Howmedica Corp.

Pfizer Hospital Products Group, Inc.

Pfizer Corporation

Robert V Kenna

Kenneth A Krackow

David S Hungerford

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.

Bone prosthesis with porous coating

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.

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.

Self-locking joint connector

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.

Modular prosthesis

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. The porous coating described provides superior resistance to failure at the coating-substrate and coating-bone interfaces, without weakening the prosthesis. The porous coating disclosed is also suitable for use in other canine bone prostheses.

Canine hip prosthesis

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.

Method and instrumentation for the replacement of a knee prosthesis

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.

Prosthetic knee joint with improved patellar component tracking

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.

Anterior cruciate ligament prosthesis

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.

Prosthetic knee implantation

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.

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.

Acetabular cup assembly

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.

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Hackensack, NJ, United States of America

Robert V Kenna