TOTAL KNEE IMPLANT

• US 20100191342A1
• Filed: 01/27/2010
• Published: 07/29/2010
• Est. Priority Date: 01/27/2009
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Claypool, Jody L., Brown, Jeffrey D., Earl, Brian D., Pendleton, John E., Sanford, Adam H., Byrd, Christopher M.
• Granted Patent: US 8,888,856 B2
• Time in Patent Office: Days
• US Class Current: 623/20.28
• CPC Class Codes: A61F 2/08 Muscles; Tendons; Ligaments sutures A61B17/04
• CPC Class Codes: A61F 2/3836 Special connection between upper and lower leg, e.g. constrained
• CPC Class Codes: A61F 2/385 also provided with condylar bearing surfaces
• CPC Class Codes: A61F 2/3868 with sliding tibial bearing
• CPC Class Codes: A61F 2/468 Testing instruments for artificial joints for testing non-implantable prostheses A61F2/76
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/304 with additional means for limiting said sliding
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/3895 unicompartimental
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/006 modular
• CPC Class Codes: A61F 2250/0073 Force-limiting means

Abstract

A knee prosthesis is provided for use in knee arthroplasty. In one exemplary embodiment, the present invention provides a tibial prosthesis having a tibial baseplate with a fixed medial bearing component and a mobile lateral bearing component. In one exemplary embodiment, the lateral bearing component is secured to the lateral portion of the tibial baseplate utilizing at least one prosthetic ligament. Additionally, in one exemplary embodiment, a stop is provided to limit anterior or posterior movement of the lateral bearing component relative to the tibial baseplate. For example, the stop may be defined by cooperating shoulders formed on the lateral bearing and the tibial baseplate.

Claims

1. A prosthetic knee system, comprising:

a femoral component having a lateral condyle and a medial condyle; and

a tibial component comprising;

a baseplate having a bone facing surface and an opposing support surface;

a medial bearing component having a medial articulation surface and a medial attachment surface, said medial attachment surface coupled with said support surface of said baseplate to fix said medial component to said baseplate, whereby movement of said medial component relative to said baseplate is substantially entirely prevented; and

a lateral bearing component having a lateral articulation surface and a lateral attachment surface, said lateral attachment surface slidingly secured to said support surface of said baseplate, wherein said lateral component is translatable relative to said baseplate.

2. The prosthetic knee system of claim 1, further comprising:

a T-shaped projection formed on one of said lateral attachment surface of said lateral component and said support surface of said baseplate,

a T-shaped groove formed on the other of said lateral attachment surface of said lateral component and said support surface of said baseplate, T-shaped projection sized and positioned to cooperate with said T-shaped groove to form a securement mechanism when said lateral attachment surface of said lateral component is slidingly secured to said support surface of said baseplate, said securement mechanism allowing translation of said lateral component in an anterior direction and a posterior direction.

3. The prosthetic knee system of claim 1, wherein lateral component is translatable relative to said baseplate along a linear path.

4. The prosthetic knee system of claim 1, wherein lateral component is translatable relative to said baseplate along an arcuate path.

5. The prosthetic knee system of claim 1, wherein said baseplate comprises a first baseplate shoulder formed on said support surface, and said lateral component comprises a first lateral component shoulder formed on said lateral attachment surface, said first baseplate shoulder and said first lateral component shoulder cooperating to limit one of anterior translation and posterior translation of said lateral component.

6. The prosthetic knee system of claim 5, wherein said baseplate comprises a second baseplate shoulder formed on said support surface, and said lateral component comprises a second lateral component shoulder formed on said lateral attachment surface, said second baseplate shoulder and said second lateral component shoulder cooperating to limit the other of anterior translation and posterior translation of said lateral component.

7. The prosthetic knee system of claim 1, wherein said lateral condyle of said femoral component cooperates with said lateral articulation surface to urge said lateral component to translate relative to said baseplate.

8. The prosthetic knee system of claim 1, further comprising a first prosthetic ligament having an elongate body, a first end, and a second end, said first end and said second end attachable to said tibial component, said femoral component comprising a crossbar disposed between said medial condyle and said lateral condyle, said elongate body of said first prosthetic ligament wrapped around said crossbar to couple said femoral component to said tibial component.

9. A prosthetic knee system, comprising:

a femoral component having a lateral condyle and a medial condyle, said femoral component defining a plurality of femoral attachment points comprising at least one of a plurality of lateral femoral attachment points and a plurality of medial femoral attachment points;

a tibial component having a lateral articulating surface and a medial articulating surface, said tibial component defining a plurality of tibial attachment points comprising at least one of a plurality of anterior tibial attachment points and a plurality of posterior tibial attachment points;

a first prosthetic ligament having an elongate body, attachable to any of said plurality of femoral attachment points, said elongate body also attachable to any of said plurality of tibial attachment points, said first prosthetic ligament extending from one of said plurality of femoral attachment points to one of said plurality of tibial attachment points to define a prosthetic ligament span, said prosthetic ligament span defining a prosthetic ligament tension, wherein said prosthetic ligament tension is variable when said first and second ends of said prosthetic ligament are attached to varying ones of said plurality of femoral attachment points and said plurality of tibial attachment points.

