Femoral neck fixation prosthesis

• US 20040162621A1
• Filed: 02/14/2004
• Published: 08/19/2004
• Est. Priority Date: 04/11/2002
• Status: Abandoned Application

• Current Assignee: Theodore W. Crofford
• Original Assignee: Theodore W. Crofford
• Inventors: Crofford, Theodore W.
• Application Number:
  US10/779,353
• Publication Number:
  US 20040162621A1
• Time in Patent Office: Days
• US Class Current: 623/22.43
• CPC Class Codes: A61B 17/175 for preparing the femur for hip prosthesis insertion
• CPC Class Codes: A61B 17/74 Devices for the head or neck or trochanter of the femur trochanteric devices connected to the proximal part of an endoprosthetic femoral shaft A61F2/30739; endoprosthetic internal fixation devices for the head or neck of the femur A61F2/3601
• CPC Class Codes: A61B 17/742 having one or more longitudinal elements oriented along or parallel to the axis of the neck
• CPC Class Codes: A61B 17/8665 Nuts
• CPC Class Codes: A61B 17/8695 Washers surrounding screw head in plate hole A61B17/8047, between bone plate and bone A61B17/8028
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3601 for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices non-prosthetic internal fixation devices for the femoral head or neck A61B17/74
• CPC Class Codes: A61F 2/4607 of hip femoral endoprostheses
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30339 Double cones, i.e. connecting element having two conical connections, one at each of its opposite ends
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30535 Special structural features of bone or joint prostheses not otherwise provided for
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• 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 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2002/4658 : for measuring dimensions, e.g. length
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0058 : Additional features; Implant or prostheses properties not otherwise provided for
• 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

Abstract

A femoral neck fixation prosthesis and method of using same which reduces bone loss and the avoids the other shortcomings of the prior art by allowing the fixation of a stable femoral head replacement while reducing the amount of the femur which must be reamed for the insertion of the prosthesis. The preferred embodiment provides that the femoral head is attached to a fixation prosthesis which extends coaxially through the canal of the femoral neck, into the femur, and is then attached to the opposite lateral wall of the femur. In this manner, the prosthesis serves to imitate the original structure of the femoral neck. No other support members, either crosspins or arms extending into the length of the femur, are required.

Claims

1. An implant for replacing the proximal portion of a femur having a substantially intact natural femoral neck and a lateral side opposite the femoral neck, the implant comprising:

a solid body member having a longitudinal axis, a distal end, and a proximal end, being configured for positioning, in use, in the natural femoral neck;

a head member having a distal end and a proximal substantially-spherical portion configured for positioning in a natural or prosthetic hip socket;

a joining member positioned between the distal end of the head member and the proximal end of the body member; and

a fastener for insertion, in use, between the distal end of the body member and the exterior of the lateral side of the femur, substantially in line with the longitudinal axis of the solid body member,

wherein no other fasteners pass within or through the femur.

2. The implant of claim 1, wherein the solid body member has a length for positioning, in use, in the natural femoral neck without passage of the distal end through the lateral side of the femur.

3. The implant of claim 1, wherein the body member comprises a collar positioned at the proximal end of the body member and configured for abutting contact, in use, with a proximal surface of the resected femoral neck.

4. The implant of claim 1 wherein the body member, the head member, and the joining member are integrally attached.

5. The implant of claim 1 wherein the body member and the joining member are an integral unit.

6. The implant of claim 1 wherein the joining member comprises at least one morse-tapered portion.

7. The implant of claim 1 wherein the joining member comprises a first morse-tapered portion which extends into a cavity in the head member and a second morse-tapered portion which extends into a cavity in the solid body member, both of the morse-tapered portions extending in substantial coaxial alignment relative to the longitudinal axis of the body member.

8. The implant of claim 1 wherein the body member, the head member, and the joining member are separable modular components.

9. The implant recited in claim 1 wherein the fastener comprises a barrel nut located at the exterior lateral side of the femur and a compression screw extending between the solid body member and the barrel nut.

10. The implant recited in claim 1 wherein the fastener comprises compression screw extending between the exterior lateral side of the femur and the solid body member.

11. The implant of claim 1 further comprising a first surface coating on at least a portion of the body member for promoting bone ingrowth into the coating following implantation.

12. The implant of claim 1, wherein the distal end of the solid body member is configured to connect with the fastener.

13. The implant of claim 1 further comprising a body extension member which extends from the distal end of the solid body member at least partially along the fastener, and which is in substantial coaxial alignment relative to the longitudinal axis of the body member.

14. The implant of claim 1 wherein at least a portion of the body member is triangular in cross section.

15. The implant of claim 1 wherein at least a portion of the body member is fluted in cross section.

16. The implant of claim 1 wherein at least a portion of the body member is scalloped in cross section.

17. The implant of claim 1 wherein at least a portion of the body member is substantially circular in cross section.

18. The implant of claim 1 wherein at least a portion of the body member is oval in cross section.

19. The implant of claim 1 wherein no additional support member is attached to the lateral side of the femur.