Leaflike shaft of a hip-joint prosthesis for anchoring in the femur

• US 7,494,510 B2
• Filed: 05/12/2006
• Issued: 02/24/2009
• Est. Priority Date: 04/13/2000
• Status: Expired due to Fees

• Current Assignee: Smith & Nephew Orthopaedics Ag (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Orthopaedics Ag (Smith & Nephew PLC)
• Inventors: Zweymuller, Karl
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US11/433,067
• Publication Number:
  US 20060276904A1
• Time in Patent Office: 1,019 Days
• Field of Search: 623 2315- 2347
• US Class Current: 623/23.35
• 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: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• 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 2/3676 Distal or diaphyseal parts of shafts
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30159 Concave polygonal shapes
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30176 V-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30205 conical
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/3082 Grooves
• CPC Class Codes: A61F 2002/30828 parallel
• CPC Class Codes: A61F 2002/30831 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3625 Necks
• CPC Class Codes: A61F 2002/365 : Connections of heads to necks
• 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 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0054 : V-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0067 : conical

Abstract

The present invention relates in certain embodiments to components of a hip-joint prosthesis. More particularly, embodiments of the invention relate to a leaf-like femoral shaft for use as part of a hip-joint prosthesis, and instruments (e.g., a rasp) and methods for implanting the shaft. The shaft includes an anchoring section extending between a proximal region and a distal end of the shaft. The shaft has a cross-sectional contour that defines a lateral side, a medial side, an anterior side and a posterior side. A corresponding rasp is preferably provided for each femoral shaft. The rasp is inserted into the femur to form a cavity having generally the same configuration as the rasp. The shaft is configured to be over-dimensioned in at least one of the anterior-posterior direction and medial-lateral direction relative to the rasped femur cavity. In one embodiment, the distance between diagonally opposite corner junctions of the shaft is substantially equal to the distance between corresponding diagonally opposite corner junctions of the femur cavity, so as to inhibit excess stress on the corticalis.

Claims

1. A hip-joint endoprosthesis system comprising:

a rasp configured for forming a cavity in a femur having substantially the same configuration as the rasp, the rasp having an anterior face, a posterior face generally opposite the anterior face, a lateral face, and a medial face generally opposite the lateral face, a distance between the anterior and posterior faces defining a first dimension, a distance between the lateral and medial faces defining a second dimension, each of the rasp faces disposed adjacent another of the rasp faces and defining an edge therebetween; and

a shaft configured to be anchored in the cavity, the shaft having an anchoring section extending between a proximal region and a distal end of the shaft, the anchoring section defining an anterior face, a posterior face generally opposite the anterior face, a lateral face, and a medial face generally opposite the lateral face, a distance between the anterior and posterior faces defining a third dimension, a distance between the lateral and medial faces defining a fourth dimension, each of the shaft faces being adjacent another of the shaft faces and defining a junction therebetween said junction being a concave facet, wherein the third dimension is greater than the first dimension.

2. The system of claim 1, wherein the third dimension is over-dimensioned relative to the first dimension by between about 1% and 3%.

3. The system of claim 1, wherein the third dimension is over-dimensioned relative to the first dimension by between about 5% and 15%.

4. The system of claim 3, wherein the third dimension is over-dimensioned relative to the first dimension by between about 8% and about 12%.

5. The system of claim 4, wherein the third dimension is over-dimensioned relative to the first dimension by about 10%.

6. The system of claim 5, wherein the fourth dimension is substantially equal to the second dimension.

7. The system of claim 1, wherein a dimension between diagonally opposite edges of the rasp is substantially equal to a dimension between diagonally opposite junctions of the shaft.