Rheumatoid foot

What is rheumatoid foot?

Rheumatoid foot describes the changes that happen in your foot and ankle joints as a result of rheumatoid arthritis (RA), a condition where your immune system mistakenly attacks the lining of your joints. Foot problems are extremely common in RA, affecting up to 90% of people with the condition, and for some, the foot is the first place symptoms appear.

What are the symptoms of rheumatoid foot?

Symptoms can vary, but often include:

• Soreness, warmth and swelling in one or more foot joints, which may come and go in flares
• Pain and stiffness, often worse first thing in the morning or after resting
• Gradual changes to the shape of your foot, such as bunions (hallux valgus) or claw-like toes
• Corns, calluses or painful lumps under the ball of your foot, from walking on an unstable foot
• Small, fleshy nodules, for example over your Achilles tendon, heel or other bony areas

Less commonly, you might notice cramp-like pain in your leg when walking, changes in the colour of your toes in the cold, or numbness or tingling in your feet. Tell your rheumatology team promptly about any new foot pain, swelling, or changes in shape, so this can be assessed.

What are the causes of rheumatoid foot and who is at risk?

Rheumatoid foot develops as a result of rheumatoid arthritis, an autoimmune condition where your immune system mistakenly attacks the tissue lining your joints. Doctors don't know exactly why this happens, though it's thought to involve a combination of genetic and environmental factors.

When a joint in your foot becomes inflamed, the ligaments and joint capsule that normally hold it in place can stretch and weaken over time. This allows the bones to shift out of position, which is why RA can gradually change the shape of your foot.

You may be more at risk of developing rheumatoid arthritis, and so rheumatoid foot, if you:

• Are female and over 30
• Smoke
• Have a family history of the condition
• Drink a lot of coffee, or eat a lot of red meat

Are there different types of rheumatoid foot?

Rheumatoid foot can affect different parts of your foot in different ways:

• Front of the foot (forefoot): the most commonly affected area. The joints where your toes meet the long foot bones can become damaged, leading to bunions (hallux valgus) and claw-like toe deformities
• Middle of the foot (midfoot): if the joints here are affected, your arch can collapse, leading to a flattened foot and a wider forefoot. The fatty padding under the ball of your foot can shift forward, leaving the bones there less protected, sometimes described as "walking on stones"
• Back of the foot (hindfoot) and ankle: less commonly affected, but if the joint that lets your ankle rotate is involved, your heel can bend outwards, making walking difficult

How is rheumatoid foot diagnosed?

Your GP will examine your joints and ask about your symptoms, and if they suspect rheumatoid arthritis, will refer you to a rheumatologist. Diagnosis is usually made using a combination of:

• Blood tests, which can show signs of inflammation
• A physical examination of your joints
• X-rays, which can show joint damage. Your feet are often X-rayed early on, as changes caused by RA can appear here before they show up in other joints
• Occasionally, an MRI or ultrasound scan, for more detail

How is rheumatoid foot treated?

Non-surgical treatment

Rheumatoid foot is usually managed by a team including a rheumatologist, podiatrist, physiotherapist and specialist nurse, working alongside your medication for rheumatoid arthritis. Medications can include:

• Painkillers and non-steroidal anti-inflammatory drugs (NSAIDs), for pain and swelling
• Disease-modifying anti-rheumatic drugs (DMARDs), such as methotrexate, which slow the disease down
• Corticosteroids, for more advanced disease
• Biologic therapies, if other treatments haven't controlled your condition

A podiatrist can also help with your feet directly, through:

• Orthoses (insoles), which reduce pressure on affected joints and can help slow further changes to your foot shape
• Advice on wider, deeper shoes that accommodate any deformity and any insoles, sometimes custom-made to fit your foot
• Protective padding or shields, to reduce pressure and friction over sensitive areas
• Treatment for corns, calluses or any skin problems that develop

Physiotherapy and regular, gentle exercise can also improve comfort and help you stay mobile, though it's best to reduce activity during a flare-up.

Surgical treatment

Surgery may be considered if your joints have been badly damaged, or if bunions, clawed toes or dislocated joints are causing significant pain that hasn't responded to other treatments. Depending on which joints are affected, this can include correcting deformities, removing damaged bone, or fusing a joint together (arthrodesis) so the bones grow into one solid piece. Fusion reduces movement in that joint but can significantly reduce pain. Your surgeon will also treat any related problems, such as corns or ulcers, at the same time.

When should I see a doctor?

Contact your rheumatology team promptly if you notice any new foot pain, swelling, changes in joint shape, or nodules, as early assessment and treatment can help limit long-term damage.

Get podiatry advice rather than treating corns or hard skin yourself. Using blades, corn plasters or paints on affected skin can break the surface and lead to a serious infection.