Method and apparatus for surface hardening implants
A method for producing a prosthetic having metal articulating surfaces is disclosed. The method includes impinging at least a portion of the articulating surface with high energy laser electromagnetic radiation, to form a lasershot peened surface. A hardened portion of the surface is then post-processed to form a layer having a predetermined finish.
1 . A prosthetic for implantation in a patient formed of a biocompatible material comprising:
an engagement surface;
a first bearing surface, a portion of said bearing surface being a laser shock peened surface,
wherein a layer of the biocompatible material includes a compressive residual stress imparted by laser shock peening that extends into the prosthetic from the laser shock peened surface.
2 . The prosthetic according to claim 1 wherein the first bearing surface is spherical.
3 . The prosthetic according to claim 1 wherein the first bearing surface is convex.
4 . The prosthetic according to claim 1 wherein the first bearing surface is concave.
5 . The prosthetic according to claim 1 further comprising a locking mechanism configured to couple a second prosthetic implant having a second bearing surface, the first bearing surface being configured to substantially surround an articulating head of a third prosthetic.
6 . The prosthetic according to claim 5 wherein said second prosthetic is selected from a group of a constraining ring, a slotted constraining ring, a bearing insert, and a bearing insert having an integral constraining ring and combinations thereof.
7 . The prosthetic according to claim 1 wherein the first bearing surface is formed of a biocompatible metal.
8 . A prosthetic for implantation in a patient formed of a biocompatible material:
a first member having a bone engagement surface and a first contact surface;
a second member, defining a second contact surface which is configured to contact said first contact surface when the prosthetic is implanted in the patient; and
wherein a portion of one of the first or second contact surface is a laser shock peened surface.
9 . The prosthetic according to claim 8 wherein said first contact surface is a hemispherical bearing surface.
10 . The prosthetic according to claim 8 wherein one of said first and second members further defines a generally spherical bearing surfaces.
11 . The prosthetic according to claim 8 wherein the first and second contact surfaces are coupling surfaces of a Morse taper joint.
12 . A prosthetic comprising:
a first portion defining a male portion of a Morse taper joint having a first coupling surface;
a second portion defining a female portion of a Morse taper joint having a second coupling surface; and
wherein at least one of the first and second coupling surfaces is a first laser shock peened surface and wherein a compressive residual stress is imparted by the laser shock peening which extends into the prosthetic from the first laser shock peened surface.
13 . The prosthetic according to claim 12 wherein both the first and second coupling surfaces are laser peened surfaces.
14 . The prosthetic according to claim 12 wherein the first portion comprises a bone engaging surface.
15 . The prosthetic according to claim 14 wherein the second portion comprises an articulating surface.
16 . The prosthetic according to claim 15 wherein the articulating surface is a second laser peened surface.
17 . The prosthetic according to claim 14 further comprising a first bearing surface, a portion of said bearing surface being a laser shock peened surface, and
a layer of material having a compressive residual stress imparted by laser shock peening extends into the prosthetic from the laser shock peened surface.
18 . A method for implanting a medical device comprising:
subjecting a surface of a first prosthetic to laser shock peening; and
implanting the first prosthetic into a prepared joint.
19 . The method according to claim 18 , further including coupling a femoral prosthetic within the surface of the first prosthetic.
20 . The method according to claim 18 , wherein the surface is a concave bearing surface and wherein the first prosthetic comprises a locking mechanism which is configured to fixably accept a second prosthetic having a second bearing surface.
21 . The method according to claim 20 , wherein the first prosthetic is an acetabular cup and the second prosthetic is a constraining ring.
22 . The method according to claim 20 , wherein the surface is a bearing surface.
23 . The method according to claim 20 , wherein the surface is a coupling surface of a Morse taper joint.
24 . The method according to claim 18 further comprising having a portion of the surface which was subjected to laser shock peening.