骨盆骨折畸形愈合对骶髂关节和髋关节影响的生物力学及有限元研究

Malunited pelvic fractures are commonly seen in clinic, in which rotational deformity and (or) angular deformity with or without malalignment are the most common manifestations. Such complication may lead to osteoarthritis, subsequently impairing the long-term functional recovery. For the patients with severe symptoms, secondary or salvage surgery will be required. However, current literatures only focused on the treatment of pelvic malunion, and no data concerning the specific relationship between the deformity and osteoarthritis was available. This project intends to produce the malunited fractures of pelvic with various deformities on the cadaveric specimens. Meanwhile, radiographic measurement and biomechanical test will be employed to explore the correlation between the deformity and alignment deviation of lower extremities and to evaluate the effect of various deformities on weight- bearing area and stress distribution of hip and sacroiliac joint. Moreover, three dimensional finite element models of malunited pelvic fractures with various rotational and angular deformities will be established. These models will also be employed to explore the correlation between the deformity and malalignment of lower extremitis, and to evaluate the effect of various deformaties on the weight-bearing area and stress distribution of hip and sacroiliac joint. The scientificity nand reliability of the study will be analyzed by comparing the biomechanical test and the finite element analysis. Based upon the systematic study, the quantitative relationship between bearing-area and stress distribution of knee joint and various residual deformity and malalignment will be analyzed, which will provide a scientific basis for assessing the quality of minimally invasive reduction of pelvic fractures and propose further reduction standards of minimally invasive treatment for pelvic fractures.

骨盆骨折术后畸形愈合在临床中较为常见，其表现形式常为旋转畸形和（或）垂直方向畸形。畸形愈合可导致骶髂关节和髋关节骨性关节炎，但目前尚没有畸形程度与骨关节炎具体关系的相关研究。本研究通过制作骨盆骨折不同程度畸形愈合模型，利用生物力学研究手段，考量不同程度骨盆畸形愈合与力线偏移的关系，考量骨盆不同程度畸形导致髋关节和骶髂关节负重面积和应力分布的改变。本研究将建立残留不同程度畸形的骨盆三维有限元模型，考量不同程度畸形与力线偏移的关系，考量骨盆畸形愈合导致骶髂关节和髋关节负重面积和应力分布的改变。通过将生物力学实验和有限元分析对比来验证研究结果的科学性、可靠性，系统分析上述数据，综合考量骨盆骨折愈合后不同程度畸形与关节负重面积和应力改变的量化关系，为临床上评估骨盆骨折复位质量提供科学依据，提出治疗骨盆骨折的复位标准。

骨盆骨折约占成人骨折的3.64%，致伤原因多高能量损伤，其中68.3%的骨盆骨折为不稳定骨折，是一种严重的创伤，死亡率高达19%。许多患者同时合并颅脑、胸、腹损伤，为抢救生命而延误了骨盆骨折的手术时机，骨盆手术常不能完成，只能使用牵引作为最终治疗，但牵引术难以达到骨折解剖复位，易使骨盆骨折最终畸形愈合。除此以外，骨盆骨折切开复位内固定术后由于复位不良或再次移位所致的畸形愈合也不少见，其表现形式常为旋转畸形和垂直方向畸形。骨盆畸形愈合可导致骶髂关节和髋关节骨性关节炎导致患者丧失劳动能力。由于骨盆结构复杂，血管及重要脏器丰富，一旦发生有症状的畸形愈合将会对治疗造成巨大困难。但目前尚无研究表明何种程度的畸形愈合可以避免术后出现骨性关节炎。若能够通过数学建模或三维有限元等手段反映骨盆骨折畸形愈合后的生物力学特点，将对治疗产生巨大积极推动作用。本研究制作骨盆骨折不同程度畸形愈合的标本模型，使用压敏片测量了开书型骨盆骨折畸形愈合、侧方挤压型骨盆骨折畸形愈合和垂直剪切型骨盆骨折畸形愈合模型中髋关节和骶髂关节负重面积和应力分布的改变。测量不同程度骨盆畸形愈合时下肢力线偏移的程度。建立不同程度畸形的骨盆三维有限元模型，测量骨盆畸形愈合后骶髂关节和髋关节负重面积和应力分布的改变情况。实验生物力学和三维有限元分析结果显示骨盆骨折畸形愈合后会影响髋关节和骶髂关节的应力，同时开书型骨盆畸形愈合和侧方挤压型骨盆畸形愈合会影响下肢力线和中轴线的距离。本实验结果用以指导牵引治疗骨盆骨折复位标准的确立和难复位型骨盆骨折手术过程中的复位质量的判断。