Porous Patents (Class 623/23.3)
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Patent number: 10729808Abstract: The invention relates to a sternum replacement implant.Type: GrantFiled: June 22, 2016Date of Patent: August 4, 2020Assignee: I.CERAMInventors: Daniel Setton, Fabrice Fiorenza, François Bertin, Frank Sturtz, Eric Denes, Delphine Donnez
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Patent number: 9833542Abstract: Prosthetic knee implant or implant component is made with a magnesium oxide stabilized transformationally toughened zirconia.Type: GrantFiled: June 25, 2012Date of Patent: December 5, 2017Assignees: Louis A. Serefin, Jr. Trust, Xylon, L.L.C.Inventors: Louis A. Serafin, Jr., Gerald J. Jerry, Jr., Nicholas H. Burlingame
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Patent number: 9809906Abstract: The present invention implements a set of grooves/ridges created on Ti at the circumferential direction to increase surface area of implant in contact with bone. These grooves/ridges protect nanofiber matrix (NFM) made with Polycaprolactone (PCL) electrospun nanofiber (ENF) and collagen at the groove from physiological loading. Controlled fabrication of a ridge made with titanium nitride (TiN) around the circumference of Ti is provided using a plasma nitride deposition technique. PCL ENF may be deposited along the sub-micrometer grooves using the electrospin setup disclosed. The method provides for fabrication of microgroove on Ti using machining or TiN deposition and filling the microgrooves with the NFM. This method has proven through experimentation to be successful in increasing in vivo mechanical stability and promoting osseointegration on Ti implants. The immobilization of MgO NP and FN with the PCL-CG NFM on microgrooved Ti as provided in the invention optimizes biological performances of Ti.Type: GrantFiled: March 23, 2017Date of Patent: November 7, 2017Assignee: University of Central OklahomaInventors: Morshed Khandaker, Shahram Riahinezhad
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Patent number: 9694102Abstract: Fired magnesium oxide stabilized transformation toughened zirconia ceramic can be for or of an implant or implant component of a one-piece unicompartmental knee spacer device; a multi-piece unicompartmental joint aligning device; a temporal mandibular joint cap implant; a vertebra cap; an ankle joint ensemble or component; a bridge, a tooth or teeth; a patellofemoral joint implant; a tibial tray for a knee joint replacement implant; an intermediary articulation plate for a tibial tray and liner for a knee joint replacement implant; or the intermediary articulation plate assembled in combination with the tibial tray.Type: GrantFiled: June 25, 2012Date of Patent: July 4, 2017Assignees: LOUIS A. SERAFIN, JR. TRUST, XYLON, L.L.C.Inventors: Louis A. Serafin, Jr., Gerald J. Jerry, Jr., Nicholas H. Burlingame
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Patent number: 9339585Abstract: A surgical implant component comprising an implant component body manufactured from a Co-based substrate alloy comprising Co, Cr, Mo, Si, and C, and a coating on a bone-ingrowth surface of the component body manufactured from a Co-based coating alloy comprising Co, Cr, Mo, Si, C and B. The coating is a network of fused particles of the Co-based coating alloy with spherical particles, irregular aspherical particles, and between about 35 and about 70 volume % porosity. A method of manufacturing the foregoing surgical implant component.Type: GrantFiled: April 3, 2014Date of Patent: May 17, 2016Assignee: KENNAMETAL INC.Inventors: Matthew Yao, Rachel Collier, Abdelhakim Belhadjhamida, Danie DeWet
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Patent number: 9278000Abstract: A porous coating for a medical implant, wherein the porous coating comprises a porous, shape memory material.Type: GrantFiled: February 11, 2013Date of Patent: March 8, 2016Assignee: MX Orthopedics, Corp.Inventors: Matthew Fonte, Matthew Palmer
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Patent number: 9259508Abstract: Ceramic bodies can be made by providing an initial green body of ceramic; and machining the initial green body to provide a machined green ceramic body. Embedding the initial green body in an embedding mass can be avoided. The initial green body can be bisqued, infiltrated an adjuvant such as machining wax, removing the infiltrated body, and machining it. Highly detailed ceramic products can be generated. The machined green ceramic body may be fired and/or further processed to provide a more finished ceramic body. Examples include a femoral component for a posterior stabilized knee implant, a component body for an artificial rotation device containing knee implant prosthesis a dental implant or bridge, an ice skating blade, and so forth. Zirconia ceramics are advantageously employed, for an example, Mg-TTZ.Type: GrantFiled: September 7, 2005Date of Patent: February 16, 2016Assignees: Louis A. Serafin, Jr. Trust, Xylon, L.L.C.Inventors: Louis A. Serafin, Jr., Gerald J. Jerry, Jr., Nicholas H. Burlingame
