Ohtsuru Tadahiko, Morita Yuji, Murata Yasuaki, Shimamoto Shuji, Munakata Yutaro, Kato Yoshiharu
Department of Orthopedic Surgery, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku Ward, Tokyo, 162-8666, Japan.
Kita Shinagawa 3rd Hospital, 3-3-7 Kita-shinagawa, Shinagawa Ward, Tokyo, 140-0001, Japan.
Eur J Orthop Surg Traumatol. 2017 May;27(4):527-532. doi: 10.1007/s00590-017-1931-y. Epub 2017 Feb 20.
The hip placement with a metal-on-metal (MOM) bearing has been used for both surface replacement and total hip arthroplasty (THA). Use of MOM bearing for hip replacement reduces the wear compared to conventional bearings.
We prospectively assessed 30 patients who underwent unilateral MOM THA. A control group of 30 patients who underwent metal-on-polyethylene THA using the implants as the other group, except for bearing, were accessed. Blood samples were collected preoperatively and at 3- , 6- , 9- , 12- , 15- , 18- , and 24-month intervals. Changes in mean blood metal ion concentration were compared between the MOM and metal-on-polyethylene groups.
A statistically significant positive correlation was observed between blood cobalt and chromium concentrations in all of the patients. The mean blood ion concentrations of the MOM were significantly higher than those of the metal-on-polyethylene. A statistically significant negative correlation was found between maximum blood cobalt concentration and cup version angle. The maximum blood chromium concentrations in the patients who had larger cup version angles were more likely to decrease.
We considered that cup version angle is one of the factors that have the greatest effect on blood metal ion concentration, and the target cup version angle that did not induce an increase in blood metal ion concentrations was approximately 20°.
金属对金属（MOM）承重的髋关节置换已用于表面置换和全髋关节置换术（THA）。与传统承重方式相比，使用MOM承重进行髋关节置换可减少磨损。
我们前瞻性评估了30例行单侧MOM THA的患者。选取30例行金属对聚乙烯THA的患者作为对照组，除承重方式外，植入物与另一组相同。术前以及术后3、6、9、12、15、18和24个月采集血样。比较MOM组和金属对聚乙烯组血金属离子平均浓度的变化。
所有患者的血钴和铬浓度之间存在统计学上显著的正相关。MOM组的血离子平均浓度显著高于金属对聚乙烯组。血钴最大浓度与髋臼假体角度之间存在统计学上显著的负相关。髋臼假体角度较大的患者血铬最大浓度更有可能降低。
我们认为髋臼假体角度是对血金属离子浓度影响最大的因素之一，不引起血金属离子浓度升高的目标髋臼假体角度约为20°。
