What to Know About Carpal Metacarpal (CMC) Arthroplasty or Thumb Joint Replacement

Carpo metacarpal arthroplasty or CMC arthroplasty is a type of surgery in which a bone at the base of your thumb is replaced with an implant. The joint where your thumb meets your hand is called your carpometacarpal joint.

Carpal metacarpal arthroplasty, commonly called CMC arthroplasty, is a type of joint replacement surgery, an alternative to the traditional gold standard surgical treatment for carpometacarpal (CMC) arthritis, called trapeziectomy.

During a trapeziectomy, a surgeon removes the bone at the base of your wrist called the trapezium. The trapezium is a small bone, measuring less than an inch in greatest diameter. During CMC arthroplasty, the removed bone is replaced with an artificial implant.

CMC arthroplasty has been found to be up to 93% successful at 10-year follow-ups for new-generation implants.

People who have CMC arthroplasty are generally very satisfied with the results, and it’s less invasive than surgical options that involve tendon grafts. However, CMC arthroplasty generally involves more risk and is more expensive than a trapeziectomy.

Read on to learn everything you need to know about CMC arthroplasty, including benefits, risks, and what to expect during the procedure.

CMC arthroplasty was first performed in 1973 . It involves replacing your trapezium with an implant to reduce pain when moving your thumb and preserve your thumb stability. Implants made up of metal and polyethylene currently seem to be the best option.

Many different types of surgery are used to treat problems with your CMC joint. Compared with alternative surgeries, some of the advantages of CMC arthroplasty are that it:

• preserves your normal thumb length and alignment, unlike trapeziectomy
• prevents instability of your wrist
• prevents further joint degeneration
• doesn’t require tendon grafts
• has high levels of satisfaction
• still provides the option for trapeziectomy if it fails

Language matters

You’ll notice we use the binary terms “males” and “females” in this article. While we realize this term may not match your gender experience, it’s the term used by the researchers whose data was cited.

We try to be as specific as possible when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.