RADIAL HEAD PROSTHESIS WITH FLOATING ARTICULAR MEMBER

• US 20160022425A1
• Filed: 10/08/2015
• Published: 01/28/2016
• Est. Priority Date: 09/10/2012
• Status: Active Grant

• Current Assignee: Acumed Llc (Berkshire Hathaway Incorporated)
• Original Assignee: Acumed Llc (Berkshire Hathaway Incorporated)
• Inventors: Huebner, Randall J., Budor, Kara J., Ehmke, Larry W., Bergquist, Jeff A.
• Granted Patent: US 9,707,084 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/3804 for elbows
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30362 with possibility of relative movement between the protrusion and the recess
• CPC Class Codes: A61F 2002/30364 Rotation about the common longitudinal axis
• CPC Class Codes: A61F 2002/30369 Limited lateral translation of the protrusion within a larger recess
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/3809 for radio-humeral joints
• CPC Class Codes: A61F 2002/3818 for proximal radio-ulnar joints, i.e. PRU joints
• CPC Class Codes: A61F 2002/3827 Radial components

Abstract

System, including apparatus, methods, and kits, for replacement of the proximal end of a radial bone with a prosthesis having a floating articular member. The prosthesis may include a head portion connected or connectable to a stem portion. While the stem portion remains operatively connected to the head portion, the head portion and/or an articular member thereof may be permitted to float in position relative to the stem portion. The head portion/articular member may float transversely (e.g., translationally) and/or rotationally with respect to the stem portion. The articular member may articulate with a humeral bone or both a humeral bone and an ulnar bone. In some embodiments, the head portion may include a fixed member for articulation with an ulnar bone and a floating member for articulation with a humeral bone.

Claims

1. A method of replacing an end of a radial bone with a radial head prosthesis having a stem portion and a head portion, the stem portion defining a long axis, the head portion being connected or connectable to the stem portion and including a first member and a second member, the method comprising:

installing the prosthesis such that the stem portion of the prosthesis is attached to a radial bone, the first member directly articulates with an ulnar bone, and the second member directly articulates with a humeral bone and is movable with respect to the first member and the stem portion when the radial head prosthesis is finally implanted and fully operational, to change an offset of the second member'"'"'s center of mass from the long axis.

2. The method of claim 1, wherein the first member of the head portion directly articulates with a prosthetic region of the ulnar bone and/or the second member of the head portion directly articulates with a prosthetic region of the humeral bone when the radial head prosthesis is finally implanted and fully operational.

3. The method of claim 1, wherein the first member of the head portion includes a cup portion, and wherein the second member of the head portion is located in the cup portion when the radial head prosthesis is finally implanted and fully operational.

4. The method of claim 3, wherein a majority of the second member is located in the cup portion when the radial head prosthesis is finally implanted and fully operational.

5. The method of claim 1, wherein the second member is rotatable with respect to the first member when the radial head prosthesis is finally implanted and fully operational.

6. The method of claim 1, wherein the head portion includes at least one resilient member that is deformable to bias a position of the second member with respect to the first member.

7. The method of claim 6, wherein the at least one resilient member biases a position of the second member along the long axis.

8. The method of claim 1, wherein the second member of the head portion is movable with respect to the stem portion and the first member of the head portion via a first interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the first member of the head portion is movable with respect to the stem portion via a second interface that allows the first member to rotate with respect to the stem portion.

9. The method of claim 1, wherein the second member of the head portion is movable with respect to the stem portion and the first member of the head portion via an interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the second member of the head portion has a spherical surface region that forms part of the interface.

10. The method of claim 1, wherein the second member of the head portion is movable with respect to the stem portion and the first member of the head portion via an interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the second member of the head portion has a planar surface region that forms part of the interface.

11. A radial head prosthesis to replace a proximal end of a radial bone, comprising:

a stem portion defining a long axis; and

a head portion connected or connectable to the stem portion and including a first member and a second member;

wherein the prosthesis is configured to be installed such that the stem portion is attached to a radial bone, the first member directly articulates with an ulnar bone, and the second member directly articulates with a humeral bone and is movable with respect to the first member and the stem portion when the radial head prosthesis is finally implanted and fully operational, to change an offset of the second member'"'"'s center of mass from the long axis.

12. The radial head prosthesis of claim 11, wherein the first member of the head portion includes a cup portion, and wherein the second member of the head portion is configured to be located in the cup portion when the radial head prosthesis is finally implanted and fully operational.

13. The radial head prosthesis of claim 11, wherein a majority of the second member of the head portion is configured to be located in the cup portion when the radial head prosthesis is finally implanted and fully operational.

14. The radial head prosthesis of claim 11, wherein the second member is rotatable with respect to the first member when the radial head prosthesis is finally implanted and fully operational.

15. The radial head prosthesis of claim 11, wherein the head portion includes at least one resilient member that is deformable to bias a position of the second member with respect to the first member.

16. The radial head prosthesis of claim 15, wherein the at least one resilient member is configured to bias a position of the second member along the long axis.

17. The radial head prosthesis of claim 11, wherein the second member of the head portion is configured to be movable with respect to the stem portion and the first member of the head portion via a first interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the first member of the head portion is configured to be movable with respect to the stem portion via a second interface that allows the first member to rotate with respect to the stem portion.

18. The radial head prosthesis of claim 11, wherein the second member of the head portion is movable with respect to the stem portion and the first member of the head portion via an interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the second member of the head portion has a spherical surface region that forms part of the interface.

19. The radial head prosthesis of claim 11, wherein the second member of the head portion is movable with respect to the stem portion and the first member of the head portion via an interface that allows changes to the offset of the second member'"'"'s center of mass from the long axis of the stem portion, and wherein the second member of the head portion has a planar surface region that forms part of the interface.

20. A method of replacing an end of a radial bone with a radial head prosthesis having a stem portion and a head portion, the head portion being connected or connectable to the stem portion and including a first member and a second member, the method comprising:

installing the prosthesis such that the stem portion of the prosthesis is attached to a radial bone, the first member directly articulates with an ulnar bone, and the second member directly articulates with a humeral bone and is movable with respect to the first member and the stem portion when the radial head prosthesis is finally implanted and fully operational.