Variable prosthesis
View Patent ↗The present teachings are directed to a shoulder prosthesis having an adjustable radial offset and/or angular inclination provided by relative rotation of an adapter interdisposed between a stem and a head. In one example, a prosthesis has a stem having a first longitudinal axis. The prosthesis can also include an adaptor including a first taper. The first taper can have a first taper axis. The prosthesis can include a head supported by the adaptor. The head can be selectively oriented and then coupled to the first taper and the combination can be selectively orientated and the coupled to the stem.
1. A variable prosthesis system, comprising:
a femoral head having an articulating surface defining a diameter and a generally opposed surface, a head female taper formed into the femoral head through the opposed surface, wherein a head center axis of the femoral head is offset a first radial distance from a head taper center axis of the head female taper;
an adapter having a first side and a generally opposed second side, the adapter defining a first adapter taper, wherein the adapter has an adapter center axis offset a radial distance from an adapter taper axis defined by the first adapter taper;
a neck defining a center axis and a male taper, the male taper configured to be connected to the adapter;
wherein the femoral head, the adapter, and the neck are connected to each other, and the head center axis of the femoral head is offset relative to the center axis of the neck.
2. The femoral prosthesis system of claim 1 , wherein the head center axis of the femoral head is defined through a center of the articulating surface.
3. The femoral prosthesis system of claim 2 , wherein the head taper center axis of the head female taper is defined through a center of the head female taper and a taper angle of the head female taper is defined relative to the head taper center axis.
4. The femoral prosthesis system of claim 3 , wherein the head center axis of the femoral head is offset about 1 mm to about 10 mm from the first radial distance from the head taper center axis of the head female taper.
5. The femoral prosthesis system of claim 1 , wherein the first adapter taper is a female adapter taper operable to receive the male taper defined by the neck.
6. The femoral prosthesis system of claim 5 , wherein the adapter center axis of the adapter is defined through a center of the adapter.
7. The femoral prosthesis system of claim 6 , wherein the adapter taper axis of the first adapter taper is defined through a center of the first adapter taper and a taper angle of the first adapter taper is defined relative to the adapter taper axis.
8. The femoral prosthesis system of claim 7 , wherein the adapter center axis of the adapter is radially offset about 1 mm to about 10 mm from the adapter taper axis.
9. The femoral prosthesis system of claim 1 , wherein the adapter is operable to be rotated relative to the femoral head to achieve an offset between a maximum offset and substantially no offset.
10. A variable prosthesis system, comprising:
a neck defining a male taper and having a first center axis extending along at least a portion of the neck;
an adapter including a first taper, the first taper having a first taper center axis;
a head rotatable relative to and fixable to the adapter, the head having an articulating surface and a head center axis;
wherein the head is coupled to the adapter and is positionable relative to the neck through rotation of the adaptor about the first taper axis for adjusting a radial offset of the head center axis relative to the first center axis of the neck, the head center axis is offset a radial distance from a head taper center axis of a head female taper;
wherein the adapter is fixable to the male taper of the neck.
11. The variable prosthesis system of claim 10 , further comprising:
a plurality of indicia with the adapter and the head, wherein the plurality of indicia indicate an alignment of the radial offset of the head relative to the adapter.
12. The variable prosthesis system of claim 11 , wherein the first taper is a first female taper and the adapter further comprises a second portion that has a second axis and the second axis is offset from the first taper axis.
13. The variable prosthesis system of claim 12 , wherein the articulating surface defines more than a hemispherical outer surface adapted for articulating engagement with at least one of a prepared acetabulum or an acetabular prosthesis.
14. The variable prosthesis system of claim 13 , further comprising:
an opposing surface opposed to the articulating surface of the head;
a female taper formed into the head through the opposing surface, wherein the female taper rotatably receives the second portion of the adaptor.
15. The variable prosthesis system of claim 14 , wherein the radial offset is about 1 mm to about 10 mm.
16. The variable prosthesis system of claim 15 , wherein the first taper of the adapter is the female taper and is operable to receive the male taper defined by the neck to fixably connect the adapter to the neck.
17. The variable prosthesis system of claim 16 , further comprising:
a shank configured to be positioned in a femur of a patient, wherein the shank extends along a second axis at an angle relative to the first axis of the neck.
18. The variable prosthesis system of claim 10 , wherein the head axis is angularly inclined relative to the first tapered axis.
19. A method of forming a variable prosthesis system, comprising:
forming a femoral head having an articulating surface defining a diameter and a generally opposed planar surface, wherein a head center axis is defined through the articulating surface;
forming a head female taper around a head taper center axis and into the formed femoral head through the opposed planar surface, wherein the head center axis is radially offset a first radial distance from the head taper center axis;
forming an adapter having a first side and a generally opposed second side with a sidewall extending between the first side and second side, the sidewall of the adapter defining a first adapter taper, the adapter further having an adapter female taper formed into the adapter through the first side, wherein the first adapter taper has a first adapter axis and the adapter female taper has a second adapter axis, wherein the first adapter axis and the second adapter axis are radially offset a second radial distance;
wherein the femoral head, the adapter, and a male taper of a neck are rotatably connectable to each other and the head center axis is offset relative to a center axis of the neck.
20. The method of claim 19 , further comprising:
forming the articulating surface of the formed femoral head to define a portion of a sphere greater than a hemisphere.
21. The method of claim 19 , wherein the first radial distance and the second radial distance are the same radial distance.