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Patent number: 9174297Abstract: An apparatus and method are provided for manufacturing an orthopedic prosthesis by resistance welding a porous metal layer of the orthopedic prosthesis onto an underlying metal substrate of the orthopedic prosthesis. The resistance welding process involves directing an electrical current through the porous layer and the substrate, which dissipates as heat to cause softening and/or melting of the materials, especially along the interface between the porous layer and the substrate. The softened and/or melted materials undergo metallurgical bonding at points of contact between the porous layer and the substrate to fixedly secure the porous layer onto the substrate.Type: GrantFiled: November 18, 2011Date of Patent: November 3, 2015Assignee: Zimmer, Inc.Inventors: Joseph R. Vargas, Steven Seelman, Clarence M. Panchison
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Patent number: 9162008Abstract: Prosthetic implant or component therefor of a magnesium oxide stabilized transformation toughened zirconia (Mg-TTZ) ceramic can be made by providing a bisqued initial green body by compressing powder through a cold isostatic press and heating to a bisque stage. Then, without embedding it in an embedding mass, the bisque is machined to have a shape of the same proportions as the shape of, but larger than, the ceramic portion of a fired prosthetic implant or component product. Firing can provide the fired Mg-TTZ ceramic body product.Type: GrantFiled: June 25, 2012Date of Patent: October 20, 2015Assignees: Xylon, L.L.C.Inventors: Louis A. Serafin, Jr., Gerald J. Jerry, Jr., Nicholas H. Burlingame
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Patent number: 8999000Abstract: A cartilage resurfacing implant is provided for replacing cartilage of an articulating portion of a bone at a skeletal joint having opposed joint surfaces. The cartilage resurfacing implant includes a body having a bearing surface and a bone interface. The bearing surface is able to support articulation with an opposing joint surface.Type: GrantFiled: December 3, 2010Date of Patent: April 7, 2015Assignee: Zimmer Technology, Inc.Inventors: Robert A. Hodorek, Antony J. Lozier, Cheryl R. Blanchard
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Publication number: 20150094820Abstract: An implant for a hip can include a lateral augment adapted to be coupled to a lateral side of a femoral body implant. The lateral augment can include a body portion having a first surface, a second surface opposite the first surface, and a protrusion extending from the second surface. The protrusion can have a shape adapted to mate with a complementary shaped recess formed in the lateral side of the femoral body implant. An aperture can be positioned in the body portion and extend through the protrusion. A fastener can be received through the aperture and adapted to be threadably secured to the lateral bore. The fastener can be configured to have a length sufficient to pass through a portion of a greater trochanter for securing the portion of the greater trochanter and the lateral augment to the femoral body implant.Type: ApplicationFiled: December 8, 2014Publication date: April 2, 2015Inventors: Aaron P. SMITH, Tyler D. WITT, Hugh APTHORP, Keith R. BEREND, Andrew FREIBERG, John BARRINGTON, David R. BROWN
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Patent number: 8986392Abstract: A femoral implant includes a main shaft with a proximal end and a smooth distal end. A porous circumferential collar is provided between the proximal end and distal end, and a porous distally-extending portion extends distally from the collar to provide for additional bone ingrowth.Type: GrantFiled: August 25, 2011Date of Patent: March 24, 2015Inventors: S. Gary Brown, Gregory Thomas Van Der Meulen, Christopher G. Sidebotham
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Patent number: 8906108Abstract: An orthopaedic prosthesis for use in a hip replacement surgery. The orthopaedic prosthesis includes a metallic foam shell and a metallic core. The metallic core includes a neck configured to receive a femoral head component and a stem extending through the metallic foam shell.Type: GrantFiled: June 18, 2012Date of Patent: December 9, 2014Assignee: DePuy Synthes Products, LLCInventors: John M. Armacost, Ryan C. Keefer, Jeffrey A. McAnelly
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Patent number: 8888862Abstract: A bone implant comprises a core 10 having an integral anchoring structure 12 at its surface. The structure 12 comprises an array of upwardly extending mutually spaced pointed claw-like teeth 14 for digging into bone to which the implant is to be attached, and a network of pores 16 underlying the array and communicating with the exterior of the surface via openings 18 between the teeth, the pores allowing for the circulation of nutrients to promote bone growth.Type: GrantFiled: May 19, 2010Date of Patent: November 18, 2014Inventors: Patrick McDonnell, Noel Harrison
