Rheumatoid arthritis is a chronic disease that attacks multiple joints throughout the body. It most often starts in the small joints of the hands and feet, and usually affects the same joints on both sides of the body.
More than 90% of people with rheumatoid arthritis (RA) develop symptoms in the foot and ankle over the course of the disease.
Rheumatoid arthritis is an autoimmune disease. This means that the immune system attacks its own tissues. In RA, the defenses that protect the body from infection instead damage normal tissue (such as cartilage and ligaments) and soften bone.
HOW IT HAPPENS
The joints of your body are covered with a lining — called synovium — that lubricates the joint and makes it easier to move. Rheumatoid arthritis causes an overactivity of this lining. It swells and becomes inflamed, destroying the joint, as well as the ligaments and other tissues that support it. Weakened ligaments can cause joint deformities — such as claw toe or hammer toe. Softening of the bone (osteopenia) can result in stress fractures and collapse of bone.
Rheumatoid arthritis is not an isolated disease of the bones and joints. It affects tissues throughout the body, causing damage to the blood vessels, nerves, and tendons. Deformities of the hands and feet are the more obvious signs of RA. In about 20% of patients, foot and ankle symptoms are the first signs of the disease.