TIBIAL BASEPLATE WITH ASYMMETRIC PLACEMENT OF FIXATION STRUCTURES

• US 20170266011A1
• Filed: 06/07/2017
• Published: 09/21/2017
• Est. Priority Date: 11/21/2011
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Wentorf, Mary S.S., Grey, Calie B., Cronin, Shaun R.
• Granted Patent: US 10,265,181 B2
• Time in Patent Office: Days
• CPC Class Codes: A61F 2/3886 for stabilising knees against anterior or lateral dislocations
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/2892 Tibia
• CPC Class Codes: A61F 2002/30326 differing in height or in length
• 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 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30891 Plurality of protrusions
• CPC Class Codes: A61F 2002/30892 parallel

Abstract

An orthopaedic knee prosthesis is provided including a tibial baseplate component having a distal, bone-contacting surface with one or more fixation structures extending distally therefrom, in which the fixation structures are asymmetrically arranged within the baseplate periphery.

Claims

1. (canceled)

2. A tibial baseplate comprising:

a first proximal surface;

a first distal surface opposite the first proximal surface, the first distal surface shaped to be disposed on a proximal resected surface of a tibia;

a first medial face;

a first lateral face opposite the first medial face; and

a first keel extending distally from the first distal surface, the first keel spaced apart from the first medial face by a first medial distance and spaced apart from the first lateral face by a first lateral distance;

wherein the first keel is medially biased toward the first medial face such that the first medial distance is less than the first lateral distance.

3. The tibial baseplate of claim 2, further comprising:

a first medial compartment defined at least in part by the medial face, a first portion of a first anterior face and a first portion of a posterior face;

a first lateral compartment opposite the first medial compartment, wherein the first lateral compartment is defined at least in part by the first lateral face, a second portion of the first anterior face and a second portion of the posterior face; and

a first, anterior-posterior axis extending centrally between the first medial and lateral compartments throughout its length, the first keel being medially offset from the first axis by a first offset distance.

4. The tibial baseplate of claim 3, wherein the first offset distance is between 5 mm and 0.5 mm, inclusive.

5. The tibial baseplate of claim 3, wherein the first axis is positioned to correspond to a home axis of a patient'"'"'s proximal tibia when the tibial baseplate is implanted onto the patient'"'"'s proximal tibia, the home axis defined as a line extending from a posterior point disposed at a geometric center of an attachment area between a posterior cruciate ligament and the patient'"'"'s proximal tibia, to an anterior point disposed on an anterior tubercle of the patient'"'"'s proximal tibia and bordering a medial third of the anterior tubercle.

6. The tibial baseplate of claim 3, wherein the tibial baseplate is symmetric about the first axis such that the first medial compartment and the first lateral compartment have substantially similar surface areas.

7. The tibial baseplate of claim 3, wherein the tibial baseplate is asymmetric about the first axis such that a first surface area of the first medial compartment differs from a second surface area of the first lateral compartment.

8. The tibial baseplate of claim 3, further comprising a first total width measured from the first medial face to the first lateral face.

9. The tibial baseplate of claim 8, wherein the first offset distance is less than 6 percent but greater than 1 percent of the first total width.

10. The tibial baseplate of claim 8, wherein the first offset distance changes as a percentage basis of the first total width as the first total width changes in dimension such that a degree of medialization of the keel changes relative to the first total width.

11. The tibial baseplate of claim 8, wherein the tibial baseplate comprises a first tibial baseplate and further comprising a second tibial baseplate having:

a second proximal surface;

a second distal surface opposite the second proximal surface, the second distal surface sized and shaped to substantially cover a proximal resected surface of a tibia;

a second medial face;

a second lateral face opposite the second medial face;

a second total width measured between the second medial face and the second lateral face, the second total width differing from the first total width whereby the first and second tibial baseplates comprise unique nominal sizes; and

a second keel extending distally from the second distal surface, the second keel spaced apart from the second medial face by a second medial distance and spaced apart from the second lateral face by a second lateral distance,

a first ratio of the first medial distance to the first total width differing from a second ratio of the second medial distance to the second total width.

12. The tibial baseplate of claim 11, wherein the first total width is greater than the second total width, and the first ratio is less than the second ratio.

13. The tibial baseplate of claim 11, wherein the first tibial baseplate is larger than the second tibial baseplate, and wherein:

the first tibial baseplate includes the first anterior face joining the first lateral face to the first medial face, the first keel being posteriorly spaced from the first anterior face by a first distance; and

the second tibial baseplate includes a second anterior face joining the second lateral face to the second medial face, the second keel being posteriorly spaced from the second anterior face by a second distance less than the first distance.

14. A tibial baseplate comprising:

a proximal surface;

a distal surface opposite the proximal surface, the distal surface shaped to be disposed on a proximal resected surface of a tibia;

a medial compartment defined at least in part by a medial face, a portion of an anterior face and a portion of a posterior face;

a lateral compartment opposite the medial compartment, wherein the lateral compartment is defined at least in part by a lateral face, a second portion of the anterior face and a second portion of the posterior face;

a keel extending distally from the distal surface; and

an anterior-posterior axis extending centrally between the medial and lateral compartments throughout its length, the keel being medially offset from the axis by a offset distance.

15. The tibial baseplate of claim 14, wherein the offset distance is between 5 mm and 0.5 mm, inclusive.

16. The tibial baseplate of claim 14, wherein the axis is positioned to correspond to a home axis of a patient'"'"'s proximal tibia when the tibial baseplate is implanted onto the patient'"'"'s proximal tibia, the home axis defined as a line extending from a posterior point disposed at a geometric center of an attachment area between a posterior cruciate ligament and the patient'"'"'s proximal tibia, to an anterior point disposed on an anterior tubercle of the patient'"'"'s proximal tibia and bordering a medial third of the anterior tubercle.

17. The tibial baseplate of claim 14, wherein the tibial baseplate is asymmetric about the axis such that a surface area of the medial compartment differs from a second surface area of the lateral compartment.

18. The tibial baseplate of claim 14, further comprising a total width measured from the medial face to the lateral face, and wherein the offset distance is less than 6 percent but greater than 1 percent of the total width.

19. The tibial baseplate of claim 14, wherein the offset distance changes as a percentage basis of the total width as the total width changes in dimension such that a degree of medialization of the keel changes relative to the total width.

20. A tibial baseplate comprising:

a proximal surface;

a distal surface opposite the proximal surface, the distal surface shaped to be disposed on a proximal resected surface of a tibia;

a medial compartment defined at least in part by a medial face, a portion of an anterior face and a portion of a posterior face;

a lateral compartment opposite the medial compartment, wherein the lateral compartment is defined at least in part by a lateral face, a second portion of the anterior face and a second portion of the posterior face;

a keel extending distally from the distal surface; and

an anterior-posterior axis extending centrally between the medial and lateral compartments throughout its length, the keel being medially offset from the axis by a offset distance;

wherein the offset distance changes as a percentage basis of the total width as the total width changes in dimension such that a degree of medialization of the keel changes relative to the total width.

21. The tibial baseplate of claim 20, wherein the offset distance is less than 6 percent but greater than 1 percent of the total width.