CMC Arthritis

What Is Thumb Arthritis (CMC Arthritis)?

Thumb arthritis, also known as CMC arthritis, is a common condition where the cartilage at the base of the thumb (where the thumb meets the wrist) wears down over time. This joint, known as the carpometacarpal (CMC) joint, allows the thumb to pivot, pinch, and grasp.

Thumb arthritis is the second most common type of hand arthritis (after the arthritis that affects the last joints of the fingers) and is more frequently seen in women over 40. It’s primarily a degenerative condition, meaning it worsens over time, though inflammatory types of arthritis (like Rheumatoid Arthritis or Lupus) can also affect this joint.

Causes

Thumb arthritis is caused by the gradual breakdown of cartilage in the CMC joint. This can occur due to:

• Aging and general wear-and-tear

• Genetics (family history of arthritis)

• Previous trauma or injury to the thumb

• Inflammatory arthritis conditions

As cartilage deteriorates, bones may rub against each other, causing pain, stiffness, and swelling.

Signs & Symptoms

The most common signs of thumb arthritis include:

• Pain at the base of the thumb, especially during pinching, gripping, or twisting (e.g., opening a jar, turning a key)

• Swelling and stiffness

• Weak grip strength

• Decreased range of motion

• A grinding sensation when moving the thumb

• Development of bone spurs, leading to an enlarged, bumpy appearance at the thumb base

Symptoms often worsen with activity and may progress slowly over time.

Diagnosis

If thumb pain starts to affect daily activities, a consultation with a hand specialist or orthopedic surgeon is recommended.

• Physical Examination: The doctor may feel or hear grinding in the joint when the thumb is gently moved.

• X-rays: Used to confirm cartilage loss, joint space narrowing, and bone spur formation.

Treatment Options

Non-Surgical Treatment

Most cases of thumb arthritis can be managed without surgery, especially in early or moderate stages. Options include:

• Anti-inflammatory medications (consult your doctor first)

• Ice or heat therapy

• Thumb bracing to support the joint

• Activity modification to reduce stress on the thumb

• Occupational therapy to teach ergonomic hand use

• Strengthening and stretching exercises

• Corticosteroid injections to reduce inflammation and pain

These treatments aim to relieve pain and improve function, though they don’t stop arthritis progression.

Surgical Treatment

Surgery is considered when:

• Non-surgical methods no longer provide relief

• Pain is severe or disabling

Surgical options include:

• Trapeziectomy: Removal of part or all of the trapezium bone in the joint

• Suspension or tendon interposition techniques to support the thumb after bone removal

• Joint fusion (arthrodesis): Fusing the bones of the thumb to eliminate motion and pain