INSTRUMENTS FOR KNEE PLACEMENT

• US 20130166034A1
• Filed: 08/12/2011
• Published: 06/27/2013
• Est. Priority Date: 08/13/2010
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Landon, Ryan Lloyd
• Granted Patent: US 9,301,846 B2
• Time in Patent Office: Days
• US Class Current: 623/20.2
• CPC Class Codes: A61B 17/154 for preparing bone for knee prosthesis
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61B 17/90 Guides therefor
• CPC Class Codes: A61B 17/92 Impactors or extractors, e.g. for removing intramedullary devices insertion or extraction of artificial joints A61F2/4603
• CPC Class Codes: A61B 2017/922 Devices for impaction, impact element
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/3877 Patellae or trochleae
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2310/00011 Metals or alloys
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

There are provided various embodiments of medical instruments to perform knee surgery. In one embodiment a finned platform for mounting a cutting block is provided. The finned platform can be used don either a femor or tibia to allow for the proper cuts when performing a knee surgery. In another embodiment, a tibial trial is shown having a fin. The fin is useful to reinforce the bone to reduce the risk of fracture during bone preparation. In another embodiment, a reamer is provided having a plurality of cutting flutes. It may be desirable to utilize a guide with the reamer to allow the reamer to cut a noncircular portion of the tibial bone. In yet another embodiment, a plurality of fixation pegs are provided on the tibial implant to allow for easy removal of such implant if a revision surgery becomes necessary.

Claims

1. A patellar implant for implantation into a patient'"'"'s natural patella adjacent a femoral implant component comprising:

a base portion made from a medical grade material having a sufficient rigidity to prevent bending when positioned within a patient'"'"'s natural patella; and

a polymeric portion made from a polymeric material positioned about a portion of the base portion and adapted to bear against a femoral component.

2. The patellar implant of claim 1, wherein said base portion has a ring with a top surface, a side surface, and a bottom surface, the bottom surface having an attachment peg extending therefrom, and the polymeric portion being attached to the top surface of the ring.

3. The patellar implant of claim 2, wherein said ring has a plurality of said attachment pegs depending from said bottom surface, the pegs being porous to allow for the boney ingrowth of a patient'"'"'s natural bone.

4. The patellar implant of claim 2, wherein the polymeric portion is molded about the top and side surfaces of the ring of the base portion.

5. The patellar implant of claim 2, wherein the polymeric portion is snap fit about the top and side surfaces of the ring of the base portion.

6. The patellar implant of claim 3, wherein the ring of the base portion is generally flat and is provided with a second generally circular ring positioned on the top surface of the generally flat ring to provide additional rigidity to the base portion, the polymeric portion being molded about the generally flat ring and the generally circular ring.

7. The patellar implant of claim 6, wherein the base portion is made of a porous metal material having a flat circular portion, the generally circular ring being attached to the flat circular portion of the base portion such that all sharp edges are removed from said base portion, the polymeric portion being molded about the base portion such that the top and side surfaces of the base portion are encapsulated with the polymeric portion extending about the sides of the base portion to provide a dovetail lock about the sides of the patellar implant.

8. The patellar implant of claim 7, wherein a thin impermeable membrane is applied about portions of the flat circular portion of the base portion including the top and side surfaces and about the generally circular ring to prevent the creation of wear particles that would then float within the surgical site.

9. The patellar implant of claim 7, wherein a thin impermeable membrane is applied about portions of the attachment pegs to prevent boney tissue ingrowth along the sides of the attachment pegs while allowing such boney tissue ingrowth at a bottom surface of said attachment pegs to allow for easier removal of the patellar implant in a revision surgery.

10. The patellar implant of claim 1 , wherein the base portion is provided with a pair of indentions provided about its periphery generally opposite each other to allow for additional polymeric material of the polymeric portion to fill in the area of the indentations to provide greater flexibility to the patellar implant.

11. The patellar implant of claim 10, wherein said indentations are positioned on the superior and inferior poles of the patellar implant when positioned with respect to a patient'"'"'s natural knee cap and the femoral component.

12. The patellar implant of claim 3, wherein the base portion is made of a material selected from the group consisting of titanium, titanium alloy, zirconium, chrome cobalt, stainless steel and ceramic, the material having a rigidity appropriate to prevent bending when positioned within a patient'"'"'s natural patella.

13. The patellar implant of claim 3, wherein the polymeric portion is made of a polyethylene material or a cross-linked polyethylene material.

14. The patellar implant of claim 3, wherein the attachment pegs are provided with a porous coating to allow for tissue ingrowth when positioned within a patient'"'"'s natural patella.

15. The patellar implant of claim 2, wherein the ring is provided with a plurality of indentations about its periphery to allow for additional polymeric material of the polymeric portion to flow about the periphery to fully bond the polymeric portion to the base portion.

16. A patellar implant for implantation into a patient'"'"'s natural patella adjacent a femoral implant component, the implant comprising:

a base portion made from a metallic material having a sufficient rigidity to prevent bending of the base portion when attached to a patient'"'"'s natural patella; and

a polymeric portion made from a polymeric material, the polymeric portion positioned about a periphery of the base portion and adapted to bear against a femoral component.

17. The patellar implant of claim 16, wherein the base portion includes a top surface, a bottom surface and a side surface extending between the top and bottom surfaces, wherein the polymeric portion encapsulates the top surface and the side surface of the ring.

18. The patellar implant of claim 16, wherein the base portion includes a ring having a top surface, a bottom surface and a side surface extending between the top and bottom surfaces, the base portion further including one or more attachment pegs extending from the bottom surface of the ring, and wherein the polymeric portion covers the top surface of the ring and extends peripherally about the side surface of the ring.

19. The patellar implant of claim 18, wherein the top surface of the base portion is generally flat, the base portion further including a ring having a generally circular cross section, the ring attached to the generally flat top surface to provide additional rigidity to the base portion.

20. The patellar implant of claim 18, wherein the side surface of the base portion and an inner surface of the polymeric portion together define a dovetail lock therebetween to retain the polymeric portion on the base portion.

21. The patellar implant of claim 18, further comprising a thin impermeable membrane extending about a periphery of the attachment pegs to prevent boney tissue ingrowth into the sides of the attachment pegs while allowing boney tissue ingrowth into a bottom surface of the attachment pegs.

22. The patellar implant of claim 16, further comprising a thin impermeable membrane positioned between adjacent surfaces of the base portion and the polymeric portion to prevent the creation of wear particles between the adjacent surfaces.

23. The patellar implant of claim 16, wherein the periphery of the base portion is provided with a pair of indentions arranged generally opposite one other with the polymer material of the polymeric portion positioned within the indentations to provide increased flexibility to the patellar implant.

24. The patellar implant of claim 16, wherein the polymeric portion is molded about the periphery of the base portion.

25. The patellar implant of claim 16, wherein the polymeric portion is attached to the periphery of the base portion by a snap fit connection.