Rheumatoid Arthritis in Thumb
RA can affect the thumb joint, which has cartilage that covers the ends of the bones.

Rheumatoid arthritis (RA) is a chronic, inflammatory disease in which the immune system mistakenly attacks the lining of the membrane that surrounds the joints, particularly the smaller joints of the hand and wrist.

  • The human hand is one of the most complex structures in the body with 27 small joints that connect 5 metacarpal bones, 8 carpal bones, and 14 "finger bones" (phalanges).
  • Hands contain one-quarter of all the bones in the body.
  • This complexity makes them the earliest and most common areas affected by RA.

Thumb arthritis occurs when cartilage wears away from the ends of the bones that form the carpometacarpal joint, causing severe pain, swelling, and decreased strength and range of motion and making it difficult to do simple tasks, such as turning doorknobs and opening jars.

Consult your doctor if you have persistent swelling, stiffness, or pain at the base of the thumb.

How does rheumatoid arthritis affect hands?

Most joints are covered with a lining called the synovium that lubricates the joint for easy movement.

In rheumatoid arthritis, the synovium becomes inflamed (synovitis), thickens, and produces an excess of joint fluid. This fluid along with the inflammatory chemicals released by the immune system causes swelling, damages cartilage, and softens the bone within the joint. 

The swollen tissues stretch the surrounding ligaments, resulting in deformity, instability, and weakened and damaged tendons and ligaments.

What causes rheumatoid arthritis in the thumb?

The thumb joint has cartilage that covers the ends of the bones and acts as a cushion, allowing the bones to glide smoothly against each other. 

As age progresses, this cartilage deteriorates, leading to a rough surface. The bones then rub against each other, resulting in friction and joint damage. Apart from the aging process, a history of trauma or injury to the thumb joint can also cause thumb arthritis.

The damaged joint may result in the formation of new bone spurs along the sides of the existing bone, which can cause visible lumps on the thumb joint. Although osteoarthritis is the most common cause of thumb arthritis, rheumatoid arthritis can affect the carpometacarpal joint although to a lesser extent than other joints of the hand.

What are the risk factors for rheumatoid arthritis in the thumb?

Although thumb arthritis can affect anyone, certain factors can make you more vulnerable to developing the condition:

  • Age (people older than 40 years are more prone to develop arthritis)
  • Gender (women are more likely than men to develop rheumatoid arthritis)
  • Obesity
  • Certain hereditary conditions (joint ligament laxity and malformed joints)
  • Injuries to the thumb joint (fractures and sprains)
  • Activities and jobs that put high stress on the thumb joint

What are the symptoms of rheumatoid arthritis in the thumb?

Pain at the base of the thumb is the first and most common symptom of thumb arthritis. This pain can occur when you are gripping, grasping, or pinching an object and using the thumb to apply force.

Other signs and symptoms include:

  • Swelling, stiffness, and tenderness at the base of the thumb
  • When touched, the affected joint may feel warm
  • Decreased strength when pinching or grasping objects
  • Decreased range of motion
  • The enlarged or bony appearance of the joint at the base of the thumb

Stiffness with immobility is characteristic of rheumatoid arthritis in the hands that is worse in the morning and can last at least 30 minutes or more.

QUESTION

The term arthritis refers to stiffness in the joints. See Answer

How to diagnose rheumatoid arthritis in the thumb

Unfortunately, there is no single test to diagnose rheumatoid arthritis in its early stages.

A healthcare provider will examine the hands and fingers and may recommend certain tests:

  • Physical examination: To look for
    • Noticeable swelling
    • Redness and warmth
    • Reduced range of motion
    • Pain
    • Joint instability
  • Imaging techniques: X-rays reveal signs of thumb arthritis, including
    • Bone spurs
    • Worn-down cartilage
    • Loss of joint space

How is thumb arthritis treated?

Currently, there is no permanent cure for arthritis, treatment generally involves a combination of medication and splints. Severe thumb arthritis might require surgery.

  • Medication:
  • Splint: A splint may help
    • Support and limit the movement of the thumb joint.
    • Decrease pain.
    • Encourage proper positioning of the joint while you complete tasks.
  • Injections: In case pain relievers and a splint are not effective, the doctor might recommend injecting a long-acting corticosteroid into the thumb joint, which may provide temporary pain relief and reduce inflammation.
  • Surgery:
    • Arthrodesis (joint fusion): The bones in the affected joint are permanently fused with the help of a plate and screws
    • Osteotomy: The bones in the affected joint are repositioned to help correct deformities
    • Trapeziectomy: Trapezium (one of the bones in the thumb joint) is removed
    • Arthroplasty (joint replacement): All or part of the affected joint is removed and replaced with an artificial implant made of plastic, ceramics, silicone, or metals 
  • Physical therapy: To help regain hand strength and movement

Try these home remedies to ease pain and improve joint mobility:

  • Apply hot or cold fomentation to the joint for 5 to 15 minutes several times a day to help relieve swelling and pain
  • Eliminate activities that may aggravate your arthritis such as spending long hours typing on a computer
  • Try strengthening and stretching exercises to reduce symptoms and improve function
  • Try adaptive equipment such as jar openers, key turners, and large zipper pulls designed for people with limited hand strength
  • Lose weight if you are overweight

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Medically Reviewed on 10/20/2022
References
Image Source: iStock image

Thumb arthritis Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/thumb-arthritis/symptoms-causes/syc-20378339

How Rheumatoid Arthritis Affects Your Hands, and 7 Ways to Keep Them Healthy Creaky Joints: https://creakyjoints.org/symptoms/how-rheumatoid-arthritis-affects-hands/

Arthritis of the Hand Cleveland Clinic: https://my.clevelandclinic.org/health/diseases/7082-arthritis-of-the-wrist-and-hand

Rheumatoid Arthritis American Society for Surgery of the Hand: https://www.assh.org/handcare/condition/rheumatoid-arthritis