Chan F W, Bobyn J D, Medley J B, Krygier J J, Yue S, Tanzer M
Jo Miller Orthopaedic Research Laboratory, Montreal General Hospital and McGill University, Quebec, Canada.
Clin Orthop Relat Res. 1996 Dec(333):96-107.
A major concern in total hip arthroplasty is the generation of polyethylene wear particles at the articulating surfaces and resulting macrophage mediated periimplant osteolysis. There is renewed interest in metal on metal bearings as a solution to this problem in view of their potential for greatly improved wear performance. Using a commercially available hip simulator, the wear performance of metal on metal femoral head and acetabular cup combinations was evaluated and various parameters affecting metal on metal implant wear were identified. Nine implants custom manufactured from 2 medical grades of CoCrMo alloy (ASTM F1537-95 and F75-92) were tested within bovine serum as the lubricant to 3 million cycles (equivalent to approximately 3 years of service in vivo). The progressive wear of the components was determined by gravimetric methods at approximately every 300,000 cycles. The wear rates were characterized by an initial period of accelerated wear after which a lower steady state wear rate was observed for subsequent cycles. The presence of calcium phosphate films on the component surfaces, the microstructure of the lower carbon, wrought alloy, and increased effective radii (decreased diametral clearances) were identified as factors that may be favorable to improved wear performance. The extent of the effect on wear of each parameter, however, cannot be discerned at this point and necessitates a study in which parametric changes are more tightly controlled. The present study suggests that the use of metal on metal articulating surfaces may mitigate the problem of osteolysis by offering improved wear performance.
全髋关节置换术中的一个主要问题是关节表面产生聚乙烯磨损颗粒，并导致巨噬细胞介导的植入物周围骨溶解。鉴于金属对金属轴承在改善磨损性能方面的潜力，人们对其作为解决这一问题的方法重新产生了兴趣。使用市售的髋关节模拟器，评估了金属对金属股骨头和髋臼杯组合的磨损性能，并确定了影响金属对金属植入物磨损的各种参数。用两种医用级别的钴铬钼合金（ASTM F1537 - 95和F75 - 92）定制制造的九个植入物，在牛血清作为润滑剂的条件下进行了300万次循环测试（相当于体内约3年的使用时间）。大约每30万次循环时，通过重量法测定部件的渐进磨损情况。磨损率的特征是初期有一个加速磨损阶段，之后在后续循环中观察到较低的稳态磨损率。部件表面存在磷酸钙膜、低碳锻造合金的微观结构以及有效半径增加（直径间隙减小）被确定为可能有利于改善磨损性能的因素。然而，目前还无法确定每个参数对磨损影响的程度，这需要进行一项对参数变化控制更严格的研究。本研究表明，使用金属对金属关节表面可能通过改善磨损性能来缓解骨溶解问题。
