Department of Biomedical Engineering, 3131 Engineering Hall, University of California, Irvine, CA, 92617, USA.
Department of Neurosurgery, Orthopedics, and Biomedical Engineering, Mayo Clinic School of Medicine, 200 1st St. SW, Rochester, MN, 55905, USA.
J Mech Behav Biomed Mater. 2024 Sep;157:106658. doi: 10.1016/j.jmbbm.2024.106658. Epub 2024 Jul 14.
Although the sacroiliac (SI) joint can be a source of lower back and buttock pain, no comprehensive characterization studies on SI cartilage have been conducted. Using the minipig as a large animal model, this study conducted the first biomechanical, biochemical, and histological characterization of SI joint cartilage. Because previous literature has reported that sacral cartilage and iliac cartilage within the SI joint are histologically distinct, concomitantly it was expected that functional properties of the sacral cartilage would differ from those of the iliac cartilage. Creep indentation, uniaxial tension, biochemical, and histological analyses were conducted on the sacral and iliac cartilage of skeletally mature female Yucatan minipigs (n = 6-8 for all quantitative tests). Concurring with prior literature, the iliac cartilage appeared to be more fibrous than the sacral cartilage. Glycosaminoglycan content was 2.2 times higher in the sacral cartilage. The aggregate modulus of the sacral cartilage was 133 ± 62 kPa, significantly higher than iliac cartilage, which only had an aggregate modulus of 51 ± 61 kPa. Tensile testing was conducted in both cranial-caudal and ventral-dorsal axes, and Young's modulus values ranged from 2.5 ± 1.5 MPa to 13.6 ± 1.5 MPa, depending on anatomical structure (i.e., sacral vs. iliac) and orientation of the tensile test. The Young's modulus of sacral cartilage was 5.5 times higher in the cranial-caudal axis and 2.0 times higher in the ventral-dorsal axis than the iliac cartilage. The results indicate that the sacral and iliac cartilages are functionally distinct from each other. Understanding the distinct differences between sacral and iliac cartilage provides insight into the structure and function of the SI joint, which may inform future research aimed at repairing SI joint cartilage.
虽然骶髂（SI）关节可能是下背部和臀部疼痛的来源，但目前尚未对 SI 关节软骨进行全面的特征描述研究。本研究以小型猪为大型动物模型，首次对 SI 关节软骨进行了生物力学、生物化学和组织学特征描述。由于先前的文献报道 SI 关节中的骶骨软骨和髂骨软骨在组织学上是不同的，因此预计骶骨软骨的功能特性将与髂骨软骨不同。对骨骼成熟的雌性尤卡坦小型猪的骶骨和髂骨软骨进行了压痕蠕变、单轴拉伸、生物化学和组织学分析（所有定量测试的 n=6-8）。与先前的文献一致，髂骨软骨似乎比骶骨软骨更具纤维性。骶骨软骨的糖胺聚糖含量高 2.2 倍。骶骨软骨的综合模量为 133±62kPa，明显高于髂骨软骨的 51±61kPa。拉伸测试分别在头尾轴和腹背轴进行，杨氏模量值范围为 2.5±1.5MPa 至 13.6±1.5MPa，取决于解剖结构（即骶骨与髂骨）和拉伸测试的方向。骶骨软骨在头尾轴上的杨氏模量比髂骨软骨高 5.5 倍，在腹背轴上高 2.0 倍。结果表明，骶骨和髂骨软骨在功能上彼此不同。了解骶骨和髂骨软骨之间的明显差异，为理解 SI 关节的结构和功能提供了线索，这可能为未来旨在修复 SI 关节软骨的研究提供信息。
