股骨髓内钉近端不同方向锁钉对内固定稳定性的生物力学对比研究

Biomechanical comparative study on the effect of different directions of locking nail of proximal femoral intramedullary nail on the stability of in-ternal fixation

目的对股骨髓内钉近端不同位置置钉的整体稳定性进行生物力学测试,为改进股骨髓内钉近端锁钉的置钉方向提供生物力学依据。方法选用2016年7~8月Sawbones股骨标准骨8个分成小粗隆置钉组,行股骨髓内钉内固定,近端锁钉按照不同方向置入,制作股骨中段骨折模型后进行轴向压缩实验,观察比较两组在相同轴向载荷下的压缩位移和压缩刚度结果。结果在相同压缩载荷下(除了载荷为100 N时)标准组平均移位均大于小粗隆置钉组,当压缩载荷在400 N及以上时,两组数据比较T波动在2.522~3.135,差异均有统计学意义(P<0.05);在压缩刚度上:当压缩载荷在700 N及以上时,两组数据比较T波动在2.481~3.275,差异均有统计学意义(P<0.05)。结论当压缩载荷≥700 N时,小粗隆置钉组压缩位移小于标准组,而其压缩刚度明显大于标准组,说明小粗隆置钉组有更强的抗压缩能力,能提供更好的抗压、抗弯曲性能和更稳定的内固定。

Objective To carry out biomechanical test for the overall stability of different positions of nail placement in proximal femoral intramedullary nail,so as to provide biomechanical basis for the improvement of nail placement directions in the locking nails of proximal femoral intramedullary nail.Methods A total of8Sawbones femur standard bones were selected from July2016to August2016were divided into two groups.They were given internal fixation of femoral intramedullary nail,and the proximal locking nails were placed in different directions.The axial compression experiment was performed after the middle femoral fracture model was prepared.The results of compressive displacements and compressive stiffness of the two groups under the same axial load were observed and compared.Results Under the same compressive load(except when the load was100N),the average displacements in the standard group were all greater than those in the control group.When the compressive load was at400N and above,the T fluctuation in the comparison of data in the two groups was2.522-3.135(P<0.05),and there were all statistically significant differences;in terms of the compressive stiffness:when the compressive load was at700N and above,the T fluctuation in the comparison of data in the two groups was2.481-3.275(P<0.05)and there were all statistically significant differences.Conclusion When the compressive load is≥700N,the compressive displacement in the small trochanter nail placement group is smaller than that in the standard group,and its compressive stiffness is significantly larger than that in the standard group,indicating that the small trochanter nail placement group has a stronger anti-compressive ability,which can provide better compression and bending resistance and more stable internal fixation.