School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado, USA.
Department of Biomedical Engineering, University of Massachusetts, Amherst, Massachusetts, USA.
Connect Tissue Res. 2022 Mar;63(2):151-155. doi: 10.1080/03008207.2021.1890723. Epub 2021 Mar 1.
PURPOSE/AIM: The knee menisci are vital for maintaining the stability of the joint, allowing for force distribution, and protecting the underlying articular cartilage during loading. Each meniscus is attached to the underlying bone via two ligamentous entheses composed of collagen fibers that are continuous throughout all four zones of the attachment: ligament, uncalcified fibrocartilage, calcified fibrocartilage, and subchondral bone. The collagen fibers of the meniscal entheses are important for proper functionality of the entheses, particularly in preventing meniscal extrusion which is a common hallmark of osteoarthritis. The goal of this work was to assess changes in collagen fiber orientation present in osteoarthritic knee joints.
Entheses were harvested from patients undergoing total knee arthroplasties and prepared histological sections were stained with picrosirius red to identify collagen fiber angle and fiber deviation.
In the calcified fibrocartilage the collagen fibers of the lateral anterior enthesis inserted at significantly (p < 0.1) shallower angles, and the fiber deviation was significantly (p < 0.1) less compared to the lateral posterior enthesis. These differences in the calcified fibrocartilage may occur as an adaptation to loading regimes of the osteoarthritic joint. When compared to the collagen fiber orientation of healthy entheses, collagen fibers in osteoarthritic tissue inserted at shallower insertion angles and demonstrated higher levels of deviation.
Changes to meniscal enthesis collagen fiber orientation with end stage osteoarthritis could offer an explanation for the change in functionality of diseased tissue and may contribute to meniscal extrusion and ultimately the degeneration of articular cartilage.
目的/目标：膝关节半月板对于维持关节稳定性、力的分布以及在负重时保护下方关节软骨至关重要。每个半月板都通过两个由胶原纤维组成的韧带附着点附着在下方的骨上，这些胶原纤维贯穿附着的四个区域：韧带、未钙化纤维软骨、钙化纤维软骨和软骨下骨。半月板附着处的胶原纤维对于附着处的正常功能很重要，特别是在防止半月板挤出，这是骨关节炎的一个常见特征。这项工作的目的是评估骨关节炎膝关节中存在的胶原纤维方向的变化。
从接受全膝关节置换术的患者中采集附着点，并制备组织学切片，用苦味酸天狼星红染色来识别胶原纤维角和纤维偏斜。
在钙化纤维软骨中，外侧前附着处的胶原纤维以明显（p < 0.1）较浅的角度插入，纤维偏斜明显（p < 0.1）小于外侧后附着处。钙化纤维软骨中这些差异的发生可能是对骨关节炎关节的负荷模式的适应。与健康附着处的胶原纤维方向相比，骨关节炎组织中的胶原纤维以较浅的插入角度插入，并表现出更高水平的偏斜。
终末期骨关节炎时半月板附着处胶原纤维方向的变化可能解释了病变组织功能的变化，并可能导致半月板挤出，最终导致关节软骨退化。
