# US 2014/0156014 A1 · Improved knee prosthesis

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- Number: US 2014/0156014 A1
- Document ID: US20140156014A1
- Status: Published application
- Kind: A1
- Application number: 13/691,728
- Filed: 2012-11-30
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Smith & Nephew, Inc.
- Applicants: Smith & Nephew, Inc.
- Inventors: Nathaniel M. Lenz
- Web page: https://patentgrep.com/patent/US20140156014A1

## CPC

- A61F 2/3886: {for stabilising knees against anterior or lateral dislocations}
- A61F 2/38: for elbows or knees
- A61F 2/389: {Tibial components (A61F2/3868 takes precedence)}
- A61F 2002/30365: {with additional means for limiting said rotation}
- A61F 2002/30369: {Limited lateral translation of the protrusion within a larger recess}
- 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

Tibial inserts and tibial femoral systems are provided for improved knee reconstruction systems. External rotation of a knee joint implant is enhanced by modifications to the post, providing a recess that allows clearance of the post against the corners of a box wall within the femoral component. The rotation provides for a more natural knee joint motion of the implant. The depth, size, and location of the post relief may be modified for certain applications to provide both improved rotational motion and constraint against undesirable motion of the knee.

## Claims

### Claim 1

A tibial insert, comprising
a base;
a post having a vertical axis, a medial and a lateral sidewall, a posterior and an anterior face, a superior end, and an inferior end, the post extending from a superior surface of the base;
a first junction between the anterior face and medial sidewall, a second junction between the anterior face and the lateral sidewall; and
a recess in the medial sidewall that extends across the first junction.

### Claim 2 (depends on 1)

The tibial insert of claim 1, wherein the recess has a first boundary disposed along the medial sidewall substantially parallel to the vertical axis and a second boundary disposed along the medial sidewall substantially perpendicular to the vertical axis.

### Claim 3 (depends on 2)

The tibial insert of claim 2, wherein the second boundary extends across the first junction.

### Claim 4 (depends on 2)

The tibial insert of claim 2, wherein the posterior face has a first width between medial and lateral sidewalls, and the anterior face has a second width between the second boundary and lateral sidewall.

### Claim 5 (depends on 4)

The tibial insert of claim 4, wherein the first width is greater than the second width.

### Claim 6 (depends on 4)

The tibial insert of claim 4, comprising a shelf disposed along the medial sidewall, extending substantially perpendicular to the first boundary.

### Claim 7 (depends on 6)

The tibial insert of claim 6, wherein the shelf is disposed superior to the base.

### Claim 8 (depends on 7)

The tibial insert of claim 7, wherein the recess has a first depth measured from the first boundary, wherein the first depth has a value of about 0.25 mm to about 1.5 mm.

### Claim 9 (depends on 8)

The tibial insert of claim 8, wherein the first depth is about 0.5 mm.

### Claim 10 (depends on 8)

The tibial insert of claim 8, wherein the recess has a minimum depth and a maximum depth.

### Claim 11 (depends on 1)

A knee prosthesis system, comprising
a femoral component having first and second condylar surfaces;
a tibial tray;
a tibial insert according to claim 1; and
the tibial insert having first and second bearing surfaces that mate with the respective first and second condylar surfaces.

### Claim 12 (depends on 11)

The knee prosthesis system of claim 11, wherein the femoral component includes a box receptacle that receives the post, the receptacle having a first set of opposing walls and a second set of opposing walls, a first wall of the first set of opposing walls being in contact with the medial sidewall at a position inferior to the first boundary and being spaced away from the medial sidewall at a position superior to the first boundary.

### Claim 13 (depends on 12)

The knee prosthesis system of claim 12, wherein rotating the post angularly about the vertical axis moves a portion of the anterior face into alignment with the first wall.

### Claim 14 (depends on 12)

The knee prosthesis system claim 12, wherein rotating the post angularly about the vertical axis disconnects a portion of the medial sidewall from the first wall.

### Claim 15 (depends on 12)

The knee prosthesis system of claim 12, wherein rotating the post angularly about the vertical axis moves the recess toward the medial sidewall.

### Claim 16

A method of actuating a knee prosthesis having a base, a post extending from the base, and a femoral component having a slot disposed generally between two condylar surfaces, the method comprising:
contacting a first wall of the slot with a first portion but not a second portion of a medial surface of the post;
contacting a second wall of the slot with a lateral surface of the post; and
rotating the post axially within the slot to align the second portion toward the first wall.

### Claim 17 (depends on 16)

The method of claim 16, wherein aligning the second portion toward the first wall reduces contacting between the second wall of the slot and the lateral surface of the post.

### Claim 18 (depends on 17)

The method of claim 17, wherein the second portion of the medial surface extends from the medial surface to an anterior surface of the post.

### Claim 19 (depends on 18)

The method of claim 18, wherein rotating the post moves the anterior face into contact with the first wall.

### Claim 20 (depends on 16)

The method of any of claim 16, comprising a step of actuating the post by a cam surface disposed within the slot.

### Claim 21

A method of treating an injured knee, comprising installing an insert in contact with the patient's proximal tibia, installing an articulating housing in contact with the patient's distal femur, inserting the insert in rotational orientation within the housing so a recessed portion of the insert can pass an inner corner of the housing during flexion or extension of the knee.