Shoulder or hip prosthesis and process for fitting same

A shoulder or hip prosthesis comprising:

• a first component comprising:
• a neck;
• and
• a plate connected to the neck, wherein the plate forms a concave surface of articulation;
• a second, intermediate component comprising:
• a first convex surface of articulation;
• a second convex surface of articulation;
• and
• a retaining member for retaining the first component in abutment against the first convex surface of the second component, wherein the retaining member and the first convex surface of the second component define a volume for receiving a projection extending radially from the plate with respect to the neck;
• and
• a third component comprising a concave surface of articulation;
• wherein the first and second convex surfaces of articulation cooperate respectively with the concave surface of articulation of the first component and the concave surface of articulation of the second component, wherein the second convex surface of articulation of the second component is unconstrained relative to the concave surface of articulation of the third component, and wherein the retaining member defines a non-circular passage in which the neck is adapted to be displaced as a function of movement of the first component with respect to the second and third components.

A shoulder or hip prosthesis comprising:

• a first component comprising:
• a plate forming a concave surface of articulation;
• a stem anchored in a medullary cavity;
• and
• a neck connecting the plate to the stem;
• a second component comprising:
• a retaining member having a non-circular passage for maintaining the first component against the second component;
• a first convex surface of articulation;
• and
• a second convex surface of articulation;
• wherein the neck of the first component is displaced within the non-circular passage of the retaining member;
• and
• wherein the retaining member and the first convex surface of articulation define a volume for receiving a radially extending part of the plate with respect to the neck;
• and
• a third component having a concave surface of articulation;
• wherein the first convex surface of articulation engages the concave surface of articulation of the first component and the second convex surface of articulation engages the concave surface of articulation of the third component;
• and
• wherein the second convex surface of articulation of the second component is unconstrained relative to the concave surface of articulation of the third component.