Thumb CMC Arthroplasty

Carpometacarpal (CMC) Joint Anatomy

The carpometacarpal joint attaches the base of the thumb to the wrist. It is formed from two bones, the metacarpal and trapezium, and allows the hand to grasp objects with a strong grip. In a normal basal joint, cartilage covers the ends of the bones, acting as a cushion and allowing bones to glide smoothly against each other.

Arthritis of the Thumb

People with osteoarthritis of the thumb can experience severe pain, swelling and decreased motion at this joint, finding it extremely difficult to do simple activities such as opening and closing the lid of a jar and turning door knobs.

Causes of Thumb Arthritis

Thumb arthritis, also called basal joint arthritis, may occur due to

  • Family history of arthritis
  • Joint injury
  • Overuse of the joint, such as in people working on assembly lines.

Impact of Thumb Arthritis

Arthritis of the thumb causes degeneration of the cartilage between the two joint bones, trapezium and metacarpal. With thumb arthritis, the cartilage that covers the ends of the bones deteriorates and its smooth surface roughens. The bones then rub against each other, resulting in friction and joint damage. Moreover, the friction between the two bones can also lead to the formation of bone spurs on the articulating surface of the bones restricting further motion of the joint.

Treatment of Thumb Arthritis

Initial treatment of thumb arthritis is aimed at managing the symptoms, but this does not eliminate the arthritis or repair the joint damage. Treatment measures include

  • Activity modification
  • Splints
  • Non-steroidal anti-inflammatory drugs
  • Corticosteroid injections

Indications of Thumb CMC Arthroplasty

When symptoms get worse, a surgical procedure called carpometacarpal arthroplasty may be recommended to reconstruct the damaged joint. The surgical procedure can be performed as an outpatient surgery.

Thumb CMC Arthroplasty Procedure

In carpometacarpal arthroplasty surgery, your surgeon removes the trapezium from the joint and replaces it with a ball made of rolled wrist tendon cut from the same wrist.

Postoperative Care for Thumb CMC Arthroplasty

After the surgery, the thumb is put in a cast for 3-4 weeks and a splint is worn continuously for another 4 weeks. To regain movement and strength of the thumb joint, physical therapy is started soon after the removal of the cast.

Downtime for Thumb CMC Arthroplasty

Total recovery time varies and depends on an individual’s healing process. Usually, normal activities can be resumed within four months of the surgery.

Risks and Complications of Thumb CMC Arthroplasty

Complications are minimal, and may include infection and numbness at the operated site.