Zhou Zongke, Qin Tingwu, Yang Jing, Shen Bin, Kang Pengde, Peil Fuxing
Department of Orthopaedic Surgery, West China Hospital of Sichuan University, Chengdu, China.
Acta Orthop Belg. 2011 Oct;77(5):670-5.
We investigated the effects of gamma irradiation versus ethylene oxide (ETO) sterilization on the mechanical strength of cortical bone grafts. Tibias were collected from cadavers of mature goats. Sixty test specimens were randomized into four groups: fresh (no processing), frozen (freezing at -70 degrees C), gamma-irradiated, and ETO-sterilized specimens. Torsion, three-point bending, and compression testing were separately performed with a material testing machine. Parameters studied included maximum stress, strain, deflection, extension, load, shear modulus, and E-modulus. Compared with findings for the fresh specimens, findings were as follows for gamma-irradiated specimens: maximal shear modulus, reduced by 48%; shear stress, by 55%; deflection, by 71%; bending stress, by 51%; bending strain, by 74%; extension, by 60%; and compression strain, by 50%. However, there were no reductions in those parameters for the frozen specimens or the ETO-sterilized specimens. These findings confirm that shear, bending, and compression strength of cortical allografts are weakened by gamma irradiation at room temperature. To maintain optimum mechanical properties, ETO sterilization of allografts is better than gamma sterilization, especially for cortical bone, because it is usually used in load-bearing settings.
我们研究了伽马射线辐照与环氧乙烷（ETO）灭菌对皮质骨移植材料机械强度的影响。从成年山羊尸体上采集胫骨。60个测试样本被随机分为四组：新鲜样本（未处理）、冷冻样本（在-70摄氏度下冷冻）、伽马射线辐照样本和ETO灭菌样本。使用材料试验机分别进行扭转、三点弯曲和压缩测试。研究的参数包括最大应力、应变、挠度、伸长、载荷、剪切模量和弹性模量。与新鲜样本的结果相比，伽马射线辐照样本的结果如下：最大剪切模量降低48%；剪应力降低55%；挠度降低71%；弯曲应力降低51%；弯曲应变降低74%；伸长降低60%；压缩应变降低50%。然而，冷冻样本和ETO灭菌样本的这些参数没有降低。这些发现证实，室温下伽马射线辐照会削弱皮质同种异体骨的剪切、弯曲和压缩强度。为保持最佳机械性能，同种异体骨的ETO灭菌优于伽马射线灭菌，尤其是对于皮质骨，因为它通常用于承重环境。
