Wear of gamma-crosslinked polyethylene acetabular cups against roughened femoral balls
Wear of gamma-crosslinked polyethylene acetabular cups against roughened femoral balls
复制标题
DOI：
10.1097/00003086-199912000-00008
复制
发表时间：
1999-12-01
影响因子：
4.2
通讯作者：
Lancaster, JG
中科院分区：
文献类型：
--
作者：
McKellop, H;Shen, FW;Lancaster, JG
在使用髋关节模拟器的临床研究和实验室测试中，已证明高分子量聚乙烯的交联可显著提高其耐磨性。然而，由于大多数实验室研究都是在清洁条件下使用假体质量、高度抛光的对立面进行的，因此人们担心有意交联的聚乙烯髋臼杯对体内第三体磨损损坏的股骨球的耐磨性如何。为了研究这一点，在髋关节模拟器中对传统和辐射交联-重熔的高分子量聚乙烯髋臼杯进行了测试，这些髋臼杯与光滑股骨球以及中度和重度粗糙化的球相对抗。在老化和未老化的情况下对髋臼杯进行测试，以加速任何氧化降解。通过在部分真空下将挤出的GUR 4150分子量为1000的聚乙烯棒料暴露于5 Mrad伽马辐射，然后将棒再熔化以消除残留的自由基，从而生产交联杯。在70 ℃和5 atm氧气下人工老化14天，在交联和重熔材料中引起的氧化可忽略不计。与光滑球相比，交联髋臼杯的磨损（老化或未老化）平均约为传统髋臼杯的15%。对于中度粗糙球，传统髋臼杯的磨损率保持不变，而未老化和老化交联髋臼杯的磨损率略有增加，但仍分别仅为传统髋臼杯的26%和20%。对于极粗糙的球，每种材料的平均磨损率显著增加，使得在最后100万次循环间隔期间，未老化和老化交联髋臼杯的平均磨损率分别为传统髋臼杯的72%和47%。也就是说，在球粗糙度范围内，交联聚乙烯显示出比传统聚乙烯显著更好的耐磨性。有或没有加速老化。
Crosslinking of ultrahigh molecular weight polyethylene has been shown to markedly improve its wear resistance in clinical studies and laboratory tests using hip joint simulators. However, because most of the laboratory studies have been done under clean conditions using prosthesis-quality, highly polished counterfaces, there is concern regarding how well an intentionally crosslinked polyethylene acetabular cup will resist abrasion by a femoral ball that has been damaged by third-body abrasion in vivo. To investigate this, conventional and radiation crosslinked-remelted acetabular cups of ultrahigh molecular weight polyethylene were tested in a hip joint simulator bearing against smooth femoral balls and against balls with moderate and severe roughening. Cups were tested with and without aging to accelerate any oxidative degradation. The crosslinked cups were produced by exposing extruded GUR 4150 bar stock of ultrahigh molecular weight polyethylene to 5 Mrad gamma radiation under a partial vacuum and then the bars were remelted to extinguish residual free radicals. Artificial aging at 70 degrees C under 5 atm oxygen for 14 days induced negligible oxidation in the crosslinked and remelted material. Against smooth balls, the wear of the crosslinked cups, with or without aging, averaged approximately 15% of that of the conventional cups. Against the moderately rough balls, the wear rate of the conventional cups was unchanged, whereas the wear rate increased slightly for the nonaged and aged crosslinked cups, but was still only 26% and 20% of that of the conventional cups, respectively. Against extremely rough balls, the mean wear rates increased markedly for each material such that during the final 1 million cycle interval, the average wear rates of the nonaged and the aged crosslinked cups were 72% and 47% of that of the conventional cups, respectively, That is, the crosslinked polyethylene showed substantially better wear resistance than conventional polyethylene across the range of ball roughnesses, with or without accelerated aging.