Thirty-four total trapezio-metacarpal prostheses have been fitted since 1971. Twenty-eight have had a follow-up for more than six months (up to a maximum of five years) and allow a valid assessment of the situation. The operations were undertaken for rheumatoid, osteoarthritic disease, and following trauma. The reasons were either pain, mechanical instability, or stiffness. Two out of three times results were good. The best results were obtained for pain and stability. Those where the indication was stiffness were less satisfying. There were five cases of loosening of the trapezial cup due to operative errors. The mediocre results in general are caused by incomplete treatment allowing an associated lesion to develop. Greater strictness in the indications and in carrying out of operation ought to ensure better results.