Posterior stabilized knee with varus-valgus constraint
First Claim
1. A knee prosthesis comprising:
- a femoral component configured to be attached to the distal end of a femur and having a medial and a lateral condyle surface spaced apart to define a notch therebetween, said notch defining an elongated cam housing having a posterior cam at one end of said cam housing; and
a tibial component including a platform configured for attachment to the proximal end of a tibia and a bearing supported on said platform, said bearing defining medial and lateral bearing surfaces configured to articulate with said medial and lateral condyle surfaces, and a spine projecting superiorly from said bearing within said cam housing when said condyle surfaces are in articulating contact with said bearing surfaces, wherein said spine defines an anterior face and an opposite posterior face facing said posterior cam, said posterior face and said posterior cam defining complementary curved surfaces configured for cooperative engagement when said femoral component and said tibial component are rotated relative to each other to at least a predetermined flexion angle.
1 Assignment
0 Petitions
Accused Products
Abstract
A femoral component of a knee prosthesis has spaced condyle surfaces defining a notch therebetween. The notch defines an elongated cam housing having an anterior cam and a posterior cam at opposite ends of the housing. The tibial component of the knee prosthesis includes a platform and a bearing supported on the platform, the bearing defining bearing surfaces configured to articulate with the condyle surfaces. The tibial component includes a spine projecting superiorly from the bearing that defines an anterior face and a posterior face. The posterior face and the posterior cam define complementary curved surfaces configured for cooperative engagement when the femoral component and the tibial component are at a predetermined flexion angle. The cam housing is configured to form a gap between the posterior cam and the spine when the knee is normally extended. In another feature, the spine includes a stiffening pin extending therethrough.
181 Citations
26 Claims
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1. A knee prosthesis comprising:
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a femoral component configured to be attached to the distal end of a femur and having a medial and a lateral condyle surface spaced apart to define a notch therebetween, said notch defining an elongated cam housing having a posterior cam at one end of said cam housing; and
a tibial component including a platform configured for attachment to the proximal end of a tibia and a bearing supported on said platform, said bearing defining medial and lateral bearing surfaces configured to articulate with said medial and lateral condyle surfaces, and a spine projecting superiorly from said bearing within said cam housing when said condyle surfaces are in articulating contact with said bearing surfaces, wherein said spine defines an anterior face and an opposite posterior face facing said posterior cam, said posterior face and said posterior cam defining complementary curved surfaces configured for cooperative engagement when said femoral component and said tibial component are rotated relative to each other to at least a predetermined flexion angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A knee prosthesis comprising:
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a femoral component configured to be attached to the distal end of a femur and having a medial and a lateral condyle surface spaced apart to define a notch therebetween, said notch defining an elongated cam housing having a posterior cam at one end of said cam housing;
a tibial component including a platform configured for attachment to the proximal end of a tibia and a bearing supported on said platform, said bearing defining medial and lateral bearing surfaces configured to articulate with said medial and lateral condyle surfaces, and a spine projecting superiorly within said cam housing when said condyle surfaces are in articulating contact with said bearing surfaces, wherein said spine defines a posterior face facing said posterior cam and configured for cooperative engagement when said posterior cam, said spine further defining a bore therethrough; and
a pin configured to be disposed within said bore, said pin formed of a material different from the material of said spine. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A knee prosthesis comprising:
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a femoral component configured to be attached to the distal end of a femur and having a medial and a lateral condyle surface spaced apart to define a notch therebetween, said notch defining an elongated cam housing having an anterior cam and a posterior cam at opposite ends of said cam housing; and
a tibial component including a platform configured for attachment to the proximal end of a tibia and a bearing supported on said platform, said bearing defining medial and lateral bearing surfaces configured for rotating contact with said medial and lateral condyle surfaces, and a spine projecting superiorly from said bearing within said cam housing when said condyle surfaces are in articulating contact with said bearing surfaces, and said spine defining an anterior face facing said anterior cam and a posterior face adapted for articulating contact with said posterior cam, wherein said cam housing is configured to define an anterior-posterior distance between said anterior cam and said posterior face of said spine when said femoral component and said tibial component are in a normally extended position relative to each other, whereby said posterior face of said spine is in articulating contact with said posterior cam only at a first predetermined flexion rotation angle between said femoral component and said tibial component. - View Dependent Claims (22, 23, 24, 25)
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26. A knee prosthesis, comprising:
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a femoral component configured to be attached to the distal end of a femur and having a medial and a lateral condyle surface spaced apart to define a notch therebetween, said notch defining an elongated cam housing having a posterior cam at one end thereof; and
a tibial component including a platform configured for attachment to the proximal end of a tibia and a bearing supported on said platform, said bearing defining medial and lateral bearing surfaces configured for rotating contact with said medial and lateral condyle surfaces, and a spine projecting superiorly from said bearing within said cam housing when said condyle surfaces are in articulating contact with said bearing surfaces, and said spine defining a posterior face adapted for articulating contact with said posterior cam, wherein the rotating contact between said bearing and said condyle surfaces is configured to carry all of the anterior-posterior shear load of the knee prosthesis from a full extension angle to a predetermined flexion angle between said femoral component and said tibial component, and said spine is arranged relative to the rotating contact between said bearing and said condyle surfaces so that said spine contacts said posterior cam at said predetermined flexion angle to share a portion of the anterior posterior shear load of the knee at flexion angles greater than said predetermined flexion angle.
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Specification