Osteoarthritis: Symptoms and treatment
Arthritis is one of the leading causes of pain and disability in America, and osteoarthritis (OA) is far and away the most common type. OA begins in the cartilage, the smooth, slippery tissue that covers the ends of the bones as they come together in joints. Healthy cartilage allows the joints to move smoothly and painlessly, but in OA the cartilage undergoes chemical and structural changes, then gradually wears away.
Scientists don't fully understand what causes OA, but they have identiﬁed factors that increase risk. Advancing age is the most important. Others include a family history of OA, obesity, biomechanical abnormalities that increase stress on joints, serious injuries, and certain repetitive activities such as frequent knee bending and lifting. Poor nutrition may also play a role.