THE ROLE OF COUNTERFACE IMPERFECTIONS IN THE WEAR OF POLYETHYLENE
THE ROLE OF COUNTERFACE IMPERFECTIONS IN THE WEAR OF POLYETHYLENE
复制标题
DOI：
10.1016/0043-1648(87)90036-6
复制
发表时间：
1987-10-15
期刊：
影响因子：
5
通讯作者：
WALLBRIDGE, NC
中科院分区：
文献类型：
--
作者：
DOWSON, D;TAHERI, S;WALLBRIDGE, NC
全置换髋关节的超高分子量聚乙烯 (UHMWPE) 髋臼杯在体内的磨损速度往往比大多数实验室磨损测试显示的要快。造成这种差异的原因是使用中的不锈钢股骨头表面产生了细小划痕。 本文介绍了线性往复磨损试验中不锈钢配合面的单一缺陷对 UHMWPE 耐磨销磨损影响的研究。缺陷的形式要么是横向或纵向划痕，要么是单个压痕，都是由金刚石标记产生的。研究发现，单个横向划痕可以显着增加聚合物的磨损率；主要因素是划痕边缘堆积的钢材。当通过补救研磨去除堆积的材料时，磨损率返回到与未受干扰的配合面的各向同性粗糙度相对应的初始值。纵向划痕对聚乙烯的磨损率产生不太明显但可识别的增加。单个金刚石压痕不会产生钢的堆积边缘，并且对聚合物的磨损率几乎没有影响。研究结果表明，硬质配合面上的简单缺陷会对聚合物的磨损产生严重影响。即使是浅横向划痕也会使磨损率增加一个数量级。对划伤的配合面进行补救性研磨，以去除堆积的材料，很大程度上恢复了无瑕疵配合面的低磨损特性。该研究支持之前提出的解释全置换髋关节体内和实验室磨损率差异的观点。
Ultrahigh molecular weight polyethylene (UHMWPE) acetabular cups of total replacement hip joints tend to wear more quicklyin vivothan indicated by most laboratory wear tests. The reason for this discrepancy has been attributed to the generation of fine scratches on the surfaces of the stainless steel femoral heads in service.In the present paper an account is given of an investigation of the influence of single imposed imperfections in stainless steel counterfaces upon the wear of UHMWPE wear pins in linear reciprocating wear tests. The imperfections were in the form of either transverse or longitudinal scratches or single indentations, all generated by diamond markers.It has been found that a single transverse scratch can increase the wear rate of the polymer to a remarkable extent; the major factor being the piled-up steel along the edge of the scratch. When the piled-up material was removed by remedial lapping the wear rate returned to its initial value corresponding to the isotropic roughness of the undisturbed counterface. Longitudinal scratches yielded a less marked yet recognizable increase in the wear rate of the polyethylene.Single diamond indentations did not generate piled-up edges of steel and had little effect upon the wear rate of the polymer.The findings demonstrate the severe effect which simple imperfections on a hard counterface can have upon the wear of polymers. Even shallow transverse scratches can increase the wear rate by an order of magnitude. Remedial lapping of the scratched counterfaces, to remove the piled-up material, largely restores the low wear characteristics of the unblemished counterfaces. The study supports the views offered previously in explanation of the difference betweenin vivoand laboratory wear rates of total replacement hip joints.