重建钢板与记忆合金固定髋臼后壁骨折的生物力学对比研究

Biomechanical Comparative Study of Posterior Wall Acetabular Fracture Fixation Between Reconstruction Plate and Memory Alloy

目的对比髋臼重建钢板与记忆合金固定髋臼后壁骨折的生物力学特点。方法福尔马林尸体骨盆标本8个,设置4个工况:后壁完整组、后壁缺损组、钢板固定组和记忆合金固定组。应用压敏片法测量并比较分析髋臼的前壁、上壁和后壁区域内的接触面积和压力。结果与后壁完整组相比,后壁缺损组的髋臼前壁和后壁负荷减少(P值分别为0.002、0.005),上壁区域负荷增加(P=0.003)。钢板固定组前壁和上壁的负荷明显不同于后壁完整组的前壁和上壁的负荷(P值分别为0.008、0.018),而后壁区域的负荷两者相比无统计学差异(P=0.151)。记忆合金固定组上壁和后壁区域的负荷与后壁完整组相比无统计学差异(P值分别为0.725、0.892),而前壁区域的负荷与后壁完整组相比降低(P=0.039)。结论这些数据表明,使用髋臼记忆合金作为髋臼后壁骨折的内固定装置可使髋关节内部分负荷参数趋向于后壁完整组。与重建钢板组相比,可改善髋关节内的负荷分布,更有益于髋臼后壁骨折的固定,从而减少术后创伤性髋关节炎发生率。

Objective To compare biomechanical characteristics of posterior wall acetabular fractures fixation between acetabular reconstruction plate and memory alloy.Methods Eight formalin cadaveric pelvis specimens were set up,and with four conditions：complete posterior wall group,posterior wall defect group,plate fixation group and memory alloy fixation group.The contact areas and pressures in the anterior,superior and posterior regions of acetabulum were measured and compared by pressure-sensitive tablet method.Results Compared with posterior wall intact group,the acetabular loads on the anterior and posterior wall were reduced in posterior wall defect group（P=0.002,0.005,respectively）,and the superior region was increased（P=0.003）.The acetabular loads on the anterior and superior walls of plate fixation group were significantly different than those of posterior wall intact group（P=0.008,0.018,respectively）,while there was no statistical difference in the load of posterior wall between two groups（P=0.151）.Compared with posterior wall intact group,the acetabular loads on the superior and posterior walls of memory alloy fixation group were not significantly different（P=0.725,0.892,respectively）,but the acetabular load on the anterior wall of memory alloy fixation group was significantly lower（P=0.039）.Conclusion These data indicate that the use of acetabular memory alloy as an internal fixation device for posterior wall acetabulum fracture makes the partial load parameters of hip joint tending to the complete posterior wall group.When compared with reconstruction plate,it can improve the load distribution of hip joint,conduce to fixation of posterior wall acetabular fracture,and with less occurrence rate of postoperative traumatic hip arthritis.