10. The prosthetic knee system of claim 9 comprising a second prosthetic ligament, said femoral component having a lateral femoral attachment point and a medial femoral attachment point, said tibial component having an anterior tibial attachment point and a posterior tibial attachment point, said first prosthetic ligament extending from said anterior tibial attachment point to one of said medial femoral attachment point and said lateral femoral attachment point, said second prosthetic ligament extending from said posterior tibial attachment point to the other of said medial femoral attachment point and said lateral femoral attachment point.

11. The prosthetic knee system of claim 9, wherein at least one of said first end and said second end of said prosthetic ligament comprises a spherical head, at least one of said femoral attachment point and said tibial attachment point comprising a spherical groove, said spherical head receivable within said spherical groove to lock said prosthetic ligament to at least one of said femoral component and said tibial component.

12. The prosthetic knee system of claim 9, further comprising a dovetail insert, said first prosthetic ligament affixed to said dovetail insert, at least one of said femoral component and said tibial component including a dovetail groove sized to receive said dovetail insert, said first prosthetic insert attached to one of said femoral component and said tibial component when said dovetail insert is received in said dovetail groove.

13. The prosthetic knee system of claim 9, wherein said first prosthetic ligament comprises a means for severing the connection between said first prosthetic ligament and one of said femoral component and said tibial component.

14. The prosthetic knee system of claim 13, wherein said means for severing comprises at least one of:

i) a pair of cooperating magnets disposed between said first end and said second end of said prosthetic ligament;

ii) a weakened portion along a portion of said elongate body of said first prosthetic ligament;

iii) a connection between said prosthetic ligament and one of said femoral component and said tibial component; and

iv) a break strength of said elongate body of said first prosthetic ligament.

15. A prosthetic knee system, comprising:

a femoral component having a lateral condyle and a medial condyle, said femoral component defining at least one femoral attachment point;

a tibial component having a lateral articulating surface and a medial articulating surface, said tibial component defining at least one tibial attachment point;

at least one prosthetic ligament having an elongate body, a first end, and a second end, said first end attachable to said femoral attachment point of said femoral component and said second end attachable to said tibial attachment point of said tibial component, whereby said femoral component is coupled with said tibial component when said first prosthetic ligament is attached to said femoral attachment point and said tibial attachment point; and

means for defining a tension in said at least one prosthetic ligament.

16. The prosthetic knee system of claim 15, wherein said means for defining a tension in said at least one prosthetic ligament comprises at least one of:

i) a number of said plurality of prosthetic ligaments;

ii) a cross-sectional size of said at least one prosthetic ligament;

iii) a material of said at least one prosthetic ligament; and

iv) a fiber orientation of said at least one prosthetic ligament.

17. A method of intraoperatively defining tension between components of a prosthetic knee system, the method comprising:

providing a femoral component having a lateral condyle and a medial condyle, the femoral component defining at least one femoral attachment point;

providing a tibial component having a lateral articulating surface and a medial articulating surface, the tibial component defining at least one tibial attachment point;

attaching a first end of a prosthetic ligament to the femoral attachment point of the femoral component;

attaching a second end of the prosthetic ligament to the tibial attachment point of the tibial component; and

selecting a tension of the prosthetic ligament.

18. The method of claim 17, wherein said step of selecting a tension comprises at least one of:

i) selecting a length of the prosthetic ligament, ii) selecting a material of the prosthetic ligament, iii) selecting a cross-sectional size of the prosthetic ligament, and iv) selecting a fiber orientation of the prosthetic ligament.

19. The method of claim 17, wherein said step of attaching the first end of the prosthetic ligament comprises attaching a plurality of first ends of a plurality of prosthetic ligaments to respective femoral attachment points, and said step of attaching a second end of the prosthetic ligament comprises attaching a plurality of second ends of the plurality of prosthetic ligaments to respective tibial attachment points.

20. The method of claim 19, wherein said step of selecting a tension comprises at least one of:

i) selecting a number of the plurality of prosthetic ligaments, ii) selecting the respective femoral attachment points for the plurality of first ends of the plurality of ligaments, and iii) selecting the respective tibial attachment points for the plurality of second ends of the plurality of ligaments.

21. The method of claim 17, further comprising, before the steps of attaching a first end of the prosthetic ligament, attaching a second end of the prosthetic ligament, and selecting a tension of the prosthetic ligament, the steps of:

attaching a first end of a provisional prosthetic ligament to the femoral attachment point of the femoral component;

attaching a second end of the provisional prosthetic ligament to the tibial attachment point of the tibial component; and

measuring tension in the provisional prosthetic ligament.