Thumb CMC Arthritis (Base of the Thumb)

What is thumb arthritis?

Thumb arthritis
Reproduced with permission from OrthoInfo. © American Academy of Orthopaedic Surgeons.

Arthritis at the base of the thumb is a type of osteoarthritis, a condition in which cartilage breaks down and releases substances that cause joint inflammation and pain.

Thumb arthritis is typically found at the carpometacarpal (CMC) joint located at the base of the thumb. The CMC joint allows the thumb to have a wide range of motion – up, down and across the palm – as well as the ability to pinch.

What are the symptoms of thumb CMC arthritis?

The most common symptoms of thumb CMC arthritis are swelling, stiffness and pain. These symptoms can be aggravated by activities that require pinching and may eventually worsen to the point of causing pain even when at rest. In severe cases, the destruction of the joint leads to malalignment, and a prominence develops at the base of the thumb as the thumb joint moves out of position. Malalignment can also lead to limited motion and weakness.

What causes thumb CMC arthritis?

The exact cause of thumb arthritis is unknown, but genetics, previous injuries (e.g. fractures or dislocations), and some inflammatory conditions have been shown to be predisposing factors. Thumb CMC arthritis is very common in women over the age of 50.

What are the treatment options for thumb arthritis?

Non-surgical options for mild symptoms include:

  • Splints and oral anti-inflammatories: Splints help stabilize the joint, while anti-inflammatories may decrease swelling and inflammation
  • Cortisone Injection: Reduces swelling and inflammation in the joint, which then reduces pain and improves function

When non-surgical treatments are not helpful, a surgical procedure called Thumb CMC Arthroplasty may be recommended:

Frequently asked questions about Thumb CMC Arthroplasty include:

What does the procedure entail?

  • The procedure involves removing the small wrist bone that is a part of the CMC joint and replacing it with a wrist flexor tendon.
  • A 1.5-inch incision is made over the CMC joint, and the trapezium wrist bone is removed.
  • A small incision is then made in the forearm to release a wrist flexor tendon.
  • The wrist flexor tendon is attached to the base of the thumb metacarpal bone with a bone anchor.
  • The remainder of the tendon is rolled into a ball and placed into the void left by the trapezium, creating a cushion between the remaining bones.
  • Incisions are closed with absorbable sutures.
  • The hand is covered by a dressing, and a plaster splint is placed on the hand to immobilize the wrist and a portion of the thumb.

How long will it take to recover from Thumb CMC Arthroplasty?

At the first post-operative visit, you will be provided with a custom splint to wear for four weeks. You will also perform gentle exercises at home, and formal therapy will begin after six weeks. It can take up to six months for the thumb to feel normal, and strength may take up to several years to improve.

Will the surgery have any long-term side effects?

Long-term studies show that strength in the hand continues to improve slowly over a number of years.

For more information about what to expect before, during and after thumb CMC arthroplasty, click the button below:

Click for more in-depth information about thumb CMC arthroplasty