Medial pivot knee prosthesis

• US 6,013,103 A
• Filed: 11/26/1997
• Issued: 01/11/2000
• Est. Priority Date: 07/11/1996
• Status: Expired due to Term

• Current Assignee: MicroPort Orthopedics Holdings, Inc. (MicroPort Scientific Corp.)
• Original Assignee: Wright Medical Technology Incorporated (Stryker Corporation)
• Inventors: Paxson, Robert D., White, Stephen E., Kaufman, Michael E., Timmerman, Irina A., Hayes, Kevin B., Buchanan, Dennis J.
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US08/979,116
• Time in Patent Office: 776 Days
• Field of Search: 623/16, 623/18, 623/20
• US Class Current: 623/20.15
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3868 with sliding tibial bearing
• CPC Class Codes: A61F 2/3877 Patellae or trochleae
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30369 Limited lateral translation of the protrusion within a larger recess
• 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 2002/30802 arcuate
• 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 2002/30943 using mathematical models
• 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 2230/0015 Kidney-shaped, e.g. bean-shaped
• 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 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium

Abstract

A knee prosthesis for replacing at least a portion of a knee joint between the distal end of a femur and the proximal end of a tibia. The knee prosthesis includes a tibial component for mounting to the proximal end of the tibia, the tibial component including a proximal surface having a semispherical medial cavity and a lateral cavity; and a femoral component for mounting to the distal end of the femur, the femoral component including a semispherical medial condylar portion for pivotally coacting with the semispherical medial cavity of the tibial component and including a semispherical lateral condylar portion for movably coacting with the lateral cavity of the tibial component; the semispherical medial condylar portion being substantially congruent with the semispherical medial cavity of the tibial component so that substantially complete surface-to-surface contact between the semispherical medial cavity of the tibial component and the semispherical medial condylar portion of the femoral component is provided throughout the range of flexion of the knee joint.

Claims

1. A knee prosthesis for replacing at least a portion of a knee joint between the distal end of a femur and the proximal end of a tibia;

the knee prosthesis comprising;

(a) a tibial component for mounting to the proximal end of the tibia, said tibial component including a proximal surface having a semispherical medial cavity and a lateral cavity; and

(b) a femoral component for mounting to the distal end of the femur, said femoral component including a medial condylar portion having a face surface for pivotally coacting with said semispherical medial cavity of said tibial component and including a lateral condylar portion having a face surface for movably coacting with said lateral cavity of said tibial component;

said face surface of said medial condylar portion having a posterior side, a distal side, an anterior side, and a semispherical shape only from a posterior point on said posterior side of said face surface of said medial condylar portion to an anterior point on said anterior side of said face surface of said medial condylar portion located about 130°

from said posterior point;

said face surface of said lateral condylar portion having a posterior side, a distal side, an anterior side, and a semispherical shape;

said semispherical shape of said face surface of said medial condylar portion being substantially congruent with said semispherical medial cavity of said tibial component so that substantially complete surface-to-surface contact between said semispherical medial cavity of said tibial component and said face surface of said medial condylar portion of said femoral component is provided only throughout the range of flexion of about 130°

of the knee joint.

2. The knee prosthesis of claim 1 in which said medial condylar portion of said femoral component includes a face surface having a posterior side, a distal side, an anterior side, and a curvature defined by a single radius of curvature in the sagittal plane from a posterior point on said posterior side of said face surface of said medial condylar portion to an anterior point on said anterior side of said face surface of said medial condylar portion.

3. The knee prosthesis of claim 1 in which said posterior point on said posterior side of said face surface of said medial condylar portion is on a transverse plane passing through the center of said single radius of curvature.

4. The knee prosthesis of claim 2 in which said anterior point on said anterior side of said face surface of said medial condylar portion is at least about 130°

from said posterior point on said posterior side of said face surface of said medial condylar portion.

5. The knee prosthesis of claim 1 in which said semispherical shape of said face surface of said lateral condylar portion of said femoral component extends only from a posterior point on said posterior side of said face surface of said lateral condylar portion at least to a distal point on said distal side of said face surface of said lateral condylar portion.

6. The knee prosthesis of claim 5 in which said posterior point on said posterior side of said face surface of said lateral condylar portion is on a transverse plane passing through the center of said single radius of curvature.

