Implantable porous metal

• US 20030220696A1
• Filed: 05/22/2003
• Published: 11/27/2003
• Est. Priority Date: 05/23/2002
• Status: Abandoned Application

• Current Assignee: Orchid Orthopedic Solutions LLC
• Original Assignee: Orchid Orthopedic Solutions LLC
• Inventors: Levine, David Jerome, Anto, Jeffrey Ewald, Graham, Donald Warren
• Application Number:
  US10/443,209
• Publication Number:
  US 20030220696A1
• Time in Patent Office: Days
• US Class Current: 623/17.17
• CPC Class Codes: A61L 27/045 Cobalt or cobalt alloys
• CPC Class Codes: A61L 27/06 Titanium or titanium alloys
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges

Abstract

An implantable composition of a biocompatible porous metal for enhanced tissue in-growth and fixation in the body. The metal has a porosity greater than 80% and up to about 95% which allows good cell population, yet it also provides structural integrity and stability allowing its use as a weight-bearing implant. In various embodiments, the metal may be titanium, which includes titanium alloys, or may be a cobalt-chromium-molybdenum alloy. The high porosity desirably facilitates in-growth of cells and/or tissues, which in turn facilitates biological fixation and biocompatibility. This is beneficial, for example, in an orthopedic implant such as a hip replacement, for facilitating in-growth of connective tissue and bone cells. The porous composition is structurally stable.

Claims

1. An implantable device comprising a biocompatible metal having a porosity greater than 80% up to about 95% and selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, capable of supporting tissue in-growth.

2. The device of claim 1 wherein the porosity is at least 90%.

3. The device of claim 1 further comprising at least one biologic agent selected from the group consisting of a cell, a tissue, a pharmaceutical and combinations thereof on at least one surface of the metal.

4. The device of claim 3 wherein the biological agent is in a matrix selected from the group consisting of a biocompatible polymer, a biocompatible vesicle, a microcapsule, a microparticle, a liposome, and combinations thereof.

5. The device of claim 3 wherein the biological agent is a diagnostic agent.

6. The device of claim 3 wherein the biological agent is a therapeutic agent.

7. The device of claim 3 wherein the biological agent contains a targeting compound.

8. The device of claim 1 for implanting at an anatomical site selected from the group consisting of a hip, a shoulder, a knee, a finger, an elbow, a mandible, and combinations thereof.

9. An implantable device comprising a structure of a biocompatible metal selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy and having a porosity greater than 80% and up to about 95% and at least one cell capable of at least about 24% in-growth in the device.

10. The device of claim 9 wherein the cell is selected from the group consisting of a quiescent cell, a dividing cell, a senescent cell, an immature cell, a cell precursor, a stem cell, and combinations thereof.

11. The device of claim 9 wherein the cell is selected from the group consisting of a bone cell, a muscle cell, a nerve cell, a skin cell, an epithelial cell, a blood cell, and combinations thereof.

12. The device of claim 9 wherein the cell is selected from the group consisting of an osteoblast, an osteocyte, an osteoclast, an erythrocyte, a leukocyte, a platelet, a megakaryocyte, a histiocyte, a plasma cell, a mast cell, a fibroblast, and combinations thereof.

13. The device of claim 9 wherein the cell comprises a tissue.

14. The device of claim 13 wherein the tissue is selected from the group consisting of connective tissue, fibrous tissue, blood, and combinations thereof.

15. An implantable device comprising a structure of a biocompatible metal selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy and having a porosity greater than 80% and up to about 95% and at least one cell filling at least about 24% of the porosity in the device.

16. An implantable structure comprising a biocompatible metal having a porosity greater than 80% and up to about 95% and selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, and at least one biological agent selected from the group consisting of a cell, a non-cell biologic agent, and combinations thereof, the structure attached to an implant.

17. The structure of claim 16 attached by sintering to the implant.

18. The structure of claim 16 attached by gluing to the implant.

19. An implantable structure comprising a biocompatible metal having a porosity greater than 80% and up to about 95% and selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, and at least one biological agent selected from the group consisting of a cell, a non-cell biologic agent, and combinations thereof, the structure fabricated on an implant.

20. An implantable structure comprising a biocompatible metal having a porosity greater than 80% and up to about 95% and selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, and at least one biological agent selected from the group consisting of a cell, a non-cell biologic agent, and combinations thereof, the structure shaped to fit an implant site.

21. A therapeutic method comprising

implanting a device comprising a biocompatible metal with pores having a porosity greater than 80% up to about 95% and selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, the device capable of supporting tissue in-growth, and

enhancing cell in-growth in said pores.

