# US 10,441,429 B2 · Femoral component for a knee prosthesis with improved articular characteristics

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- Number: US 10,441,429 B2
- Document ID: US10441429B2
- Status: Granted
- Kind: B2
- Application number: 15/462,742
- Filed: 2017-03-17
- Published: 2017-07-06
- Granted: 2019-10-15
- Earliest claimed: 2011-06-16
- Assignees: Zimmer, Inc.
- Applicants: Zimmer, Inc.
- Inventors: Raymond C. Parisi; Nick Drury; Charles A. Baldridge
- Web page: https://patentgrep.com/patent/US10441429B2

## CPC

- A61F 2/3859: {Femoral components}
- A61F 2/3868: {with sliding tibial bearing}
- A61F 2/3886: {for stabilising knees against anterior or lateral dislocations}
- A61F 2002/30192: {J-shaped}
- A61F 2310/00029: Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
- A61F 2310/00059: Chromium or Cr-based alloys
- A61F 2310/00101: Molybdenum or Mo-based alloys
- A61F 2310/00491: Coating made of niobium or Nb-based alloys
- A61F 2310/00544: Coating made of tantalum or Ta-based alloys
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)

## Abstract

An orthopaedic knee prosthesis includes a femoral component which exhibits enhanced articular features, minimizes removal of healthy bone stock from the distal femur, and minimizes the impact of the prosthesis on adjacent soft tissues of the knee.

## Claims

### Claim 1

A posterior-stabilized femoral component adapted to articulate with a tibial bearing component in a knee prosthesis, the tibial bearing component including a proximally extending spine, the femoral component comprising:
medial and lateral condyles shaped to articulate with the tibial bearing component through a range of motion, in which full extension corresponds to zero degrees flexion of the knee prosthesis and positive flexion corresponds to greater than zero degrees flexion of the knee prosthesis,
said medial and lateral condyles comprising inwardly facing condylar walls forming an intercondylar space therebetween, said intercondylar space having a medial/lateral width; and
a femoral cam sized and positioned to engage the spine of the tibial bearing component in positive flexion through a portion of the range of motion, said femoral cam comprising a medial/lateral cam length spanning said intercondylar space such that said femoral cam joins said medial and lateral condyles to one another,
said femoral cam having an articular surface comprising:
a central articular surface;
a convex medial transition surface flanking said central articular surface and disposed between said central articular surface and said medial condyle; and
a convex lateral transition surface flanking said central articular surface and disposed between said central articular surface and said lateral condyle,
said convex medial transition surface and said convex lateral transition surface each defining an arc extending in a medial/lateral direction, said arc defining a radius in a coronal cross-section of the femoral cam equal to between 6-12 mm.

### Claim 2 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein said central articular surface comprises up to 25% of said medial/lateral cam length.

### Claim 3 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein said convex medial transition surface and said convex lateral transition surface and said articular surface cooperate to comprise between 80% to 91% of said medial/lateral cam length.

### Claim 4 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein said central articular surface comprises a cylindrical surface having an axial extent along the medial/lateral direction.

### Claim 5 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein said femoral cam defines a plurality of convex surfaces in a sagittal plane, with at least one convex surface being a proximal surface defining a radius of between 10-11.5 mm, at least one convex surface being a posterior surface defining a radius of between 2.5-12 mm, and at least one convex surface being a distal surface defining a radius between 2-3 mm.

### Claim 6 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein the femoral component defines a femoral component coordinate system comprising:
a component sagittal plane extending along a proximal/distal direction and an anterior/posterior direction, the component sagittal plane equidistant from said medial and lateral condylar walls; and
a component coronal plane extending along the proximal/distal direction and a medial/lateral direction, the component coronal plane perpendicular to the component sagittal plane.

### Claim 7 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein said convex medial transition surface, said lateral transition surface, and said central articular surface cooperate to occupy the entire medial/lateral width of said intercondylar space.

### Claim 8 (depends on 1)

The posterior-stabilized femoral component of claim 1, wherein the radius of said arc of the convex medial transition surface and convex lateral transition surface are equal to between 40% and 60% of said medial/lateral cam length.