January 22nd, 2011

Stage 4. At this point, inflamed synovium can grow (proliferate), spreading over the top of joint cartilage. When synovium grows in this way, it is called pannus. The pannus produces enzymes called collagenases, which can destroy collagen, the cartilage proteins. Neutrophils in the joint fluid can also release harmful enzymes. Although there are many beneficial enzymes in the body, these particular enzymes can break down, or degrade, the cartilage that protects the bone and joints.
Collagenases can also cause bone to break down in the area in which the synovitis meets bone. This results in the formation of tiny holes or erosions in the bone and cartilage. Erosions often occur first at the point at which protective cartilage ends at the margins of joints.
Stage 5. If the arthritis is left untreated, the pannus can further invade and erode through cartilage and bone by producing more enzymes. Any loss of cartilage reduces the amount of cushioning between the bones of the joint.
When cartilage is roughened by this erosion, the ability to have smooth joint motion is lost. People with RA can feel a grating sensation in the joint during movement, and their physicians can feel the grating of the joint during physical examination. This grating is called crepitus. If the breakdown of cartilage is persistent, the cartilage can be totally eroded by
In stage 5 RA uncontrolled swelling can cause ligaments and tendons to stretch, adding to the instability of the joint. Muscles become smaller (atrophy) and weaker because of disuse. Stretched ligaments and tendons and atrophied muscles interfere with the joint’s ability to function properly, often resulting in a joint that does not move as it was intended to. Inflammation and pannus can spread along the tendons in tenosynovitis, making the tendons weak and putting them at risk for rupture. When the cartilage is eroded and the supporting structures are loosened, other changes often occur which alter the shape and function of the joint. These mechanical changes are a result more of abnormal forces occurring across the joint than of ongoing inflammation in the joint itself.
Late in this stage, after the cartilage is totally eroded, the amount of inflammation and swelling often decreases. This is sometimes referred to as a burned-out joint. At this stage the stretched supporting structures can actually become even looser as the swelling pushing against them decreases. The looseness of these supporting structures can seriously affect the stability of the joint.

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This entry was posted on Saturday, January 22nd, 2011 at 9:34 am and is filed under Arthritis. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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