title: Effects of gamma irradiation and repetitive freeze-thaw cycles on the biomechanical properties of human flexor digitorum superficialis tendons.
abstract: An increasing number of tissue banks have begun to focus on gamma irradiation and freeze-thaw in the reconstruction of anterior cruciate ligaments using allografts. The purpose of this study was to evaluate the biomechanical properties of human tendons after exposure to gamma radiation and repeated freeze-thaw cycles and to compare them with fresh specimens. Forty flexor digitorum superficialis tendons were surgically procured from five fresh cadavers and divided into four groups: fresh tendon, gamma irradiation, freeze-thaw and gamma irradiation+freeze-thaw. The dose of gamma irradiation was 25 kGy. Each freeze-thaw cycle consisted of freezing at -80 °C for 7 day and thawing at 25 °C for 6 h. These tendons underwent 4 freeze-thaw cycles. Biomechanical properties were analyzed during load-to-failure testing. The fresh tendons were found to be significantly different in ultimate load, stiffness and ultimate stress relative to the other three groups. The tendons of the gamma+freeze-thaw group showed a significant decrease in ultimate load, ultimate stress and stiffness compared with the other three groups. Gamma irradiation and repeated freezing-thawing (4 cycles) can change the biomechanical properties. However, no significant difference was found between these two processes on the effect of biomechanical properties. It is recommended that gamma irradiation (25 kGy) and repetitive freeze-thaw cycles (4 cycles) should not be adopted in the processing of the allograft tendons.
authors.affiliation: Department of Orthopaedics, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China. rendejie@163.com
authors.forename: Dejie
authors.initials: D
authors.lastname: Ren
authors.forename: Kang
authors.initials: K
authors.lastname: Sun
authors.forename: Shaoqi
authors.initials: S
authors.lastname: Tian
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
authors.forename: Cailong
authors.initials: C
authors.lastname: Zhang
authors.forename: Wenhao
authors.initials: W
authors.lastname: Wang
authors.forename: Hongjie
authors.initials: H
authors.lastname: Huang
authors.forename: Jihua
authors.initials: J
authors.lastname: Zhang
authors.forename: Yujie
authors.initials: Y
authors.lastname: Deng
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D015925:Cryopreservation / Q000379:methods*; D005615:Freezing; D005720:Gamma Rays; D006801:Humans; D008297:Male; D013710:Tendons; D016474:Weight-Bearing