Institute of Biomedical Manufacturing and Life Quality Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Shanghai 200240, China.
Department of Trauma and Orthopedics, Shanghai First People's Hospital, Medical School, Shanghai Jiao Tong University, No. 650, New Songjiang Road, Shanghai 201620, China.
Med Eng Phys. 2014 Jun;36(6):745-53. doi: 10.1016/j.medengphy.2014.01.002. Epub 2014 Feb 6.
The anterior part of the sacroiliac joint (SIJ) is a synovial joint, with little gliding and rotary movement between the contact surfaces of SIJ during locomotion. Due to its complex structure, especially when considering the surrounding ligaments, it is difficult to construct an accurate three-dimensional (3-D) finite element model for the human pelvis. Most of the pelvic models in the previous studies were simplified with either SIJ fusing together or without the sacral bone. However, the influence of those simplifications on the load transmission in human pelvis has not been studied, so the reliability of those studies remains unclear. In this study, two 3-D pelvic models were constructed: an SIJ fusing model and an SIJ contacting model. In the SIJ fusing model, the SIJ interfaces were fused together. In the SIJ contacting model, the SIJ interfaces were just in contact with each other without fusion. Compared with the SIJ contacting model, the SIJ fusing model have smaller movements in the SIJ. The stress distribution area in the SIJ fusing model on sacroiliac cartilages was also different. Those differences contributed to the decline of tensile force in the SIJ surrounding ligaments and the re-distribution of stress in the pelvic bones. In addition, the SIJ fusing model was far less sensitive to the increase in modulus of the sacroiliac cartilages, and decrease in stiffness of the ligaments surrounding the SIJ. The presence of synovia in the SIJ had greater influence on the load transmission in the human pelvic system. Therefore, the effect of the presence of synovia should not be neglected when the biomechanical behavior of human pelvis is being studied, especially for those studies related to clinical applications.
骶髂关节（SIJ）的前部分是一个滑膜关节，在运动过程中，SIJ 接触面之间的滑动和旋转运动很小。由于其复杂的结构，尤其是考虑到周围的韧带，很难为人体骨盆构建一个准确的三维（3-D）有限元模型。以前的研究中大多数骨盆模型都进行了简化，要么是将 SIJ 融合在一起，要么是没有骶骨。然而，这些简化对人体骨盆中力的传递的影响尚未得到研究，因此这些研究的可靠性仍不清楚。在这项研究中，构建了两个 3-D 骨盆模型：一个 SIJ 融合模型和一个 SIJ 接触模型。在 SIJ 融合模型中，SIJ 界面融合在一起。在 SIJ 接触模型中，SIJ 界面只是相互接触而没有融合。与 SIJ 接触模型相比，SIJ 融合模型中的 SIJ 运动幅度较小。SIJ 融合模型中骶髂软骨的应力分布区域也不同。这些差异导致了 SIJ 周围韧带中的张力下降和骨盆骨中的应力重新分布。此外，SIJ 融合模型对骶髂软骨模量的增加和 SIJ 周围韧带刚度的降低不那么敏感。SIJ 中的滑膜的存在对人体骨盆系统中的力传递有更大的影响。因此，在研究人体骨盆的生物力学行为时，不应忽视滑膜的存在的影响，特别是对于那些与临床应用相关的研究。
