Femoral augments for use with knee joint prosthesis

• US 20040172137A1
• Filed: 03/05/2004
• Published: 09/02/2004
• Est. Priority Date: 08/27/2001
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Mayo Foundation For Medical Education And Research (Mayo Clinic), Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Blaylock, Jeff, Dykema, Scott, Donkers, Ron, Lewallen, David G., Cook, Michael, Hanssen, Arlen D., Hall, Maleata, Meyers, John
• Granted Patent: US 7,892,288 B2
• Time in Patent Office: Days
• US Class Current: 623/20.16
• CPC Class Codes: A61F 2/30734 Modular inserts, sleeves or augments, e.g. placed on proximal part of stem for fixation purposes or wedges for bridging a bone defect
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/461 of knees
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30708 Means for distinguishing between left-sided and right-sided devices, Sets comprising both left-sided and right-sided prosthetic parts
• CPC Class Codes: A61F 2002/30736 Augments or augmentation pieces, e.g. wedges or blocks for bridging a bone defect
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30827 Plurality of grooves
• 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 2002/4619 : for extraction
• CPC Class Codes: A61F 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2002/4641 : for disconnecting
• CPC Class Codes: A61F 2002/4696 : optical
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0004 : Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2250/0084 : Means for distinguishing between left-sided and right-sided devices; Sets comprising both left-sided and right-sided prosthetic parts
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00544 : Coating made of tantalum or Ta-based alloys

Abstract

A femoral augment, or set of augments, for use with a knee joint prosthesis, where the femoral augment includes a main body portion, an aperture formed within the main body portion and extending in a generally distal/proximal direction, and a pair of legs extending outwardly from said main body portion in a generally posterior direction. In the preferred embodiment, the aperture is configured to receive a stem extension implant, and to allow it to pass through. Additionally, the legs of the femoral augment are preferably configured to be seated proximal of a proximal side of a pair of condylar portions of a femoral component of a knee joint prosthesis. The present invention is intended for situations in which the distal portion of the femur is defective, and it provides a method and devices that allow for preservation of healthy peripheral bone, while still providing the necessary augmentation to the distal portion of the femur.

Claims

1. A femoral augment for use with a knee joint prosthesis, said femoral augment comprising:

a main body portion defining an aperture extending in a generally distal/proximal direction; and

a pair of legs extending outwardly from said main body portion in a generally posterior direction.

2. The femoral augment defined in claim 1, wherein said aperture is configured to receive a stem extension implant.

3. The femoral augment defined in claim 1, wherein said pair of legs is configured to be positioned proximal to a base of a femoral component of a knee joint prosthesis.

4. The femoral augment defined in claim 1, wherein said pair of legs is configured to be positioned proximal to a proximal side of a pair of condylar portions of a femoral component of a knee joint prosthesis.

5. The femoral augment defined in claim 4, wherein said main body portion includes a recessed portion to accommodate a pair of inner rails that extend generally in the proximal direction from the pair of condylar portions of a femoral component of a knee joint prosthesis.

6. The femoral augment defined in claim 1, wherein a proximal side of said main body portion defines a relatively flat surface with a generally trapezoidal shape, wherein said trapezoidal shape is defined by a longer base section and a shorter base section that are connected by two leg sections, where said longer base section is of a greater length than said shorter base section.

7. The femoral augment defined in claim 6, wherein said longer base section of said trapezoidal shape includes a curved portion.

8. The femoral augment defined by claim 6, wherein said longer base section of said trapezoidal shape is a generally straight line.

9. The femoral augment defined by claim 6, wherein said leg sections of said trapezoidal shape are each curved.

10. The femoral augment defined in claim 1, wherein outer medial and lateral surfaces of said main body portion are tapered inwardly towards a proximal direction to define a generally conical portion of a generally quadrilateral-shaped cross-section with a truncated proximal surface.

11. The femoral augment defined in claim 10, wherein at least one of an outer anterior surface and an outer posterior surface of said generally conical portion includes a cutout portion adjacent said truncated proximal surface.

12. The femoral augment defined in claim 1, wherein at least an exterior surface of said femoral augment is composed of a tantalum based porous metal.

13. The femoral augment defined in claim 5 wherein inner, opposed surfaces of said legs are sloped towards each other such that said recessed portion is narrowest near a proximal portion thereof and widest near a distal portion thereof, whereby said sloped inner surfaces facilitate positioning of said femoral augment in a lateral/medial tilted orientation with respect to a femoral component of a knee joint prosthesis.

