JP2005040250A - Orthopaedic implant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an orthopaedic implant in which micropores formed in a porous surface are regularly arranged and a neonatal bone can uniformly grow in the porous surface and which can be stably secured to a thigh bone. <P>SOLUTION: A mesh sheet laminate 7 is bonded to the outer face of the stem portion 2 inserted and fixed into a bone marrow cavity of the proximal portion of the thigh bone, a porous face 6 regularly arranged is formed in the outer face of the stem portion 2, a mesh sheet laminate 7 is formed of mesh sheets 7a, 7b laminated such that the micropores are aligned. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an orthopedic implant used for an artificial hip joint, an artificial knee joint or the like.
[0002]
[Prior art]
An orthopedic implant is required to have a structure capable of withstanding a load and sliding according to a use situation in addition to biocompatibility. Examples of metallic materials that satisfy these requirements include SUS316, Co—Cr alloy, titanium, and titanium alloy. Orthopedic implants are usually made of a titanium alloy.
[0003]
When used as an artificial hip joint, the orthopedic implant has a structure having a stem portion attached to the bone marrow cavity of the proximal part of the femur, and when used as an artificial knee joint, the structure having an inner surface in contact with the distal part of the femur It is.
[0004]
An orthopedic implant used for a hip prosthesis is made by applying polymethyl acrylate, which acts as bone cement, to the outer surface of the stem and attaching the stem to the proximal bone marrow cavity of the femur via the bone cement layer. Fixed to the femur.
[0005]
In the above orthopedic implant, the stem part is fixed to the femur via the bone cement layer, so that the bone cement layer deteriorates over a long period of use, and loosening occurs between the stem part and the bone cortex of the femur, The binding force to the femur may be reduced.
[0006]
For orthopedic surgery, a porous metal pad is joined to the support surface by laser welding means to form a porous surface, and the new bone of the femur is infiltrated into the pores formed on the porous surface to securely bond to the femur Implants are known (for example, Patent Document 1).
[0007]
In addition, in order to bond the orthopedic implant so that the femur does not loosen, a recess is formed on the surface of the stem portion, and titanium wire or titanium particles are sintered or diffusion bonded to the recess to have pores. When a porous surface is formed and the stem portion is attached to the bone marrow cavity of the femur, the new bone of the femur is invaded into the pore formed in the porous surface of the stem portion, and the orthopedic implant is securely attached to the femur. Technical means for coupling to the above have been developed by the present inventors.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-43216 (see page 1)
[0009]
[Problems to be solved by the invention]
The orthopedic implant is formed of titanium wire or titanium particles whose porous surface is sintered or diffusion-bonded. Therefore, the pores formed in the porous surface are random in arrangement and pore size, and thus the thigh The direction of penetration of the porous surface of the new bone into the pores is also random, and uniform growth of the new bone on the porous surface is difficult, and it cannot be stably fixed to the femur.
[0010]
The present invention has been made in consideration of the above points. By forming the porous surface with a mesh sheet laminate, the pores of the porous surface are aligned in the vertical and horizontal directions, and the porous surface is formed. An object of the present invention is to provide an orthopedic implant that can uniformly grow new bone and can be stably fixed to the femur.
[0011]
[Means for Solving the Problems]
The orthopedic implant of the present invention has a stem portion to be attached to the bone marrow cavity of the femur, a mesh sheet laminate is bonded to the outer surface of the stem portion, and pores are regularly arranged on the outer surface of the stem portion. By forming the porous surface, the new bone can be uniformly grown on the porous surface of the stem portion, and stable fixation to the femur can be performed.
[0012]
The orthopedic implant of the present invention has a porous surface having an inner surface in contact with the distal part of the femur, a mesh sheet laminate bonded to the inner surface in contact with the distal part of the femur, and pores regularly arranged on the inner surface. By forming the surface, the new bone can be uniformly grown on the porous surface on the inner surface, and stable fixation to the femur can be performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing an orthopedic implant in which the present invention is applied to an artificial hip joint. As shown in FIG. 1, an orthopedic implant 1 according to the present invention includes a stem portion 2 fixed to the proximal bone marrow cavity of the femur, and a neck portion 3 offset-connected to the proximal end of the stem portion 2. A spherical portion 4 coupled to the neck portion 3 and a shell plug 5 disposed on the spherical portion 4 so as to be rotatable in all directions. A porous surface 6 is formed in a portion near the neck portion 3 of the stem portion 2.
