Carl H Nelson

US Patent:

6652260, Nov 25, 2003

Filed:

Jun 12, 2001

Appl. No.:

09/879564

Inventors:

Carl Nelson - Little Rock AR
J. Marcus Hollis - Milton FL
Charlene Flahiff - Durham NC

Assignee:

The Board of Trustees of the University of Arkansas - Little Rock AR

International Classification:

B29C 4350

US Classification:

425398, 425408, 425422, 425436 R, 425436 RM

Abstract:

A press to form a composite acetabular allograft cup for use in hip replacement surgery is disclosed. The acetabular cup formed by the press comprises bone cement and cancellous bone chips. The press includes a two-piece mold for forming the acetabular cup. The mold is removable from the press and may be available in many different sizes to accommodate a range of patients. A screw-type compression means is utilized to force the acetabular cup into the desired shape. A compression gauge allows the operator to monitor the pressure applied as the acetabular cup is formed to prevent excessive crushing of cancellous bone chips. Breaking jaws are used to separate the acetabular cup from the upper portion of the mold after the bone cement has set and the acetabular cup is formed.

US Patent:

62939718, Sep 25, 2001

Filed:

Jun 29, 1999

Appl. No.:

9/343135

Inventors:

Carl Nelson - Little Rock AR
J. Marcus Hollis - Milton FL
Charlene Flahiff - North Little Rock AR
William Hogue - Little Rock AR

Assignee:

Board of Trustees of the University of Arkansas - Little Rock AR

International Classification:

A61F 234

US Classification:

623 2363

Abstract:

A composite allograft press comprises a loading frame and a two piece mold to form an composite allograft and in particular an acetabular cup from impacted cancellous bone chips and cement. Pressure is applied by a manually operated lever through a rack-and-pinion gear mechanism to a plunger attached to one part of the mold. Compression load switches in-line with the plunger indicate the correct loading to the mold to produce a composite allograft in which the inner surface is smooth and comprised essentially of hardened bone cement material. The outer portion of the allograft may have limited cement extrusions but the exterior of the cup primarily shows exposed cancellous bone surface. In surgery a composite allograft; e. g. , an acetabular cup, is fixed in the acetabulum with bone screws to fill an acetabular defect.

US Patent:

42850711, Aug 25, 1981

Filed:

Jul 2, 1979

Appl. No.:

6/054027

Inventors:

Carl L. Nelson - Little Rock AR
Darrel W. Haynes - Little Rock AR
Michael J. Weber - Little Rock AR

International Classification:

A61F 103

US Classification:

3 1912

Abstract:

A prosthetic cement spacer for controlling the thickness of cement applied between a prosthetic insert and a support member, such as an acetabulum, includes a generally cylindrical standoff body portion fabricated from acrylic bone cement and a pointed wire concentric with said standoff body and outwardly extending from one end a sufficient length to anchor into the acetabulum bone surface. The method of use of these prosthetic cement spacers involves preparation of the acetabulum so that there is sufficient clearance space for the prosthetic cement spacers and then to insert the pointed wires into the acetabulum bone surface in an equilateral triangular arrangement thereby providing three points of contact for the prosthetic insert, such as an acetabular cup. By selecting three prosthetic cement spacers all having substantially the same standoff body height, the clearance region between the acetabulum bone surface and the acetabular cup is controlled and provides a uniform cement thickness throughout thereby providing an improved bonding arrangement.

US Patent:

44175710, Nov 29, 1983

Filed:

Nov 10, 1980

Appl. No.:

6/205455

Inventors:

Carl L. Nelson - Little Rock AR
Darrel W. Haynes - Little Rock AR
Michael J. Weber - Little Rock AR

International Classification:

A61F 124

US Classification:

128 92B

Abstract:

A prosthetic cement spacer for controlling the thickness of cement applied between a prosthetic insert and a support member, such as an acetabulum, includes a generally cylindrical standoff body portion fabricated from acrylic bone cement and a pointed wire concentric with said standoff body and outwardly extending from one end a sufficient length to anchor into the acetabulum bone surface. The method of use of these prosthetic cement spacers involves preparation of the acetabulum so that there is sufficient clearance space for the prosthetic cement spacers and then to insert the pointed wires into the acetabulum bone surface in an equilateral triangular arrangement thereby providing three points of contact for the prosthetic insert, such as an acetabular cup. By selecting three prosthetic cement spacers all having substantially the same standoff body height, the clearance region between the acetabulum bone surface and the acetabular cup is controlled and provides a uniform cement thickness throughout thereby providing an improved bonding arrangement.

US Patent:

58240780, Oct 20, 1998

Filed:

Mar 11, 1996

Appl. No.:

8/647424

Inventors:

Carl Nelson - Little Rock AR
J. Marcus Hollis - Milton FL
Charlene Flahiff - North Little Rock AR
William Hogue - Little Rock AR

Assignee:

The Board of Trustees of The University of Arkansas - Little Rock AR

International Classification:

A61F 200
B30B 1514

US Classification:

623 66

Abstract:

A composite allograft press comprises a loading frame and a two piece mold to form an composite allograft and in particular an acetabular cup from impacted cancellous bone chips and cement. Pressure is applied by a manually operated lever through a rack-and-pinion gear mechanism to a plunger attached to one part of the mold. Compression load switches in-line with the plunger indicate the correct loading to the mold to produce a composite allograft in which the inner surface is smooth and comprised essentially of hardened bone cement material. The outer portion of the allograft may have limited cement extrusions but the exterior of the cup primarily shows exposed cancellous bone surface. In surgery a composite allograft; e. g. , an acetabular cup, is fixed in the acetabulum with bone screws to fill an acetabular defect.

US Patent:

59818280, Nov 9, 1999

Filed:

Jul 24, 1998

Appl. No.:

9/121938

Inventors:

Carl Nelson - Little Rock AR
J. Marcus Hollis - Milton FL
Charlene Flahiff - North Little Rock AR
William Hogue - Little Rock AR

Assignee:

Board of Trustees of the University of Arkansas - Little Rock AR

International Classification:

A61F 228
A61F 232

US Classification:

623 16

Abstract:

A composite allograft press comprises a loading frame and a two piece mold to form an composite allograft and in particular an acetabular cup from impacted cancellous bone chips and cement. Pressure is applied by a manually operated lever through a rack-and-pinion gear mechanism to a plunger attached to one part of the mold. Compression load switches in-line with the plunger indicate the correct loading to the mold to produce a composite allograft in which the inner surface is smooth and comprised essentially of hardened bone cement material. The outer portion of the allograft may have limited cement extrusions but the exterior of the cup primarily shows exposed cancellous bone surface. In surgery a composite allograft; e. g. , an acetabular cup, is fixed in the acetabulum with bone screws to fill an acetabular defect.