Engh C Anderson, MacDonald Steven J, Sritulanondha Supatra, Thompson Abigail, Naudie Douglas, Engh Charles A
Anderson Orthopaedic Research Institute, Alexandria, VA 22307, USA.
Clin Orthop Relat Res. 2009 Jan;467(1):101-11. doi: 10.1007/s11999-008-0540-9. Epub 2008 Oct 15.
Metal-on-metal bearing total hip arthroplasty is performed more commonly than in the past. There may be manufacturing differences such as clearance, roughness, metallurgy, and head size that affect performance. In a prospective, randomized trial, we compared 2-year postoperative ion levels for a 28-mm metal-on-polyethylene bearing with 28-mm and 36-mm metal-on-metal bearings. We measured serum, erythrocyte, and urine ion levels. We observed no difference in the ion levels for the 28-mm and 36-mm metal-on-metal bearings. The ion levels in these patients were lower than reported for most other metal-on-metal bearings. Although both erythrocyte and serum cobalt increased, erythrocyte chromium and erythrocyte titanium did not increase despite a four- to sixfold serum chromium and a three- to fourfold serum titanium increase. This may represent a threshold level for serum chromium and serum titanium below which erythrocytes are not affected.
Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
金属对金属承重全髋关节置换术的实施比过去更为普遍。可能存在诸如间隙、粗糙度、冶金学和股骨头尺寸等制造差异会影响其性能。在一项前瞻性随机试验中，我们比较了28毫米金属对聚乙烯承重假体与28毫米和36毫米金属对金属承重假体术后2年的离子水平。我们测量了血清、红细胞和尿液中的离子水平。我们观察到28毫米和36毫米金属对金属承重假体的离子水平没有差异。这些患者的离子水平低于大多数其他金属对金属承重假体的报告水平。尽管红细胞和血清中的钴都增加了，但尽管血清铬增加了四到六倍，血清钛增加了三到四倍，红细胞中的铬和钛并未增加。这可能代表了血清铬和血清钛的一个阈值水平，低于该水平红细胞不受影响。
I级，治疗性研究。有关证据水平的完整描述，请参阅作者指南。
