Clinical and Laboratory Wear Studies of Zirconia-on-UHMWPE Combination in Cementless THA
Clinical and Laboratory Wear Studies of Zirconia-on-UHMWPE Combination in Cementless THA
复制标题
非骨水泥 THA 中氧化锆与 UHMWPE 组合的临床和实验室磨损研究
DOI：
10.4028/www.scientific.net/kem.240-242.823
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
T. Matsushita
中科院分区：
文献类型：
--
作者：
Takashi Nakamura;K. Tanaka;J. Tamura;K. Kawanabe;Y. Takigawa;N. Sugano;Y. Saegusa;Y. Takatori;S. Kondo;K. Ninomiya;N. Mashima;T. Matsushita
我们研究了氧化锆股骨头在体内和体外的磨损性能。在非骨水泥型THA中，聚乙烯与传统氧化锆股骨头的体内磨损率为0.139 mm/年，与金属背衬聚乙烯与金属股骨头的报告磨损率相比，这相对令人满意。然而，氧化锆的降解仍存在一些问题。因此，目前的制造商对传统的氧化锆进行了改进。使用改进的氧化锆股骨头进行髋关节模拟器测试的结果令人满意。因此，目前改进的氧化锆更耐降解，将有助于在延长的时间内减少聚乙烯磨损。氧化锆陶瓷（Y-TZP）具有高机械强度和优异的耐磨性能，这已在许多体外研究中得到证实[1]。1985年，氧化锆陶瓷被成功地引入临床，作为股骨头，在THA中与高分子量聚乙烯部件进行关节连接。另一方面，人们对与长期植入相关的低温降解存在一些担忧。因此，氧化锆陶瓷已经被几个制造商改进以消除这种降解。关于氧化锆-聚乙烯关节面组合的临床磨损行为的研究仍然很少。在本研究中，我们测量了聚乙烯与传统氧化锆的临床磨损。此外，我们研究了改良氧化锆的磨损性能，尤其是在髋关节模拟器磨损试验中与交联聚乙烯（CPE）接合时，因为最近预计CPE可显著减少磨屑。在此基础上，我们讨论了氧化锆作为替代轴承材料的有效性。材料和方法临床磨损测量：1992年至1994年，作为日本的一项多中心临床试验，共94例髋关节使用Kobelco H-5系统（科比钢铁有限公司，科比，日本），其中使用了22或26 mm组配式氧化锆股骨头。氧化锆的机械性能如表1所示。在这些病例中，我们对74个髋关节的聚乙烯内衬线性磨损进行了X线检查。氧化锆股骨头采用环氧乙烷灭菌，聚乙烯内衬和金属植入物采用伽马辐照灭菌。关键工程材料在线：2003-05-15 ISSN：1662-9795，Vols. 240-242，pp 823-826 doi：10.4028/www.scientific.net/KEM.240-242.823 © 2003 Trans Tech Publications Ltd，Switzerland版权所有。未经Trans Tech Publications Ltd（www.scientific.net）的书面许可，不得以任何形式或任何方式复制或传播本文的任何内容。（Semanticscholar.org-13/03/20，21：20：59）表1.改性氧化锆的机械性能密度（g/cm 3）6. 05晶粒尺寸（m）0. 2单斜相（%）14抗弯强度（MPa）1666断裂韧性（Kgf/mm 2/3）16.8维氏硬度1270弹性模量（GPa）201实验室磨损试验：最近，制造商已经改进了氧化锆，与常规氧化锆（H5）相比，导致晶粒尺寸减小20%，对LTD的抗性更高，并且静态和动态断裂强度增加。将改进的氧化锆与H5氧化锆进行比较的静态断裂强度测试和水热老化测试的结果分别示于图1和图2中。如图2所示，包括抛光方法的改进导致对相变的高得多的抗性。使用改进的氧化锆股骨头和传统的CoCrMo股骨头作为对照，进行髋关节模拟器磨损试验（26 mm股骨头，450 kgf载荷，高达2 Mc）。检查以下滑动组合：a）CoCrMo-on-PE B）CoCrMo-on-CPE c）改进的氧化锆-on-PE d）改进的氧化锆-on-CPE。Fig. 1. H5和改进氧化锆之间静态断裂强度的比较结果图3显示了临床磨损数据。平均随访6.6年时，平均线性磨损率为0.139 ± 0.092 mm/年。在74个髋关节中，6个髋关节显示磨损率增加（超过0.3mm/年），而60个髋关节显示小于0.2mm/年。100
We investigated the wear performance of zirconia femoral heads in vivo and in vitro. The in vivo wear rate of polyethylene against the conventional zirconia heads in cementless THA was 0.139 mm/year, which is relatively satisfactory as compared to the reported wear rates of metal-backed polyethylene against metal heads. However, there still exist some problems concerning the degradation of zirconia. Therefore, the present manufacturer has improved the conventional zirconia. The results of hip simulator testing using the improved zirconia heads were satisfactory. Thus, the current improved zirconia which is more resistant to the degradation would contribute to the polyethylene wear reduction over the extended periods. Introduction Zirconia ceramics (Y-TZP) possess high mechanical strength and excellent wear properties, which have been confirmed in numerous in vitro studies [1]. In 1985, zirconia ceramics were successfully introduced into clinical use as femoral heads in articulation with ultrahigh molecular weight polyethylene components in THA. On the other