Cement-less type artificial joint stem with the use of composite material

• US 20060184250A1
• Filed: 10/09/2003
• Published: 08/17/2006
• Est. Priority Date: 10/09/2003
• Status: Abandoned Application

• Current Assignee: BI Tec Limited
• Original Assignee: BI Tec Limited
• Inventors: Bandoh, Shunichi, Zako, Masaru
• Application Number:
  US10/545,082
• Publication Number:
  US 20060184250A1
• Time in Patent Office: Days
• US Class Current: 623/23.320
• CPC Class Codes: A61F 2/30723 Plugs or restrictors for sealing a cement-receiving space tools for inserting plugs A61F2/4614; sealing collars for use during cementing A61B17/8808
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30828 parallel
• 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 2002/30892 parallel
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/30952 : using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• 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 2002/3686 : bent
• CPC Class Codes: A61F 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2210/0071 : thermoplastic
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0026 : differing in surface structures
• CPC Class Codes: A61F 2250/0029 : differing in bending or flexure capacity
• 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 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

This invention provides cement-less type artificial joint stems with the use of complex material which can be connected to bone without using cement, does not get loose over a long period of time, has excellent durability, and has appropriate external form and stiffness to meet the condition of each patient. Stem 1 with the use of composite material inserted in the insertion hole 8 which is penetrated into the bone 7 and fixed to the bone 7 without using cement, has the external form of the epiphysis which fits the internal form of the insertion hole 8, has the main part 3 with changing stiffness so that in the neighborhood of the boundary between the epiphysis and diaphysis, stiffness becomes lower as approaching toward the diaphysis, and possesses a neck part 2 to place a spherical head in an artificial joint provided at the proximal end of the main part.

Claims

1. A cement-less artificial joint stem with the use of composite material to be inserted in an insertion hole which is penetrated into bone and fixed to bone without using cement, comprising:

a main part which has an external form of an epiphysis approximately fitting an internal form of the insertion hole, wherein stiffness around a boundary between epiphysis and diaphysis of said main part which is formed that the ratio of members giving stiffness on the cross section area perpendicular to the axis decreases as approaching toward the diaphysis so as to lower the stiffness as approaching the diaphysis; and

a neck to place a spherical head in an artificial joint provided at a proximal end of the main part,

and a guide section which is positioned at the tip of the main part in the diaphysis and has lower bending and stretching stiffness than that of the main part, wherein

the main part has the first external layer with heightened twisting stiffness which contacts the internal surface of the insertion hole;

the main structure layer with heightened twisting stiffness which is positioned in the first external layer and continues from the neck;

the core layer with lower twisting stiffness than the main structure layer and the first external layer which is positioned inside the main structure layer; and

the inner most layer which is positioned between the core layer and the main structure layer.

2. The cement-less artificial joint stem with the use of composite material of claim 1, further comprising

the main structure of the main part further comprises a taper part which thickness decreases as moving toward the direction of the diaphysis in the neighborhood of the boundary between the epiphysis and diaphysis.

3. The cement-less type artificial joint stem with the use of composite material of claim 1, wherein

clearance of a predetermined quantity between an external surface of the guide section and an internal surface of the insertion hole is reserved.

4. The cement-less type artificial joint stem with the use of either one of composite material mentioned in claims 1-3, wherein

an external surface corresponding to the epiphysis has a convexo-concave surface treatment section thereon.

5. The cement-less type artificial joint stem with the use of composite material of claim 4, wherein

said convexo-concave external surface treatment section has an adhesive layer containing hydroxyapatite on the most external surface, and

fiber of composite material is positioned along with the convexo-concave external surface without breakage.

7. The cement-less type artificial joint stem with the use of composite material of claim 2, wherein

clearance of a predetermined quantity between an external surface of the guide section and an internal surface of the insertion hole is reserved.

6. (canceled)