Patents by Inventor Robert V. Kenna

Robert V. Kenna has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5441537
    Abstract: An improved metallic bone prosthesis having a porous coating for bone ingrowth or interlocking with bone cement is disclosed. The porous coating comprises two layers of generally ball-shaped metallic particles bonded together at their points of contact, e.g. by sintering, and defining between them a plurality of connected interstitial pores having an average pore size of from about 350 microns to about 500 microns. A high resistance to failure at the coating-substrate and bone-coating (or cement-coating) interfaces is achieved with the use of the improved prosthesis. Also disclosed are a novel method for affixing the porous coating to a metal substrate, and a knee joint prosthesis having bearing portions designed so that the function of said prosthesis closely approximates that of the natural knee.
    Type: Grant
    Filed: December 4, 1992
    Date of Patent: August 15, 1995
    Assignee: Howmedica Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5320115
    Abstract: A surgical method for arthroscopic repair or replacement of the anterior cruciate ligament is disclosed. A preferred embodiment of the method generally includes forming osseous tunnels in the tibia and femur, opening into the intercondylar region. A patellar tendon graft is harvested from the knee, having bone plugs naturally attached to each end. The graft is secured in the osseous tunnels by an interference fit with a bone screw inserted between the tunnel walls and the bone plugs. Specialized instrumentation for performing the method steps is also disclosed. Such instrumentation includes: a combination drill for cutting an osseous tunnel and harvesting a bone core, an intercondylar guide for locating a pilot hole on the femoral condyle, single-fluted and multi-fluted hand and power reamers for forming an osseous tunnel, and a work station for facilitating preparatory steps performed on graft material.
    Type: Grant
    Filed: January 16, 1991
    Date of Patent: June 14, 1994
    Assignee: Applied Biological Concepts
    Inventor: Robert V. Kenna
  • Patent number: 5192324
    Abstract: An improved metallic bone prosthesis having a porous coating for bone ingrowth or interlocking with bone cement is disclosed. The porous coating comprises two layers of generally ball-shaped metallic particles bonded together at their points of contact, e.g. by sintering, and defining between them a plurality of connected interstitial pores having an average pore size of from about 350 microns to about 500 microns. A high resistance to failure at the coating-substrate and bone-coating (or cement-coating) interfaces is achieved with the use of the improved prosthesis. Also disclosed are a novel method for affixing the porous coating to a metal susbstrate, and a knee joint prosthesis having bearing portions designed so that the function of said prosthesis closely approximates that of the natural knee.
    Type: Grant
    Filed: January 2, 1990
    Date of Patent: March 9, 1993
    Assignee: Howmedica Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5151104
    Abstract: A device suitable for use in a wide variety of types of joints of the body of a human or other mammal is provided. The device is especially useful for implantation into the human femur so as to repair an anterior cruciate ligament. The device is self-locking and can be used to connect two parts of a joint together by means of an artificial ligament (if desired) or by means of a biological graft (either allegraft or autogenous, including bone with a natural tendon attached thereto). The device permits the surgeon very simply to do a revision from such a mechanical ligament to a biological graft or vice-versa, as desired; that is, the device of the invention is fully revisable. A method of connecting two parts of a joint is also given.
    Type: Grant
    Filed: October 26, 1989
    Date of Patent: September 29, 1992
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5108437
    Abstract: A modular prosthesis features at least one male-female fitting, with the female portion being located on one end of one segment of that prosthesis and the mating male portion being located on one end of a second prosthesis segment, with at least the proximal part of the male-female fitting having a taper. The two parts of that fitting can be locked together by a locking mechanism in the form of a novel spacer which also has a taper which mates with the taper of the male-female fitting described above. Multiple modular segments can be assembled together so as to produce a prosthesis as required by the patient.
    Type: Grant
    Filed: September 14, 1988
    Date of Patent: April 28, 1992
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5047056
    Abstract: A canine hip prosthesis with a porous coating for bone ingrowth is disclosed. The femoral prosthesis generally comprises a stem for insertion into the intramedullary canal of a canine femur which stem is divided into a proximal portion and a longer distal portion. The stem exhibits a compound curvature along its length, including a slight posterior bow, which provides the prosthesis with a glove-like fit in the prepared intramedullary canal of the canine femur. Provided on the proximal portion of the stem is a porous coating which generally comprises two layers of ball-shaped metallic particles bonded together at their points of contact, e.g. by sintering, which define between themselves a plurality of connected interstitial pores. The size of the particles is from -30 to +35 U.S. Standard mesh size, and the pore size is between about 0.014 and 0.020 inches.
