Objective To test the bio - mechanical index of dynamic compression interlocking nail in the femoral transverse fracture model at manual pressure and mechanical pressure process and to compared it with static interlocking nail, sum dynamic compressional intramedullary nails biomechanical characteristics. Methods Transverse femur fracture model was established With 16 adult specimens of the femur, excluding bone. They were divided into two groups. The models were fixed using the Shi Seke ordinary SIN and DCIN. 0 ~ 500N axial load during manual compression fracture strain and displacement in two models were tested. Then its 500 ~ 4000N strain fracture under axial load and displacement were determinded at the axial mechanical pressure. Results In the manual compression process, compression produced by strain and displacement in the fracture model of DCIN in the axial direction was significantly greater than that of the normal SIN ( P < 0. 05 ). In the process of mechanical pressure, DCIN set the direction of axial compression fracture model of the induced strain was significantly less than the SIN group did ( P <0. 05 ) and the displacement was the opposite. And in the mechanical pressure process of SIN with the load increasing, the nail shear deformation oc-cured earlier than DCIN group did. Conclusion SIN DCIN manual pressure group process and mechanical properties in torsion and bending was no significant difference. Mechanical compression process, DCIN group increased its power by stressing fracture conductivity and reducing nail shear.%目的 通过测试动力性加压交锁髓内钉(dynamic compressional interlocking nail,DCIN)在股骨横断骨折模型中手动加压及机械加压情况下的生物力学指标,对比其与静力交锁髓内钉(Static intramedullary nail,SIN)之间的差异,探讨DCIN的生物力学特点.方法 使用无骨病16根成人股骨标本制作成股骨横断骨折模型,分为两组,每组8根,分别使用史塞克公司生产的普通SIN及DCIN固定.测试两组模型在0~500N轴向载荷的手动加压过程中骨折断端应变及位移变化,再测试在500~4000N轴向载荷下骨折断端应变及位移变化.结果 在手动加压过程中,DCIN的骨折模型其骨折端在轴向压缩方向上产生的应变及位移大于普通SIN(P<0.05).两组抗弯曲能力性能基本相同,在扭转0~2.5N.m扭矩过程中,DCIN组发生扭转的角度小于SIN组(P<0.05).在机械加压过程中,DCIN组骨折模型其轴向压缩方向产生的应变小于SIN组(P<0.05),位移则与之相反.DCIN组在机械加压过程中随着载荷增大,锁钉发生剪切变形较SIN迟.结论 DCIN手动加压过程使骨折端紧密接触,提供稳定、可靠的力学传导环境,其动力化设计增加了经骨折端的应力传导,并减少了锁钉剪力.
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