Collier J P, Sutula L C, Currier B H, Currier J H, Wooding R E, Williams I R, Farber K B, Mayor M B
Dartmouth Biomedical Engineering Center, Thayer School of Engineering, Dartmouth College, Hanover, NH 03755-8000, USA.
Clin Orthop Relat Res. 1996 Dec(333):76-86.
Polyethylene has been used for more than 30 years as an orthopaedic bearing material; however, there has been recent concern regarding the early failure of a small percentage of the polyethylene bearings. The damage seen in some retrieved polyethylene components has been linked to gamma radiation sterilization in air, which was widely used by the industry for years. Gamma radiation in air has been documented to cause an increase in oxidation and degradation of mechanical properties with time. The degradation of polyethylene initiated by gamma sterilization in air has led the orthopaedic industry toward alternative sterilization methods, including gamma radiation in an inert gas or vacuum environment, ethylene oxide gas sterilization, and gas plasma sterilization. For many of these alternative techniques, little clinical performance data exist. This study is a comparative evaluation of sterilization methods using the same analytic techniques that have been used to document the effects of gamma sterilization in air on polyethylene. Fourier transform infrared spectroscopy, electron spin resonance, and uniaxial tensile testing are used to compare, respectively, the oxidation levels, free radical concentration, and mechanical properties of material sterilized by each method. The polyethylene is evaluated before sterilization, poststerilization, and postartificial aging. All examined alternative sterilization methods, when compared with gamma sterilization in air, caused less material degradation during a component's preimplantation shelf life.
聚乙烯作为一种骨科植入材料已使用了30多年；然而，最近人们对一小部分聚乙烯植入材料的早期失效表示担忧。在一些回收的聚乙烯部件中发现的损伤与空气中的伽马射线灭菌有关，多年来该行业广泛使用这种灭菌方式。有文献记载，空气中的伽马射线会导致材料随时间推移氧化增加以及机械性能下降。空气中伽马射线灭菌引发的聚乙烯降解促使骨科行业寻求替代灭菌方法，包括在惰性气体或真空环境下进行伽马射线灭菌、环氧乙烷气体灭菌和气体等离子体灭菌。对于许多这些替代技术，几乎没有临床性能数据。本研究使用与记录空气中伽马射线灭菌对聚乙烯影响相同的分析技术，对灭菌方法进行了比较评估。分别使用傅里叶变换红外光谱、电子自旋共振和单轴拉伸试验来比较每种方法灭菌后材料的氧化水平、自由基浓度和机械性能。对聚乙烯在灭菌前、灭菌后和人工老化后进行评估。与空气中伽马射线灭菌相比，所有检测的替代灭菌方法在部件植入前的保质期内导致的材料降解都更少。
