The major types of arthritis that affect the foot and ankle are osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
Osteoarthritis is a degenerative joint disease where the cartilage covering the bones wears away slowly. As the cartilage erodes, it becomes frayed and rough, and the protective space between the bones diminishes. Ankle osteoarthritis can be caused by a previous ankle injury or the natural wear and tear on the joint as you age. Injury can damage the cartilage directly, or it can alter the mechanics of the ankle joint.
Other risk factors may contribute to the development of osteoarthritis, including obesity and family history. Being overweight can add weight to bearing joints, including the ankle. Genetics may also play a role in advancing the disease. For example, being flat-footed may affect how you walk and add stress to the ankle joint.
Rheumatoid arthritis is a chronic, autoimmune disease affecting numerous joints throughout the body; the condition often begins in the foot and ankle. It is symmetrical, meaning it typically impacts the same joint on both sides of the body.
With rheumatoid arthritis, the cells of the immune system attack the synovium covering the joint, causing it to swell. This leads to damage to the bones, cartilage, ligaments and tendons. Over time, the structure of the ankle joints can be affected, leading to disability and permanent changes in the shape of the joints.
The causes of rheumatoid arthritis are unclear. Some researchers believe that specific genes may make people more susceptible to the disease. Often infection or specific environmental factors act as a trigger to activate the genes.
Post-traumatic arthritis is caused by the wearing out of a joint that has had a physical injury. The injury could be from sports, dance, a car accident, a fall, or any other source of physical trauma. Dislocations and fractures, especially those that damage the ankle joint surface, are the most common injuries that lead to post-traumatic arthritis. The disease can manifest many years after the initial injury.