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CMC Joint Arthroplasty with Flexor Tendon Interposition

What is CMC joint arthritis?

Thumb carpometacarpal (CMC) arthritis is a disorder where the cartilage of the thumb CMC joint erodes, causing pain, inflammation, stiffness, and swelling of the joint. The thumb CMC is located at the base of thumb where it meets the wrist. After the cartilage protecting the thumb CMC joint erodes, you are left with the bone of the thumb rubbing and grinding on the bone of the wrist. Due to the importance of this joint and its involvement in thumb movement, thumb CMC joint arthritis can be severely debilitating. Symptoms usually start with pain in the base of the thumb, but can also include swelling or weakness of the joint. You may notice difficulty manipulating small objects when using your thumb.


The procedure to treat CMC joint arthritis is called CMC arthroplasty with flexor tendon interposition. In this surgery, two incisions will be made in the forearm and a section of a flexor tendon (usually the flexor carpi radialis) is harvested. The wrist bone that is currently grinding on the thumb is removed.  Then part of that tendon will be placed into the thumb CMC joint space to cushion the joint, replacing the eroded cartilage, and the other part of the tendon is used to secure the cushion in place.  The surgery lasts approximately 1 hour and is performed on an outpatient basis, meaning you will be able to go home on the same day of the procedure.

Things to know:​

  • You will be discharged in a temporary splint that must be kept clean and dry until you are seen for follow up.
  • You will follow up with us in the office 1-2 days after the procedure. You will be sent for a custom thumb spica splint that is removable for showering ONLY.
  • After 48 hours you may shower. While showering, you may use soap and water, but be sure to pat the incision dry. It is important that you do not submerge your surgical incision in water (i.e. no bath tubs, swimming pools, washing dishes, etc.). While showering, it is important you do not use your hand/arm. After showering, pat incision dry and replace splint.
  • It is important to elevate your arm on a couple of pillows to alleviate pain and swelling.
  • Sutures will remain in place for 10-14 days.
  • Typically follow up appointments are scheduled in two-week intervals following surgery, so we can monitor your recovery.
  • You will wear your splint at all times for 6 weeks. After 6 weeks, you will be referred for Occupational Therapy of the affected hand and wrist.
  • The splint will gradually be discontinued in the weeks to follow as you progress with occupational therapy. Your lifting restrictions will gradually be increased over the next 2-3 months.

Postoperative restrictions are as follows:

  • NO use of the affected hand.
  • Must wear splint at all times, except while showering.