万古霉素骨水泥抗压强度的影响因素

Influential factors for the compressive intensity of bone cement mixed with vancomycin

目的:骨水泥负载的万古霉素治疗耐药菌所致人工关节感染具有可靠的疗效,随着万古霉素剂量的增加,骨水泥的强度势必会受到削弱,但临床上对固定人工关节的骨水泥的强度要求较高,因此观察不同比例的万古霉素、骨水泥混合物以及不同混合方法对骨水泥抗压强度的影响,为人工关节感染的治疗和预防提供力学参数。方法:实验于2007-04/2007-05在吉林大学力学实验中心电子万能试验机实验室完成的。①实验材料:Simplex○RP不透射线骨水泥,礼来日本公司生产的万古霉素,日本岛津AG-10TA自动控制电子万能试验机。②实验方法:设定4个组别,对照组不加入万古霉素;实验1,2,3组,分别将1g、2g、2g万古霉素混入40g骨水泥;其中对照组,实验1组,实验2组在手动搅拌下混合,实验3组在真空搅拌下混合。应用自制不锈钢模具制成4组高12mm,直径6mm的圆柱形标准试件。③评估指标:将试件置于电子万能试验机上测试压缩的最大载荷、位移、应力、应变。结果:最大载荷和最大应力以实验3组最高,实验2组最低,采用配对t检验,实验2,3组相比,差异有显著性意义(P<0.05),其余各组比较,差异无显著性意义(P>0.05);最大位移和最大应变以实验2组最高,实验3组最低,采用配对t检验,实验2,3组相比,差异有显著性意义(P<0.05),其余各组比较,差异无显著性意义(P>0.05)。结论:手动搅拌下万古霉素和骨水泥质量配比不超过5.0%时不会影响骨水泥的压缩强度,配比相同的万古霉素骨水泥在真空下搅拌比手动搅拌具有更高的强度。

AIM： Vancomycin loaded by bone cement has reliable therapeutic effect in treating infection of joint prosthesis caused by drug-resistance bacteria. The intensity of bone cement would be impaired if we increase the dosage of vancomycin. Because bone cement used to fix joint prosthesis should be clinically more intensive, in this study, we investigate the effects of different mixing ratio of vancomycin and bone cement and mixing means on the compressive intensity of bone cement so that we can supply mechanical parameters for the treatment and prevention of artificial joint infection. METHODS： The experiment was performed at the mechanical laboratory, Experimental Center of Mechanics of Jilin University from April to May 2007. （1）Four groups were set up. Control group was not added vancomycin （Lilly company, Japan）; three experimental groups were added 1, 2, and 2 g vancomycin to 40 g bone cement （Simplex P）. Bone cement was manually mixed in the control group, the first and second experimental groups, and the third group was mixed in vacuum space. With the self-designed stainless steel mould, cylindrical standard samples were made with 12 mm in height and 6 mm in diameter. （2）The maximal loads, bias, stress and strain of all test pieces were tested on AG-10TA electronic omnipotent trial machine （Shimadzu, Japan）. RESULTS： The maximal loads and stress were found in the third experimental group, and the minimal ones in the second experimental group. By t -test, there were remarkably differences between the second and the third experimental groups （P 〈 0.05）, but there was no remarkable difference compared with other groups （P 〉 0.05）. The bias and strain were found the highest in the second experimental group, and the lowest in the third experimental group, which was statistically different in t-test （P 〈 0.05）, but there was no remarkable difference compared with other groups （P 〉 0.05）. CONCLUSION： Vancomycin cannot affect the strength of bone cement if they are manually mixed and the ratio of vancomycin and bone cement is not exceeded 5.0%. Bone cement with higher strength is obtained if mixed in vacuum space with the same ratio of vancomycin and bone cement.