构建关节软骨的滚压加载装置

背景：通常使用的加载装置或反应器有灌流式生物反应器、液压系统、直接动态压缩装置、剪切系统、拉伸装置或其中部分的组合。以上每一种载荷单独作用都没有实现软骨功能化培养,但即使是这几种的组合也不足以表征软骨的力学状态,构建的软骨功能与天然软骨仍有较大差距。 目的：首次提出和研制了一种用于关节软骨构建的滚压加载装置,并在滚压加载条件下分析软骨的受力状态。 方法：该装置包括滚动控制系统和压缩调节机构。滚动控制系统通过步进电机、丝杠控制辊子滚动速度,由齿轮和齿条啮合形成辊子纯滚动,辊子能够以均匀速度滚过培养物。压缩调节机构通过楔形滑块的相对滑动可以保证工作面平行升降,从而可以对培养物产生均匀、可调的压缩量。 结果与结论：该装置对培养物提供了滚压的力学条件,使培养物处于动态压缩变形和剪切变形的复合加载过程。在滚压的力学条件下,有限元分析表明培养物受到复杂力学状态。培养物浅表层受到交替出现的压力、拉应力;中层在滚动方向平面内应力与表面有一定夹角,角度由-45°~+45°呈周期变化;深层处应力都为压应力,与3个坐标轴方向接近。该装置的加载运动方式与关节的运动方式一致,滚压加载可能有利于功能化关节软骨结构、功能的构建。     

Micro-anatomical response of cartilage-on-bone to compression: mechanisms of deformation within and beyond the directly loaded matrix

The biomechanical function of articular cartilage relies crucially on its integration with both the subchondral bone and the wider continuum of cartilage beyond the directly loaded contact region. This study was aimed at visualizing, at the microanatomical level, the deformation response of cartilage including that of the non-directly loaded continuum. Cartilage-on-bone samples from bovine patellae were loaded in static compression until a near-equilibrium deformation was achieved, and then chemically fixed in this deformed state. Full-depth cartilage-bone sections, incorporating the indentation profile and beyond, were studied in their fully hydrated state using differential interference contrast microscopy. Morphometric measurements of the indented profile were used in combination with a force analysis of the tangential layer to investigate the extent to which the applied force is attenuated in moving away from the directly loaded region. This study provides microscopic evidence of a structure-related response in the transitional zone of the cartilage matrix. It is manifested as an intense chevron-type shear discontinuity arising from the constraints provided by both the strain-limiting articular surface and the osteochondral attachment. The discontinuity persists well into the non-directly loaded continuum of cartilage and is proposed as a force attenuation mechanism. The structural and biomechanical analyses presented in this study emphasize the important role of the complex microanatomy of cartilage, highlighting the interconnectivity and optimal recruitment of the load-bearing elements throughout the zonally differentiated cartilage depth.     

Osteochondritis dissecans of the elbow: histopathological assessment of the articular cartilage and subchondral bone with emphasis on their damage and repair

Osteochondritis dissecans (OCD) of the elbow is a localized injury of the articular cartilage and subchondral bone that is commonly seen in the young athlete. In the present study, the extent of damage and repair on the articular cartilage and subchondral bone was examined histologically using specimens of 25 osteochondral cylinders and seven loose bodies obtained from 25 young athletes who had undergone osteochondral autograft surgery. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assays for detecting apoptotic cells and immunohistochemistry of matrix metalloproteinases (MMP) were performed on the osteochondral cylinder specimens. The histological findings of the OCD of the elbow showed that the articular cartilage exhibited degenerative change, mimicking osteoarthritis, and was markedly damaged as the lesion progressed. TUNEL-positive cells and MMP-3- and -13-expressing cells were distributed in the degenerative articular cartilage and reparative fibrocartilage tissue. Separation occurred at either the deep articular cartilage or the subchondral bone, with the former being dominant in the early OCD lesions. The present results suggest that the primary pathological changes in OCD of the elbow were due to damage of articular cartilage induced by repeated stress following degenerative and reparative process of articular cartilage and subchondral fracturing, and separation subsequently occurred on the cartilage and developed onto the subchondral bone in its advanced stages.     

Which morphology of dry bone articular surfaces suggests so-called fibrous ankylosis in the elderly human sacroiliac joint?

