Thumb joint replacement

Replacement of the worn thumb-base joint with a small ball-and-socket implant, keeping the thumb at its full length. Compared with trapeziectomy in randomised trials it gives similar pain relief and hand-function scores, faster recovery and a stronger pinch, with a risk of implant loosening, dislocation or wear; ten-year results for modern dual-mobility designs are not yet available.

Related terms

• Treatment

  Trapeziectomy

  Removal of the trapezium so that the worn thumb-base joint no longer exists; the space fills with scar tissue and the thumb settles slightly. The standard operation for painful thumb-base arthritis, with good pain relief in about four in five people at five to eighteen years; pinch strength does not return to normal. Adding a tendon sling or spacer makes little or no difference.

• Outcome measure

  Key pinch

  The grip between the pad of the thumb and the side of the index finger, as when turning a key, measured with a pinch gauge in kilograms. The strength most affected by thumb-base arthritis and the outcome that separates the operations: it fades over years after trapeziectomy and is about 0.9 kg stronger after joint replacement in pooled trials.

Articles mentioning this term

1. Patient information · 26 September 2026

   Thumb-base arthritis

   Thumb-base (CMC) arthritis: symptoms, splints, exercises, injections, and how trapeziectomy compares with joint replacement in recovery, strength and risk.

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