Assembler for modular prosthesis

1. An adapter for a modular prosthesis head, the head defining a trunnion bore having a trunnion installation axis, an outer spherical perimeter surface, and a planar face symmetric about the trunnion installation axis, the planar face opposite of the outer spherical perimeter surface, comprising:

an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, a circumferential channel in an outer surface of said anvil body disposed between and parallel to said planar surfaces, an anvil axis extending through and perpendicular to said planar surfaces and a spherical depression defined in said top surface with said spherical depression conforming to, and configured to mate with, the outer spherical perimeter surface;

an anvil axis interaction structure defined in said bottom surface with said anvil axis interaction structure symmetric about said anvil axis; and

a shell, enclosing said anvil body, said shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to and disposed within said circumferential channel with said circumferential ledge spaced apart from and parallel to said shell planar portion and said sidewall further defining a shell cavity;

wherein said shell further defines a shell alignment axis when the modular prosthesis head is installed in said depression and both the modular prosthesis head and anvil are installed in said shell cavity with said shell alignment axis non-rotatingly aligned with the trunnion installation axis and with said anvil axis responsive to an engagement of said shell with both said anvil body and the planar face.

2. The adapter of claim 1 wherein said planar face extends a first predetermined distance away from said top surface when the modular prosthesis head is installed in said depression and said trunnion installation axis is aligned with said anvil axis and the planar face is parallel to said top planar surface, wherein said circumferential channel is spaced apart from said top planar surface by a second predetermined distance, and wherein said shell planar portion is spaced apart from said circumferential ledge by a third predetermined distance equal to a sum of said first predetermined distance and said second predetermined distance.

3. The adapter of claim 1 wherein said shell includes two or more shell portions.

4. The adapter of claim 1 wherein the modular prosthesis head includes an indicia on an outer head surface aligned with the trunnion installation axis and wherein said anvil axis interaction structure includes an aperture extending into said depression.

5. An adapter for a modular prosthesis head, the head defining a trunnion installation axis, an outer spherical perimeter surface, and a planar face symmetric about the trunnion installation axis, comprising:

an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, a circumferential channel in an outer surface of said anvil body disposed between and parallel to said planar surfaces, an anvil axis extending through and perpendicular to said planar surfaces and a depression defined in said top surface with said depression complementary to the outer spherical perimeter surface and symmetric about said anvil axis;

an anvil axis interaction structure defined in said bottom surface with said anvil axis interaction structure symmetric about said anvil axis; and

a shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to said circumferential channel with said circumferential ledge spaced apart from and parallel to said shell planar portion and said sidewall further defining a shell cavity;

wherein said shell further defines a shell alignment axis when the modular prosthesis head is installed in said depression and both the modular prosthesis head and anvil are installed in said shell cavity with said shell alignment axis aligned with the trunnion installation axis and with said anvil axis;

wherein the modular prosthesis head includes an indicia on an outer head surface aligned with the trunnion installation axis and wherein said anvil axis interaction structure includes an aperture extending into said depression;

wherein said shell defines a shell bottom spaced apart from said shell planar portion, wherein said bottom surface extends through said shell bottom when the modular prosthesis head is installed in said depression and both the modular prosthetic head and anvil are installed in said shell cavity, and wherein said indicia is visible through said aperture when the modular prosthetic head is installed in said depression and both the modular prosthetic head and anvil are installed in said shell cavity and when said anvil axis is aligned with the trunnion installation axis.

6. The adapter of claim 1 wherein said anvil axis interaction structure is configured for receipt of an installation force applicator aligned with said shell alignment axis.

7. An adapter for a modular prosthesis component, the component defining an installation axis, a distal perimeter surface, and a proximal face, opposite of the distal perimeter surface, symmetric about the installation axis, comprising:

an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, a circumferential channel in an outer surface of said anvil body disposed between and parallel to said planar surfaces, an anvil axis extending through and perpendicular to said planar surfaces and a depression defined in said top surface with said depression conforming to, and configured to mate with, the distal perimeter surface and symmetric about said anvil axis;

an anvil axis interaction structure defined in said bottom surface with said anvil axis interaction structure symmetric about said anvil axis; and

a shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to said circumferential channel with said circumferential ledge spaced apart from and parallel to said shell planar portion and said sidewall further defining a shell cavity;

wherein said shell further defines a shell alignment axis when the modular prosthetic component is installed in said depression and both the modular prosthetic component and anvil are installed in said shell cavity with said shell alignment axis non-rotatingly aligned with the installation axis and with said anvil axis responsive to an engagement of said shell with both said anvil body and the planar face.