Osteoarthritis (OA) is, by far, the most common form of arthritis and affects more than 20 million Americans. It is a condition that adversely affects hyaline articular cartilage, the tough gristle that caps the ends of long bones.
Hyaline cartilage is made up of a matrix consisting of a combination of proteoglycans (complexes of proteins and sugars) and chondrocytes. Chondrocytes are cartilage cells that manufacture matrix under normal healthy circumstances. They are responsible for nourishing the matrix as well.
However, when OA develops, a distinct change in the joint environment occurs. Chondrocytes begin to elaborate destructive enzymes causing cracks in the cartilage. These are called "fibrillations."
The synovium (lining of the joint) becomes inflamed, and the underlying bone becomes sclerotic (hard) and forms spurs.
The soft tissue structures surrounding the joint such as ligaments, tendons, and muscles also become affected as a secondary result of OA.
One joint that is often ignored because it is not as commonly affected as others is the ankle.
Approximately 1 per cent of people have ankle osteoarthritis. However, the incidence of this condition is expected to increase.
OA of the ankle typically comes about as a result of injury. The most common injuries leading to ankle OA are fractures, ligament injuries, and osteochondral injuries. The latter are a peculiar type of condition that causes a small section of cartilage and underlying bone to die.
Other types of arthritis such as rheumatoid arthritis can also lead to OA of the ankle. Because trauma is the leading cause of ankle OA, people with ankle OA tend to be younger than patients with OA involving other weight-bearing joints.
Despite the relatively small number of people affected, the health burden of ankle OA is still enormous. People with ankle OA have difficulty with performing vocational and recreational activities as well as activities of daily living, according to a number of studies.
Treatment of ankle OA involves the same modalities as that used for other weight-bearing joints. Weight loss, physical therapy, exercise, patient education, and assistive devices such as braces can be helpful adjuncts. Non-steroidal anti-inflammatory drugs, analgesics, and neutriceuticals such as glucosamine and chondroitin are also possible additions. Joint injections involving glucocorticoids and viscosupplements can be used. More recently, the utilization of autologous stem cell procedures to slow down and possibly regrow damaged cartilage has appeared promising.
Surgery should be a last resort. Unlike the knee and hip, joint replacements for the ankle are less than adequate. Fusion of the joint carries risks both during the procedure as well as after.