The most common site for degenerative arthritis is at the carpometacarpal (CMC) joint of the thumb—that is, the joint at the base of the thumb between the metacarpal and the bone of the wrist, or carpus, known as the trapezium.  This type of arthritis is therefore also referred to as basal-joint arthritis, trapeziometacarpal arthritis, or carpometacarpal arthritis of the thumb.
Such arthritis can in some instances be attributed to specific forceful, repetitive activities and may be work related.  In other situations, a prior fracture or injury may be found to be the cause.  Most frequently, no specific cause is evident, and the arthritis develops for unknown reasons.
CMC arthritis of the thumb is most often seen to develop in postmenopausal women.  This is thought to be due to the ligamentous changes and laxity which occur in this age group.

Symptoms
With CMC arthritis, everyday tasks (such as holding eating utensils or objects such as a glass of water) and "pinching" activities (such as striking a match) may become quite painful or even impossible to perform.  When such pain becomes so severe that it interferes substantially with one's quality of life and hampers one's ability to perform many customary activities, surgical reconstruction is indicated.

Treatment
The treatment of CMC arthritis initially begins with splinting the thumb in a comfortable position and taking oral antiinflammatory medications.  This may reduce the initial inflammation and may suffice to allow reasonable function.  Sometimes a cortisone injection into the joint can be helpful.
All such treatments, however, are only temporizing measures and do not eliminate the underlying arthritis.  If the problem persists and becomes incapacitating, then further treatment is needed.

Surgery
The procedure accepted most frequently by hand surgeons is a resection (surgical removal) of the trapezium, with placement of a rolled-up tendon to provide a cushion in the space that remains, to resolve the pain of this arthritis.  In conjunction with this procedure, the ligament of the base of the thumb metacarpal is usually reconstructed so that the thumb remains stable and strong.
Other procedures are also available to treat this problem, such as fusion of the CMC joint or placement of a prosthesis at the site.
Because fusion limits thumb movement and decreases function, unless there is some specific reason for it to be done, this is usually not the best option.
And while some prostheses exist on the market at this time, there is not adequate clinical experience with them, or sufficient documentation of their long-term success.  Considering that a prosthesis requires placement of a foreign substance at the base of the thumb, it must be shown, before such a procedure can be considered an intelligent alternative, that the procedure would offer a significant advantage over the trapezium resection described above.