髋臼骨折不同内固定方式的生物力学稳定性研究

目的:探讨3种不同的内固定方式固定髋臼双柱骨折的生物力学稳定性。方法 :16个髋关节标本随机分为4组,其中1组完整髋臼作为正常对照组,其余3组模拟双柱骨折后,分别按下列方法内固定:前柱螺钉加后柱钢板(SP),前柱钢板加后柱螺钉(PS),后柱双钢板(PP)。通过连续垂直加载,记录骨折的位移程度和髋臼的接触特性。结果:在载荷800 N时,SP、PS和PP 3组髋臼平均纵向位移位分别为(1.92±0.81)、(2.09±1.13)、(3.44±0.75)mm,SP与PP组比较差异有统计学意义(P=0.033)。SP、PS和PP 3组髋臼平均横向位移位分别为(0.63±0.33)、(0.77±0.45)、(1.44±0.56)mm,SP组与PS组相比较差异有统计学意义(P=0.047)。800 N载荷压力下,在髋臼负重区,与正常对照组相比,SP、PS和PP组分别接触面积增加了6%、9%和27%,其中PP组与正常对照组差异存在统计学意义(P=0.027);在髋臼负重区,与正常对照组相比,SP、PS和PP组平均应力分别增加了4%、29%和39%,其中PP组与正常对照组差异存在统计学意义(P=0.003)。结论:在生物力学的稳定性和接触性方面,前柱螺钉加后柱钢板有较大优势。

Biomechanical stability study on different internal fixation for acetabular fracture

Objective: To investigate the biomechanical stability of the acetabular fracture with three different internal fixation methods.Methods: Sixteen both-column acetabular fracture models were randomly divided into three groups:The specimens of 16 hip joints were randomly divided into 4 groups. Among them, 1 group of complete acetabulum were used as normal control group, and the other 3 groups simulated two column fracture models and were fixed in the following methods, respectively:anterior wall with screw and posterior with plate (SP), anterior wall with plate and posterior wall with screw (PS) and both wall with plate (PP). The degree of fracture displacement and the contact characteristics of the acetabulum were recorded by continuous vertical loading.Results: The mean longitudinal displacement under the load 800 N of SP, PS and PP three groups were (1.92±0.81), (2.09±1.13) and (3.44±0.75) mm, there was significant difference between SP and PP group (P=0.033). And the mean horizontal displacement of SP, PS and PP three groups were (0.63±0.33), (0.77±0.45) and (1.44±0.56) mm, there was significant difference between SP and PP group (P=0.047).Compared with normal control group in the acetabular area under the loading 800 N, the contact area of SP, PS and PP groups were increased by 6%, 9% and 27%, there was significant difference between PP and normal control group (P=0.027). Meanwhile, the mean stress of SP, PS and PP groups were increased by 4%, 29% and 39%, there was significant difference between PP and intact acetabulum group (P=0.003).Conclusion: Anterior column screw combined with posterior column plate has better biomechanical stability and contact characteristics than other two methods.