三种内固定方法固定髋臼后壁骨折的力学研究

Biomechanical Evaluation on the Three Fixations of the Simulated Different Scale Fractures on the posterior Wall of Acetabulum

目的研究不同比例髋臼后壁骨折不同内固定方法的固定强度,以确定最理想的内固定方法。方法将18具骨盆标本制成左右配对的髋关节,随机分成三组,然后人为造成髋臼后壁关节面1/3骨折、2/3骨折、3/3骨折。用两枚皮质骨螺钉、重建钢板以及重建钢板加两枚皮质骨螺钉三种内固定方式固定每一组骨折,屈髋90°对模型分别进行生物力学测试,测量各组骨折块的分离位移及分离3 mm时的载荷,以比较不同比例后壁骨折不同内固定方法的固定强度。结果统计显示1/3比例骨折螺钉组与钢板、钢板加螺钉组间差别无意义(P>0.05),2/3、3/3比例骨折螺钉组与钢板、钢板加螺钉组间差别有显著意义(P<0.01),而钢板组与钢板加螺钉组之间差别无意义(P>0.05)。结论髋臼后壁1/3比例骨折,单用两枚皮质骨螺钉固定已经足够;2/3和3/3比例骨折以重建钢板内固定较为理想,在钢板之外再加两枚螺钉并不能增加内固定强度,反而增加了手术创伤及难度。

Objective To define the optimal internal fixation method by means of studying the strength of various internal fixations of simulated different scale fractures On posterior acetabular wall. Methods Eighteen cadaveric pelvis were made into hip lioints,divided into three groups randomly. Then cause the fracture of 1/3,2/3 and 3/3 articular surface of the posterior wall of acetabulum. The models were fixed with one of the three different methods ： two cortical screws （CS）, reconstruction plate （RP） , and reconstruction plate plus two cortical screws （CS ＋ RP）. Then tests were performed on each model with 90 flexion of the hip. Measure the displacements of the fragments and the loadings when the displacements were 3 mm. Results There is no significant difference between the CS and RP or RP ＋CS（P〉0.05）in the group of 1/3 fracture,but with significance （P〈0.01）in the groups of 2/3 and 3/3 fractures, and no significance between the RP and RP＋CS（P〉0.05）. Conclusion It is enough stability when fix the 1/3 fracture with CS only;the ideal method of intemal fixation of 2/3 and 3/3 fracture of the posterior wall of acetabulum is RP,while RP＋CS is not stronger than RP only and it may add more operative trauma and difficulty to operate.