Evaluating the fit of an orthopaedic implant

• US 5,989,261 A
• Filed: 07/29/1997
• Issued: 11/23/1999
• Est. Priority Date: 03/13/1997
• Status: Expired due to Term

• Current Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Ltd (Zimmer Biomet Holdings, Inc.)
• Inventors: Heldreth, Mark Alan, McGinley, Shawn Elliott, Zawadzki, Steven A., Walker, Peter Stanley, Blamey, Jonathan, Wadcock, Michael, Insall, John Nevil
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): REIP, DAVID OWEN
• Application Number:
  US08/898,360
• Time in Patent Office: 847 Days
• Field of Search: 606/79, 606/85, 606/86, 606/87, 606/88, 606/102, 623/16, 623/18, 623/20
• US Class Current: 606/102
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/3872 Meniscus for implantation between the natural bone surfaces
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30393 with additional means for limiting said rotation
• CPC Class Codes: A61F 2002/304 with additional means for limiting said sliding
• 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 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0034 D-shaped

Abstract

The invention provides means for evaluating the fit of a knee replacement prosthesis on a resected tibial surface. A provisional instrument for this purpose includes a positioning tray having a peripheral profile corresponding to that of the tibial platform of the prosthesis, the tray having an upper surface and an under surface which is substantially flat and free from projections and the tray having a plurality of holes for receiving pins for temporarily attaching the positioning tray in a desired position on the resected tibial surface. Also disclosed is a jig for guiding, drilling and broaching operations, the jig having an aperture which is shaped to guide the broach. In addition, the invention includes a tibial broach which includes a hollow body having an upper end and a lower end and having an anvil at its upper end, an interior face and a posterior face which slopes downwardly towards a lower end, the posterior face having a series of teeth which are formed in the hollow body, such that bone cut by the teeth as the broach is driven into an intramedullary canal of a tibia passes into the hollow body.

Claims

1. A provisional instrument component for evaluating the fit of a knee replacement prosthesis on a resected tibial surface, said component comprising a positioning tray having a peripheral profile corresponding to that of a tibial platform of the prosthesis, the tray having an upper surface and an under surface which is substantially flat and free from projections and said tray having a plurality of holes for receiving pins for temporarily attaching the positioning tray in a desired position on said resected tibial surface, wherein a boss is carried on the upper surface of the tray for guiding a temporary plastics meniscal bearing component on said upper surface with freedom of movement in the anterior-posterior direction.

2. An instrument kit for fitting and evaluating the fit of a knee replacement prosthesis on a resected tibial surface, which comprises a tibial sizing and positioning tray having a plurality of holes therein for receiving pins for temporarily attaching the positioning tray in a desired position on said resected tibial surface and a jig for a tibial broach having a peripheral profile which corresponds with said positioning tray and having locating holes which correspond with the holes in said positioning tray, the jig also having an aperture which is shaped to guide the broach, the positioning tray having a peripheral profile corresponding to that of the tibial platform of the prosthesis, the tray having an upper surface and an under surface which is substantially flat and free from projections.

3. A tibial broach which comprises a hollow body having an upper end and a lower end, the hollow body being closed at its upper end and having an open lower end whose edges are sharpened, said hollow body having an anterior face and a posterior face which slopes downwardly and inwardly towards said lower end, wherein said posterior face is formed with a series of teeth adapted to cut bone on driving the broach into a tibia, said posterior face having apertures permitting bone cut by the teeth to enter the hollow body.

4. A broach as claimed in claim 3 wherein said hollow body has substantially parallel lower lateral and medial faces and upper lateral and medial faces which slope upwardly and outwardly towards the upper end of the lower body, the upper lateral and medial faces being formed with cutting teeth.