Arthritis

Arthritis is a general term used to describe painful joints. There are more than 100 types of arthritis related diseases. Osteoarthritis strikes more than 16 million people in the United States as they grow older. By the age of 40, many people show signs of arthritis on X-rays but have no symptoms. Women and men get arthritis equally, but men tend to develop the disease at an earlier age. By age 65, half of all adults have osteoarthritis in one or more joints. After the age of 75, arthritis is even more prevalent. It appears most frequently in the hips, knees, hands, and spine.

The knee joint is formed by the upper and lower bones of the leg (femur and tibia), forming a hinge joint. The ends of the two bones that make up the knee joint and the kneecap (patella) are covered by cartilage. Osteoarthritis thins the cartilage and it begins to crack and pull away from the bone. As the cartilage wears away, the bones start to rub against each other making knee movement painful. The three most common types of arthritis are osteoarthritis, inflammatory arthritis and traumatic arthritis.