记忆合金三维内固定系统治疗髋臼骨折的生物力学研究

目的阐明按髋臼解剖学特点与镍钛合金的特性而设计的髋臼三维记忆内固定系统(acetabulartridimentionalmemoryalloyfixationsystem,ATMS)应用于髋臼骨折治疗的生物力学基础。方法从稳定性及头臼对应解剖与应力分布两个方面进行研究。6具成人新鲜骨盆股骨标本左右侧两两对应分为实验组与对照组,造成髋臼骨折模型后,实验组与对照组将骨折块复位,直视下分别用ATMS及重建钢板与螺钉紧密固定。制作可多向调节的万能旋转加载夹具,按前屈、后伸、直立三种状态从100N至500N进行加载,比较两组在经度及纬度方向的位移,分析髋臼骨折ATMS固定的稳定性;在直立位状态加载至500N,利用压敏片计算髋关节在前屈、后伸、直立三种状态下两组头臼接触面积及接触应力,分析髋臼骨折ATMS固定后头臼之间的解剖关系与应力分布状态。结果实验组与对照组在不同载荷、不同髋关节状态下测得的数据无显著的统计学差异。结论ATMS应用于髋臼骨折固定具有良好的稳定性、头臼对应解剖关系与应力分布状态。

Biomechanical study of acetabular tridimensional temoryalloy fixation system (ATMS) for treatment of acetabular fractures

Objective To elucidate the biomechanical foundation of Acetabular Tridimensional Memoryalloy - Fixation System (ATMS) for treatment of acetabular fractures. Methods The experiment consists of two parts, one is to study the stability of the fixed acetabulum posterior wall with ATMS, the other is to research the fitness of the femoral head and the fixed acetabulum as well as the stress distribution. Six fresh pelvis and femur specimens were divided into two groups, the experimental group consists of the left sides, and the control group consists of the right sides. After the fractures of the posterior wall were made, the acetabular fragments were replaced and were fixed by ATMS in the experimental group, whereas fixated by the plates and screws in the control group. A adjustable jig which can be adjusted in multiple directions was made. The specimens were loaded from 100N to 500N in three status: flexion, extension, and erection. The fixation in latitude and longitude of the two groups was compared, and the stability of fixation of posterior wall of the acetabulum was analyzed. The two groups were then loaded to 1000N in erection status. And the pressure-sensitive slices were used to calculate the contact area, the mean pressure and maximum pressure of anterior wall, superior aspect and posterior wall of the acetabulum, and to analyzed the fitness of femoral head and the acetabulum as well as the stress distribution. Results There was no significant difference between the two groups in the different status with different loads. It also showed that when loaded with 1000N, there was no significant difference between two groups in the contact area, mean pressure and maximum pressure of every part of acetabulum. Conclusion Fixation of posterior wall of the acetabulum with ATMS had good stability and good fitness and stress distribution of the femoral head and the repaired acetabulum.