What Is Osteoarthritis?

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What is Osteoarthritis?

Osteoarthritis (OA) is the most common type of arthritis, and typically only affects older people.

Osteoarthritis affects cartilage, the hard but slippery tissue that covers the ends of bones where they meet to form a joint. Healthy cartilage allows bones to glide over one another. In Osteoarthritis the surface layer of cartilage breaks down and wears away. This allows bones under the cartilage to rub together, causing pain, swelling, and loss of motion of the joint.

A Healthy Joint


In a healthy joint, the ends of bones are encased in smooth cartilage. Together, they are protected by a joint capsule lined with a synovial membrane that produces synovial fluid. The capsule and fluid protect the cartilage, muscles, and connective tissue.

A Joint with Severe Osteoarthritis


With osteoarthritis, the cartilage becomes worn away, spurs grow out from the edge of the bone, and synovial fluid increases. Altogether, the joint feels stiff and sore.

Osteoarthritis Symptoms

People with osteoarthritis usually have joint pain and some limitations in joint movement. Unlike some other forms of arthritis, OA affects only joint function.

Osteoarthritis most commonly occurs in the weight-bearing joints of the hips, knees and lower back. It also affects the neck, small finger joints, the base of the thumb and the big toe. OA rarely affects other joints except when injury or stress is involved

Osteoarthritis Treatment

It is important that you take an active role in the treatment of your Osteoarthritis and in prevention of additional joint damage. There are steps you can take to lower your risk for developing osteoarthritis. The most important thing you can do if you suspect you have any form of arthritis is to get a proper diagnosis and begin early, aggressive treatment.