Abstract: A bone clamp having a ratchet mechanism including ratchet teeth having rounded peaks with curved valleys therebetween and a curved pawl having a curvature similar to the valleys spanning the peaks of the ratchet teeth. The ratchet mechanism of the current invention distributes the interaction forces between the ratchet teeth and the pawl and therefore is resistive to shear stresses which could otherwise compromise the structural integrity of the ratchet mechanism.
Type:
Grant
Filed:
October 12, 2000
Date of Patent:
July 8, 2003
Assignee:
Zimmer, Inc.
Inventors:
Frank Townsend, Patrick Rousseau, Mark A. Bryant
Abstract: A method for producing an orthopedic implant having enhanced fatigue strength. A forged implant substrate having an elongated stem is incorporated with a melting point lowering substance. Then, metal particles are sintered to the substrate, forming a porous layer on the substrate which enhances bone ingrowth or the mechanical interlock with bone cement. Advantageously, the sintering occurs at a lower temperature than if the substance were not incorporated into the substrate, which in turn results in an enhanced fatigue strength of the inventive implant. The fatigue strength of a forged or cast implant can also be improved by nitrogen diffusion hardening and/or thermally processing the implant after the porous coating is adhered by sintering. Further, the fatigue strength can be further improved by combining incorporating the melting point lowering substance with nitrogen diffusion hardening and/or aging treatment subsequent to sintering.
Abstract: A method of forming an orthopedic implant having a porous surface layer thereon. A mask includes a cut-out configured to receive a portion of the implant therein. The implant is placed within the cut-out and thereby masked. A water soluble binder solution is sprayed onto at least a part of the unmasked portion of the implant using a sprayer, thereby forming a binder layer on the implant. The binder solution includes water, ethanol, gelatin, glycerin, and a colorant. A porous layer including a plurality of metallic particles is contacted with the binder layer. The porous layer is bonded with the surface of the implant with a sintering process.
Type:
Grant
Filed:
June 14, 2000
Date of Patent:
April 8, 2003
Assignee:
Zimmer, Inc.
Inventors:
Richard Calvert Compton, Clarence Panchison, Michael S. Hawley, Jay B. Moore, William B. Clarke
Abstract: An orthopaedic instrument and a method for its use in sizing a glenoid implant anchor site and for pressurizing bone cement in the anchor site. The instrument has a shaft with a handle on one end thereof and a pressure plate on the other end thereof. An implant site probe, corresponding in shape to the glenoid implant anchor, extends outwardly from a bone facing surface of the pressure plate. A seal against the bone facing surface surrounds the implant site probe. Forcing the implant site probe into the implant site filled with bone cement forces bone cement into the cancellous bone surrounding the implant site.
Type:
Grant
Filed:
May 11, 2000
Date of Patent:
October 1, 2002
Assignee:
Zimmer, Inc.
Inventors:
Randy Allard, Louis U. Bigliani, Evan Flatow, John Meyers, Terry Schlotterback, David Willard
Abstract: A method for producing an orthopaedic implant having enhanced fatigue strength. A forged implant substrate having an elongated stem is incorporated with a melting point lowering substance. Then, metal particles are sintered to the substrate, forming a porous layer on the substrate which enhances bone ingrowth or the mechanical interlock with bone cement. Advantageously, the sintering occurs at a lower temperature than if the substance were not incorporated into the substrate, which in turn results in an enhanced fatigue strength of the inventive implant. The fatigue strength of a forged or cast implant can also be improved by nitrogen diffusion hardening and/or thermally processing the implant after the porous coating is adhered by sintering. Further, the fatigue strength can be further improved by combining incorporating the melting point lowering substance with nitrogen diffusion hardening and/or aging treatment subsequent to sintering.