Total shoulder prosthesis

摘要

A shoulder prosthesis includes a humeral stem designed to be implanted within the patient's humeral canal and a head portion designed to cooperate with the glenoid cavity of a shoulder. The head portion, which has a spherical shape generated by revolution about an axis, is connected to the humeral stem by a link that includes 1) a ball fixed to a proximal end of the stem and 2) a spherical socket made in the head portion and forming a housing for the ball. The axis of revolution of the head portion is off-set with respect to the center of the ball. The assembly formed by the socket and the ball constitutes a joint capable of making the orientation of the head portion vary in relation to the stem by rotation about the center of the ball. The head portion is lockable to the stem, preferably by a conical push rod which moves into an axial conical bore under the action of a tightening screw, to cause compression of the ball against the spherical cavity by blocked lateral expansion of the ball.