The joint at the base of the thumb is a saddle shaped joint, where most of the thumb movement occurs. This joint is prone to developing osteoarthritis.

This presents with pain on the radial side of the wrist and pain on axial loading of the thumb. The diagnosis is confirmed with X-rays.

This can be treated with steroid injections. Surgery may be an option if all else fail.

Surgical treatment involves removing one of the small wrist bones (the trapezium) with tendon interposition. This can improve the pain but may leave the patient with weakness in grip strength.

An alternative operation is to fuse the joint. Fusion is the process by which two bones on either side of the joint are made to heal together as one. this will involve the use of plate and/or screws. This would offer pain relief and will maintain grip strength but will restrict movement.

Replacements for this joint are available but with varying degrees of success.