Dual mobility cup reverse shoulder prosthesis

A reverse shoulder prosthesis system, the system comprising:

• a baseplate having a coupling surface and an opposite mounting surface with a peripheral surface connecting the coupling surface and the mounting surface to define a thickness of the baseplate therebetween;
• a glenosphere coupled to the baseplate, the glenosphere having a truncated spherical portion with a flat surface coupled to the coupling surface of the baseplate, the truncated spherical portion having an equator and a geometric center defined at the equator and located along a central axis of the glenosphere that is axially distanced from the mounting surface of the baseplate to define a total offset of the glenosphere, the truncated spherical portion including an exterior convex surface defining a radius from the geometric center of the glenosphere, the equator being disposed in a first plane and the flat surface being disposed in a second plane parallel to the first plane with each of the equator and the flat surface being centered about the central axis of the glenosphere with a perpendicular distance between the first and second planes defining a glenosphere center of rotation offset;
• a humeral socket having an interior concave surface extending circumferentially about a central axis of the humeral socket and a peripheral edge extending circumferentially about the central axis of the socket, the peripheral edge being axially spaced from an intersection of the central axis of the socket and the interior concave surface to define a depth (D1) of the humeral socket;
• and
• a cup positioned between the exterior convex surface of the glenosphere and the interior concave surface of the humeral socket, the cup being moveable relative to the glenosphere and to the humeral socket, the cup having a first cup surface and an opposing second cup surface defining a thickness of the cup therebetween, each of the first and second cup surfaces extending circumferentially about a central cup axis,
• the first cup surface having a first radius (R1) along the central cup axis and forming an exterior convex surface of the cup in bearing engagement with the interior concave surface of the humeral socket,
• the second cup surface having a second radius (R2) along the central cup axis and forming an interior concave surface of the cup in bearing contact engagement with the exterior convex surface of the glenosphere,
• wherein a ratio of the depth (D1) of the humeral socket to the first radius (R1) of the first cup surface (D1:R1) is 0.45+40 percent.