股骨静力交锁髓内钉生物力学性能及对骨折愈合的影响

背景:交锁髓内钉是治疗股骨骨折的常用内固定器械,术中是否常规提拉加压,以及术后是否及时动力化,对骨折愈合起着至关重要的作用,如何通过干扰各种因素来提高骨折愈合率是人们研究的重点.目的:观察股骨静力交锁髓内钉生物力学性能及对骨折愈合的影响.方法:采用甲醛浸泡的成人尸体股骨标本8对,制成中段横形骨折模型后分别用静力型交锁髓内钉(髓内钉组)、TiNi环抱式接骨板(环抱器组)、有限接触动力加压接骨板(加压钢板组)固定,测试抗轴向压缩、抗三点弯曲和抗扭转力学性能,计算应力遮挡率.结果与结论:髓内钉组与加压钢板组相比,抗轴向压缩性能和抗三点弯曲性能相当(P>0.05),但抗扭转性能较弱(P<0.05);与环抱器组相比,抗轴向压缩性能和抗三点弯曲性能较强(P<0 05),而抗扭转性能差异无显著性意义(P>0.05);髓内钉组的应力遮挡率与加压钢板组差异无显著性意义(P>0.05),明显高于环抱器组(P<0.01).提示交锁髓内钉的生物力学稳定性可靠,但应力遮挡率较高,临床应用时需及时对其动力化,促进骨折愈合.

Biomechanical performance and effect of static interlocking intramedullary nails on femoral fracture healing

BACKGROUND: Interlocking intramedullary nails(SliN)is frequently used to treat femoral fracture.Routine pulling and compression and postoperative motorization are important for fracture healing.To improve fracture healing rate has been focused using various factors.OBJECTIVE: To explore the biomechanical performance of static SliN in fixation of femoral fracture,and the effect on fracture healing.METHODS: A total of 8 pairs of femurs from adult cadavers immersed in formalin were used to prepare models of midpiece transverse fracture.The fracture was respectively fixed using static SliN,TiNi shape-memory sawtooth-arm embracing internal fixator(TiNi SMA),and dynamic compression plate(DCP).The anti-compression,anti-bending,and anti-torsion rigidity were measured,and the stress shielding rate was calculated.RESULTS AND CONCLUSION: SliN was similar to DCP group in anti-compression rigidity and anti-bending rigidity(P > 0.05),but the anti-torsion was lower than DCP group(P<0.05).Compared with TiNi SMA group,SliN displayed greater anti-compression rigidity and anti-bending rigidity(P<0.05),but similar anti-torsion(P > 0.05).SliN was similar to DCP group in stress shielding rate(P>0.05),but significantly greater than TiNi SMA group(P<0.01).The biomechanics of SliN was stable,but the stress shielding rate was high.Changing static interlocking into dynamic interlocking in time is necessary in clinic to promote fracture healing.