Schmidt M, Weber H, Schön R
Sulzer Orthopedics, Baar, Switzerland.
Clin Orthop Relat Res. 1996 Aug(329 Suppl):S35-47. doi: 10.1097/00003086-199608001-00004.
The development of a metal combination for modular hip systems was motivated by the following observations: (1) wear particles from polyethylene acetabular components can lead to a foreign body reaction and late aseptic loosening and (2) well designed all metal hip prostheses had very low wear rates, usually causing no osteolytic problems. The following challenges had to be met: (1) metal alloy with the maximum wear resistance; (2) the optimal clearance (difference in diameter) between 28-mm ball head and acetabular component; and (3) equipping modern, modular hip systems with metal combinations while maintaining compatibility with existing components. The realization of a metal combination consisted of the stable anchoring of a standard metal lining in a polyethylene insert that, combined, is intended to provide adequate load transfer and fit to either the bone cement bed or the titanium shell. The metal lining is manufactured from a carbide containing cobalt chromium molybdenum wrought alloy (Protasul-21WF). From 1988 to 1995, approximately 40,000 metal combinations (Metasul) were implanted. From these, 44 single components, with a maximum time in situ of 5.5 years, were retrieved and examined. The total linear wear rate averaged 2 to 5 micrometers per year per component after the initial conditioning phase. Under these conditions, particle induced late aseptic loosening is not to be expected.
（1）聚乙烯髋臼部件产生的磨损颗粒可导致异物反应和晚期无菌性松动；（2）设计良好的全金属髋关节假体磨损率极低，通常不会引发骨溶解问题。需要应对以下挑战：（1）具有最大耐磨性的金属合金；（2）28毫米球头与髋臼部件之间的最佳间隙（直径差）；（3）为现代模块化髋关节系统配备金属组合，同时保持与现有部件的兼容性。金属组合的实现包括将标准金属衬里稳固地锚固在聚乙烯衬垫中，二者结合旨在提供足够的负荷传递，并适配骨水泥床或钛壳。金属衬里由含钴铬钼锻造合金（Protasul - 21WF）的硬质合金制成。1988年至1995年期间，约40000个金属组合（Metasul）被植入体内。从这些植入物中，取出并检查了44个单个部件，其最长在位时间为5.5年。在初始适应阶段后，每个部件的年总线性磨损率平均为2至5微米。在这些条件下，预计不会出现颗粒诱导的晚期无菌性松动。
