Rheumatoid arthritis (RA) is a systemic disease that attacks multiple joints throughout the body. About 90% of people with rheumatoid arthritis eventually develop symptoms related to the foot or ankle. Usually symptoms appear in the toes and forefeet first, then in the hindfeet or the back of the feet, and finally in the ankles.
Other inflammatory types of arthritis that affect the foot and ankle include gout, ankylosing spondylitis, psoriatic arthritis, and Reiter's syndrome.
The exact cause of RA is unknown, but there are several theories. Some people may be more likely to develop RA because of their genes. However, it usually takes a chemical or environmental "trigger" to activate the disease. In RA, the body's immune system turns against itself. Instead of protecting the joints, the body produces substances that attack and inflame the joints.
Signs and Symptoms
The most common symptoms of RA in the foot are pain, swelling, and stiffness. Symptoms usually appear in several joints on both feet. You may feel pain in the joint or in the sole or ball of your foot. The joint may be warm and the way you walk may be affected. You may develop corns or bunions, and your toes can begin to curl and stiffen in positions called claw toe or hammertoe.
If your hindfoot (back of the foot) and ankle are affected, the bones may shift position. This can cause the long arch on the bottom of your foot to collapse (flat foot), resulting in pain and difficulty walking.
Because RA affects your entire system, you may also feel feverish, tired, and experience a loss of appetite. You may develop lumps near your joints, particularly around the elbow.
Sometimes arthritis symptoms in the foot are the first indication that you have RA. Your doctor will ask you about your medical history, occupation, and recreational activities as well as any other persistent or previous conditions in your feet and legs. The appearance of symptoms in the same joint on both feet or in several joints is an indication that RA might be involved.
Your doctor will also request X-rays to see how much damage there is to the joints. Blood tests will show whether you are anemic or have an antibody called the rheumatoid factor, which is often present with RA. If you've already been diagnosed with RA, you and your doctor should be aware that the disease will probably spread to your feet and ankles. Watch for early signs such as swelling and foot pain.
*Source: American Orthopaedic Foot & Ankle Society® http://www.aofas.org
*This material was codeveloped by the American Academy of Orthopaedic Surgeons