Osteoarthritis (OA) is the most common form of arthritis. It is a degenerative joint disease in which the cartilage that covers the ends of bones in the joint deteriorates, causing pain and loss of movement as bone begins to rub against bone. OA commonly affects the joints of the fingers, knees, hips, and spine. Osteoarthritis is more common in older people because they have been using their joints longer. Using the joints to do the same task over and over or simply using them over time can make osteoarthritis worse. Younger people can also get osteoarthritis. Athletes are at risk because they use their joints so much. People who have jobs that require the same movement over and over are also at risk. Injuries to a joint increase the risk of arthritis in the joint later on. Excess weight can accelerate arthritis in the knees, hips and spine. The most common symptom of Osteoarthritis is pain in the affected joint(s) after repetitive use. Joint pain is usually worse later in the day. There can be swelling, warmth, and creaking of the affected joints. Symptoms of OA may greatly vary. Some patients can be debilitated by their symptoms. On the other hand, others may have remarkably few symptoms in spite of dramatic degeneration of the joints apparent on x-rays. Symptoms also can be intermittent.

These 2 forms have very different causes, risk factors, and effects on the body, yet they often share a common symptom - persistent joint pain.

What are the causes of arthritis?
Primary OA is mostly related to aging. With aging, the water content of the cartilage increases and the protein makeup of cartilage degenerates. Repetitive use of the joints over the years irritates and inflames the cartilage, causing joint pain and swelling. Eventually, cartilage begins to degenerate by flaking or forming tiny crevasses. Inflammation of the cartilage can also stimulate new bone outgrowths (spurs) to form around the joints. Sometimes osteoarthritis follows an injury to a joint. For example, a young person might hurt his knee badly playing soccer. Then, years after the knee has apparently healed, he might get arthritis in his knee joint.

RA is an autoimmune disease. This means the body's natural immune system does not operate as it should; it attacks healthy joint tissue, initiating a process of inflammation and joint damage. RA is a type of chronic arthritis that occurs in joints on both sides of the body (such as hands, wrists or knees). This symmetry helps distinguish RA from other types of arthritis. Rheumatoid arthritis occurs most frequently in the 30-50 age group, although can start at any age. It is strongly associated with the HLA marker DR4 - hence Family history is an important risk factor. The disease affects Females:Males in a 4:1 ratio.