Asymmetric tibial components for a knee prosthesis
First Claim
1. A tibial prosthesis for use in a tibial arthroplasty, the prosthesis having:
- an anterior edge;
a posterior edge generally opposite the anterior edge and disposed between a lateral compartment of the tibial prosthesis and a medial compartment of the tibial prosthesis, wherein the lateral compartment is asymmetric with respect to the medial compartment about the component anteroposterior axis to define a component asymmetry;
a distal surface comprising a bone contacting surface;
a proximal surface comprising a tibial bearing engagement surface; and
a first alignment indicia on the anterior edge and a second alignment indicia on the posterior edge indicating a component anteroposterior axis designed to be aligned with an anatomic anteroposterior axis of the tibia, the anatomic anteroposterior axis defined as a line extending from a posterior point of the tibia to an anterior point at an anterior tubercle of the tibia, wherein the anterior point is medially spaced from a midpoint of the anterior tubercle by an amount equal to ⅙
th of an overall mediolateral width of the anterior tubercle such that the anterior point lies on the medial third of the anterior tubercle;
the component anteroposterior axis bisecting the anterior edge and extending to the posterior edge;
wherein in use the prosthesis is configured to be positioned and oriented with respect to the tibia by aligning the first and second alignment indicia with the anatomic anteroposterior axis and by centering the first alignment indicia with respect to the anterior point of the tibial tubercle, and positioning the second alignment indicia with respect to the posterior point of the tibia, whereby the component asymmetry corresponds to an asymmetry of a resected proximal surface of the tibia such that the tibial component covers a large proportion of the resected proximal surface.
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Abstract
An orthopedic tibial prosthesis includes a tibial baseplate with an asymmetric periphery which promotes proper positioning and orientation on a resected tibia, while also facilitating enhanced kinematics, soft-tissue interaction, and long-term fixation of the complete knee prosthesis. The asymmetric baseplate periphery is sized and shaped to substantially match portions of the periphery of a typical resected proximal tibial surface, such that proper location and orientation is evident by resting the baseplate on the tibia. The baseplate periphery provides strategically positioned relief and/or clearance between the baseplate periphery and bone periphery, such as in the posterior-medial portion to prevent deep-flexion component impingement, and in the anterior-lateral portion to avoid undue interaction between the anatomic iliotibial band and prosthesis components.
441 Citations
15 Claims
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1. A tibial prosthesis for use in a tibial arthroplasty, the prosthesis having:
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an anterior edge; a posterior edge generally opposite the anterior edge and disposed between a lateral compartment of the tibial prosthesis and a medial compartment of the tibial prosthesis, wherein the lateral compartment is asymmetric with respect to the medial compartment about the component anteroposterior axis to define a component asymmetry; a distal surface comprising a bone contacting surface; a proximal surface comprising a tibial bearing engagement surface; and a first alignment indicia on the anterior edge and a second alignment indicia on the posterior edge indicating a component anteroposterior axis designed to be aligned with an anatomic anteroposterior axis of the tibia, the anatomic anteroposterior axis defined as a line extending from a posterior point of the tibia to an anterior point at an anterior tubercle of the tibia, wherein the anterior point is medially spaced from a midpoint of the anterior tubercle by an amount equal to ⅙
th of an overall mediolateral width of the anterior tubercle such that the anterior point lies on the medial third of the anterior tubercle;the component anteroposterior axis bisecting the anterior edge and extending to the posterior edge; wherein in use the prosthesis is configured to be positioned and oriented with respect to the tibia by aligning the first and second alignment indicia with the anatomic anteroposterior axis and by centering the first alignment indicia with respect to the anterior point of the tibial tubercle, and positioning the second alignment indicia with respect to the posterior point of the tibia, whereby the component asymmetry corresponds to an asymmetry of a resected proximal surface of the tibia such that the tibial component covers a large proportion of the resected proximal surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A tibial prosthesis for use in a tibial arthroplasty, the tibial prosthesis comprising
an anterior edge; -
a PCL cutout area generally opposite the anterior edge and comprising a portion of a posterior edge of the tibial prosthesis, the PCL cutout and disposed between a lateral compartment of the tibial prosthesis and a medial compartment of the tibial prosthesis, wherein the lateral compartment is asymmetric with respect to the medial compartment about the component anteroposterior axis to define a component asymmetry; a distal surface comprising a bone contacting surface; a proximal surface comprising a tibial bearing engagement surface; and a first alignment indicia on the anterior edge and a second alignment indicia on the posterior edge indicating a component anteroposterior axis designed to be aligned with an anatomic anteroposterior axis of the tibia, the anatomic anteroposterior axis defined as a line extending from a posterior point of the tibia to an anterior point at an anterior tubercle of the tibia, wherein the anterior point is medially spaced from a midpoint of the anterior tubercle by an amount equal to ⅙
th of an overall mediolateral width of the anterior tubercle such that the anterior point lies on the medial third of the anterior tubercle;the component anteroposterior axis bisecting the anterior edge and bisecting the PCL cutout area, wherein in use the prosthesis is configured to be positioned and oriented with respect to the tibia by aligning the first and second alignment indicia with the anatomic anteroposterior axis and by centering the first alignment indicia with respect to the anterior point of the tubercle, and centering the second alignment indicia with respect to a connection point of the tibia to the posterior cruciate ligament, whereby the component asymmetry corresponds to an asymmetry of a resected proximal surface of the tibia such that the tibial component covers a large proportion of the resected proximal surface. - View Dependent Claims (15)
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Specification