 and 15 kGy will improve bone allograft mechanical performance and promote integration,while retaining sterility assurance levels. Improved quality of allograft bone will promote superior clinical outcomes.
Keyword Allograft bone
Arthroplasty
Biomechanics
Osteoblast
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Biomedical Sciences Publications
 
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