14. An implant system for use with a knee joint prosthesis, said system comprising:

at least one femoral component of a knee joint prosthesis, said at last one femoral component including a pair of condylar portions; and

at least one femoral augment configured to be positioned proximal of said at least one femoral component, said at least one femoral augment including;

a main body portion; and

a pair of legs extending outwardly from said main body portion in a generally posterior direction, said pair of legs configured to be seated upon a proximal side of said pair of condylar portions of said at least one femoral component.

15. The implant system defined in claim 14, wherein:

said at least one femoral component is configured to accept a stem extension implant; and

said at least one femoral augment includes an aperture formed within said main body portion and extending generally in a distal/proximal direction, wherein said aperture is configured to receive the stem extension implant.

16. The implant system defined in claim 14, further comprising a plurality of said femoral augments, wherein:

said at least one femoral augment includes a plurality of femoral augments, and further wherein at least one of said femoral augments includes a proximal side of said main body portion that defines a relatively flat surface with a generally trapezoidal shape, wherein said trapezoidal shape is defined by a longer base section and a shorter base section that are connected by two leg sections; and

at least one of said plurality of femoral augments, other than said at least one femoral augment with said relatively flat surface with said generally trapezoidal shape, includes outer medial and lateral surfaces of said main body portion that are tapered inwardly towards a proximal direction to define a generally conical portion of a generally quadrilateral-shaped cross-section with a truncated proximal surface.

17. The implant system defined in claim 14, further comprising a pusher configured and arranged for implanting one of said at least one femoral augments into a distal portion of a femur.

18. The implant system defined in claim 14, further comprising at least one provisional femoral augment corresponding in shape and size to said at least one femoral augment.

19. The implant system defined in claim 18, further comprising:

at least one groove on an inner surface of said at least one provisional femoral augment; and

a provisional remover configured to cooperate with said at least one groove for removal of said provisional femoral augment from an implanted position.

20. The implant system defined in claim 14, wherein said at least one femoral component includes a plurality of femoral components of different sizes, and further wherein said at least one femoral augment is configured to cooperate with femoral components of more than one different size.

21. The implant system defined in claim 14, wherein:

said at least one femoral component includes a plurality of femoral components of different sizes; and

said at least one femoral augment includes a plurality of femoral augments of different sizes, with each of said different sizes including differences in medial/lateral dimensions and/or differences in anterior/posterior dimensions, and

further wherein femoral augments of multiple distal/proximal heights are provided of at least some of said different sizes.

22. The implant system defined in claim 14, wherein said femoral augment is configured and arranged to allow positioning in an offset or tilted location with respect to said femoral component, in order to maximize contact with remaining endosteal bone of the distal femur.

23. The implant system defined in claim 22, wherein:

said pair of legs of said femoral augment is configured to be positioned proximal to a proximal side of a pair of condylar portions of said femoral component;

said main body portion of said femoral augment includes a recessed portion to accommodate a pair of inner rails that extend generally in the proximal direction from said pair of condylar portions of said femoral component; and

further wherein inner, opposed surfaces of said legs are sloped towards each other such that said recessed portion is narrowest near a proximal portion thereof and widest near a distal portion thereof, whereby said sloped inner surfaces facilitate positioning of said femoral augment in a lateral/medial tilted orientation with respect to said femoral component.

24. A set of femoral augments for use with a knee joint prosthesis, said set comprising a plurality of femoral augments, of a plurality of different sizes, wherein each of said femoral augments comprises:

a main body portion; and

a pair of legs extending outwardly from said main body portion in a generally posterior direction, said pair of legs configured to be seated upon a proximal side of a pair of condylar portions of a femoral component.

25. The set of femoral augments as defined in claim 24, wherein said plurality of different sizes includes variations in medial/lateral dimensions and/or variations in anterior/posterior dimensions, and further wherein said set of femoral augments also includes femoral augments of a plurality of different distal/proximal heights in at least one of said different sizes.

26. The set of femoral augments as defined in claim 24, wherein:

at least one of said femoral augments is symmetrical, with respect to its lateral and medial sides, thereby allowing implantation into either a right femur or a left femur;

at least one of said femoral augments is asymmetrical, with respect to its lateral and medial sides, thereby limiting its implantation location to a right femur; and

at least one of said femoral augments is asymmetrical, with respect to its lateral and medial sides, thereby limiting its implantation location to a left femur.