Skaggs D L, Warden W H, Mow V C
Department of Orthopaedic Surgery, Columbia-Presbyterian Medical Center, New York, New York 10032.
J Orthop Res. 1994 Mar;12(2):176-85. doi: 10.1002/jor.1100120205.
Although collagen fibers are arranged predominantly in the circumferential direction in the knee meniscus, there is evidence for radially oriented fibers within human menisci. A bovine medial meniscus model was used to study the hypothesis that radial fibers alter the radial tensile properties of the meniscus. The architecture of the collagen network and tensile properties of the bovine medial meniscus were examined; attention was given to large "radial tie fibers" and their regional variation. Menisci were sectioned serially into slices 400 microns thick. Polarized light microscopy showed that the distribution of radial tie fibers varied greatly among the anterior, central, and posterior regions. These radial tie fibers were larger and more frequent in the posterior region. Radial fibers persisted over many adjacent sections with similar architecture, which led to our hypothesis that they may be arranged in continuous sheets in which the morphology varies by region. Radially oriented specimens for tensile testing were grouped according to the number of radial tie fibers (full, partial, and no fiber) and region (anterior, central, and posterior). Uniaxial tensile testing was performed on a testing machine at a strain rate of 0.00017 sec-1 until failure. The tensile modulus, ultimate tensile stress, and ultimate tensile strain were determined. The presence of radial tie fibers in the specimen had a significant effect on the tensile modulus and ultimate tensile stress. Specimens containing full radial tie fibers were stiffest and failed at the lowest strains; in specimens from the posterior region, the tensile modulus was 392%, the ultimate tensile stress was 314%, and the ultimate tensile strain was 68% that of the specimens with no radial fibers. In no-fiber specimens, the tensile modulus in the posterior region was 225% of the modulus in the anterior region, and the ultimate tensile strain in the posterior region was 68% that of the strain in the anterior region. The abundance of radial tie fibers in the posterior region seems to contribute to the increased stiffness of this region. The preferential stiffening of the posterior region by these radial fibrous sheets may be well suited to the manner in which the bovine medial meniscus functions in load-bearing.
尽管在膝关节半月板中胶原纤维主要沿圆周方向排列，但有证据表明人类半月板内存在径向排列的纤维。使用牛内侧半月板模型来研究径向纤维改变半月板径向拉伸特性的假说。研究了牛内侧半月板胶原网络的结构和拉伸特性；重点关注大的“径向连接纤维”及其区域差异。半月板被连续切成400微米厚的薄片。偏振光显微镜显示，径向连接纤维在前部、中部和后部区域的分布差异很大。这些径向连接纤维在后部区域更大且更常见。径向纤维在许多相邻切片中持续存在，结构相似，这使我们推测它们可能排列成连续的薄片，其形态因区域而异。根据径向连接纤维的数量（完整、部分和无纤维）和区域（前部、中部和后部）对用于拉伸测试的径向取向标本进行分组。在测试机上以0.00017秒-1的应变率进行单轴拉伸测试，直至破坏。测定拉伸模量、极限拉伸应力和极限拉伸应变。标本中径向连接纤维的存在对拉伸模量和极限拉伸应力有显著影响。含有完整径向连接纤维的标本最硬，在最低应变下破坏；在后部区域的标本中，拉伸模量是无径向纤维标本的392%，极限拉伸应力是314%，极限拉伸应变是68%。在无纤维标本中，后部区域的拉伸模量是前部区域模量的225%，后部区域的极限拉伸应变是前部区域应变的68%。后部区域丰富的径向连接纤维似乎有助于该区域硬度的增加。这些径向纤维片对后部区域的优先强化可能非常适合牛内侧半月板在承重中的功能方式。