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Patent number: 8858646Abstract: A hip prosthesis is provided for insertion into a femur. In one exemplary embodiment, the hip prosthesis includes a stem having a proximal end, a distal end, and a longitudinal axis. This stem may include anterior and posterior locking surfaces which diverge away from the longitudinal axis. A shank portion may extend distally from the anterior and posterior locking surfaces and converge at an angle distally toward the longitudinal axis.Type: GrantFiled: May 7, 2012Date of Patent: October 14, 2014Assignee: Zimmer, Inc.Inventors: Natalia Fridshtand, Douglas W. Gabel, Steven J. Charlebois, David L. Glass, Steven A. Zawadzki, Jeffrey P. Matney
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Patent number: 8641772Abstract: A hip-joint prosthesis includes a shaft which is configured to be inserted into the femur and whose surface has an osteoinductive finish. This finish is provided exclusively in the metaphyseal portion of the shaft and laterally from the line delineating the maximum antero-posterior dimension of the shaft cross section. This ensures a better involvement of the metaphyseal spongiosa in the flow of forces, without compromising the ability to perform follow-up surgery on the prosthesis.Type: GrantFiled: April 11, 2011Date of Patent: February 4, 2014Assignee: Waldemar Link GmbH & Co. KGInventor: Helmut D. Link
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Patent number: 8556981Abstract: An implant having a porous tissue ingrowth structure and a bearing support structure is disclosed. The implant includes a metal insert having a bone ingrowth structure, an intermediate structure and a bearing support structure. A bearing surface is formed from a polymer material and attached to the bearing support structure. The intermediate structure has a porosity sufficient to inhibit the polymer material from translating through the bearing support structure to the bone ingrowth structure.Type: GrantFiled: September 18, 2009Date of Patent: October 15, 2013Assignee: Howmedica Osteonics Corp.Inventors: Eric Jones, Christopher J. Sutcliffe, Robin Stamp
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Patent number: 8535386Abstract: An implant assembly comprises a stem and an augment. The augment includes a porous outer region which is integrally formed onto a solid inner region. The augment further includes, solid posts integrally formed on the solid inner region and extend through the porous outer region to the outer surface of the augment. The posts are integrally formed with and surrounded by the porous region and are designed to allow assembly of the augment to the stem without damaging the structure of the porous region. A method of attaching the augment is described, wherein a tool is designed to grip to posts of the augment and apply loads through these posts during assembly.Type: GrantFiled: October 21, 2010Date of Patent: September 17, 2013Assignee: Howmedica Osteonics Corp.Inventors: Damon J. Servidio, G. Douglas Letson
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Patent number: 8535385Abstract: A prosthetic system that includes a prosthetic implant and a support structure secured to an inner surface of the cavity in the end of the bone is disclosed. The support structure defines a channel that extends through the length of the support structure. The prosthetic implant is received in the channel, and a portion of the prosthetic implant is secured to an inner surface of the channel by an adhesive. The stem of the prosthesis beyond the channel may be cemented or uncemented. The support structure may have an approximately funnel shape. The support structure may be a hollow porous cylindrical sleeve. The support structure may comprise a pair of partially hemispherical components arranged in spaced apart relationship thereby defining a channel between the pair of components. The support structure may comprise a plurality of pedestals secured to the inner surface of the cavity of the bone.Type: GrantFiled: August 8, 2011Date of Patent: September 17, 2013Assignee: Zimmer, Inc.Inventors: Arlen D. Hanssen, David G. Lewallen
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Patent number: 8414654Abstract: An implant device for humans or mammals has a body structure having an exposed surface and one or more selected portions of the exposed surface having a bone formation enhancing 3-dimensional pattern. The exposed surface can be on exterior portions of the body structure or internal portions of the body structure or both. The one or more selected portions of the exposed portions having the bone formation enhancing 3-dimensional patterns are in the external exposed surfaces or in the internal exposed surfaces or both internal and external exposed surfaces.Type: GrantFiled: November 23, 2011Date of Patent: April 9, 2013Assignee: Amendia, Inc.Inventor: Timothy Ganey
