Antioxidant-stabilized joint implants
Methods of making a wear and oxidation resistant medical implant are disclosed.
1. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant preform;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with the desired surfaces exposed to the beam;
(d) machining the medical implant preform into a medical implant; and
(e) packaging and sterilizing the medical implant,
wherein step (c) comprises irradiating the medical implant preform with an electron scattering device comprising fibers in contact with or close to the surface to be irradiated.
2. The method of claim 1 further comprising annealing the medical implant preform after step (c).
3. The method of claim 1 , wherein the antioxidant used in blending in step (a) is vitamin E.
4. The method according to claim 1 , wherein the material is pre-heated to an elevated temperature before irradiation such that the material is irradiated between 100° C. and 130° C.
5. The method according to claim 1 , wherein the antioxidant concentration in the blend is 0.1 wt % to 5 wt %.
6. The method according to claim 1 , wherein the irradiation dose is in the range of about 25 kGy to about 150 kGy.
7. The method according to claim 1 , wherein the radiation dose rate is between about 1 kGy/pass to 50 kGy/pass.
8. The method according to claim 1 , wherein the sterilization is a gamma sterilization.
9. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant preform;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with the desired surfaces exposed to the beam;
(d) machining the medical implant preform into a medical implant; and
(e) packaging and sterilizing the medical implant,
wherein step (c) comprises irradiating the medical implant preform with an electron scattering device comprising metallic fibers or metallic wool or metallic brushes.
10. The method according to claim 1 , wherein the electron scattering device is situated within a millimeter of intended surfaces to be irradiated.
11. The method according to claim 1 , wherein the electron scattering device is situated within thirty centimeters of intended surfaces to be irradiated.
12. The method according to claim 1 , wherein the polymeric materials comprises ultrahigh molecular weight polyethylene, and the antioxidant used in step (a) is vitamin E.
13. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with desired surfaces exposed to a beam with an electron scattering device; and
(d) packaging and sterilizing the medical implant,
wherein the electron scattering device comprises fibers in contact with or close to the surface to be irradiated.
14. The method of claim 13 further comprising annealing the medical implant preform after step (c).
15. The method of claim 13 , wherein the antioxidant used in blending in step (a) is vitamin E.
16. The method according to claim 13 , wherein the material is pre-heated to an elevated temperature before irradiation such that the material is irradiated between 100° C. and 130° C.
17. The method according to claim 13 , wherein the antioxidant concentration in the blend is 0.1 wt % to 5 wt %.
18. The method according to claim 13 , wherein the irradiation dose is in the range of about 25 kGy to about 150 kGy.
19. The method according to claim 13 , wherein the radiation dose rate is between about 1 kGy/pass to 50 kGy/pass.
20. The method according to claim 13 , wherein the sterilization is a gamma sterilization.
21. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with desired surfaces exposed to a beam with an electron scattering device; and
(d) packaging and sterilizing the medical implant,
wherein the electron scattering device comprises metallic fibers or metallic wool or metallic brushes.
22. The method according to claim 13 , wherein the electron scattering device is situated within a millimeter of intended surfaces to be irradiated.
23. The method according to claim 13 , wherein the electron scattering device is situated within thirty centimeters of intended surfaces to be irradiated.
24. The method according to claim 13 , wherein the polymeric materials comprises ultrahigh molecular weight polyethylene, and the antioxidant used in step (a) is vitamin E.
25. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant preform;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with desired surfaces exposed to the beam;
(d) doping the medical implant preform with one or more antioxidant(s); and
(e) machining the medical implant preform into a medical implant,
wherein step (c) comprises irradiating the medical implant preform with an electron scattering device comprising fibers in contact with or close to the surface to be irradiated.
26. The method of claim 25 further comprising annealing the medical implant preform after step (c).
27. The method of claim 25 , wherein the antioxidant used in blending in step (a) and doping in step (d) is vitamin E.
28. The method according to claim 25 , wherein the material is pre-heated to an elevated temperature before irradiation such that the material is irradiated between 100° C. and 130° C.
29. The method according to claim 25 , wherein the antioxidant concentration in the blend is 0.1 wt % to 5 wt %.
30. The method according to claim 25 , wherein the irradiation dose is in the range of about 25 kGy to about 150 kGy.
31. The method according to claim 25 , wherein the radiation dose rate is between about 1 kGy/pass to 50 kGy/pass.
32. A method of making a wear and oxidation resistant medical implant, the method comprising:
(a) blending a polymeric material with one or more antioxidant(s);
(b) consolidating the blended polymeric material into a medical implant preform;
(c) irradiating the medical implant preform with low energy electrons at below 2 MeV with desired surfaces exposed to the beam with an electron scattering device;
(d) doping the medical implant preform with one or more antioxidant(s); and
(e) machining the medical implant preform into a medical implant,
wherein the electron scattering device comprises metallic fibers or metallic wool or metallic brushes.
33. The method according to claim 25 , wherein the electron scattering device is situated within a millimeter of intended surfaces to be irradiated.
34. The method according to claim 25 , wherein the electron scattering device is situated within thirty centimeters of intended surfaces to be irradiated.
35. The method according to claim 25 , wherein the polymeric materials comprises ultrahigh molecular weight polyethylene, and the antioxidant used in step (a) is vitamin E.