Posterior-stabilized total knee prosthesis
AssigneeZimmer, Inc.
InventorAdam H. Sanford
Life of this patent
Estimating the term…
Abstract
In an orthopaedic knee joint prosthesis, an intercondylar fossa of a femoral component cooperates with a spine formed in a tibial component to reproduce the screw home mechanism of a natural knee. When the femoral component and tibial component are positioned to correspond with slight flexion of the knee, the components are mutually rotationally locked against internal or external rotation. At higher degrees of flexion, such as greater than about 10-20 degrees of flexion, internal/external rotation of the tibia is permitted. The tibia is in an externally rotated position when locked, thereby reproducing the screw home mechanism and providing high stability.
Claims20
A knee joint prosthesis moveable between an extension orientation and a flexion orientation, the prosthesis comprising:
- a femoral component comprising:
- a lateral condyle having a lateral condylar inner wall;
- a medial condyle having a medial condylar inner wall;
- and
- an intercondylar fossa bounded on two sides by said lateral condylar inner wall and said medial condylar inner wall;
- and
- a tibial component comprising:
- a tibial articulating surface;
- a spine extending proximally from said tibial articulating surface, said spine including a base adjacent said tibial articulating surface, said base having a lateral base wall and an opposed medial base wall with a base width defined between said lateral base wall and medial base wall, said spine including a peak disposed proximally of said base and having a lateral peak surface and an opposed medial peak surface, a peak width defined between said lateral peak surface and medial peak surface, said peak width less than said base width;
- said lateral condylar inner wall cooperating with said lateral base wall, and said medial condylar inner wall cooperating with said medial base wall to prevent internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the extension orientation;
- and
- said lateral condylar inner wall cooperating with said lateral peak surface, and said medial condylar inner wall cooperating with said medial peak surface to permit at least one of internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the flexion orientation.
A knee joint prosthesis moveable between an extension orientation and a flexion orientation, the prosthesis comprising:
- a femoral component comprising:
- a lateral condyle having a lateral condylar inner wall defining an anterior lateral wall segment and a posterior lateral wall segment;
- a medial condyle having a medial condylar inner wall defining an anterior medial wall segment and a posterior medial wall segment;
- an intercondylar fossa bounded on two sides by said lateral condylar inner wall and said medial condylar inner wall, said intercondylar fossa including an anterior space between said anterior lateral wall segment and said anterior medial wall segment, said intercondylar fossa including a posterior space between said posterior lateral wall segment and said posterior medial wall segment;
- a tibial component comprising:
- a tibial articulating surface;
- a spine extending proximally from said tibial articulating surface, said spine having a lateral spine wall and an opposed medial spine wall;
- said anterior space of said intercondylar fossa cooperating with said lateral spine wall and said medial spine wall to prevent internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the extension orientation;
- and
- said posterior space of said intercondylar fossa cooperating with at least one of said lateral spine wall and said medial spine wall to permit internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the flexion orientation.
A knee joint prosthesis moveable between an extension orientation and a flexion orientation, the prosthesis comprising:
- a tibial component comprising tibial means for guiding internal and external rotation of said tibial component;
- and
- a femoral component comprising a femoral means for guiding internal and external rotation of said tibial component;
- said femoral means for guiding cooperating with said tibial means for guiding to prevent internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the extension orientation;
- and
- said femoral means for guiding cooperating with said tibial means for guiding to permit at least one of internal rotation and external rotation of said tibial component when the knee joint prosthesis is in the flexion orientation.
Dependencies are inferred from the claim text.