Arthritis mutilans is a rare form of inflammatory arthritis that causes severe damage to joints and bone tissue.

Arthritis mutilans primarily affects joints in the hands and feet. The severe inflammation damages bones and soft tissues in the affected joint, and this can lead to bone loss, movement problems, and changes in the shape of the joint.

Below, we describe what can lead to this condition, how doctors diagnose it, and what treatment entails.

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Arthritis mutilans may occur independently but is most common in people with psoriatic arthritis (PsA) or rheumatoid arthritis (RA).

Around 5% of people with PsA develop arthritis mutilans. This rate is lower in people with RA.

Both PsA and RA are long-term, progressive autoimmune diseases that cause inflammation throughout the body, especially in the joints. An autoimmune disease occurs when the immune system malfunctions and attacks healthy cells.

If a person does not receive effective treatment, both PsA and RA can lead to joint damage and potentially to arthritis mutilans.

Rare causes

While arthritis mutilans typically arises as a progression of RA or PsA, its symptoms can also develop in people with other conditions.

Reports have described arthritis mutilans symptoms in people with juvenile idiopathic arthritis, multicentric reticulohistiocytosis, and systemic lupus erythematosus, for example.

However, cases of arthritis mutilans in people with these conditions are often isolated, and in many instances, they are not contemporary.

The main symptom of arthritis mutilans is severe bone tissue destruction. This can cause the area to become irregularly shaped and can limit movement. The condition is progressive, meaning that it worsens over time, at different rates in different people.

If a person does not receive effective treatment, arthritis mutilans can lead to severe bone resorption in the hands and feet. This can occur in late-stage PsA and RA. Bone resorption shortens the fingers or toes and otherwise changes their shape.

Arthritis mutilans can cause bones in the affected area to dissolve and no longer provide enough support. This can result in soft tissue collecting near the base of the finger, for example. Terms for this include “telescoping finger” and opera glass hand.

Arthritis mutilans can also change the shape of fingers or toes as the affected joints fuse or wear away. This can result in a loss of function in the joints. This type of fusion is called ankylosis.

A 2015 review of approaches to psoriatic arthritis mutilans found that medical professionals usually look for bone and joint tissue destruction as a diagnostic marker. They also check for shortening and telescoping.

In addition, assessing which underlying illness has led to the condition is crucial in developing a treatment plan.

Learn more about the differences between RA and PsA here.

Arthritis mutilans worsens over time. Receiving early, aggressive treatment can help delay or prevent further damage.

As with many forms of arthritis, physical therapy can be an important part of treatment if the person can undertake it. Medical professionals also typically recommend a tailored course of medication, which may include drugs to treat the cause of arthritis mutlians.

A 2020 review of PsA treatment recommended nonsteroidal anti-inflammatory drugs and corticosteroids as important, first-line approaches. The aim of this treatment is to reduce inflammation and improve joint health.

Also, disease-modifying antirheumatic drugs may decrease arthritis disease activity, and medications called tumor necrosis factor inhibitors may reduce inflammation in people with PsA or RA.

For severe cases, a doctor may recommend surgery to repair bone and tissue damage caused by arthritis mutilans. For example, a person may benefit from bone graft procedures or surgical joint fusing. However, due to the rareness of this condition, establishing the effectiveness of these procedures will require more evidence.

Arthritis mutilans is a rare form of advanced joint disease, and it is most common in people with PsA and RA. It is a progressive condition and worsens if a person does not receive effective treatment.

A range of physical therapies, medications, and in severe cases, surgery, may slow the progression of the disease and improve the quality of life.

If a person does not receive effective treatment, arthritis mutilans can lead to severe bone destruction and loss of movement. It can also change the shape of the affected joints.