Cartilage repair implant with soft bearing surface and flexible anchoring device

• US 20020173855A1
• Filed: 02/08/2002
• Published: 11/21/2002
• Est. Priority Date: 02/05/2001
• Status: Active Grant

• Current Assignee: Formae, Inc.
• Original Assignee: Formae, Inc.
• Inventors: Mansmann, Kevin A.
• Granted Patent: US 9,050,192 B2
• Time in Patent Office: Days
• US Class Current: 623/23.72
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/40 for shoulders
• CPC Class Codes: A61F 2/4618 of cartilage
• CPC Class Codes: A61F 2002/30006 differing in density or specific weight
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30016 differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30148 lozenge- or diamond-shaped
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30751 for attaching cartilage scaffolds to underlying bone
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30894 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/30973 : Two joined adjacent layers having complementary interlocking protrusions and recesses
• CPC Class Codes: A61F 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2210/0071 : thermoplastic
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0015 : differing in density or specific weight
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0019 : differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00365 : Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61L 27/52 : Hydrogels or hydrocolloids

Abstract

A non-resorbable implant for repairing or replacing damaged or diseased cartilage in a mammalian joint (such as a knee) is disclosed. This implant uses a relatively soft and bendable “bearing surface”, which is bonded or otherwise coupled (preferably through one or more intermediate layers that provide greater strength) to a flexible anchoring grid. All components which make up the implant should be flexible, so that the implant can be rolled up and surgically inserted into a joint using a minimally invasive incision, preferably by arthroscopic means. In one embodiment, an anchoring grid is implanted first and secured to a prepared bone surface, using pins, cement, or other suitable means. The component with the bearing surface is then “unrolled” by the surgeon across a relatively small area of bone condyle that has been denuded of its cartilage cover. In this embodiment, which is likely to be well-suited for treating relatively small cartilage defects, such as in “grade 4” chondromalacia, the implant can be “tacked down” by the surgeon as it is unrolled, to attach it to the bone in various spaced locations around the periphery and interior of the implant. In an alternate embodiment which may be better suited for repairing larger cartilage defects, a flexible anchoring component is inserted first, and anchored to the bone; then, a bearing surface component is inserted and coupled to the already-installed anchoring component.

Claims

1. A flexible surgical implant for repairing damaged hyaline cartilage in a mammalian joint, comprising:

a. an anchoring portion which allows secure fixation of the anchoring portion to a prepared hard bone surface area from which a damaged segment of native cartilage has been removed, wherein the anchoring portion is provided with or designed to interact with at least one anchoring protrusion which will extend into accommodating bone and which will allow a properly anchored implant to resist shear stresses of a type and magnitude that will be encountered in the joint being repaired; and

,

b. a bearing surface portion having a lubricious articulating surface.

2. The flexible surgical implant of claim 1, wherein the bearing surface portion comprises a hydrogel.

3. The flexible surgical implant of claim 1, wherein the anchoring portion comprises a plurality of anchoring protrusions.

4. The flexible surgical implant of claim 1, wherein the anchoring portion comprises a main body having a plurality of anchoring pins coupled to the main body by flexible means which allow the anchoring pins to be folded against the main body during insertion into the joint being repaired.

5. The flexible surgical implant of claim 1, wherein the anchoring portion and the bearing surface portion are separate components prior to implantation, and wherein the bearing surface portion is designed to be inserted into a joint by a surgeon and then securely affixed to an anchoring portion which has previously been affixed to a prepared hard bone surface inside the joint.

6. The flexible surgical implant of claim 5, wherein the anchoring portion comprises:

(i) an anchoring layer component which is designed to be pressed against a hard bone surface, and which is provided with a plurality of anchor pin holes; and

,

(ii) a plurality of anchor pins which can be driven through the anchor pin holes and into a hard bone surface.

7. The flexible surgical implant of claim 5, wherein the anchoring portion comprises a rim which is sufficiently flexible to allow the rim to be squeezed into an elongated form having a width of about 75% or less of its normal relaxed width.

8. The flexible surgical implant of claim 5, wherein the anchoring portion comprises a layer which is sufficiently flexible to allow it to be rolled into a cylindrical arc wherein the opposed edges of the arc have an angular displacement of 110 degrees or less.

9. The flexible surgical implant of claim 1, wherein the anchoring portion and the bearing surface portion are fabricated together as a single implant which is sufficiently flexible to allow it to be rolled into a cylindrical arc wherein the opposed edges of the arc have an angular displacement of 110 degrees or less.

10. A surgical implant for repairing damaged hyaline cartilage in a mammalian joint, comprising:

a. at least one anchoring component which can be inserted into a prepared accommodating hard bone surface from which a damaged segment of native cartilage has been removed, wherein the anchoring component is capable of allowing a properly anchored implant to resist shear stresses of a type and magnitude that will be encountered in the mammalian joint being repaired, and wherein the anchoring component is made of a porous material that promotes osseous tissue ingrowth to establish stronger anchoring as such tissue ingrowth occurs; and

,

b. a bearing surface portion having a lubricious articulating surface.

11. The surgical implant of claim 10 wherein the bearing surface portion comprises a synthetic hydrogel.

12. The surgical implant of claim 10 wherein the bearing surface portion comprises a synthetic porous hydrophilic polymer.