髋臼前壁骨折模型的建立及不同内固定方式的生物力学稳定性比较

Establishment of acetabular anterior wall fracture model and comparison of biomechanical stability of different internal fixation methods

目的建立髋臼前壁骨折模型,比较4种内固定方式的生物力学稳定性。方法选取20个防腐成人半骨盆标本,建立髋臼前壁骨折模型。将骨折模型随机分为4组,A组采用真骨盆上缘重建接骨板固定,B组采用真骨盆内缘重建接骨板固定,C组采用顺行拉力螺钉固定,D组采用逆行拉力螺钉固定。对各组标本进行轴向压缩实验,测量骨折断端水平位移,计算剪切刚度,比较4组不同内固定方式的稳定性。结果相同加载载荷下,骨折断端水平位移:A组>B组>C组>D组,内固定剪切刚度:D组>C组>B组>A组。载荷为400 N时各组水平位移及内固定剪切刚度差异均无统计学意义(P>0.05),载荷为800 N至2000 N时,除C组与D组间水平位移及内固定剪切刚度差异无统计学意义外(P>0.05),其余各组间比较差异均有统计学意义(P<0.05)。结论髋臼前壁骨折模型可用于髋臼前壁骨折的生物力学分析,采用拉力螺钉固定髋臼前壁骨折的稳定性高于重建接骨板固定方式,其中顺行拉力螺钉固定与逆行拉力螺钉固定的稳定性相似。

Objective To establish the acetabular anterior wall fracture model and compare the biomechanical stability of 4 kinds of internal fixation methods. Methods 20 fresh adult half pelvis specimens were selected to establish the acetabular anterior wall fracture model. The fracture models were randomly divided into 4 groups. Models in group A was fixed with a reconstruction plate along the upper margin of the pelvis, in group B was fixed with a reconstruction plate along the inner margin of the pelvis, and in group C was fixed with an antegrade lag screw, and in group D was fixed with a retrograde lag screw. The axial compression experiments were performed to measure the horizontal displacement of the fracture end in each group, and the shear rigidity was calculated. The biomechanical stability of the 4 groups was compared. Results Under the same load, the horizontal displacement of the fracture end： group A 〉group B 〉group C〉group D; the internal fixation shear rigidity： group D〉group C〉group B〉group A. There was no significant difference between the 4 groups in the horizontal displacement and the shear rigidity of internal fixation when the load was 400 N （P〉0.05）. When the load was 800 N to 2000 N, there was no significant difference between group C and group D in the horizontal displacement and the shear rigidity of internal fixation （P〉0.05）, and there was significant difference between the other groups （P〈0.05）. Conclusions The acetabular anterior wall fracture model established in this study can be used for biomechanical analysis of acetabular anterior wall fracture. The stability of lag screw fixation was higher than that of reconstruction plate fixation, and the stability of antegrade lag screw fixation was similar to that of retrograde lag screw fixation.