Rasmussen T J, Feder S M, Butler D L, Noyes F R
Orthopedic and Sports Medicine Consultants, Shawnee Mission, Kansas.
Arthroscopy. 1994 Apr;10(2):188-97. doi: 10.1016/s0749-8063(05)80092-1.
Pairs of frozen human patellar tendon-bone (PTB) ligament allografts were exposed to either 0 or 4 Mrad of gamma irradiation sterilization, the latter value based on recent reports suggesting higher dosage levels for adequate sterilization against the human immunodeficiency virus. All specimens were subjected to three levels of loading: lower functional loads, higher functional loads, and failure. Lower functional loads were simulated by performing in vitro static and cyclic creep tests, similar to loads that the surgeon and patient would apply before and after implantation, respectively. Higher functional loads, simulating moderate activities of daily living, were represented by the slope of the linear portion of the force-elongation curve or linear stiffness. Failure or trauma was then simulated by failing the grafts in tension at a high strain rate. We found that the irradiation treatment shortened the tendon by only 0.6 mm, which was nevertheless statistically significant (p < 0.01). By contrast, 4 Mrad did not significantly alter either static or cyclic creep (p > 0.05) at lower functional loads. Instead, irradiation produced the greatest changes during failure testing, reducing both the graft's linear stiffness by 12% (p < 0.025) and maximum force by 26% (p < 0.001). Although our data do not describe how an allograft might perform during the early healing and later collagen-remodelling phases, such in vitro studies remain important if we are to optimize allograft properties before arthroscopic anterior and posterior cruciate ligament reconstruction.
将成对的冷冻人髌腱-骨（PTB）韧带同种异体移植物分别进行0或4兆拉德的γ射线辐照灭菌处理，后一数值是基于近期报告得出的，该报告表明需要更高的剂量水平才能充分杀灭人类免疫缺陷病毒。所有标本均承受三个加载水平：较低功能负荷、较高功能负荷和破坏。通过进行体外静态和循环蠕变试验来模拟较低功能负荷，分别类似于外科医生和患者在植入前后施加的负荷。模拟日常生活中度活动的较高功能负荷由力-伸长曲线线性部分的斜率或线性刚度表示。然后通过以高应变率拉伸移植物使其破坏来模拟破坏或创伤。我们发现辐照处理仅使肌腱缩短了0.6毫米，不过这在统计学上具有显著意义（p < 0.01）。相比之下，4兆拉德在较低功能负荷下对静态或循环蠕变均无显著影响（p > 0.05）。相反，辐照在破坏测试期间产生的变化最大，使移植物的线性刚度降低了12%（p < 0.025），最大力降低了26%（p < 0.001）。尽管我们的数据并未描述同种异体移植物在早期愈合和后期胶原重塑阶段的表现，但如果我们要在关节镜下前后交叉韧带重建之前优化同种异体移植物的性能，此类体外研究仍然很重要。
