锁定加压接骨板固定股骨近端假体周围骨折的生物力学分析

Biomechanical Analysis on Locking Compression Plate for Fixing Periprosthetic Proximal Femur Fracture

目的评价锁定加压接骨板(locking compression plate,LCP)固定股骨近端假体周围骨折(periprosthetic proximal femur fracture,PPFF)的生物力学强度。方法采用LCP和倒置股骨远端微创锁定接骨板(less invasive stabilization system,LISS)分别固定8对左、右配对的Vancouver B1型成人尸体PPFF标本,假体柄对应长度的股骨分别采用4枚双层皮质锁定螺钉固定(LCP组)和4枚单层皮质锁定螺钉固定(LISS组),骨折远端均采用4枚双层皮质锁定螺钉固定,两种接骨板使用锁定螺钉的螺孔距骨折端的距离相等。通过4点弯曲试验和扭转试验,对比分析两组的最大弯曲载荷、最大弯曲位移、抗弯刚度、最大扭矩、最大扭转角度和抗扭转刚度。结果 LCP组最大弯曲载荷、最大弯曲位移和抗弯刚度均大于LISS组,但差异无统计学意义(P>0.05)。LCP组最大扭矩、最大扭转角度和抗扭转刚度均大于LISS组,差异具有统计学意义(P<0.05)。结论 LCP抗扭转刚度明显优于LISS,对PPFF固定的力学稳定性更好。

Objective To evaluate biomechanical strength of locking compression plate( LCP) for fixation of periprosthetic proximal femur fractures( PPFF). Methods Eight matched pairs of Vancouver type B1 adult cadaveric PPFF specimens were fixed with the LCP and the inverted distal femoral less invasive stabilization system( LISS),respectively. Four bicortical locking screws( LCP group) and four unicortical locking screws were used to the length of prosthesis stem,and four double cortical locking screws were used to fix the distal end of the fracture in two groups,the distance from the locking screws to the fracture were also equal. The maximum bending load,maximum bending displacement,bending stiffness,maximum torque,maximum torsional angle and torsional stiffness of two groups in four-point bending test and torsion test were compared and analyzed.Results The maximum bending load,maximum bending displacement and bending stiffness of LCP group were all larger than those of LISS group,but the difference was not statistically significant( P> 0. 05). The maximum torque,maximum torsional angle and torsional stiffness of LCP group were obviously larger than those of LISS group,and there was a statistical difference between two groups( P<0. 05). Conclusions The stiffness of antitorsion with LCP is significantly better than that with LISS. Consequently,LCP has better biomechanical stability for PPFF.