JAMES SCOTT DAVIDSON
Pilots at Donnybrook Dr, Memphis, TN

5064439, Nov 12, 1991

Jan 20, 1987

7/005091

Fu-Kuo Chang - Palo Alto CA
Kenneth Reifsnider - Blacksburg VA
James A. Davidson - Germantown TN
Frederick S. Georgette - Memphis TN

Richards Medical Company - Memphis TN

A61F 228

623 66

Orthopedic device of biocompatible polymer with oriented fiber reinforcement. There is provided a device such as a hip stem which has a longitudinally curved body. The reinforcing fibers are continuous filament fiber plies with parallel oriented fibers in each ply. The plies are curved longitudinally to approximately correspond to the curve of the body. In one embodiment, there are longitudinally oriented fiber plies at or near the surfaces of the device and plies with fibers offset at 5. degree. -40. degree. from the longitudinal axis between the surface layers. The fiber orientation is balanced by providing a ply of negatively angled offset fibers of a similar angle for each positively angled offset ply. The device is made by molding plies preimpregnated with polymer (prepregs) simultaneously, by molding a plurality of prepregs into segments which are then molded together, or by molding a segment and incrementally molding additional layers of prepregs thereto in a series of progressively larger molds.

5496359, Mar 5, 1996

Aug 26, 1993

8/112587

James A. Davidson - Germantown TN

Smith & Nephew Richards, Inc. - Memphis TN

A61N 104

607115

Cardiovascular, vascular, and percutaneous implants, as well as catheters and other surgical instruments, fabricated from a core or substrate of a low modulus metal coated with blue to black zirconium oxide or zirconium nitride. The coating provides enhanced thrombogenicity, biocompatibility, blood compatibility, corrosion-resistance, friction and microfretting resistance, durability, and electrical insulation, where applicable. The coatings may be applied to low modulus metallic substrates by physical or chemical vapor deposition as well as other ion-beam assisted methods. Preferably, however, for optimizing attachment strength, the implants and surgical instruments are fabricated from zirconium or zirconium-containing alloys and the coatings are formed by oxidizing or nitriding through an in situ method that develops a coating from and on the metal surface of the implant or instrument, without need for depositing a coating on the metal surface.

5782910, Jul 21, 1998

Jun 6, 1996

8/468536

James A. Davidson - Germantown TN

Smith & Nephew, Inc. - Memphis TN

A61F 222

623 3

Cardiovascular and other medical implants fabricated from low-modulus Ti--Nb--Zr alloys to provide enhanced biocompatibility and hemocompatibility. The cardiovascular implants may be surface hardened by oxygen or nitrogen diffusion or by coating with a tightly adherent, hard, wear-resistant, hemocompatible ceramic coating. The cardiovascular implants include heart valves, total artificial heart implants, ventricular assist devices, vascular grafts, stents, electrical signal carrying devices such as pacemaker and neurological leads, defibrillator leads, and the like. It is contemplated that the Ti--Nb--Zr alloy can be substituted as a fabrication material for any cardiovascular implant that either comes into contact with blood thereby demanding high levels of hemocompatibility, or that is subject to microfretting, corrosion, or other wear and so that a low modulus metal with a corrosion-resistant, hardened surface would be desirable.

5372660, Dec 13, 1994

Aug 26, 1993

8/112612

James A. Davidson - Germantown TN
Ajit K. Mishra - Memphis TN
Robert A. Poggie - Memphis TN

Smith & Nephew Richards, Inc. - Memphis TN

C22C 1400

148421

Surface and near surface hardened medical implants are provided. These implants are fabricated from titanium alloys that contain an amount of zirconium sufficient to permit the formation of a significant amount of zirconium oxide at the surface of the implant to cause surface hardening. Further, the zirconium-containing titanium alloy implants are characterized in having an alloy core with an oxygen-rich layer surrounding the core, and a surface layer, overlying the oxygen-rich layer, including mixed oxides of the metals present in the alloy. A zirconium-rich interface may sometimes be present between the oxygen-rich layer and the mixed-oxide surface layer. The method of producing these surface hardened implants includes the steps of heating the implant in an oxygen containing environment at a temperature sufficient to allow oxygen to diffuse to and react with the implant surface and near surface.

5716400, Feb 10, 1998

Jun 6, 1995

8/468537

James A. Davidson - Germantown TN

Smith & Nephew, Inc. - Memphis TN

A61F 224

623 2

Cardiovascular and other medical implants fabricated from low-modulus Ti--Nb--Zr alloys to provide enhanced biocompatibility and hemocompatibility. The cardiovascular implants may be surface hardened by oxygen or nitrogen diffusion or by coating with a tightly adherent, hard, wear-resistant, hemocompatible ceramic coating. The cardiovascular implants include heart valves, total artificial heart implants, ventricular assist devices, vascular grafts, stents, electrical signal carrying devices such as pacemaker and neurological leads, defibrillator leads, and the like. It is contemplated that the Ti--Nb--Zr alloy can be substituted as a fabrication material for any cardiovascular implant that either comes into contact with blood thereby demanding high levels of hemocompatibility, or that is subject to microfretting, corrosion, or other wear and so that a low modulus metal with a corrosion-resistant, hardened surface would be desirable.

