两种骨水泥翻修动力髋螺钉固定失败的生物力学比较研究

Biomechanical comparison of augmentation and restoration for failure of dynamic hip screw internal fixation by two kinds of bone cement

目的:比较用磷酸钙骨水泥(CPC)与聚甲基丙烯酸甲酯(PMMA)骨水泥强化修复股骨粗隆间骨折动力髋螺钉(DHS)内固定失败的生物力学性能。方法:15例老年人骨质疏松股骨标本,制成EvansⅢ型骨折模型,随机分成3组,每组5例,一组为对照组(正常DHS固定),另两组再制成DHS内固定失败模型,分别应用CPC强化和PMMA强化DHS固定修复,然后对标本进行生物力学测试。结果:PMMA组的轴向刚度、剪切刚度、抗扭转强度均比对照组大,其中轴向刚度与对照组相比差异无统计学意义(P>0.05),剪切刚度、抗扭转强度与对照组比较差异均有统计学意义(P<0.05);CPC组轴向刚度、剪切刚度比对照组小,差异有统计学意义(P<0.05),抗扭转强度与对照组相似(P>0.05)。结论:从两种骨水泥的生物力学特性角度看,采用PMMA比CPC强化修复DHS松动失败更有一定的优势。

Objective： To compare the biomechanical characteristics of calcium phosphate cement（CPC） and polymethyl-methacrylate（PMMA）cement augmentation and restoration for the failure of dynamic hip screw（DHS） internal fixation in femoral interchanteric fracture models.Methods： 15 osteoporotic femoral specimens were made for the Evans Ⅲ type models,and which were randomly divided into three groups.The control group（5 cases） fixed with DHS,the rest made for the models of the failure of DHS internal fixation,and which divided into two groups,one group of DHS internal fixation with CPC augementation and restoration,another group with PMMA cement.To measure the biomechanical characteristics of the construction.Results： The axial rigidity,shearing rigidity,anti-torsional stiffness of PMMA group were more than those of control group,there were significant differences between PMMA group and control group in Shearing rigidity and the anti-torsional stiffness（P0.05）,the axial rigidity of PMMA group was similar to that of the control group（P0.05）.The axial and Shearing rigidity in CPC group was less significantly than that in the control group（P0.05）,the anti-torsional stiffness in CPC group was similar to that in the control group（P0.05）.Conclusion： PMMA cement augmenting and restoring for the failure of DHS internal fixation has more advantages than CPC,according to the biomechanical characteristics of two kinds of bone cement.