A fusion (arthrodesis is the official medical name for a fusion) of any joint is designed to eliminate pain by allowing the bones to grow together, or fuse, into one solid bone. Doing so reduces pain but also reduces the functional range of motion of the joint. Fusions are used in many joints and were very common before the invention of artificial implants for the replacement of arthritic joints. Even today, joint fusions are still very commonly used for treating the pain of arthritis.

A fusion of the basal joint of the thumb is done quite often in younger people who need a strong grip, or pinch, more than they need the fine motion of the thumb.

To perform a fusion of the basal joint an incision is made over the joint from the back of the hand. The joint is then opened so that the surgeon can see the joint surfaces.

The cartilage is removed from both joint surfaces to leave two surfaces of raw bone.

The two joint surfaces are then placed together and held in place with a metal pin. The metal pin allows the surgeon to hold the two bones in the correct alignment. This prevents the bones from moving too much as they grow together or fuse.

It usually takes about six weeks before the bones are fused.