Savarino L, Granchi D, Ciapetti G, Cenni E, Nardi Pantoli A, Rotini R, Veronesi C A, Baldini N, Giunti A
Laboratorio di Fisiopatologia degli Impianti Ortopedici, Istituti Ortopedici Rizzoli, Bologna, Italy.
J Biomed Mater Res. 2002;63(5):467-74. doi: 10.1002/jbm.10299.
Polyethylene (PE) wear has been shown to be a problem in long-term joint replacement using metal-on-PE bearing. The use of metallic heads articulating with metallic cups could solve this problem: success will be enhanced if wear and corrosion of the articulating surfaces are maintained at a low level. New models with metal-on-metal bearing have been proposed, to be used mainly for young subjects: such coupling seems to have a reduced release, but it is unclear yet if the medium-term corrosion rate is really negligible or, on the contrary, it is significantly higher than in the metal-on-PE bearing. Aim of our study was the comparison of ion release in the serum of two groups of patients who had the same type of stable cementless prosthesis, but different bearing: twenty-six patients with metal-on-metal (Group A) and fifteen patients with metal-on-PE bearing (Group B) were examined. The follow-up was 14-38 months for group A and 18-34 months for group B. The serum concentration of chromium (Cr), cobalt (Co) and molybdenum (Mo) was measured. Twenty-two patients before surgery were used for comparison (Group C). The reference values were obtained from a population of twenty-two healthy subjects (Group D). Our findings indicate that metal-on-metal bearings produce a significantly higher systemic release of cobalt and chromium (ng/ml) when compared with levels found in metal-on-PE, pre-surgery and reference groups. Such a high release should induce to improve the bearing materials or, at least, to study the biologic fate of metal ions and consequently their long-term effects. In such a way a risk-to-benefit ratio for the patient could be established.
在使用金属对聚乙烯（PE）关节面的长期关节置换中，聚乙烯磨损已被证明是一个问题。使用金属股骨头与金属髋臼杯的关节面可以解决这个问题：如果关节面的磨损和腐蚀保持在低水平，成功率将会提高。已经提出了使用金属对金属关节面的新型号，主要用于年轻患者：这种关节面似乎释放量较低，但中期腐蚀率是否真的可以忽略不计，或者相反，是否明显高于金属对聚乙烯关节面，目前尚不清楚。我们研究的目的是比较两组接受相同类型稳定非骨水泥假体但关节面不同的患者血清中的离子释放情况：检查了26例使用金属对金属关节面的患者（A组）和15例使用金属对聚乙烯关节面的患者（B组）。A组的随访时间为14 - 38个月，B组为18 - 34个月。测量了血清中铬（Cr）、钴（Co）和钼（Mo）的浓度。将22例手术前患者用于比较（C组）。参考值来自22名健康受试者（D组）。我们的研究结果表明，与金属对聚乙烯关节面组、手术前组和参考组相比，金属对金属关节面会产生显著更高的钴和铬全身释放量（纳克/毫升）。如此高 的释放量应促使改进关节面材料，或者至少研究金属离子的生物学归宿及其长期影响。通过这种方式，可以为患者确定风险效益比。