5509933, Apr 23, 1996

Mar 24, 1993

8/036414

James A. Davidson - Germantown TN
Ajit K. Mishra - Memphis TN

Smith & Nephew Richards, Inc. - Memphis TN

A61F 228, A61F 500, A61F 236

623 16

Biocompatible medical implants from a high strength, low modulus, hot worked titanium alloy containing titanium, about 10-20 wt. % or 35 to about 50 wt. % niobium and up to 20 wt. % zirconium. In particular, the titanium implants have a modulus of elasticity closer to that of bone than other typically used metal alloys and does not include any elements which have been shown or suggested as having short or long term potential adverse effects from a standpoint of biocompatibility. To fabricate the alloy, it is necessary to heat to above the. beta. -transus temperature (or to a temperature in a range from 100. degree. C. below and up to the. beta. -transus), hot work the alloy, rapidly cool to below the. beta. -transus, and age the cooled alloy for a period of time to develop its strength while maintaining its low modulus (less than about 90 GPa). The alloy is suitable for a range of uses where the properties of low modulus, high strength and corrosion resistance are desirable.

5477864, Dec 26, 1995

Aug 26, 1993

8/112599

James A. Davidson - Germantown TN

Smith & Nephew Richards, Inc. - Memphis TN

A61B 500

128772

Cardiovascular and other medical implants fabricated from low-modulus Ti-Nb-Zr alloys to provide enhanced biocompatibility and hemocompatibility. The cardiovascular implants may be surface hardened by oxygen or nitrogen diffusion or by coating with a tightly adherent, hard, wear-resistant, hemocompatible ceramic coating. The cardiovascular implants include heart valves, total artificial heart implants, ventricular assist devices, vascular grafts, stents, electrical signal carrying devices such as pacemaker and neurological leads, defibrillator leads, and the like. It is contemplated that the Ti-Nb-Zr alloy can be substituted as a fabrication material for any cardiovascular implant that either comes into contact with blood thereby demanding high levels of hemocompatibility, or that is subject to microfretting, corrosion, or other wear and so that a low modulus metal with a corrosion-resistant, hardened surface would be desirable.

5152794, Oct 6, 1992

Jul 23, 1990

7/557173

James A. Davidson - Germantown TN

Smith & Nephew Richards Inc. - Memphis TN

A61F 228, A61F 230, A61F 504

623 16

Orthopedic implants of zirconium or zirconium-based alloy coated with blue or blue-black zirconium oxide or zirconium nitride to provide low friction, highly wear resistant coatings especially useful in artificial joints, such as hip joints, knee joints, elbows, etc. The invention zirconium oxide or nitride coated prostheses are also useful to reduce microfretting wear in multi-component surgical implants subject to such wear. Further, the coatings provide a barrier against implant corrosion caused by ionization of the metal prosthesis. Such protection can be extended by the use of oxidized or nitrided porous coatings of zirconium or zirconium alloy beads or wire mesh into which bone spicules may grow so that the prosthesis may be integrated into the living skeleton.

5211663, May 18, 1993

Jun 24, 1991

7/719805

Paul Kovacs - Memphis TN
James A. Davidson - Germantown TN

Smith & Nephew Richards, Inc. - Memphis TN

A61F 228, A61F 230, A61F 202, A61K 102

623 16

Passivated implants and passivation methods that provide superior corrosion resistance and surface performance characteristics as compared to conventional nitric acid passivation are disclosed. The method uses either the spontaneous or galvanic passivation of metallic prosthetic implants in aqueous alkali salt solutions containing non-aggressive oxyanions to produce a thin and uniform passive coating on the metal implant, thereby rendering the implant more stable in the biological environment.

5348026, Sep 20, 1994

Sep 29, 1992

7/953475

James A. Davidson - Germantown TN

Smith & Nephew Richards Inc. - Memphis TN

A61B 1900, A61F 202, A61F 228, A61F 230

128898

A bone screw and its method of manufacturing provides a low modulus osteoinductive bone screw with a high resistance to insertion torquing. The method includes the steps of pre-torquing a plurality of reinforcing fibers, molding a polymer matrix to bond with the pre-torqued fibers, and wherein the screw apparatus is coated with an osteoinductive material such as BMP, growth factors, hydroxyapatite or calcium phosphate.