METHODS OF PREDETERMINING THE CONTOUR OF A RESECTED BONE SURFACE AND ASSESSING THE FIT OF A PROSTHESIS ON THE BONE

• US 20070255288A1
• Filed: 03/14/2007
• Published: 11/01/2007
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Mahfouz, Mohamed, Earl, Brian
• Granted Patent: US 8,231,634 B2
• Time in Patent Office: Days
• US Class Current: 606/102
• CPC Class Codes: A61B 2034/108 Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 5/1075 for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer A61B8/0858 takes precedence
• CPC Class Codes: A61B 5/1077 Measuring of profiles
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30948 using computerized tomography, i.e. CT scans

Abstract

Methods for predetermining a contour of a resected bone surface and assessing a fit of a prosthesis on the resected bone surface, for designing prostheses to fit discrete patient populations, and for designing customized prostheses.

Claims

1. A method of virtually assessing the fit of a prosthesis for placement on a resected bone surface, the method comprising the steps of:

creating a two-dimensional outline of the resected bone surface;

creating a two-dimensional outline of a first prosthesis; and

comparing the two-dimensional outline of the resected bone surface with the two-dimensional outline of the first prosthesis.

2. The method of claim 1, further comprising, if said comparing step results in an acceptable match of the outlines, the step of selecting the first prosthesis for physical placement on the resected bone surface.

3. The method of claim 2, further comprising, if said comparing step results in an unacceptable match of the outlines, the steps of creating a two-dimensional outline of a second prosthesis and comparing the two-dimensional outline of the resected bone surface with the two-dimensional outline of the second prosthesis.

4. The method of claim 3, further comprising, if said second comparing step results in an acceptable match of the outline of the resected bone surface and the outline of the second prosthesis, the step of selecting the second prosthesis for physical placement on the resected bone surface.

5. The method of claim 1, wherein said first creating step comprises the steps of:

obtaining a three-dimensional contour of the resected bone surface;

identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface;

manipulating the first planar surface to be coplanar with the second planar surface; and

outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.

6. The method of claim 1, wherein said second creating step comprises the steps of:

obtaining a three-dimensional contour of the first prosthesis;

identifying a vertex between a first planar surface of the first prosthesis and a second planar surface of the first prosthesis;

manipulating the first planar surface to be coplanar with the second planar surface; and

outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the first prosthesis.

7. The method of claim 1, wherein said comparing step comprises superimposing the two-dimensional outline of the resected bone surface on the two-dimensional outline of the first prosthesis.

8. An apparatus for virtually assessing the fit of a prosthesis for placement on a resected bone surface, the apparatus comprising:

a first computer adapted to create a two-dimensional outline of the resected bone surface;

a second computer for creating a two-dimensional outline of a first prosthesis; and

a third computer for comparing the two-dimensional outline of the resected bone surface with the two-dimensional outline of the first prosthesis.

9. The apparatus of claim 8, wherein said first computer comprises:

a processor for identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface based on a three-dimensional contour of the resected bone surface;

wherein said first computer is adapted to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.

10. The apparatus of claim 8, wherein said second computer comprises:

a processor for identifying a vertex between a first planar surface of the first prosthesis and a second planar surface of the first prosthesis based on a three-dimensional contour of the first prosthesis;

wherein said second computer is adapted to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the first prosthesis.

11. A method of designing a prosthesis to substantially fit a resected bone surface based on a population of bones, the method comprising the steps of:

creating a plurality of two-dimensional outlines corresponding to each resected bone surface for each bone of the population; and

determining a contour of a bone engaging surface of a prosthesis using the plurality of two-dimensional outlines, wherein the contour substantially matches the plurality of two-dimensional outlines of the resected bone surfaces.

12. The method of claim 11, wherein said using step comprises the step of determining the contour of the bone engaging surface of the prosthesis using a best fit approximation of the plurality of two-dimensional outlines of the resected bone surfaces.

13. The method of claim 11, wherein said creating step comprises the steps of:

obtaining a three-dimensional contour of each resected bone surface;

identifying a vertex between a first planar surface of each resected bone surface and a second planar surface of each resected bone surface;

manipulating the first planar surface to be coplanar with the second planar surface; and

outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline for each resected bone surface.

14. An apparatus for designing a prosthesis to substantially fit a resected bone surface based on a population of bones, the apparatus comprising:

a first computer for creating a plurality of two-dimensional outlines corresponding to each resected bone surface for each bone of the population; and

a second computer for determining a contour of a bone engaging surface of a prosthesis which substantially matches the plurality of two-dimensional outlines of the resected bone surfaces.

15. The apparatus of claim 14, wherein said first computer comprises:

a processor for identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface based on a three-dimensional contour of the resected bone surface;

wherein said first computer is adapted to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline for each resected bone surface.

16. A method of creating a prosthesis for placement on a resected bone surface, the method comprising the steps of:

creating a two-dimensional outline of the resected bone surface; and

determining a contour of a bone engaging surface of a prosthesis using the two-dimensional outline of the resected bone surface.

17. The method of claim 16, wherein said creating step comprises the steps of:

obtaining a three-dimensional contour of the resected bone surface;

identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface;

manipulating the first planar surface to be coplanar with the second planar surface; and

outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.

18. An apparatus for creating a prosthesis for placement on a resected bone surface, the apparatus comprising:

a first computer for creating a two-dimensional outline of the resected bone surface; and

a second computer for determining a contour of a bone engaging surface of a prosthesis using the two-dimensional outline of the resected bone surface.

19. The apparatus of claim 18, wherein said first computer comprises:

a processor for identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface based on a three-dimensional contour of the resected bone surface;

wherein said first computer is adapted to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.