正常步态下髋臼底接触面积与压力分布的三维有限元分析

背景：认识髋关节的正常压力分布特点,将有助于进一步了解正常髋关节的力学机制与异常载荷下关节软骨的病理学行为。目的：运用三维有限元的方法,分析正常步态过程中头臼间接触面积和应力分布情况。方法：应用CT扫描技术和计算机图像处理系统,建立髋臼的三维有限元模型,利用髋臼模型模拟髋臼在完整步态过程中连续32个位相时的受力状况,并对各位相时接触面积进行计算。结果与结论：获得了髋臼在32个位相时的应力峰值分布呈双峰形,在起步位相时达到峰值（4.2MPa）,支撑期接触面积明显高于跨步期。始终接触部位集中在髋臼顶部,偏内侧,而髋臼前角与后角始终没有应力传导。髋臼软骨在不同位相的应力分布明显不同,支撑期应力增高区分布在臼顶区,而跨步期应力增高区在臼软骨的内侧缘。结果显示髋臼的接触应力增高区及接触面的分布对临床研究有重要意义,可提示导致髋臼骨性关节炎的好发因素。

Three-dimensional finite analysis of hip contact area and contact pressure during normal walking

BACKGROUND：Estimation of the hip joint contact area and pressure distribution during activities of daily living is important in predicting joint degeneration mechanism,prosthetic implant wear,providing biomechanical rationales for preoperative planning and postoperative rehabilitation.OBJECTIVE：To explore the hip joint contact area and pressure distribution during different trait phases,which is important in predicting joint degeneration mechanism.METHODS：CT scanning and computer image processing system were used to establish the model to simulate the situation of acetabulum for 32 phases during the trait.A finite element solves was used to calculate stress and contact area.RESULTS AND CONCLUSION：Stress distribution within the acetabular cartilage was obtained and regions with elevated stress at 32 phases were located.The stress distributions of 32 phases were significantly different.The stress demonstrated the bimodal shape of a pronounced phush-off often seen in trial gait cycle（4.2 MPa）.The regions of elevated stress and contact area of acetabulum both occurred during stance phases of a gait cycle.Persistent stress-transfer located on medial roof,while on anterior and posterior horn there is always no stress-transfer.The elevated stress located roof during stance phases and medial acetabular cartilage during swing-phases respectively.These results can be used to rationalize rehabilitation protocols,functional restrictions after complex acetabular reconstructions,the renions of elevated stress and contact area of acetabulum are important,which provide an insight into the factors contribution to the arthritis.