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Patent number: 8266780Abstract: An orthopedic implant. The implant includes a metal portion having an internal three-dimensional cavity, the cavity having an opening to an outer surface of the metal portion, a ledge circumferentially surrounding at least a portion of the opening, and a porous metal insert formed in a three-dimensional shape conforming to the shape of the cavity and enclosed by the cavity without being bonded to the cavity. The insert is retained inside the cavity by the ledge.Type: GrantFiled: February 27, 2008Date of Patent: September 18, 2012Assignee: Biomet Manufacturing Corp.Inventors: Mark A. Bollinger, Brian M. May
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Publication number: 20120221116Abstract: A hip prosthesis is provided for insertion into a femur. In one exemplary embodiment, the hip prosthesis includes a stem having a proximal end, a distal end, and a longitudinal axis. This stem may include anterior and posterior locking surfaces which diverge away from the longitudinal axis. A shank portion may extend distally from the anterior and posterior locking surfaces and converge at an angle distally toward the longitudinal axis.Type: ApplicationFiled: May 7, 2012Publication date: August 30, 2012Applicant: ZIMMER, INC.Inventors: Natalia Fridshtand, Douglas W. Gabel, Steven J. Charlebois, David L. Glass, Steven Zawadzki, Jeffrey P. Matney
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Patent number: 8221504Abstract: A method of preparing an implant for bone in-growth comprising: providing a metal implant body, the metal implant body having a metal load bearing layer on an outer surface, the metal load bearing layer having a plurality of pores therein, the pores configured to promote bone in-growth into the load bearing layer; providing calcium sulfate hemi-hydrate; providing a diluent; mixing the calcium sulfate hemi-hydrate and the diluent to form a calcium sulfate paste; applying the calcium sulfate paste to the load bearing layer such that the calcium paste substantially impregnates at least a portion of the pores and forms an excess layer of the calcium sulfate paste on an outer surface of the load bearing layer; and wiping the calcium sulfate paste to remove the excess layer and thereby expose the outer surface of the load bearing layer while leaving the calcium sulfate paste impregnated in the pores.Type: GrantFiled: February 23, 2005Date of Patent: July 17, 2012Assignee: Wright Medical Technology, Inc.Inventors: Kelly C. Richelsoph, Linda Morris, Jantzen A. Cole
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Patent number: 7947084Abstract: A hip-joint prosthesis includes a shaft which is configured to be inserted into the femur and whose surface has an osteoinductive finish. This finish is provided exclusively in the metaphyseal portion of the shaft and laterally from the line delineating the maximum antero-posterior dimension of the shaft cross section. This ensures a better involvement of the metaphyseal spongiosa in the flow of forces, without compromising the ability to perform follow-up surgery on the prosthesis.Type: GrantFiled: August 5, 2005Date of Patent: May 24, 2011Assignee: Waldemar Link GmbH & Co. KGInventor: Helmut D. Link
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Patent number: 7842096Abstract: A hip prosthesis for insertion into a femur. In one exemplary embodiment, the hip prosthesis includes a stem having a proximal end, a distal end, and a longitudinal axis. This stem may include anterior and posterior locking surfaces which diverge away from the stem. A shank portion may extend distally from the anterior and posterior locking surfaces and converge at an angle distally toward the stem.Type: GrantFiled: February 22, 2005Date of Patent: November 30, 2010Assignee: Zimmer Technology, Inc.Inventors: Natalia Fridshtand, Douglas W. Gabel, Steven J. Charlebois, David L. Glass, Steven Zawadzki, Jeffrey P. Matney
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Publication number: 20100042226Abstract: An orthopaedic implant includes a body member having a first region with a first porosity and a second region with a second porosity. At least one physical characteristic of the first porosity is different than at least one physical characteristic of the second porosity.Type: ApplicationFiled: August 13, 2009Publication date: February 18, 2010Inventors: Paul S. Nebosky, Sarah L. Zimmerman, Gregory C. Stalcup