22. The method of claim 21 producing at least 24% cell in-growth.

23. A method to enhance mandibular bone regeneration comprising

(a) implanting in a mandible a biocompatible porous metal structure having greater than 80% and up to about 95% porosity, the metal selected from the group consisting of titanium and a cobalt-chromium-molybdenum alloy, and

(b) attaching the implanted structure to the patient'"'"'s mandible to enhance bone in-growth in the porous structure.

24. The method of claim 23 wherein the implanted structure further comprises hydroxylapatite.

25. The method of claim 23 wherein the mandible has a surface topography and the structure is shaped to the surface topography.

26. The method of claim 23 wherein the structure is attached to the patient'"'"'s mandible by screwing or stapling.

27. An implantable device for localized thermal tumor therapy in a patient comprising

(a) implanting at a tumor site the device comprising a biocompatible porous metal structure having greater than 80% and up to about 95% porosity, the metal selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, and

(b) increasing the temperature of the implant for a duration to thermally treat the tumor with radiant energy to the implanted structure.

28. The method of claim 27 wherein the energy is selected from the group consisting of x-rays, gamma-rays, microwaves, and combinations thereof.

29. The method of claim 27 wherein the temperature is increased to result in a temperature of the implant in the range greater than 98.6°

F. and up to 107°

F.

30. The method of claim 27 further comprising repeating step (b) at a desired treatment interval.

31. The method of claim 27 wherein a laser provides radiant energy.

32. A method of cell in-growth in an implantable structure comprising

(a) inoculating a cell on a biocompatible metal structure having a porosity greater than 80% and up to about 95%, the metal selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy, and

(b) providing culture conditions to the inoculated structure to obtain cell in-growth of at least 24%.

33. The method of claim 32 wherein the cell in-growth is at least 27%.

34. The method of claim 32 wherein the cell in-growth is in the range of 24% and up to about 48%.

35. The method of claim 32 wherein culture conditions are selected from the group consisting of nutrient media, temperature, O₂/CO₂ saturation, supplements, and combinations thereof.

36. The method of claim 32 wherein the cell is selected from the group consisting of a quiescent cell, a dividing cell, a senescent cell, an immature cell, a cell precursor, a stem cell, and combinations thereof.

37. The method of claim 32 wherein the cell is selected from the group consisting of a bone cell, a muscle cell, a nerve cell, a skin cell, an epithelial cell, a blood cell, and combinations thereof.

38. The method of claim 32 wherein the cell is selected from the group consisting of an osteoblast, an osteocyte, an osteoclast, an erythrocyte, a leukocyte, a platelet, a megakaryocyte, a histiocyte, a plasma cell, a mast cell, a fibroblast, and combinations thereof.

39. The method of claim 32 wherein the cell comprises a tissue.

40. The method of claim 32 wherein inoculation occurs in vivo.

41. The method of claim 32 wherein inoculation occurs in vitro.

42. An implantable composition comprising at least one biological agent and a biocompatible sinterable material having a porosity greater than 80% up to about 95%.

43. The composition of claim 42 wherein the biocompatible sinterable material is selected from the group consisting of an elemental metal, an alloy, and a ceramic.

44. The composition of claim 42 wherein the biocompatible sinterable material is selected from the group consisting of titanium, a titanium alloy, and a cobalt-chromium-molybdenum alloy.

45. An article comprising an implantable metal structure having interconnected pores to provide a porosity greater than about 80% up to about 95%, a density less than 15% of theoretical, and a tensile strength of at least 5000 psi, the pores defining an interfacial surface capable of supporting tissue growth into the structure.

46. The article of claim 45 on a device capable of implantation in a mammal.

47. The article of claim 45 on a prosthesis.

48. The article of claim 45 further comprising at least one therapeutic agent.

49. An article comprising a porous metal selected from the group consisting of titanium, a titanium alloy, and a Cobalt-Chromium-Molybdenum alloy, the metal formed into a reticulated structure having at least 80% and up to 95% interconnected pores, the structure having a tensile strength of at least 5000 psi.

50. The article of claim 49 as a freestanding implant.

51. The article of claim 49 on an implantable device.

52. A reconstructive method comprising implanting in a patient at a site requiring tissue replenishment under replenishment facilitating conditions a structure of a metal selected from the group consisting of titanium, a titanium alloy, a cobalt-chromium-molybdenum alloy, the structure having an interconnected porosity greater than about 80% up to about 95%, a theoretical density less than 15%, and a tensile strength of at least 5000 psi, the pores defining an interfacial surface for in-growth of tissue into the structure thereby replenishing tissue at the site.

53. The method of claim 52 replenishing atrophied bone.

54. The method of claim 52 where the structure is implanted in a mandible.

55. The method of claim 52 replenishing tissue at a site from which a tumor was removed.