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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. It can lead to flat feet and deformed toes.
Over 90% of people with rheumatoid arthritis (RA) develop foot and ankle symptoms during the course of the disease.
Rheumatoid arthritis is an autoimmune disease. This means that the immune system attacks its own tissue. In rheumatoid arthritis (RA), the defences that protect the body from infection instead damage normal tissues (such as cartilage and ligaments) and soften the bones.
How does this happen ?
The joints in your body are lined with a coating - called synovium - that lubricates the joint and makes movement easier. In rheumatoid arthritis, this lining becomes overactive. It swells and becomes inflamed, destroying the joint and the ligaments and other tissues that support it. Weakening of the ligaments can lead to joint deformities, such as claw or hammer toe. Softening of the bone (osteopenia) can lead to stress fractures and bone collapse.
In RA, the joint wall swells and becomes inflamed. This slowly destroys the joint.
Rheumatoid arthritis is not an isolated disease of the bones and joints. It affects tissues throughout the body, causing damage to blood vessels, nerves and tendons. Deformities in the hands and feet are the most obvious signs of RA. In about 20% of patients, foot and ankle symptoms are the first signs of the disease.
Rheumatoid arthritis affects about 1% of the population. Women are more often affected than men, with a ratio of up to 3:1. Symptoms most often develop between the ages of 40 and 60.
Destruction of joints by rheumatoid arthritis
The exact cause of RA is not known. There may be a genetic reason - some people may be more likely to develop the disease because of family heredity. However, doctors suspect that it takes a chemical or environmental 'trigger' to activate the disease in people who inherit RA.
The most common symptoms are pain, swelling and stiffness. Unlike osteoarthritis, which usually affects a specific joint, RA symptoms usually occur in both feet, affecting the same joints in each foot.
As the disease progresses, it will cause deformity of the feet and ankles.
The main function of the hindfoot is to perform the lateral movement of the foot. Difficulty walking on uneven ground, grass or gravel are the first signs. Pain is common just below the fibula on the outside of the ankle.
As the disease progresses, the alignment of the foot may be altered as the bones move out of their normal position. This can lead to a flat foot deformity. Pain and discomfort may be felt along the posterior tibial tendon (the main tendon that supports the arch of the foot) on the inside of the ankle, or on the outside of the ankle below the fibula.
In RA, the ligaments that support the midfoot weaken and the arch collapses. With the loss of the arch, the front of the foot is directed outwards. Rheumatoid arthritis also damages the cartilage, causing arthritic pain that can be present with or without shoes. Over time, the shape of the foot may change as the structures that support it degenerate. This can create a large bony prominence (bump) on the arch of the foot. All these changes in the shape of the foot can make it very difficult to wear shoes.
Changes that occur in the forefoot are unique to RA patients. These include bunion, claw toes and metatarsalgia (pain in the forefoot). Although each individual deformity is common, it is the combination of deformities that makes the problem worse.
Bunion is usually severe and the big toe often goes over the second toe.
There can also be very painful bumps on the sole of the foot, creating calluses. The bumps develop when the bones in the middle of the foot are pushed down due to joint dislocations in the toes. Dislocations of the lower toes (toes two to five) cause them to become very prominent on the top of the foot. This creates claw toes and makes it very difficult to wear shoes. In severe cases, ulcers can form because of the abnormal pressure.
Foot deformities in rheumatoid arthritis
Rheumatoid arthritis is often treated by a team of health professionals. These professionals may include rheumatologists, physiotherapists, occupational therapists, pedorthists, rehabilitation doctors or orthopaedic surgeons.
Although there is no cure for rheumatoid arthritis, there are many treatment options to help people manage pain, stay active and lead a normal life.
Although orthopaedic treatment can relieve symptoms, it does not stop the progression of the disease. Specific drugs called disease-modifying antirheumatic drugs are designed to prevent the immune system from destroying the joints. The appropriate use of these drugs is directed by a rheumatologist.
Orthopaedic treatment of RA depends on the location of the pain and the extent of cartilage damage. Many patients will achieve some relief of symptoms with appropriate non-surgical treatment.
Your doctor may recommend surgery depending on the extent of cartilage damage and your response to non-surgical options.
Fusion of the affected joints is the most common type of surgery for RA. Fusion involves taking the two bones that form a joint and fusing them together to make one.
The front of the foot is where there are the most surgical options for some patients. Surgeons can now perform joint-sparing operations to correct bunion and hammertoes in some patients. Your surgeon will consider the most appropriate options for your case.
Author : Philippe Vesin - Pedorthist