    Type: Grant
    Filed: February 16, 1990
    Date of Patent: September 10, 1991
    Assignee: Pfizer, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5037423
    Abstract: A novel method for replacing a previously implanted knee joint prosthesis in a patient is disclosed in which the previously implanted femoral component is replaced with a revision femoral component having thicker distal and posterior bearing portions so as to restore the natural anatomic transverse joint plane and collateral ligamentous balance in extension and flexion of the prosthetic joint. Instrumentation for use in this method includes a novel revision cutting jig which is used in the preparation of the distal end of the femur for the implantation of the revision femoral component.
    Type: Grant
    Filed: May 7, 1990
    Date of Patent: August 6, 1991
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 5035700
    Abstract: A three-component knee joint prosthesis is disclosed including femoral, tibial and patellar components. During flexion of the prosthetic knee, the patellar component, which has a convex bearing surface, cooperates with and is guided by a patellar track defined by the anterior plate portion, lateral condylar bearing portion and medial condylar bearing portion of the femoral component and a web portion joining the two femoral condylar bearing portions. The inner regions of the two femoral condylar bearing portions are steeply sloped towards the web portion to permit the patellar component to "ride deeply" upon the femoral component at high degrees of flexion, thereby reducing quadriceps tension and expanding the permissible range of motion in flexion.
    Type: Grant
    Filed: July 6, 1990
    Date of Patent: July 30, 1991
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4944760
    Abstract: A novel method for replacing a previously implanted knee joint prosthesis in a patient is disclosed in which the previously implanted femoral component is replaced with a revision femoral component having thicker distal and posterior bearing portions so as to restore the natural anatomic transverse joint plane and collateral ligamentous balance in extension and flexion of the prosthetic joint. Instrumentation for use in this method includes a novel revision cutting jig which is used in the preparation of the distal end of the femur for the implantation of the revision femoral component.
    Type: Grant
    Filed: October 26, 1983
    Date of Patent: July 31, 1990
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4944756
    Abstract: A three-component knee joint prosthesis is disclosed including femoral, tibial and patellar components. During flexion of the prosthetic knee, the patellar component, which has a convex bearing surface, cooperates with and is guided by a patellar track defined by the anterior plate portion, lateral condylar bearing portion and medial condylar bearing portion of the femoral component and a web portion joining the two femoral condylar bearing portions. The inner regions of the two femoral condylar bearing portions are steeply sloped towards the web portion to permit the patellar component to "ride deeply" upon the femoral component at high degrees of flexion, thereby reducing quadriceps tension and expanding the permissible range of motion in flexion.
    Type: Grant
    Filed: February 3, 1988
    Date of Patent: July 31, 1990
    Assignee: Pfizer Hospital Products Group
    Inventor: Robert V. Kenna
  • Patent number: 4834756
    Abstract: An improved metallic bone prosthesis having a porous coating for bone ingrowth or interlocking with bone cement is disclosed. The porous coating comprises two layers of generally ball-shaped metallic particles bonded together at their points of contact, e.g. by sintering, and defining between them a plurality of connected interstitial pores having an average pore size of from about 350 microns to about 500 microns. A high resistance to failure at the coating-substrate and bone-coating (or cement-coating) interfaces is achieved with the use of the improved prosthesis. Also disclosed are a novel method for affixing the porous coating to a metal substrate, and a knee joint prosthesis having bearing portions designed so that the function of said prosthesis closely approximates that of the natural knee.
    Type: Grant
    Filed: October 15, 1985
    Date of Patent: May 30, 1989
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4828562
    Abstract: An adjustable housing suitable to be used with another housing and with a synthetic ligament so as to provide (for example) an anterior cruciate ligament prosthesis system for a knee joint is provided. The adjustable housing features an interior having a step shoulder located therein. A set screw in the housing fixes the synthetic ligament at a desired level of tension. The system has many significant advantages including (but not limited to) being able to withstand very high loads and being able to be retensioned repeatedly and easily without replacing the artificial ligament.
