Rheumatoid arthritis of the foot and ankle
Rheumatoid arthritis of the foot and ankle is a chronic disease that causes painful inflammation of the joints. The inflammation can become so severe that it affects the appearance and function of the lower extremities. This disease usually begins in the small joints of the hands and feet, affecting the same joints on both sides of the body. More than 90 percent of people afflicted with rheumatoid arthritis will develop symptoms in the foot and ankle.
Rheumatoid arthritis is an autoimmune disease, which means it causes the immune system to attack its own tissues and bones. The joints in your body are covered with a lining called the synovium. This lining lubricates the joints to allow them to move easily through the lining. Rheumatoid arthritis in the foot and ankle attacks the lining and causes inflammation and swelling throughout the entire area. It damages the joints, the surrounding tissue and the ligaments supporting the affected joints. These weakened or destroyed ligaments can cause joint deformities in the feet, such as hammertoe or claw toe. Softening of the surrounding bones can lead to stress fractures and eventually the total collapse of the affected bone.
Rheumatoid arthritis of the foot and ankle not only destroys the joints and surrounding tissue, but it also can damage the corresponding blood vessels and nerves. In about 20 percent of patients, foot and ankle symptoms are the first sign of rheumatoid arthritis.
The most common symptoms of rheumatoid arthritis of the foot and ankle are pain, swelling and stiffness in the affected area. The symptoms appear in both feet, typically affecting the same joint in each. Broken down by affected areas of the foot and ankle, symptoms include:
- Ankle – Difficulty with inclines and stairs is generally the first symptom of rheumatoid arthritis in the ankle. Walking on level ground and standing also eventually become difficult and painful as the disease progresses.
- Hindfoot – This region of the foot includes the heel and talus. The main function of the hindfoot region is to absorb shock from impact and displace it evenly to both sides of the foot. The hindfoot helps balance the body, so it’s not surprising that symptoms of rheumatoid arthritis in this area of the foot include a loss of balance and difficulty maneuvering over uneven terrain. As the disease progresses, the bones move out of alignment and cause other deformities such as flatfoot. Pain is most commonly felt in the tendon that supports the arch under the foot.
- Midfoot – The midfoot consists of the top area of the foot. It serves to connect the hindfoot to the toes of the forefoot. When affected by rheumatoid arthritis of the foot and ankle, the ligaments become weakened and the arch collapses. The loss of the arch leads to cartilage damage and overall deformity of the forefoot, causing it to point outward. As rheumatoid arthritis progresses, the entire mid-to-front section of the foot continues to point more severely to the left or right. A large bump on the arch of the foot is formed as a result, and shoes become increasingly difficult to wear. Severe pain and difficulty walking are two results of this deformity.
- Forefoot – This region covers the toes and ball of the foot. The symptoms of rheumatoid arthritis of this foot area include bunions, claw toes and pain underneath the ball of the foot.
- Bunions – A bunion is an abnormal growth in the joint of the big or little toe that results in a large bump causing misalignment of the affected toe. The bunion can become severe and force the big toe to cross over the adjacent toe.
- Claw toes – Claw toes are dislocations of the smaller toes (second through fifth metatarsals) that cause them to protrude upward in an arch over the top of the foot. Claw toes eventually result from calluses. Calluses are big, painful bumps most commonly on the ball of the foot. These bumps form when the bones of the midfoot become dislocated and are pushed down. It is a very painful condition that makes it practically impossible to wear covered shoes.
The exact cause of rheumatoid arthritis of the foot and ankle is unknown. Women are affected more than men, with a ratio of about three to one. Symptoms of this disease usually develop after the age of 40. There may be a genetic factor, as some people seem to be more likely to develop rheumatoid arthritis because of family heredity. Doctors suspect that a chemical or environmental factor triggers the disease in people who have a genetic predisposition to rheumatoid arthritis.
Treatments for rheumatoid arthritis of the foot and ankle depend upon the side effects from the disease and range from bracing, medication and injections to surgical reconstruction.