System and method for joint resurface repair

• US 8,177,841 B2
• Filed: 02/06/2008
• Issued: 05/15/2012
• Est. Priority Date: 05/01/2000
• Status: Expired due to Term

• Current Assignee: Arthrosurface, Inc (Anika Therapeutics Incorporated)
• Original Assignee: Arthrosurface, Inc (Anika Therapeutics Incorporated)
• Inventors: Ek, Steven W.
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US12/027,121
• Publication Number:
  US 20080172125A1
• Time in Patent Office: 1,560 Days
• Field of Search: 623/20.14, 623/20.31, 623/20.32, 623/20.35, 623/20.3, 623/20.36, 623/14.12, 623/908
• US Class Current: 623/14.12
• CPC Class Codes: A61B 17/1635 for grafts, harvesting or transplants
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes 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 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30116 partial circles, i.e. circular segments
• CPC Class Codes: A61F 2002/30607 Kits of prosthetic parts to be assembled in various combinations for forming different prostheses
• CPC Class Codes: A61F 2002/3085 with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/3895 unicompartimental
• CPC Class Codes: A61F 2002/4658 for measuring dimensions, e.g. length
• CPC Class Codes: A61F 2002/4663 for measuring volumes or other three-dimensional shapes
• CPC Class Codes: A61F 2230/0004 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0006 circular
• CPC Class Codes: A61F 2250/0062 Kits of prosthetic parts to be assembled in various combinations for forming different prostheses

Abstract

An implant comprising a first, second, and third segment wherein the second and third segments partially overlap the first segment and define a load bearing surface comprising an anterior-posterior (AP) curvature including at least two tangential curves of the portion of the articular surface of the femoral condyle, the tangential curves having different radii of curvature. A drill guide comprises a body portion including a first, second and third bushing spaced along the body portion to establish a first, second and third axes, respectively. Each axis may be substantially normal to the articular surface at three different points along a curvature of the articular surface comprising the two tangential curves. A measuring device comprises a housing defining a longitudinally passageway and an outrigger. A guide pin may be received in the longitudinal passageway and a measuring device determines how far the guide pin is in the passageway.

Claims

1. An implant for replacing a portion of an articular surface of a bone comprising:

first, second, and third segments each comprising a truncated, generally circular perimeter having a center corresponding to a center of a first, second, and a third generally circular excision site formed in said articular surface, respectively, wherein said second and said third segments partially overlap said first segment on opposing ends of said first segment, said first, said second, and said third segments comprise a bone contacting surface and a load bearing surface, said load bearing surface comprising an anterior-posterior (AP) curvature and a medial lateral (ML) curvature, wherein said AP curvature comprises at least two tangential curves of said portion of said articular surface of said bone, said tangential curves having different radii of curvature.

2. The implant of claim 1, wherein said first, said second, and said third segments each comprise a generally circular shape truncated along said AP curvature of said implant.

3. The implant of claim 1, wherein said first, said second, and said third segments each comprise a generally circular shape truncated along said ML curvature of said implant.

4. The implant of claim 1, wherein said bone contacting surface comprises at least one mounting feature configured to secure said implant to said bone.

5. The implant of claim 4, wherein said at least one mounting feature is configured to securely engage with a mounting screw.

6. The implant of claim 5, wherein said at least one mounting feature includes an opening configured to engage with a post of said mounting screw.

7. The implant of claim 1, wherein said first, said second, and said third truncated, generally circular segments comprise first, second, and third axes extending through respective centers of said segments, respectively, wherein said first axis is substantially normal to said portion of said articular surface.

8. The implant of claim 7, wherein said second and said third axes are substantially normal to said portion of said articular surface.

9. The implant of claim 8, wherein a first angle α

₁ between said first axis and said second axis and a second angle β

₁ between said first axis and said third axis are substantially symmetrical.

11. The method of claim 9, wherein said first, said second, and said third segments comprise a first, a second, and a third axis extending through a center of a respective one of said segments, respectively, and wherein a first angle α

₁ between said first axis and said second axis and a second angle β

₁ between said first axis and said third axis are substantially symmetrical.

10. A method of forming an implant for replacing a portion of an articular surface extending across at least two tangential curves of a bone, said tangential curves having different radii of curvature, said method comprising:

establishing a reference axis extending substantially normal to a point of origin on said portion of said articular surface;

establishing a reference plane that is parallel to a tangential plane extending through said point of origin on said articular surface;

measuring a first distance between said reference plane and a first point on said articular surface at a distance R1 along an anterior-posterior (AP) curvature of said portion of said articular surface from said reference axis;

measuring a second distance between said reference plane and a second point on said articular surface at a distance R2 along said AP curvature of said portion of said articular surface from said reference axis, wherein R1 is less than R2; and

providing an implant comprising;

first, second, and third segments each comprising a truncated, generally circular perimeter having a center corresponding to a center of a first, second and third generally circular excision site formed in said articular surface, respectively, wherein said second and said third segments partially overlap said first segment on opposing ends of said first segment, said first, said second, and said third segments comprise a bone contacting surface and a load bearing surface, said load bearing surface comprising an AP curvature and a ML curvature, wherein said AP curvature of said implant comprises said at least two tangential curves of said portion of said articular surface of said bone, said tangential curves having different radii of curvature.

12. The method of claim 10, further comprising:

measuring at least two distances between said reference plane and a third and fourth point on said articular surface at a distance along a medial-lateral (ML) curvature of said portion of said articular surface from said reference axis; and

providing said load bearing surface comprising a second curvature approximating said ML curvature of said portion of said articular surface.

13. The method of claim 10, wherein said first curvature approximating said at least two tangential and different curves of said articular surface is determined based on only said first and said second distances taken at distances R1 and R2, respectively, from the reference axis.

14. The method of claim 10, comprising measuring two points at a distance R2 along said AP curvature of said portion of said articular surface from said reference axis, wherein one of said two points is taken at a point anterior from said reference axis and said other said two points is taken at a point posterior from said reference axis.