    Type: Grant
    Filed: February 4, 1988
    Date of Patent: May 9, 1989
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4825857
    Abstract: A tool for use in preparing a distal femur for the implantation of a prosthetic knee includes a central section having at least one handle. A positioning pin extends outwardly from the central section. A distal femoral condyles cutting jig is selectively connected to the central section.
    Type: Grant
    Filed: March 10, 1986
    Date of Patent: May 2, 1989
    Assignee: Howmedica, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4787383
    Abstract: A prosthetic knee is implanted after cutting the femor and tibia in the proper manner with the aid of instruments which include axial alignment guides and a series of cutting jigs.
    Type: Grant
    Filed: January 16, 1987
    Date of Patent: November 29, 1988
    Assignee: Howmedica, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4784663
    Abstract: A three-component acetabular cup assembly for receiving and releasably retaining the femoral head component of a prosthesis, said cup assembly comprising an outer metal shell, a cup-shaped inner bearing of substantially rigid plastic fixedly secured within said metal shell, and a locking ring made from the same plastic as the inner bearing; the outer surface of the bearing and the inner surface of the locking ring having cooperating configurations forming a secure but releasable latch.
    Type: Grant
    Filed: November 30, 1987
    Date of Patent: November 15, 1988
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4755183
    Abstract: A prosthesis for an anterior cruciate ligament features first and second elongate members, first and second separately tensionable cords, a catch means on the bore surface of each elongate member, and a means for securing the elongate members to the femur and tibia, respectively. The prosthesis has the significant advantage of being able to replace and to perform in substantially the same manner as a natural anterior cruciate ligament. The separate tensioning followed by fixing of the two cords in the implanted prosthesis results in a substantially smoother and more stable range of motion than has been possible with prior art prostheses.
    Type: Grant
    Filed: February 9, 1987
    Date of Patent: July 5, 1988
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4718911
    Abstract: A three-component acetabular cup assembly for receiving and releasably retaining the femoral head component of a prosthesis, said cup assembly comprising an outer metal shell, a cup-shaped inner bearing of substantially rigid plastic fixedly secured within said metal shell, and a locking ring made from the same plastic as the inner bearing; the outer surface of the bearing and the inner surface of the locking ring having cooperating configurations forming a secure but releasable latch.
    Type: Grant
    Filed: February 19, 1986
    Date of Patent: January 12, 1988
    Assignee: Pfizer Hospital Products Group Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4714469
    Abstract: A spinal implant adapted to replace a disc between adjacent vertebrae having a predetermined thickness and profile chosen to match the space between said vertebrae and characterized by elongated protuberances adapted to be located in grooves drilled in said vertebrae and a porous coating on at least a portion of its surface. A method and apparatus for placement of said spinal implant are also disclosed.
    Type: Grant
    Filed: February 26, 1987
    Date of Patent: December 22, 1987
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4666450
    Abstract: An acetabular cup assembly prosthesis comprises the combination of a support shell for introduction into an acetabulum and a socket insert in nesting engagement within the shell. The shell has a generally hemispherical outer surface and a downwardly extending concavity surrounded by a peripheral rim, At least one anchoring post secures the shell to the acetabulum, and a central opening in the bottom of the concavity serves as a connection location for the socket insert. The insert has a hemispherical concavity that articulates with the rounded head of a femoral prosthesis, while the outer surface of the insert nests within the concavity of the support shell. A central fastening tab extends from the insert into locking engagement with the opening in the support shell, and structure is provided to prevent relative rotation of the shell and insert.
    Type: Grant
    Filed: August 26, 1983
    Date of Patent: May 19, 1987
    Assignee: Pfizer Hospital Products Group, Inc.
    Inventor: Robert V. Kenna
  • Patent number: 4653488
    Abstract: A prosthetic knee is implanted after cutting the femor and tibia in the proper manner with the aid of instruments which include axial alignment guides and a series of cutting jigs.
    Type: Grant
    Filed: November 19, 1985
    Date of Patent: March 31, 1987
    Assignee: Howmedica, Inc.
    Inventors: Robert V. Kenna, David S. Hungerford, Kenneth A. Krackow