FEMORAL HEAD CENTER LOCATING APPARATUS AND METHOD

• US 20090076507A1
• Filed: 09/13/2007
• Published: 03/19/2009
• Est. Priority Date: 09/13/2007
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Hui, Sudip, Walriven, Dale E., Patmore, Donald M., Collins, James S., Claypool, Jody L.
• Granted Patent: US 7,892,240 B2
• Time in Patent Office: Days
• US Class Current: 606/53
• CPC Class Codes: A61B 17/15 Guides therefor arrangements for guiding straight saw blades in general B23D51/025
• CPC Class Codes: A61B 17/1703 using imaging means, e.g. by X-rays
• CPC Class Codes: A61B 17/1717 for applying intramedullary nails or pins
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

A femoral head center locating mechanism and method for using same. The femoral head center locating mechanism may include a frame and a plurality of lasers which emit laser beams which intersect to identify a reference point relative to a center of a femoral head.

Claims

1. A method for identifying a reference point relative to a femoral head center of a femur, comprising the steps of:

moving the femur along an arc of a circle to a first position;

moving the femur along the arc of the circle to a second position;

moving the femur along the arc of the circle to a third position;

projecting a first light beam from a first midpoint between the first position and the second position;

projecting a second light beam from a second midpoint between the second position and the third position; and

identifying the reference point relative to the femoral head center by determining an intersection of the first light beam and the second light beam.

2. The method of claim 1, wherein the first position and the second position define a first chord of the circle, said first projecting step comprising projecting the first light beam in a direction substantially perpendicular to the first chord.

3. The method of claim 2, wherein said first projecting step further comprises projecting the first light beam in a direction which substantially bisects the first chord.

4. The method of claim 1, wherein the second position and the third position define a second chord of the circle, said second projecting step comprising projecting the second light beam in a direction substantially perpendicular to the second chord.

5. The method of claim 4, wherein said second projecting step further comprises projecting the second light beam in a direction which substantially bisects the second chord.

6. The method of claim 1, further comprising the step of providing a frame having a first post corresponding to the first position, a second post corresponding to the second position, and a third post corresponding to the third position, wherein the first, second, and third posts are arranged parallel to each other, wherein the first position, the second position, and the third position lie in a plane extending perpendicular to each of the first, second, and third posts.

7. The method of claim 1, further comprising the step of providing a line extending through the reference point and extending perpendicular to the first light beam and the second light beam, the line extending through the femoral head center.

8. An apparatus for identifying a reference point relative to a femoral head center of a femur, the apparatus comprising:

a frame comprising;

a first post;

a second post;

a third post;

a first segment connecting said first post and said second post; and

a second segment connecting said second post and said third post; and

a first light emitting device positioned at a midpoint of said first segment; and

a second light emitting device positioned at a midpoint of said second segment.

9. The apparatus of claim 8, wherein said second post is hingedly connected to said first post and said third post is hingedly connected to said second post.

10. The apparatus of claim 8, wherein said first post and said third post are rotatable relative to said second post.

11. The apparatus of claim 8, wherein said first post, said second post, and said third post define an arc of a circle with a center point correlated to the femoral head center.

12. The apparatus of claim 11, wherein said first segment corresponds to a first chord of said circle and said second segment corresponds to a second chord of said circle, said first light emitting device positioned at a midpoint of said first chord and said second light emitting device positioned at a midpoint of said second chord.

13. The apparatus of claim 8, wherein said first light emitting device emits a first light beam in a direction substantially perpendicular to said first segment and said second light emitting device emits a second light beam in a direction substantially perpendicular to said second segment.

14. The apparatus of claim 13, wherein said first light beam intersects said second light beam at the reference point relative to the femoral head center.

15. The apparatus of claim 8, wherein said first light emitting device and said second light emitting device comprise a first laser and a second laser.

16. The apparatus of claim 8, wherein said first post, said second post, and said third post are arranged parallel to each other.

17. The apparatus of claim 8, wherein said first segment lies perpendicular to said first post and said second post.

18. The apparatus of claim 8, wherein said second segment lies perpendicular to said second post and said third post.