Patent ID: 8641770

Claim:
A prosthesis for the basal joint of the thumb, comprising: a socket member including a socket base portion and a socket cap portion, each of said socket base portion and socket cap portion defining a partial spherical recess; and means for securing said socket base portion and socket cap portion together so that said partial spherical recesses cooperate to form an internal, partial spherical socket; a first metacarpal component including means for securing the first metacarpal component at the proximal end of a first metacarpal bone and including a proximally extending, partial spherical projection, said partial spherical projection being received and supported for rotation by said partial spherical socket, with the partial spherical socket enclosing the partial spherical projection sufficiently that the partial spherical projection is entrapped by and cannot be dislodged from the partial spherical socket as long as the partial spherical projection remains intact and the socket base portion and socket cap portion are secured together and remain intact.