title: Effects of (60)Co gamma radiation dose on initial structural biomechanical properties of ovine bone--patellar tendon--bone allografts.
abstract: Gamma radiation is established as a procedure for inactivating bacteria, fungal spores and viruses. Sterilization of soft tissue allografts with high dose (60)Co gamma radiation has been shown to have adverse effects on allograft biomechanical properties. In the current study, bone-patellar tendon-bone (BPTB) allografts from 32 mature sheep were divided into two treatment groups: low-dose radiation at 15 kGy (n = 16) and high-dose radiation at 25 kGy (n = 16) with the contralateral limb serving as a 0 kGy (n = 32) non-irradiated control. Half of the tendons from all treatment groups were biomechanically tested to determine bulk BPTB mechanical properties, cancellous bone compressive properties, and interference screw pull-out strength. The remaining tissues were prepared, implanted, and mechanically tested in an acute in vitro anterior crucial ligament (ACL) reconstruction. Low-dose radiation did not adversely affect mechanical properties of the tendon allograft, bone, or ACL reconstruction compared to internal non-irradiated control. However, high-dose radiation compromised bulk tendon load at failure and ultimate strength by 26.9 and 28.9%, respectively (P < 0.05), but demonstrated no negative effect on the cancellous bone compressive properties or interference screw pull-out strength. Our findings suggest that low dose radiation (15 kGy) does not compromise the mechanical integrity of the allograft tissue, yet high dose radiation (25 kGy) significantly alters the biomechanical integrity of the soft tissue constituent.
authors.affiliation: Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523-1374, USA.
authors.forename: Kirk C
authors.initials: KC
authors.lastname: McGilvray
authors.forename: Brandon G
authors.initials: BG
authors.lastname: Santoni
authors.forename: A Simon
authors.initials: AS
authors.lastname: Turner
authors.forename: Simon
authors.initials: S
authors.lastname: Bogdansky
authors.forename: Donna L
authors.initials: DL
authors.lastname: Wheeler
authors.forename: Christian M
authors.initials: CM
authors.lastname: Puttlitz
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000528:radiation effects; D016025:Bone Transplantation; D001842:Bone and Bones / Q000528:radiation effects*; D005720:Gamma Rays; D017847:Patellar Ligament / Q000528:radiation effects* / Q000637:transplantation*; D012756:Sheep / Q000601:surgery*; D013242:Sterilization / Q000379:methods*