Usually, joint degeneration with aging results in articular cartilage defects, which results in bony ankylosis. However, the sacroiliac articular cartilage is maintained even in the elderly and the fibrous tissues make so-called 'fibrous ankylosis'. Macroscopically and histologically, we observed two sacroiliac joints obtained from one young cadaver as well as 23 sacroiliac joints from 23 elderly cadavers. Each joint was divided into two pieces along the long axis: one half was processed for routine histology after decalcification, whereas the other half was macerated to provide a dry bone specimen. The articular cartilage consistently contained abundant fibers and some of the fibers connected to tight intra-articular fiber bands. Fiber insertion into the thin subchondral bone displayed a tidemark in a spotty manner. Thus, the calcified fibrocartilage seemed to be present and seemed to provide fine granularity on the dry bone specimen. The joint cavity was sometimes closed with fibrocartilage-like tissues: we termed this complete fibrous ankylosis. The dry bone specimen corresponding to complete fibrous ankylosis exhibited significant microporosity and granularity because of fragmented subchondral bone. Moreover, bony ankylosis along the sacroiliac joint margin also contained fibrocartilage-like tissues. Therefore, complete fibrous ankylosis is also likely to be the preliminary step to bony ankylosis in the entire joint area. Consequently, microporosity with granularity seemed to be the most critical anthropological characteristic for estimation of sacroiliac joint movability.     

Treatment of triplane fractures of the head of the proximal phalanx

We report the morphology and treatment of 2 cases of a triplane intra-articular bicondylar fracture of the head of the proximal phalanx. Fracture lines in the coronal, sagittal, and transverse planes characterize this fracture, making it highly unstable. Open reduction and internal fixation using two 1.5-mm interfragmentary screws oriented in a dorsal to volar direction resulted in anatomic restoration of the articular surfaces and satisfactory functional results. In 1 case, autogenous cancellous bone graft was harvested from the ipsilateral radial styloid to support the articular fragments.     

牙周美学治疗中的数字化概念

随着数字化技术的飞速发展,数码微笑设计、3D扫描、3D打印、虚拟牙合架等技术逐步进入牙周美学治疗领域。口腔医学的数字化技术经历了从二维到三维重建的过程,更加精准、简便、快速,为临床医生的工作和医患、医技沟通带来了便利。文章就牙周美学治疗中的数字化概念的研究与发展做一综述。     

FS-3D-FISP序列在膝关节软骨损伤诊继中的应用

目的 分析FS-3D-FISP扫描序列对关节软骨损伤的诊断能力,为关节软骨损伤的临床诊断和治疗提供可靠的影像学依据.方法 对临床拟行膝关节镜检查的膝关节疼痛患者进行术前MR成像,对MR图像进行二维和三维重建处理.结果 与关节镜对照,34例膝关节软骨损伤患者MR检查结果：FS-3D-FISP序列敏感性为91.4%、特异性为97%、Kappa值为0.818.结论 FS-3D-FISP序列与关节镜诊断结果之间具有良好的一致性.关节软骨损伤的三维成像有利于临床术前对重度膝关节软骨损伤进行立体定位诊断.     

纤维软骨和透明软骨不同染色方法的对比研究

目的 研究不同软骨染色方法在髁突软骨、股骨软骨和生长板软骨中的染色差异。方法 取健康雌性新西兰大白兔颞下颌关节髁突、膝关节股骨,分别进行苏木精-伊红（HE）染色、甲苯胺蓝染色、阿利新蓝染色、番红O 阿利新蓝染色、番红O染色、番红O 快绿染色,光学显微镜下观察分析各软骨组织结构。结果 HE染色髁突纤维软骨各层结构清晰,关节软骨基质呈嗜碱性蓝染,骨组织呈嗜酸性红染;甲苯胺蓝染色关节软骨基质呈蓝紫色,骨组织不着色;阿利新蓝染色软骨基质呈淡蓝色,骨组织不着色;番红O 阿利新蓝染色关节软骨呈浅蓝色,骨组织呈淡红色,但是髁突软骨纤维层和增殖层红染;番红O染色中髁突软骨基质呈红色,股骨软骨和生长板软骨呈橘黄色,骨组织呈淡红色;番红O 快绿染色关节软骨基质呈红色,骨组织呈绿色,在髁突纤维软骨中纤维层呈明显绿染。结论 不同的染色方法可以特异性展现软骨组织结构。在今后透明软骨和纤维软骨的研究中,因根据研究对象、研究目的等选用适合的染色方法,以期最佳的反映研究部位的形态结构。     

Chondrocyte apoptosis: a cause or consequence of osteoarthritis?

Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degradation and changes in the subchondral bone. Over the last two decades, there has been increasing evidence showing association between cartilage degradation and chondrocyte death, and different types of cell death in cartilage have been reported, including apoptosis and chondroptosis as well as necrosis, but which of these types of cell death predominate in OA is debatable. There are also some methodological difficulties in detecting the specific form of cell death in articular cartilage. Current 'gold standard' for detecting chondrocyte death is electron microscopy which suggests that the morphological changes of chondrocytes in OA cartilage are attributed to apoptosis and/or chondroptosis. However, the current literature appears to suggest that classic apoptosis plays an important role in OA; but whether chondrocyte apoptosis is a cause or a result of cartilage degeneration in OA is hotly contested. Studies of suitable animal models, especially longitudinal studies, are needed to address the cause-and-effect relationship.