[The thumb saddle joint].

In the management of patients with osteoarthritis of the carpometacarpal joint of the thumb, good to very good results can be achieved both subjectively and objectively by surgical intervention. In young patients who do manual hard work and have isolated post-traumatic osteoarthritis of the trapeziometacarpal joint, the treatment method of choice is still arthrodesis. However, in women with postclimacteric osteoarthritis, which is very frequent, we prefer arthroplasty. Resection of the trapezium is a technique only used in selected cases, as it results in considerable loss of stability and strength. We prefer Silastic interposition arthroplasty to cemented total replacement. In patients with major involvement of the joints at the trapezium (especially where it connects with the scaphoid), the treatment of choice is implantation of a Swanson trapezium prosthesis, accompanied by surgical stabilization of the soft tissue. The good results we have achieved with this method, as reported in this paper, also justify its application in the future. In patients with isolated osteoarthritis of the carpometacarpal joint of the thumb we shall use the modified Swanson prosthesis more frequently in the future.