Effects Of Gamma Irradiation And Repetitive Freeze-thaw Cycles On The Biomechanical Properties Of Human Tendon

Objective: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.Methods: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 was25kGy. Each freeze-thaw cycle consisted of freezing at-80℃for7day and thawing at25℃for6h. These tendons underwent4freeze-thaw cycles. Biomechanical properties were analyzed during load-to-failure testing.Results: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 (4cycles) can change the biomechanical properties. However, no significant difference was found between these two processes on the effect of biomechanical properties. Conclusion:It is recommended that gamma irradiation (25kGy) and repetitive freeze-thaw cycles (4cycles) should not be adopted in the processing of the allograft tendons.