hand, there have been some concerns about the low temperature degradation associated with the long-term implantation. Therefore, zirconia ceramics have been improved by several manufacturers to eliminate such degradation. There still are only a few studies about the clinical wear behavior of zirconia-on-polyethylene bearing combination. In the present study, we measured the clinical wear of polyethylene against the conventional zirconia. In addition, we investigated the wear properties of the improved zirconia especially when articulated with crosslinked polyethylene (CPE) in the hip simulator wear tests, because CPE has recently been expected to reduce wear debris dramatically. Based on these data, we discussed the effectiveness of zirconia as one of alternate bearing materials. Materials and Methods Clinical wear measurement: Between 1992 and 1994, as a multicenter clinical trial in Japan, a total of 94 hips undergone cementless THA using a Kobelco H-5 system (Kobe Steel Ltd., Kobe, Japan), in which a 22 or 26mm modular zirconia head was used. The mechanical properties of zirconia are shown in Table 1. Among these cases, we investigated 74 hips radiographically as to the linear wear of polyethylene liner. Zirconia heads were sterilized by EtO and polyethylene liners and metal implants were sterilized with gamma irradiation. Key Engineering Materials Online: 2003-05-15 ISSN: 1662-9795, Vols. 240-242, pp 823-826 doi:10.4028/www.scientific.net/KEM.240-242.823 © 2003 Trans Tech Publications Ltd, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications Ltd, www.scientific.net. (Semanticscholar.org-13/03/20,21:20:59) Table 1. Mechanical properties of the improved zirconia Density (g/cm 3 ) 6.05 Grain size ( m) 0.2 Monoclinic phase (%) 14 Flexural strength (MPa) 1666 Fracture toughness (Kgf/mm 2/3 ) 16.8 Vickers hardness 1270 Elastic modulus (GPa) 201 Laboratory wear test: Recently the manufacturer has improved the zirconia, resulting in the grain size decrease by 20%, higher resistance to LTD, and increased static and dynamic fracture strength, as compared to the conventional zirconia (H5). The results of static fracture strength test and hydrothermal aging test comparing the improved zirconia with the H5 zirconia are shown in Figures 1 and 2, respectively. As shown in Figure 2, improvement including the polishing method resulted in the much higher resistance to phase transformation. Using the improved zirconia head and conventional CoCrMo head as control, hip simulator wear tests were conducted (26mm heads, 450kgf load, up to 2Mc). The following sliding combinations were examined; a) CoCrMo-on-PE b) CoCrMo-on-CPE c) improved zirconia-on-PE d) improved zirconia-on-CPE. Fig. 1. Comparison of static fracture strength between H5 and improved zirconia Results Figure 3 shows the clinical wear data. At 6.6 years of mean follow-up, the mean linear wear rate was 0.139 0.092mm/year. Of the 74hips, 6 hips showed the increased wear rate (more than 0.3mm/year), whereas 60 hips showed less than 0.2mm/year. 100