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Patent number: 7211113Abstract: An endoprosthesis utilizes a biomechanical structure based on the lever model of first degree. Contrary to the widespread practice, the inventive structure has a stem placed inside the femur bone, which is not rigidly attached to this bone. Accordingly, the bone, following its known tendency to slightly pivot away from the medial plane of the body in response to the loads, does not directly contact the stem. The neck portion experiences even greater loads then the stem. The supporting anchor has a region extending laterally from the stem and pressing against a supporting surface of the housing, which also extends laterally from the body of the housing. Since the stem, supporting anchor and neck are typically constitute a one-piece component, the lateral surfaces of the supporting anchor and housing are in continuous frictional contact during displacement of the stem and housing relative to one another.Type: GrantFiled: May 18, 2004Date of Patent: May 1, 2007Inventors: Lev Zelener, Konstantin Sherepo, Marina Zelener, Anton Svetlanov
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Patent number: 7147813Abstract: A method of addressing a condition of a living body comprising the steps of using an energy beam to form a set of pores in a work piece biocompatible membrane. The pores should have a mean area of less than 500 ?m through the biocompatible membrane, thereby producing a microporous membrane adapted to facilitate tissue in growth. This membrane is placed at least partially about an article that is adapted to be implanted in a living body, which is implanted into the living body, thereby addressing the condition.Type: GrantFiled: April 4, 2005Date of Patent: December 12, 2006Assignee: Isense CorporationInventors: Kenneth Ward, Jerome J. Boogaard
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Patent number: 6913623Abstract: An orthopedic implant includes a metal core having a first end, a second end, a first elastic modulus, and a first porosity. A proximal body is fused directly onto the metal core between the first and second ends. The proximal body has a second elastic modulus, which is less than the first elastic modulus, and a second porosity, which is greater than the first porosity. The porosity of the proximal body may vary throughout.Type: GrantFiled: August 15, 2000Date of Patent: July 5, 2005Assignee: Centerpulse Orthopedics, Inc.Inventor: Mengke Zhu
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Patent number: 6875386Abstract: A method of producing a biocompatible microporous membrane comprising the steps of providing a biocompatible membrane and using an energy beam to form a set of pores having a minor axis of less than 15 ?m through the biocompatible membrane. One embodiment includes the steps of producing a first layer of material, defining a first set of pores; producing a second layer of material, defining a second set of pores and wherein the second set of pores is defined so as to cooperatively engage the first set of pores; and aligning and joining the first layer of material to the second layer of material to form a laminated membrane, having through-passageways formed by the first set of pores at least partially aligned with the second set of pores.Type: GrantFiled: February 11, 2003Date of Patent: April 5, 2005Assignee: iSense Corp.Inventors: Kenneth Ward, Jerome J. Boogaard
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Publication number: 20030045941Abstract: A prosthesis for implanting into a bone having a cavity is disclosed. The prosthesis comprises a body and a stem. A first coating including a bone ingrowth promoting material that promotes ingrowth of bone onto the stem and a bioabsorbable material that delays the ingrowth of bone onto the stem is disposed on a proximal portion of the stem outer surface. A second coating including the bone ingrowth promoting material and the bioabsorbable material is disposed on a distal portion of the stem outer surface. The ratio of bone ingrowth promoting material to bioabsorbable material in the first coating is greater than the ratio of bone ingrowth promoting material to bioabsorbable material in the second coating whereby the affixation of the bone to the proximal zone of the stem is faster and stronger over time than the affixation of the bone to the distal zone of the stem.Type: ApplicationFiled: August 22, 2002Publication date: March 6, 2003Inventor: David G. Lewallen
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Patent number: 6514288Abstract: The present invention provides an improved prosthetic stem for implantation in a bone. Specifically, the present invention provides a prosthetic femoral stem having a strengthening rib protruding from the substrate thereof and being flush with a porous coating formed thereon. The strengthening rib is advantageously positioned so as to increase the cross-sectional moment of inertia of the prosthetic femoral stem and thereby decrease the stress on the anterio-lateral surface of the femoral stem. A protrusion in accordance with the present invention may also be utilized with a prosthetic femoral stem absent a porous coating. In such an embodiment, the height of the protrusion is such that the protrusion will be surrounded by the cement mantle formed when the prosthetic femoral component is cemented in a femoral canal.Type: GrantFiled: February 23, 2001Date of Patent: February 4, 2003Assignee: Zimmer, Inc.Inventors: Steven L. Meulink, Jack D. Jennings, James L. Crumley, II, Tracy R. Gilliland
