Evaluation of the Effect of Freezing and Gamma Irradiation on Different Types of Tendon Allografts by DIC Assisted Tensile Testing

Abstract

This study aimed to evaluate the changes in the endurance properties of four types of tendons caused by freezing and gamma irradiation. Four types of grafts were harvested: quadriceps, semitendinosus + gracilis, tibialis anterior, and peroneus longus. These were put into three groups: Group A was the control group, tested without freezing or irradiation. Grafts in Group B were frozen and irradiated (target dose: 21 kGy), while grafts in Group C were again frozen and irradiated (target dose: 42 kGy). Maximum load, tensile modulus, tensile strength, strain at maximum force and fracture strain were calculated from the force-elongation graphs of cyclic load tests. The higher gamma irradiation dose (Group C) significantly decreased the strains at tensile strength of the quadriceps tendons (p = 0.0004–0.0237), compared to the other two groups. In the case of the quadricep tendons (p = 0.0151), there is a significant decrease in Young’s modulus after gamma irradiation with the dose of 42 kGy. According to the results of the study, the tibialis anterior and the peroneus longus are recommended in ACL reconstruction when gamma irradiation is required, while quadricep tendons, which are usually used for an autograph, are not suitable for allograft reconstruction after gamma irradiation from the viewpoint of mechanical properties.