- See:
Chondral and Osteochondral Injuries of the Knee
Enchondral Ossification
Articular Cartilage: Injury and Potential for Repair:
Osteoarthritis
- Discussion:
-
hyaline cartilage caps ends of bones that form synovial joints;
- in other hyaline cartilage structures, surrounding perichondrium contains both capillaries for nutrition and the cells that
become involved in
appositional growth;
- articular cartilage has no more than a peripheral rim of perichondrium on its free surface, and calcified cartilage abutting bone
limits diffusion from blood vessels supplying subchondral bone;
- nourishment is supplied
synovial fluid that bathes cartilage;
- withdrawal of synovial fluid often leads to rapid deterioration of cartilage;
- it provides both a cushion & slick surface for movement; (see
lubrication)
- thickness of articular cartilage varies from joint to joint, and in humans it is thickest over ends of femur & tibia, ranging from 2-4 mm;
-
type II collagen is the primary type of collagen in articular cartilage;
- 4 Zones of artiuclar cartilage:
-
superficial layer (tangential zone);
- makes up 10% of cartilage;
- consists of 2 sub-zones:
- fibrilar sheet / lamina splendens is the more superficial layer;
- clear film consisting of a sheet of small fibrils with little polysaccharide and no cells;
- cellular layer w/ flattened
chondrocytes;
- flat chondrocytes and collagen fibers are arranged tangentially to the articular surface;
- thinnest layer, with the highest content of
collagen and the lowest concentration of
proteoglycans;
- collagen (type IX) is arranged at right angles to adjacent bundles and parallel to the articular surface;
- subsequently has greatest ability to resist shear stresses and serves as a gluiding surface for joint;
- may also function to limit passage of large molecules between
synovial fluid and cartilage;
- superficial zone is the first to show changes of osteoarthritis;
-
transitional layer
- this zone is involves transition between the shearing forces of surface layer to compression forces in the cartilage layers;
- composed almost entirely of
proteoglycans
- spherical chondrocytes
- less strongly bound;
-
deep radial layer
- largest part of the articular cartilage
- it distributes loads and resists compression;
-
collagen fibers and
chondrocytes are perpendicular to the subchondral plate;
-
calcified cartilage layer
- contains the tidemark layer;
- tidemark is basophilic line which stradles the boundry between calcified and uncalcified cartilage;
- separates
hyaline cartilage from subchondral bone;
- type X collagen is present mainly in the calcified cartilage layer and in
hypertrophic zone of the growth plate;
The effect of antibiotics on the destruction of cartilage in experimental infectious arthritis.
The deleterious effects of drying on articular cartilage.
The effects of exposure of articular cartilage to air. A histochemical and ultrastructural investigation.
Periodic rewetting enhances the viability of chondrocytes in human articular cartilage exposed to air.
The potential for regeneration of articular cartilage in defects created by chondral shaving and subchondral abrasion. An experimental investigation in rabbits.
The induction of neochondrogenesis in free intra-articular periosteal autografts under the influence of CPM. An experimental investigation in the rabbit.
Cell origin and differentiation in the repair of full-thickness defects of articular cartilage.
Mesenchymal Cell-Based Repair of Large, Full-Thickness Defects of Articular Cartilage.
Rib perichondrial grafts for the repair of full-thickness articular-cartilage defects. A morphological and biochemical study in rabbits.
An ultrastructural study of normal young adult human articular cartilage. C Weiss et al. JBJS. Vol 50-A. 1968. p 663-674.
The viability of articular cartilage in fresh osteochondral allografts after clinical transplantation.
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