The term pathological mechanisms of osteoarthritis refers to how osteoarthritis develops. Osteoarthritis is arthritis thought to be joint breakdown, inflammation and pain associated with "wear and tear." This contrasts with rheumatoid arthritis, which is caused by the immune system. Osteoarthritis has effects on cartilage, bone, and the layer of tissue lining the joint space known as the synovium.
Cartilage
Cartilage is a stiff connective tissue found between joints. The cells of cartilage are called chondrocytes. They make protein fibers composing the cartilage. In osteoarthritis, the cartilage is worn down and the bones are no longer cushioned against each other, bone touches bone. Stress on the chondrocytes and cartilage may lead to its breakdown, according to "Harrison's Principles of Internal Medicine."
Bone
As a result of the bone-on-bone effects of osteoarthritis, the bone around the joint thickens. This thickening, called sclerosis, can be seen on x-ray. Bone minerals such as calcium deposit near the joint, making it stiffer. Advancing age is a strong predictor of this development, according to "Robbins & Cotran Pathologic Basis of Disease" by Dr. Vinay Kumar.
Synovium
According to "Harrison's Principles of Internal Medicine" the synovium refers the tissues surrounding the joint, and includes a fluid that bathes and lubricates the joint. Fragments of connective tissue such as cartilage can be found in the osteoarthritic joint. These tissues in the joint space lead to inflammation, which can further erode the joint and cause pain and swelling. Crystal deposits, such as calcium crystals, can also be found in the synovial space.
References
- "Robbins & Cotran Pathologic Basis of Disease"; Vinay Kumar et al; 8th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony Fauci et al; 17th Ed 2008