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Patent number: 6494916Abstract: A prosthetic implant that contains a stem integrally connected to a neck, a head that sits on top of the neck, and a porous assembly disposed around them stem. The porous assembly contains a first porous tube and a second porous tube, wherein the second porous tube is disposed within the first porous tube, and the stem is disposed within the second porous tube. The porous assembly is a heat absorbent porous assembly which tends to maintain its temperature within a specified range.Type: GrantFiled: July 30, 2001Date of Patent: December 17, 2002Assignee: Biomed Solutions, LLCInventors: Omotunde M. Babalola, Patrick R. Connelly, Stuart G. MacDonald
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Publication number: 20020151983Abstract: 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.Type: ApplicationFiled: April 3, 2002Publication date: October 17, 2002Inventor: H. Ravindranath Shetty
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Publication number: 20020120344Abstract: The present invention provides an improved prosthetic stem for implantation in a bone. Specifically, the present invention provides a prosthetic femoral stem having a strengthening rib protruding from the substrate thereof and being flush with a porous coating formed thereon. The strengthening rib is advantageously positioned so as to increase the cross-sectional moment of inertia of the prosthetic femoral stem and thereby decrease the stress on the anterio-lateral surface of the femoral stem. A protrusion in accordance with the present invention may also be utilized with a prosthetic femoral stem absent a porous coating. In such an embodiment, the height of the protrusion is such that the protrusion will be surrounded by the cement mantle formed when the prosthetic femoral component is cemented in a femoral canal.Type: ApplicationFiled: February 23, 2001Publication date: August 29, 2002Inventors: Steven L. Meulink, Jack D. Jennings, James L. Crumley, Tracy R. Gilliland
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Patent number: 6312473Abstract: It is an object of the present invention to provide an improved orthopedic implant system with satisfied biological, mechanical and morphological compatibilities. Solid metal femoral stem and solid metal acetabular head are covered with diffusion-bonded foamed-shaped sheet made of commercially pure titanium or titanium alloy(s). The open-cells in said foamed metal sheet are impregnated with biocompatible polymethyl methacrylate resin cement, which is reinforced with selected oxides including alumina, magnesia, zirconia, or a combination of these oxides along with an application of a small amount of a metal primer agent.Type: GrantFiled: October 20, 1999Date of Patent: November 6, 2001Inventor: Yoshiki Oshida
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Patent number: 6302913Abstract: This invention relates to a biomaterial useful in bone repair and replacement, and to implants for cranofacial, orthopaedic, and especially dental applications. The implants have a unique geometric configuration, their surfaces defining concavities having a shape and dimensions which induce or enhance the rate and/or amount of bone growth at the implant site. The biomaterial preferably has a specific porous configuration and the implant may be at least coated with such a biomaterial of hydroxyapatite, for example.Type: GrantFiled: November 22, 1996Date of Patent: October 16, 2001Assignee: Implico B.V.Inventors: Ugo Ripamonti, Anthony Nigel Kirkbride
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Publication number: 20010014829Abstract: The present invention is intended to provide a plastic jacket for a cementless artificial joint stem, wherein shear force detrimental to the service life of an artificial joint can be markedly reduced and stress shielding phenomena can also be markedly relieved, due to the construction of the plastic jacket which can be fixed to the bone canal and can enclose the surface of the stem so as to allow for the stem of artificial joint to slide vertically relative to the bone, and wherein osteolysis of a bone due to the infiltration of wear particles can be minimized by curbing the gap formation between the bone and the stem.Type: ApplicationFiled: February 9, 2001Publication date: August 16, 2001Inventor: Yong-San Yoon