7. The knee prosthesis of claim 5 in which said distal point on said distal side of said face surface of said lateral condylar portion is at least only about 90°

from said posterior point on said posterior side of said face surface of said lateral condylar portion.

10. The knee prosthesis of claim 1 in which the center of said semispherical medial cavity of said proximal surface of said tibial component is centered about a point located generally over the posterior one third of said proximal surface of said tibial component.

11. The knee prosthesis of claim 1 in which said femoral component has a patellar flange portion joining the anterior ends of said medial and lateral condylar portions together with said medial and lateral condylar portions substantially parallel to and spaced apart from one another to form an intercondylar notch therebetween;

in which said patellar flange portion has a patellar groove in the posterior or face surface thereof extending to the intercondylar notch to enable contact with a patellar component to 100°

of flexion.

8. A knee prosthesis for replacing at least a portion of a knee joint between the distal end of a femur and the proximal end of a tibia;

the knee prosthesis comprising;

(a) a tibial component for mounting to the proximal end of the tibia, said tibial component including a proximal surface having a semispherical medial cavity and a lateral cavity; and

(b) a femoral component for mounting to the distal end of the femur, said femoral component including a medial condylar portion having a face surface for pivotally coacting with said semispherical medial cavity of said tibial component and including a lateral condylar portion having a face surface for movably coacting with said lateral cavity of said tibial component;

said face surface of said medial condylar portion having a spherical shape only from about 40°

anterior to about 90°

posterior and being substantially congruent with said semispherical medial cavity of said tibial component so that substantially complete surface-to-surface contact between said semispherical medial cavity of said tibial component and said face surface of said medial condylar portion of said femoral component is provided only throughout the range of flexion of about 130°

of the knee joint.

9. A knee prosthesis for replacing at least a portion of a knee joint between the distal end of a femur and the proximal end of a tibia;

the knee prosthesis comprising;

(a) a tibial component for mounting to the proximal end of the tibia, said tibial component including a proximal surface having a semispherical medial cavity and a lateral cavity; and

(b) a femoral component for mounting to the distal end of the femur, said femoral component including a medial condylar portion having a semispherical face surface for pivotally coacting with said semispherical medial cavity of said tibial component and including a lateral condylar portion having a face surface for movably coacting with said lateral cavity of said tibial component;

said face surface of said lateral condylar portion having a spherical shape only from about 0°

distal to about 90°

posterior;

said semi spherical face surface of said medial condylar portion being substantially congruent with said semispherical medial cavity of said tibial component so that substantially complete surface-to-surface contact between said semispherical medial cavity of said tibial component and said face surface of said medial condylar portion of said femoral component is provided throughout the range of flexion of the knee joint.

12. A knee prosthesis for replacing at least a portion of a knee joint between the distal end of a femur and the proximal end of a tibia;

the knee prosthesis comprising;

(a) a tibial component for mounting to the proximal end of the tibia, said tibial component including a proximal surface having a semispherical medial cavity and a lateral cavity;

the center of said semispherical medial cavity of said proximal surface of said tibial component being centered about a point located generally over the posterior one third of said proximal surface of said tibial component; and

(b) a femoral component for mounting to the distal end of the femur, said femoral component including a medial condylar portion having a face surface for pivotally coacting with said semispherical medial cavity of said tibial component and including a lateral condylar portion having a face surface for movably coacting with said lateral cavity of said tibial component;

said face surface of said medial condylar portion of said femoral component having a posterior side, a distal side, an anterior side, and a semispherical shape that extends only from a posterior point on said posterior side of said face surface of said medial condylar portion to an anterior point on said anterior side of said face surface of said medial condylar portion located about 130°

from said anterior point;

said semispherical shape of said face surface of said medial condylar portion being substantially congruent with said semispherical medial cavity of said tibial component so that substantially complete surface-to-surface contact between said semispherical medial cavity of said tibial component and said semispherical medial condylar portion of said femoral component is provided only throughout the range of flexion of about 130°

of the knee joint;

said face surface of said lateral condylar portion of said femoral component having a posterior side, a distal side, an anterior side, and a semispherical shape that extends only from a posterior point on said posterior side of said face surface of said lateral condylar portion to a distal point on said distal side of said face surface of said lateral condylar portion located about 90°

from said posterior point.