Stable cartilage defect repair plug

• US 20080249632A1
• Filed: 02/26/2007
• Published: 10/09/2008
• Est. Priority Date: 02/26/2007
• Status: Active Grant

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Sports Medicine LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Stone, Kevin T., Troxel, Karen
• Granted Patent: US 7,758,643 B2
• Time in Patent Office: Days
• US Class Current: 623/23.5
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/4644 Preparation of bone graft, bone plugs or bone dowels, e.g. grinding or milling bone material bone material A61F2/28; disintegrating or milling devices B02C
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30004 the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30036 differing in release or diffusion time
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30233 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30327 : differing in diameter
• CPC Class Codes: A61F 2002/30332 : Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30448 : using adhesives
• CPC Class Codes: A61F 2002/30459 : stapled
• CPC Class Codes: A61F 2002/30461 : sutured, ligatured or stitched
• CPC Class Codes: A61F 2002/30677 : Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30733 : Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30795 : Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0066 : stapled
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0014 : having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2250/0035 : differing in release or diffusion time
• CPC Class Codes: A61F 2250/0039 : differing in diameter
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00341 : Coral, e.g. aragonite, porite
• CPC Class Codes: A61F 2310/00365 : Proteins; Polypeptides; Degradation products thereof

Abstract

A method of distributing a load to a cartilage defect repair plug is provided. A load is applied to a first articulation layer. The load is distributed to a second layer and the load is transferred in the normal direction to the first density of subchondral bone. The load is distributed to a third layer and the load is transferred in the normal direction to a second density of subchondral bone. The load is then distributed to a fourth layer and the load is transferred in the normal direction to a third density of subchondral bone.

Claims

1. A method of distributing a load to a cartilage defect repair plug, comprising:

a. applying the load to a first articulation layer of a cartilage defect repair plug, where the first articulation layer has a first periphery;

b. distributing the load to a second layer having a second periphery and further transferring the load in a normal direction to a first density of subchondral bone;

c. distributing the load to a third layer having a third periphery that is smaller than the second periphery and further transferring the load in the normal direction to a second density of subchondral bone that is less dense than the first density of subchondral bone; and

d. distributing the load in a fourth layer having a fourth periphery that is smaller than the third periphery and further transferring the load in the normal direction to a third density of subchondral bone that is less dense than the second density of subchondral bone.

2. The method of claim 1, wherein the cartilage plug has a decreasing cross section area as measured transverse to a longitudinal axis.

3. The method of claim 1, wherein the cartilage defect repair plug has a decreasing cross section length as measured transverse to a longitudinal axis.

4. The method of claim 1, further comprising determining a thickness of a surrounding cartilage at an implant site opening.

5. The method of claim 4, further comprising shaping the cartilage defect repair plug articulation layer to have a similar thickness to the implant site opening.

6. The method of claim 1, further comprising disposing the cartilage defect repair plug into an implant site opening using a technique selected from:

impacting, screwing, or press-fit techniques.

7. The method of claim 1, further comprising securing the cartilage defect repair plug to an implant site using an attachment method selected from the group consisting of:

mechanical attachment, adhesive attachment, chemical attachment, and combinations thereof.

8. The method of claim 1, wherein the articulation layer is made of a first material and the second, third, and fourth layers are made of a second material.

9. The method of claim 1, wherein the articulation layer comprises a resorbable polymer material selected from the group consisting of:

lactocarbonate;

polyurethane urea;

polymers and copolymers of trimethylene carbonate, lactic acid, and glycolic acid; and

combinations thereof.

10. The method of claim 1, wherein the second, third, and fourth layers comprise a porous material selected from the group consisting of:

calcium sulfate, calcium phosphate, tricalcium materials, polymers and copolymers of glycolic acid and lactic acid, and combinations thereof.

11. The method of claim 1, wherein the normal direction is a 90°

angle to respective densities of subchondral bone.

12. A method of preparing a cartilage defect repair plug for distributing a load at a cartilage defect site, comprising:

a. securing a first synthetic resorbable material having a first porosity to a second synthetic resorbable material having a second porosity;

b. adsorbing a bioactive agent into the first synthetic resorbable material; and

c. shaping the first synthetic resorbable material and the second synthetic resorbable material to have a stepped cone geometry to provide a plurality of right angled layers such that when a load is applied on the cartilage plug, the load is distributed in the normal direction to the first synthetic resorbable material of the cartilage plug.

13. The method of claim 12, further comprising adsorbing the bioactive agent into the second resorbable material.

14. The method of claim 12, wherein the securing is selected from the group consisting of:

mechanical attachment, adhesive attachment, chemical attachment, and combinations thereof.

15. The method of claim 12, wherein shaping the cartilage defect repair plug further comprises contouring the cartilage defect repair plug to match an opening in an implant site to provide a press-fit of the cartilage defect repair plug into the implant site.

16. The method of claim 12, further comprising removing a region of at least one of the first resorbable material and the second resorbable material to form a bore in the cartilage defect repair plug.

17. The method of claim 16, further comprising depositing a bioactive material in the bore for delivery to the implant site;

wherein the bioactive material is selected from the group consisting of;

chondrocytes, undifferentiated cells, differentiation media, growth factors, platelet concentrate, nutrients, bone morphogenic proteins, osteogenic factors, and combinations thereof.

18. A method of distributing a load to a cartilage defect repair plug, comprising:

a. removing from an implant site a region of cartilage and underlying regions of a calcified cartilage interface and a subchondral bone tissue to form an implant site opening having a longitudinal axis;

wherein the implant site opening at the cartilage, the calcified cartilage interface, and a first region of the subchondral bone having a first density have the same cross section size and the implant site opening has a progressively decreasing cross section from a second region of the subchondral bone having a second density that is less than the first density of subchondral bone to a distal most end of the implant site opening as measured transverse to the longitudinal axis to provide a stepped cone geometry, wherein the cone provides a plurality of right angled layers at the implant site;

b. disposing a resorbable cartilage plug in the implant site opening and mating a cartilage plug articulation layer and an adjacent, upper region of a demineralized bone matrix cartilage plug base having substantially similar cross section sizes to the stepped cone geometry of the implant site opening; and

c. distributing the load from the cartilage plug articulation layer to the adjacent, upper region of the demineralized bone matrix cartilage plug base in a normal direction to the first region of subchondral bone.

19. The method of claim 18, further comprising shaping the cartilage defect repair plug articulation layer to have a similar thickness to a thickness of the cartilage surrounding the implant site opening.

20. The method of claim 18, further comprising disposing the cartilage defect repair plug into an implant site opening using a technique selected from:

impacting, screwing, or press-fit techniques.

21. The method of claim 18, further comprising securing the cartilage defect repair plug to an implant site using an attachment method selected from the group consisting of:

mechanical attachment, adhesive attachment, chemical attachment, and combinations thereof.