金属对金属髋关节假体的生物学效应

Biological effects of metal on metal hip prostheses

学术背景:金属对金属髋关节假体有着超过30年以上的使用记录。随着年轻患者使用日渐增多,金属离子在体内累积所引起生物学效应,如细胞毒性、遗传毒性、致癌性、金属过敏等受到重视和关注。目的:论文阐述了金属对金属髋关节假体植入人体后,产生金属离子的诱因以及人体组织分布情况,特别是金属离子血清浓度变化情况、金属对金属髋关节假体生物学效应的病理表现。并探讨了金属离子血清浓度变化的影响因素及金属离子生物学效应的机制。检索策略:由第一作者应用计算机检索Pubmed数据库2004-01/2007-11的相关文献,检索词"Metals,Total hip replacements",并限定文章语言种类为English。同时计算机检索中国期刊全文数据库2000-01/2007-11的相关文献,检索词"关节置换,金属离子",并限定文章语言种类为中文。共检索到267篇文献,对资料进行初审,纳入标准:①文章所述假体为金属对金属界面假体。②文章所述术式为髋关节置换术。③文章所述中心为金属离子生物学效应方面内容。排除标准:①非金属对金属界面假体。②其他部位的关节置换术。③文章所述中心为冶金学内容。④重复性研究。文献评价:阅读标题和摘要进行初筛,排除因研究目的与此文无关的194篇,内容重复性的研究58篇,Meta分析0篇,共保留30篇中英文文献做进一步分析。6篇为综述,其余均为临床或基础实验研究。资料综合:金属对金属假体在体内通过电化学(腐蚀)过程和机械增强电化学(磨损–腐蚀)过程释放金属离子。其随体液传播到各种人体组织,引起一系列生物学效应。人体对金属离子反应呈剂量依赖性,其血清浓度的高低决定生物学效应的大小。一般认为金属离子血清浓度影响因素有①排泄因素。②机械因素。③个体因素。④其他。目前认为金属离子生物学效有①炎症反应。②氧化损伤。③细胞凋亡。④骨质及细胞外基质溶解。⑤致癌。⑥宿主反应。其机制与腐蚀反应、巨噬细胞激活、活性氧生成、成骨细胞功能抑制、破骨细胞激活、金属–蛋白复合物生成等有关。其后果是一系列病理变化:①异物肉芽肿性滑膜炎。②引流淋巴结病变。③淋巴结铬沉着病。④恶性病变。⑤金属过敏反应。结论:目前无更好的产品来替代金属对金属髋关节假体。通过对其生物学效应的研究,人们逐渐关注两个问题。第一,什么是安全的磨损率?第二,什么是有害金属离子血清浓度标准?

BACKGROUND： Metal on metal （MoM） hip prosthesis has been used for more than 30 years. With the increasing number of young patients who used it, the metal ions cumulative in the body may cause the biological effects, such as cell toxicity, genetic toxicity, carcinogenicity and metal allergy, etc, which have received attention and concern. OBJECTIVE： To describe what influences the production of metal ions, and how metal ions distribute in human tissue after MoM hip prosthesis implantation. In particular the change of the metal ions serum level and the MoM hip prosthesis biological effects of the pathological manifestations were investigated. This paper also focused on the factors influencing metal ions serum level and the mechanism of metal ions biological effects. RETRIEVAL STRATEGY： A computer-based search of Pubmed database was undertaken to identify the articles between January 2004 and November 2007, with the key items of ＂metals, total hip replacement＂ and language was limited to English. Meanwhile the China Journal Full-text Database was retrieved for the related articles published from January 2000 to November 2007, with the words of ＂joint replacement, metal ions＂ in Chinese. Totally 267 articles were screened out, and checked primarily. Inclusion criteria： （1）prosthesis interface described the articles for MoM;（2）procedure described in the articles for hip replacement;（3） articles focused on biological effects of metal ions. Exclusion criteria： （1）non-MoM interface of the prosthesis;（2）non-hip arthroplasty;（3）articles described the metallurgy;（4）reproducibility study. LITERATURE EVALUATION： Both titles and abstracts were screened preliminarily, excluding 194 articles of unrelated objectives, 58 articles of repeated contents and 0 Meta analysis. Finally 30 articles were taken into further analysis, including 6 reviews and other basic or clinical trials. DATA SYNTHESIS： MoM prosthesis releases metal ions in the body through electrochemical process （corrosion） and enhanced machinery plus electrochemical process （wear-corrosion）. It spreads to various body tissues by body fluid, and raises a number of biological effects. Human body shows a reaction of metal ions in a dose-dependent manner, and metal ions serum level decides the biological effects. Generally we consider the serum concentration of metal ions is influenced by （1）ion excretion factors. （2） mechanical factors. （3）individual factors. （4）others. At present, the biological effects of metal ions include （1）inflammatory response, （2）oxidative damage, （3）apoptosis, （4）osteoporosis and extracellular matrix dissolution, （5）carcinogenesis, （6）host response. Its mechanism is related with corrosion, macrophage activation, reactive oxygen generation, osteoblast function inhibition, osteoclast activation, metal-protein complex formation, and so on. The consequence is a series of pathological changes： （1）foreign body granuloma synovitis, （2）draining lymph node lesions, （3）chromium calmly disease, （4）malignant lesions, （5）metal allergy. CONCLUSION： There is no better product to replace MoM hip prosthesis. Through the study of their biological effects, people gradually concern about two issues. First： What is a safe wear rate？ Second： What is harmful serum level of metal ions？