动力髋部螺钉与股骨近端髓内钉固定不稳定股骨转子间骨折的生物力学比较  

Biomechanical evaluation on dynamic hip screw versus proximal femoral nail fixation for unstable femoral intertrochanteric fractures

作　　者：易先宏[1] 陈红卫[2] 潘骏[1] 

机构地区：[1]温州医学院附属第二医院骨科,浙江温州325027 [2]浙江省义乌市中心医院骨科,浙江义乌322000

出　　处：《医用生物力学》2013年第2期235-239,共5页Journal of Medical Biomechanics

基　　金：浙江省义乌市科技计划项目(11-3-03)

摘　　要：目的比较动力髋部螺钉(dynamic hip screw,DHS)与股骨近端髓内钉(proximal femoral nail,PFN)固定不稳定型股骨转子间骨折的生物力学稳定性。方法 8对新鲜冰冻人体股骨标本行标准4部分截骨术,每对分别以DHS及PFN固定后分为DHS组及PFN组,行生物力学测试。在持续加载负荷(0.2、0.4、0.6、0.8、1.0、1.2和1.4 kN)后测量骨折端分离移位程度以反映内植物的稳定性。每个标本重复加载5次,计算其平均值后绘制载荷-距离曲线,并计算刚度值。设定最初载荷为1.4 kN,加载速度10 N/s,每次加载600 N,当压力逐渐增加至最高值时停止,维持10 s后压力逐渐减小至0 N。记录内固定失败时加载的最大压力值作为内植物最大强度。结果所有标本均顺利完成测试,内固定物均无断裂。在不同负荷下DHS组位移变化值与刚度值平均值分别为(3.92±2.21)mm和(215.28±58)N/mm;PFN组分别为(4.22±1.80)mm和(197.06±34.20)N/mm,两组比较均无统计学差异性(P>0.05)。PFN组为钉尾端发生新的骨折;DHS组均为钢板远端皮质螺钉处发生骨折,并无螺钉切出股骨头。PFN组内固定失败时平均载荷为(4 312±560)N,DHS组(3 954±520)N,两组比较无统计学差异(P>0.05)。结论 PFN与DHS治疗不稳定型股骨转子间骨折在强度及轴向稳定性上并无本质性差别。临床上需根据具体骨折情况选用合适的内固定材料,治疗中应尽量做到解剖复位,对于难以解剖复位者要力争恢复内后侧骨皮质的连续性。Objective To investigate the biomechanical stability of DHS （ dynamic hip screw） and PFN （ proximal femoral nail） for treating unstable intertrochanteric fractures. Methods A standard 4-part osteotomy was per- formed in 8 pairs of fresh frozen human cadaver femurs, which were then randomly assigned to two groups： PFN group and DHS group for biomechanical testing. These specimens were applied to a cyclic load up to 0.2, 0.4, 0.6, 0.8, l, l. 2, 1.4 kN, respectively. Fracture displacement was measured during the loading to determine bi- omechanical stability of the implant. Each specimen was repeatedly loaded for 5 times to calculate the average displacement and draw the load-displacement curve. For failure testing, the initial load and loading rate was set at 1.4 kN and 10 N/s, respectively. The applied compressive load was increased by 600 N each time for five cy- cles. The pressure was gradually increased to its peak force, and sustained for 10 second before it was gradually decreased to 0 N. The highest force value sustained before failure was defined as the maximum strength of the implant. Results The biomechanical testing on all specimens was completed successfully. There was no damage to the internal fixation. The average displacement （215.28 _＋58） N/mm, while those in PFN group were significant difference was found between the DHS and and stiffness in DHS group were （3.92 _＋ 2.21 ） mm and （4.22 ___ 1.80） mm and （ 197.06 _＋34.20） N/mm, so no the PFN group （ P 〉 0.0.5）. New fracture occurred at the distal end of nail in PFN group. The DHS was fractured at the distal cortical screw, but no nail was cut out of the femoral head. The average load required for failure was （4 312 _＋560） N in PFN group and （3 954 _＋520） N in DHS group, and no significant difference was found between the two groups（ P 〉 0.05）. Conclusions The test shows that the PFN does not appear to offer any distinct biomechanical advantage over the DHS in the treatment of unstable intertrocha

关 键 词：动力髋部螺钉 股骨近端髓内钉 骨折 生物力学测试 

分 类 号：R318.01[医药卫生—生物医学工程]