Osteoarthritis is a condition in which the cartilage that protects and cushions the joints breaks down over time. Eventually, the bones—formerly separated by the cartilage—rub against each other, resulting in damage to the tissue and underlying bone and causing painful joint symptoms.

Osteoarthritis is the most common form of arthritis and is a major cause of disability in older adults. It most often affects the spine, fingers, thumbs, hips, knees, or toes.

Symptoms include:

• Pain, commonly in the fingers, thumbs, hips, or knees but also in the spine and toes. The pain is usually related to activity of the joint and is worse at the end of the day or after periods of activity. As the disease progresses, pain is present even during rest.
• Stiffness (lasting less than 1 hour) after periods of inactivity, such as in the morning after a night's sleep.
• Limited motion of the joint.
• Tenderness and occasional swelling caused by fluid in or around the joint (synovitis).
• Enlargement of joints, such as the development of bony knobs on the finger joints.
• Grinding sensation with movement (crepitus), often accompanied by pain.

The symptoms of osteoarthritis can usually be successfully managed with medicine and home treatment. Although osteoarthritis usually gets worse, in some cases symptoms may not get worse or may even improve slightly with time. Joint replacement surgery may be necessary in severe cases.