For 20% of patients, foot and ankle joints are the first ones affected by this chronic systemic autoimmune disease. Both symptoms and possible foot deformities are described below.
A person with rheumatoid arthritis in the foot and ankle typically has some of the following symptoms:
Swelling. The toes, feet, and ankles may swell due to inflammation and a buildup of synovial fluid in the joints. Swelling is often most noticeable at the big toe joint, the ankle, and the instep.
Redness, warmth, and tenderness. The skin over the affected joints may appear flushed and feel warm or hot to the touch. The joints may feel tender to the touch or when bearing weight. For example, because of joint changes, the fat pad at the ball of the foot may not longer offer cushion when standing and walking, resulting in tenderness and pain.
Pain and stiffness in the heels, balls of feet, toes or ankles. People with rheumatoid arthritis often complain of stiffness and pain in the feet, especially in the morning or after prolonged periods of inactivity. Walking, climbing stairs, and even wearing shoes may become difficult. Pain and stiffness can be especially pronounced where the base of the arch meets the heel, on the inside of the ankle, and in the toes.
Achilles tendon pain. Located at the back of the ankle, above the heel, the Achilles tendon can become inflamed and cause pain, particularly when walking uphill or squatting down.
Symmetrical inflammation. Unlike osteoarthritis, which may only affect one foot or ankle at a time, rheumatoid arthritis usually occurs to the same degree on both sides of the body.
Malaise, fever, and fatigue. As an autoimmune disorder that affects the whole body, rheumatoid arthritis impacts more than just the bones and joints. Patients may feel tired, feverish, and generally unwell during flare-ups.1
Rheumatoid nodules. These round, hard bumps often form underneath the skin in people with rheumatoid arthritis. They frequently appear on the balls of the feet, and also may appear on the sides of the feet, on the toes, or on the instep. Rheumatoid nodules can rub up against shoes and cause pain when walking.
Some people have persistent symptoms, while others may go for long periods with no symptoms before flare-ups return. The disease progresses at different rates for different people, with some people experiencing rapid joint damage that can result in permanent foot deformity.2
Common Types of Foot Deformities
The advent of medications to treat rheumatoid arthritis has reduced the likelihood of severe deformities to the toes and foot. However, deformities are possible when bone and soft joint tissue have degraded and bones no longer align normally.
The most common foot deformities are described below.
Dislocated toes may result when metatarsophalangeal joints degenerate. The dislocated toes may angle outward, toward the smallest toe.
Bunions occur when the big toe dislocates and becomes misaligned. The top of the big toe angles toward the smaller toes while the base of the big toe juts away from the foot. This misalignment creates a large bony bump, or bunion, on the side of the foot. In addition, the big toe may cross over the second toe.
Claw toes and hammer toes, where one or more toes become permanently bent in an abnormal position. People with severe claw toes can have a difficult time finding shoes that fit, and even when they do, the friction between shoes and toes can injury the skin. Walking may be challenging.
Flatfoot deformity, which occurs in severe cases of rheumatoid arthritis that have damaged the ligaments, tendons, and sometimes even the bones of the midfoot. As these tissues are injured, the foot's natural arch collapses, and the foot turns abnormally outward from the ankle and heel. A large bump may also form on the inside of the foot in the arch's former location.
A widened forefoot may develop as the joints and tissues in the front half of the foot degrade, causing the forefoot to spread out.
Foot deformities may be prevented or postponed with treatment. If moderate or severe foot deformities do appear a doctor may recommend they be corrected with surgery.