Prosthetic device and method of implantation

• US 5,863,295 A
• Filed: 04/18/1997
• Issued: 01/26/1999
• Est. Priority Date: 06/01/1994
• Status: Expired due to Term

• Current Assignee: Zimmer Trabecular Metal Technology, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Implex Corp. (Consorteum Holdings, Inc.)
• Inventors: Averill, Robert G., Zubok, Rafail, Cohen, Robert C.
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/844,443
• Time in Patent Office: 648 Days
• Field of Search: 606/80, 606/85, 623/22, 623/23
• US Class Current: 128/898
• CPC Class Codes: A61B 17/16 Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans arthroscopic bone cutters A61B17/320016; dental implant drills potentially for other surgical use A61C8/0089; bone grinders A61F2/4644, A22C17/06; A61B17/1662 takes precedence over all other subgroups except A61B17/17
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence
• CPC Class Codes: A61B 17/1684 for the shoulder
• CPC Class Codes: A61F 2/30734 Modular inserts, sleeves or augments, e.g. placed on proximal part of stem for fixation purposes or wedges for bridging a bone defect
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30879 Ribs
• CPC Class Codes: A61F 2002/30909 Nets
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/3625 Necks
• CPC Class Codes: A61F 2002/3631 with an integral complete or partial peripheral collar or bearing shoulder at its base
• CPC Class Codes: A61F 2002/365 Connections of heads to necks
• CPC Class Codes: A61F 2230/0008 elliptical or oval
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00413 Coating made of cobalt or of Co-based alloys
• CPC Class Codes: A61F 2310/00796 Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A hip prosthesis for implanting into the medullary canal of a femur, which comprises a stem for implanting into the canal of the femur, the stem having a proximal end and a distal end, the stem also including a proximal locking zone substantially adjacent the proximal end, the proximal locking zone including a proximal locking surface which circumferentially press-fits within the canal of the femur and a neck extending at an angle from the proximal end of the stem for receiving the femoral head of the prosthesis.

Claims

1. A method for implanting a prothesis stem having a proximal and a distal end into a medullary canal of a femur, said prothesis stem having a proximal locking zone substantially adjacent said proximal end which presents a geometric profile for press-fit engagement within said canal, said method comprising the steps of:

a) resecting a head and neck portion of said femur;

b) reaming a bore along said medullary canal of said femur;

c) inserting a trial implant into said bore to prepare said bore for said geometric profile of said proximal locking zone of said stem, wherein said proximal locking zone of said stem is substantially adjacent said proximal end of said stem and having a geometric profile substantially similar to and of a size less than said geometric profile of said prosthesis stem, wherein said proximal locking zone includes an outwardly flared circumferential proximal locking surface which extends about said proximal end of said stem, said proximal locking surface circumferentially press-fits within the canal of the femur, wherein said outwardly flared circumferential proximal locking surface includes a first planar locking surface on an anterior side of said prosthesis, a second planar locking surface on a posterior side of said prosthesis, and a convex locking surface extending between and merging into said first and second planar locking surfaces on a lateral side of said prosthesis;

d) removing said trial implant from said bore; and

e) inserting said prosthesis stem into said bore, said proximal locking zone of said prosthesis stem engaging said bore in a press-fit engagement to securely lock said prosthesis stem into said bore in said medullary canal of said femur.

2. The method according to claim 1, wherein said step of reaming includes a first reaming with a first cylindrical reamer of a given diameter.

3. The method according to claim 2, wherein said step of reaming further includes a second reaming with a tapered reamer after said first reaming, to prepare said bore for said geometric profile of said prosthesis stem.

4. The method according to claim 2, wherein said step of reaming includes a second reaming with a second cylindrical reamer having a diameter substantially greater than said diameter of said first cylindrical reamer.

5. The method according to claim 4, wherein said step of reaming further includes a third reaming with a tapered reamer after said second reaming, to prepare said bore for said geometric profile of said prosthesis stem, and wherein said trial implant includes a proximal locking zone which presents a geometric profile substantially like said geometric profile of said locking zone of said stem, said geometric profile of said trial implant being of a size which is slightly less than a size of said geometric profile of said stem.

6. The method according to claim 1 wherein said proximal locking surfaces of said trial implant are recessed and bounded by a circumferentially extending proximal ridge and a circumferentially extending distal ridge.