不同钉位布局影响股骨颈骨折内固定效应的生物力学研究

目的:观察应用多枚钉内固定治疗股骨颈骨折时采取不同钉位布局对骨折断端固定效应的影响,为临床操作中寻求最佳钉位布局奠定基础。方法:通过特制壮年人体尸骨股骨颈骨折模型,进行直视下解剖复位后,分别应用3钉倒三角形、3钉正三角形和双钉平行3种不同钉位布局内固定方法完成内固定。在生物力学万能试验机上进行轴向压缩和扭转实验,观察不同生物应力下断端相对的位移距离、轴向刚度、水平剪切刚度和扭转强度等项目,取得试验数据后经统计学处理,进行组间对比,观察其差异的显著性。结果:在3种钉位布局的内固定方法之中,以股骨矩核心下2～3mm处进钉位为下位顶点的倒三角形钉位布局能获得最坚强的固定效应,相同应力下其位移距离最小而各项刚度最大;而股骨矩核心上位和中下位双钉固定法固定效应最差,表现为相同应力下位移距离最大和各项刚度最小。结论:尽可能选择以股骨矩核心下2～3mm处进钉位为下位顶点的倒三角钉位布局法,尽可能减少应用双钉位布局法。

Biomechanical study on the effect of different nailing positions for the fixation of femoral neck fracture(FNF)

Objective:To investiage the effect of different nailing position for the fixation of femoral neck fracture(FNF),so as to determine the best nailing position in the treatment of FNF with internal fixation.Methods:Six femoral bones were obtained from adult cadavers(all were male)and used to produce model of femoral neck fracture.After dissection and repositioning,internal fixation methods with three different nailing positions triangle,inverted triangle and dual-nailing,were performed to the models.Biomechanical pressure was applied to the point of fracture,and the shift in positions of the femoral bone was recorded.The experimental data were then computed and compared.Results:Among the three nailing positions in the fixation of FNF,the inverted triangle at a position 2 to 3 mm below the femoral core was found to be the best fixation of FNF with the shortest displacement and the highest stiffness under the same biomechanical pressure.The dual-nailing had the weakest effect with the longest displacement and the lowest stiffness.Conclusion:The inverted triangle method at a position 2 to 3 mm below the femoral core should be employed in future,while the method of dual-nailing should be discontinued.