Abstract：
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.
摘要：
虽然骶髂关节可能是下背部和臀部疼痛的来源，尚未对SI软骨进行全面的表征研究。使用小型猪作为大型动物模型，这项研究进行了第一次生物力学，生物化学，SI关节软骨的组织学特征。因为以前的文献报道SI关节内的骶骨软骨和髂软骨在组织学上是不同的，同时，预计the骨软骨的功能特性将与the骨软骨的功能特性不同。蠕变压痕,单轴张力,生物化学，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组织学分析（所有定量试验n=6-8）。与先前的文献一致，髂软骨似乎比骶骨软骨有更多的纤维性。骶软骨中糖胺聚糖含量高2.2倍。骶骨软骨的总模量为133±62kPa,显著高于髂软骨，其仅具有51±61kPa的聚集体模量。在颅尾轴和腹背轴进行拉伸测试，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vs.iliac）和拉伸试验的方向。骶骨软骨的杨氏模量在颅尾轴中比在腹背轴中高5.5倍，在腹背轴中高2.0倍。结果表明，the骨和the软骨在功能上彼此不同。了解骶骨和髂软骨之间的明显差异可以深入了解SI关节的结构和功能，这可能为未来的研究提供信息，旨在修复SI关节软骨。
