Overview

Osteoarthritis (OS-tee-oh-are-THRY-tis) (OA) is one of the oldest and most common forms of arthritis. Known as the “wear-and-tear” kind of arthritis, OA is a chronic condition characterized by the breakdown of the joint’s cartilage. Cartilage is the part of the joint that cushions the ends of the bones and allows easy movement of joints. The breakdown of cartilage causes the bones to rub against each other, causing stiffness, pain and loss of movement in the joint.

Osteoarthritis is known by many different names, including degenerative joint disease, ostoarthrosis, hypertrophic arthritis and degenerative arthritis. Your doctor might choose to use one of these terms to better describe what is happening in your body, but for our purposes, we will refer to all of these as osteoarthritis.

It is thought that osteoarthritis dates back to ancient humans. Evidence of osteoarthritis has been found in ice-aged skeletons. Today, an estimated 21 million Americans live with OA. Despite the longevity and frequency of the disease, the cause is still not completely known and there is no cure. In fact, many different factors may play a role in whether or not you get OA, including age, obesity, injury or overuse and genetics. Your OA could be caused by any one or by a combination of any of these factors.

There are several stages of osteoarthritis:

1. Cartilage loses elasticity and is more easily damaged by injury or use.
   
2. Wear of cartilage causes changes to underlying bone. The bone thickens and cysts may occur under the cartilage. Bony growths, called spurs or osteophytes, develop near the end of the bone at the affected joint.
   
3. Bits of bone or cartilage float loosely in the joint space.
   
4. The joint lining, or the synovium, becomes inflamed due to cartilage breakdown causing cytokines (inflammation proteins) and enzymes that damage cartilage further.

Changes in the cartilage and bones of the joint can lead to pain, stiffness and use limitations. Deterioration of cartilage can:

• Affect the shape and makeup of the joint so it doesn’t function smoothly. This can mean that you limp when you walk or have trouble going up and down stairs.
  
• Cause fragments of bone and cartilage to float in joint fluid causing irritation and pain.
  
• Cause bony spurs, called osteophytes, to develop near the ends of bones
  
• Mean the joint fluid doesn’t have enough hyaluronan, which affects the joint’s ability to absorb shock.
  
• Result in inflammation.

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.

It is important that you take an active role in the treatment of your OA and in prevention of additional joint damage. There are even steps you can take to lower your risk for developing OA at all.

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. There are several other conditions that are similar to OA, including rheumatoid arthritis, that have different treatment plans. It is important that you are being treated properly for your arthritis. You should also know that treatment may change as the disease progresses or improves.