ACETABULAR CUP PROSTHESIS

• US 3,840,904 A
• Filed: 04/30/1973
• Issued: 10/15/1974
• Est. Priority Date: 04/30/1973
• Status: Expired due to Term

• Current Assignee: Raymond G. Tronzo
• Original Assignee: Raymond G. Tronzo
• Inventors: Tronzo, Raymond G.
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Frinks, Ronald L.
• Application Number:
  US05/355,875
• Time in Patent Office: 533 Days
• Field of Search: 3/1 128/92C,92CA,92BA,92BB,92BC,92D
• US Class Current: 623/22.32
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30176 V-shaped
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/3054 about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30845 with cutting edges
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/3412 with pins or protrusions, e.g. non-sharp pins or protrusions projecting from a shell surface
• CPC Class Codes: A61F 2002/342 the outer shell having circumferential protrusions parallel to the equatorial plane, e.g. circumferential fins or wings
• CPC Class Codes: A61F 2002/3425 the outer shell having non-meridian protrusions, e.g. fins or wings, located in planes inclined or perpendicular with respect to the equatorial plane
• CPC Class Codes: A61F 2002/3429 with an integral peripheral collar or flange, e.g. oriented away from the shell centre line
• CPC Class Codes: A61F 2002/4619 for extraction
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2310/00011 Metals or alloys

Abstract

An acetabular cup prosthesis which has facilities for ready removal. In one form it has grooves to guide a surgical saw on the inside, preferably to cut the prosthesis in quadrants for removal, and also having threaded sockets to insert a tool to remove the quadrants. Additionally or alternatively, it has protrusions from its rear not adapted to offer much resistance in case of removal. In the preferred form two blades protrude from the rear and are offset, so that they come to a point and also form a knife edge at the side. Outrigger blades are provided extending perpendicular to the diameter and terminating at a less height than the radius. In the preferred form the rear of the prosthesis has a porous coating and also the blades have a porous coating. In alternate forms, spikes extend from the rear of the prosthesis offset and in parallel relation, either from one side in a cluster or from one side distributed over that side. In another form there is a screw which extends from the rear end offset to the axis of symmetry. In another form there are blades which lie along the rear, for example parallel to one another and parallel to the diameter or at right angles to the diameter.

Claims

1. An acetabular cup prosthesis including a cup shaped insertion and a guide groove across the inside of the insertion at substantially diametrical distance for a surgical saw by which it can be cut up for removal.

2. An acetabular cup prosthesis of claim 1, having guide grooves at the inside surface which are of substantially diametrical length and of cruxiform formation.

3. An acetabular cup prosthesis of claim 2, having in each quadrant of the cup a threaded opening for receiving a threaded extraction tool, the openings being near the center of the cup.

4. An acetabular cup prosthesis of claim 2, having converging blades from the back of the cup diminishing in size away from the cup and the blades having a common edge and making a V in cross-section.