Tibial implant for a knee prosthesis

• US 5,658,341 A
• Filed: 01/09/1995
• Issued: 08/19/1997
• Est. Priority Date: 03/10/1993
• Status: Expired due to Fees

• Current Assignee: Medinov SA
• Original Assignee: Medinov SA
• Inventors: Delfosse, Jacques
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/331,521
• Time in Patent Office: 953 Days
• Field of Search: 623/16, 623/18, 623/19, 623/20, 623/22, 623/23
• US Class Current: 623/20.32
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• 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 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws

Abstract

A tibial implant for knee prosthesis has a tibial socket (1) accepting a tibial plate (2) notably in polyethylene. The tibial socket (1) has a recess (1a) with a shape and section chosen to allow, from the upper face of said socket (1), the engagement, centering and holding in place, with the capability of angular orientation, of an anchoring and/or stabilizing pin with fins (3).

Claims

1. A tibial implant for a knee prosthesis comprising:

a tibial socket configured to accept a polyethylene trial plate; and

, an elongated pin for anchorage in the bone and for supporting the tibial implant, said pin terminating at opposite ends wherein a head portion is formed at one end, said head portion having radial stabilizing fins extending outwardly from said pin;

said tibial socket having a conical wall with a recess formed therein defining an internal counterbore and slits formed in said wall wherein said socket is configured to receive said head and said stabilizing fins of said pin;

said head having a threaded internal counterbore formed therein for accepting a screw and having vertical slits formed around said counterbore;

said screw having a flattened cone-shaped head with a section that conmmnicates with said internal counterbore such that insertion of the screw into the pin causes diametric expansion of the head which securely and rigidly binds the pin to the tibial socket.

2. The tibial implant of claim 1, wherein the tibial socket further comprises a protuberance projecting from a lower face of said tibial socket at the recess in said tibial socket.

3. The tibial implant of claim 1, wherein the protuberance has a flattened cone-shaped extension.

4. The tibial implant of claim 1, wherein the recess and the head are substantially circular in shape.

5. The tibial implant of claim 1, wherein the tibial socket has through holes to facilitate insertion of spongy bone screws for fixing the tibial socket.

6. The tibial implant of claim 1, wherein the tibial socket has a peripheral rim;

wherein the tibial plate has a peripheral collar; and

wherein said peripheral rim engages said peripheral collar for snap fitting of said tibial plate to said tibial socket.