This organization distinguishes articular cartilage from the fibrocartilage that appears in some healing response. The deepest layer, the tidemark, is calcified and attaches to the subchondral bone (Figure 1). Articular cartilage has characteristic zones, in which the more superficial zone aspects have the collagen oriented parallel to the joint (for gliding) and the deep layer has its collagen oriented perpendicular to the joint (for compressibility). The key to both properties is water: articular cartilage contains chondrocytes, proteoglycan and collagen molecules (almost all Type II), but at least 2/3rd of its mass is water. In brief, articular (hyaline) cartilage decreases friction and distributes loads. These joints are covered by articular cartilage. The anterior aspect of the distal femur (trochlea) meets the patella to form the patellofemoral articulation. The medial and lateral condyles of the femur rest on the tibial plateau to form the tibiofemoral articulation. The knee is a hinged synovial joint and consists of two articulations– the tibiofemoral and patellofemoral. When bone pathology is absent, repair of the surface cartilage may be very helpful clinically, whereas when bone changes are present, the cartilage damage is merely the surface manifestation of the disease, and treating it alone is often futile. Articular cartilage damage can be seen with or without changes in the underlying bone. Acute focal defects can accompany injuries such as an ACL tear and patellar dislocation. (The colloquial expression “cartilage damage” might also include meniscal tears, which is an altogether separate category of disease.) Chondral injuries include both single focal defects and diffuse damage more characteristic of degenerative joint disease. Chondral injuries of the knee are lesions of the articular cartilage of the knee joint.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |