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US5203807A Expired / Lapsed US ⏱️ 0.0 years remaining

Knee joint prosthesis articular surface

Assignee: Smith and Nephew Inc
•
Filing: 1991-07-10
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Granted: 1993-04-20
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Expires: 2011-07-10
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Abstract

Abstract A knee replacement prosthesis includes a tibial component and a femoral component with improved articular surface geometries. The improved geometries allow substantial internal rotation of the tibial component with respect to the femoral component during at least the first twenty degrees (20°) of flexion. The tibial and femoral components are capable of flexing about an axis that reaches an inclination of from about ten degrees (10°) to about fifty degrees (50°) to the horizontal.

Inventors

  • 👤 David L. Evans
  • 👤 Mark S. Gosney

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 17:44
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/38

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 169 words
A prosthesis for surgical implantation for replacement of a patient's knee having two spaced apart condylar portions, or for replacement of a portion thereof comprising: a) a tibial component that includes one or more concave tibial condylar articulating surfaces; b) a femoral component that includes one or more distal femoral condyles, each with a convex femoral condylar articulating surface that articulates against one of said tibial condylar articulating surfaces of the tibial component; c) the concave tibial and convex femoral condylar articulating surfaces being correspondingly shaped to define during at least the first few degrees of flexion from a beginning position a flexion axis with an inclination of from about ten degrees (10°) to about fifty degrees (50°) with respect to a transverse plane tangent to distal femoral condyles; and d) the concave tibial and convex femoral condylar articulating surfaces being correspondingly shaped and conforming articular surfaces through the first few degrees of flexion from a beginning fully extending position, with substantial congruent surface area contact between said components.
Claim 2
Dependent Claim 169 words
A prosthesis for surgical implantation for replacement of a patient's knee having two spaced apart condylar portions, or for replacement of a portion thereof comprising: a) a tibial component that includes one or more concave tibial condylar articulating surfaces; b) a femoral component that includes one or more distal femoral condyles, each with a convex femoral condylar articulating surface that articulates against one of said tibial condylar articulating surfaces of the tibial component; c) the concave tibial and convex femoral condylar articulating surfaces being correspondingly shaped to define during at least the first few degrees of flexion from a beginning position a flexion axis with an inclination of from about ten degrees (10°) to about fifty degrees (50°) with respect to a transverse plane tangent to distal femoral condyles; and d) the concave tibial and convex femoral condylar articulating surfaces being correspondingly shaped and conforming articular surfaces through the first few degrees of flexion from a beginning fully extending position, with substantial congruent surface area contact between said components.
Claim 3
Dependent Claim 35 words
The apparatus of claim 1 wherein the femoral component is capable of external rotation with respect to the tibial component, at least during the first few degrees of flexion from a beginning fully extending position.
Claim 4
Dependent Claim 21 words
The apparatus of claim 1 wherein a medial side of the prosthesis and lower toward a lateral side of the prosthesis.
Claim 5
Dependent Claim 15 words
The apparatus of claim 1 wherein the tibial component includes a single condylar articulating surface.
Claim 6
Dependent Claim 15 words
The apparatus of claim 1 wherein the femoral component includes a single condylar articulating surface.
Claim 7
Dependent Claim 18 words
The apparatus of claim 1 wherein the tibial component has a pair of spaced apart condylar articulating surfaces.
Claim 8
Dependent Claim 18 words
The apparatus of claim 1 wherein the femoral component has a pair of spaced apart condylar articulating surfaces.
Claim 9
Dependent Claim 43 words
The apparatus of claim 1 wherein the condylar articulating surfaces are generated by rotating a curved line profile about an inclined axis that is inclined between ten (10) and fifty (50) degrees with respect to the distal femoral condyles in the frontal plane.
Claim 10
Dependent Claim 26 words
The apparatus of claim 8 wherein the curved profile is rotated about the inclined axis by a measure between one and one hundred twenty degrees (1°-120°).
Claim 11
Dependent Claim 184 words
A knee joint prosthesis comprising: a) a tibial component with a concave tibial articulating condylar surface; b) a femoral component with a convex femoral articulating condylar surface that includes one or more distal femoral condyles; c) means for attaching the tibial component to a patient's tibia; d) means for attaching the convex femoral component to the patient's femur; e) the concave tibial and convex femoral components being correspondingly shaped to define an inclined flexion axis with an inclination of from about ten degrees (10°) to about fifty degrees (50°) with respect to a transverse plane tangent to the distal femoral condyles during at least the first few degrees of flexion from a beginning fully extending position, with substantial congruent surface area contact between said components; and f) the concave tibial and convex femoral articulating condylar surfaces being correspondingly shaped conforming articular surfaces to define said flexion axis; and g) wherein substantial internal rotation of the tibial component is enabled with respect to the femoral component during flexion, with substantial congruent area contact maintained between the conforming concave tibial and convex femoral condylar articulating surfaces.
Claim 12
Dependent Claim 184 words
A knee joint prosthesis comprising: a) a tibial component with a concave tibial articulating condylar surface; b) a femoral component with a convex femoral articulating condylar surface that includes one or more distal femoral condyles; c) means for attaching the tibial component to a patient's tibia; d) means for attaching the convex femoral component to the patient's femur; e) the concave tibial and convex femoral components being correspondingly shaped to define an inclined flexion axis with an inclination of from about ten degrees (10°) to about fifty degrees (50°) with respect to a transverse plane tangent to the distal femoral condyles during at least the first few degrees of flexion from a beginning fully extending position, with substantial congruent surface area contact between said components; and f) the concave tibial and convex femoral articulating condylar surfaces being correspondingly shaped conforming articular surfaces to define said flexion axis; and g) wherein substantial internal rotation of the tibial component is enabled with respect to the femoral component during flexion, with substantial congruent area contact maintained between the conforming concave tibial and convex femoral condylar articulating surfaces.

References Cited (Backward Citations)

US4911721A Cited
EP0328463A1 Cited
US4959071A Cited
EP0346183A1 Cited
GB2219942A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-04-19 1996-10-19 1997-04-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-04-19 2000-10-19 2001-04-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-04-19 2004-10-19 2005-04-20 $7700.00 Window Closed / Lapsed

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