Hayes D W, Brower R L, John K J
Department of Podiatric Surgery and Traumatology, Broadlawns Medical Center, Des Moines, Iowa, USA.
Clin Podiatr Med Surg. 2001 Jan;18(1):35-53.
Articular cartilage plays a vital role in joint morphology. An understanding of articular cartilage anatomy and physiology will enable the physician to more fully appreciate its function and necessity. Articular cartilage is made up of four basic biological layers or zones. Each zone possesses attributes necessary to make articular cartilage as a whole strong, durable, and more able to withstand shear and axial forces through a joint. Cartilage metabolism is relatively slow in comparison with other tissues; hence, it is much more difficult for defects in cartilage to heal spontaneously. There are many ways in which articular cartilage can incur damage. Mechanical injury, be it acute or insidious, causes cartilage to fissure and fracture. This results in painful and inflamed joints along with disruption of the cartilage. Metabolic diseases also can produce joint destruction, inflammation, and pain. The resultant defects fail to heal spontaneously because of slow metabolism of cartilage. These chondral defects eventually may penetrate subchondral bone. Disruption of the layers of cartilage eventually will cause collapse and loss of integrity of the entire joint apparatus as a whole. More than 250 years ago, Hunter stated, "Ulcerated cartilage is a troublesome thing--once [it is] destroyed it is not repaired." Articular cartilage defects are very difficult to repair effectively. Cartilage defects can heal spontaneously, if the defect extends to subchondral bone. The reparative substance, fibrocartilage, is less durable and much less smooth. There are many techniques and procedures in which chondral or osteochondral defects can be filled. Promoting subchondral bleeding is the method most commonly used clinically. This allows pleuripotent cells to fill the defect with eventual fibrocartilage. Implants are gaining favor as a method of inducing a more pure, hyaline-like cartilage into cartilage defects. Gene therapy and tissue engineering are at the forefront of cartilage research today. Cartilage injury and repair remains today a very difficult topic of study. Understanding the anatomy of articular cartilage, the pathomechanics of injury, and methods available for cartilage repair, will help the physician more adequately approach treatment options.
关节软骨在关节形态中起着至关重要的作用。了解关节软骨的解剖结构和生理功能将使医生能够更全面地认识其功能和必要性。关节软骨由四个基本的生物层或区域组成。每个区域都具有使关节软骨整体坚固、耐用且更能承受通过关节的剪切力和轴向力所必需的特性。与其他组织相比，软骨代谢相对缓慢；因此，软骨缺损自发愈合要困难得多。关节软骨受损的方式有很多。机械损伤，无论是急性的还是隐匿性的，都会导致软骨出现裂隙和骨折。这会导致关节疼痛、发炎以及软骨破坏。代谢性疾病也会导致关节破坏、炎症和疼痛。由于软骨代谢缓慢，由此产生的缺损无法自发愈合。这些软骨缺损最终可能会穿透软骨下骨。软骨层的破坏最终会导致整个关节装置的塌陷和完整性丧失。250多年前，亨特指出：“溃疡的软骨是个麻烦事——一旦被破坏就无法修复。”关节软骨缺损很难有效修复。如果缺损延伸至软骨下骨，软骨缺损可以自发愈合。修复物质纤维软骨的耐用性较差且光滑度也低得多。有许多技术和方法可用于填充软骨或骨软骨缺损。促进软骨下出血是临床上最常用的方法。这能使多能细胞填充缺损并最终形成纤维软骨。植入物作为一种向软骨缺损诱导生成更纯净、类似透明软骨的方法正越来越受到青睐。基因治疗和组织工程是当今软骨研究的前沿领域。如今，软骨损伤和修复仍然是一个非常困难的研究课题。了解关节软骨的解剖结构、损伤的病理力学以及软骨修复可用的方法，将有助于医生更充分地选择治疗方案。
