Currier B H, Currier J H, Collier J P, Mayor M B, Scott R D
Dartmouth Biomedical Engineering Center, Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
Clin Orthop Relat Res. 1997 Sep(342):111-22.
Polyethylene has been used for more than 30 years as an orthopaedic bearing material; however, recently concern has been focused on the early failure of some polyethylene bearings. The damage seen in some bearings has been linked to gamma radiation sterilization performed in an air environment. Gamma sterilization in air has been documented to cause an increase in oxidation and degradation of mechanical properties that continue with time. However, not all retrieved bearings that are gamma sterilized in air exhibit the elevated oxidation and mechanical property degradation that lead to early component failure. Bearings that are gamma sterilized in air oxidize while sitting in inventory before implantation. Shelf oxidation rate was estimated based on analysis of a series of never implanted tibial bearings. This shelf oxidation rate allowed estimation of in vivo oxidation for retrieved tibial bearings of known sterilization date. Bearings with less than 1 year of shelf life after gamma sterilization in air had lower in vivo oxidation and better in vivo performance than did those with longer shelf life before implantation. Shelf time before implantation appears to be a significant factor in the success or failure of bearings that are gamma sterilized in air.
聚乙烯作为一种骨科植入材料已被使用超过30年；然而，最近人们的关注点集中在一些聚乙烯植入物的早期失效问题上。在一些植入物中观察到的损伤与在空气环境中进行的伽马射线灭菌有关。有文献记载，在空气中进行伽马灭菌会导致氧化增加以及机械性能随时间持续下降。然而，并非所有在空气中进行伽马灭菌的回收植入物都表现出导致早期部件失效的氧化增加和机械性能下降。在空气中进行伽马灭菌的植入物在植入前库存存放期间会发生氧化。基于对一系列从未植入的胫骨植入物的分析，估算了库存氧化率。这种库存氧化率使得能够对已知灭菌日期的回收胫骨植入物的体内氧化情况进行估算。在空气中进行伽马灭菌后库存保质期不到1年的植入物，其体内氧化程度较低，体内性能也优于植入前库存保质期较长的植入物。植入前的库存时间似乎是在空气中进行伽马灭菌的植入物成败的一个重要因素。
