1.Traditional Chinese Medicine of Changzhou;2.the 2nd Affiliated Hospital of Soochow University;3.Institute of Orthopaedics, Soochow University
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。通过四点弯曲试验和扭转试验，根据弯曲载荷-弯曲位移和扭矩-扭转角度曲线的线性部分计算LCP组和LISS组的抗弯刚度和抗扭转刚度，采用配对t检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组的最大弯曲载荷、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）。前者的最大扭矩、最大扭转角度和抗扭转刚度均大于后者，差异具有统计学意义（P﹤0.05）。结论 LCP的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 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 4 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. Four point bending test and torsion test were performed until the internal fixation failed. The bending stiffness and the torsional stiffness of LCP group and LISS group were calculated from the linear curve of bending load- bending displacement and torque- torsional angle. The paired t -test was used to analyze the maximum bending load, maximum bending displacement, bending stiffness, maximum torque, maximum torsional angle and torsional stiffness of two groups. Results The maximum bending load, maximum bending displacement and bending stiffness of LCP group were all higher than those with LISS, 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 LISS group，there was a statistical difference between two groups (P < 0.05). Conclusion The stiffness of anti-torsion with LCP was significantly better than that of LISS. Consequently, LCP have better biomechanical stability for PPFF.