[0014]
The porous surface 6 formed on the stem portion 2 of the orthopedic implant 1 is formed by a mesh sheet laminate 7 in which two titanium or titanium alloy mesh sheets 7a and 7b are laminated as shown in FIG. Has been. Each mesh sheet 7a, 7b has substantially circular pores regularly arranged in the vertical and horizontal directions. The thickness of the mesh sheets 7a and 7b and the pore diameter are selected according to the use conditions. The pore diameter is preferably 5 to 800 microns.
[0015]
The mesh sheet laminate 7 is formed by laminating two mesh sheets 7a and 7b having the same pore so that the pores coincide with each other, or two mesh sheets 7a and 7b having different pores. It is formed by laminating so that the pores overlap.
[0016]
The mesh sheet laminate 7 is cut into a shape corresponding to an annular groove formed on the outer surface of the stem portion 2, arranged in the annular groove, and coupled to the stem portion 2 by diffusion bonding means or sintering means. In this case, the outer surface of the stem portion 2 and the surface 6a of the porous surface 6 are preferably the same plane.
[0017]
Further, when the mesh sheet laminate 7 is a plurality of mesh sheets having different pores, the mesh sheet having a large pore diameter is positioned on the lower side and the mesh sheet having a smaller pore diameter is positioned on the upper side, Laminate the cross section in the thickness direction to be trapezoidal, or stack the mesh sheet with a rough hole diameter in the middle and the mesh sheet 7 with a small hole diameter up and down to make the cross section in the thickness direction oval. Is preferred. By controlling the cross section of the mesh sheet laminate 7 in the thickness direction, it is possible to prevent the new bone generated in the bone marrow of the femur from falling off.
[0018]
Moreover, the mesh sheet laminated body 7 can control space height by making lamination | stacking thickness into 0.1 mm-3.0 mm by adjusting the number of sheets of a mesh sheet.
[0019]
In the orthopedic implant shown in FIG. 1, the stem portion 2 is fixed to the bone marrow cavity at the proximal portion of the femur, the shell plug 5 is fixed to the bone head portion lacking the hip joint, and the spherical portion connected to the neck portion 3 4 is fitted to the shell plug 5. The porous surface 6 formed by the mesh sheet laminate 7 arranged in the stem portion 2 has pores regularly arranged in the vertical and horizontal directions and is continuous without interruption. Since each pore of the porous surface faces the bone marrow cavity of the femur, new bone generated in the bone marrow of the femur enters the pores of the porous surface 6 through a minimum distance, Grown uniformly on the porous surface 6. Further, by forming the porous surface 6 of the stem portion 2 with the mesh sheet laminate 7, the generated new bone can be easily penetrated into the deep layer portion of the porous surface. Thereby, the orthopedic implant 1 becomes. It will be securely fixed to the femur.
[0020]
FIG. 3 is a perspective view of an orthopedic implant 10 in which the present invention is applied to an artificial knee joint. The orthopedic implant 10 shown in FIG. 3 has an overall shape that surrounds the distal portion of the femur and has an inner surface that contacts the distal portion of the femur. Porous surfaces 11 and 11 are formed on the inner surface of the orthopedic implant 10. Each porous surface 11 is formed of a mesh sheet laminate in the same manner as the porous surface 6 of the orthopedic implant 1 shown in FIG.
[0021]
An orthopedic implant 10 according to the present invention forms a porous surface by a mesh sheet laminate on the inner surface, and the porous surface has pores regularly arranged in the vertical and horizontal directions and is continuous without interruption. Since the bone marrow faces the bone marrow cavity of the femur, the new bone generated by the bone marrow of the femur can be uniformly grown on the porous surface and can be securely fixed to the distal portion of the femur.
[0022]
Furthermore, the orthopedic implant according to the present invention combines a mesh sheet laminate on the surface in contact with the bone, forms a porous surface in which the pores are regularly arranged on the surface, and is generated by bone marrow on the porous surface. The newly formed bone can be applied to bones other than the femur by uniformly growing it.
[0023]
【The invention's effect】
As described above, according to the present invention, the porous surface is formed of a mesh sheet laminate, and the pores formed on the porous surface are regularly arranged, so that the new bone is formed on the porous surface. Uniform growth is possible and it can be securely fixed to the femur.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an orthopedic implant according to the present invention.
FIG. 2 is an enlarged view showing a part of a main part of the orthopedic implant shown in FIG. 1 in cross section.
FIG. 3 is a perspective view of another embodiment of an orthopedic implant according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Orthopedic implant 2 Stem part 6 Porous surface 7 Mesh sheet laminated body

Claims (7)

In an orthopedic implant having a stem portion attached to the bone marrow cavity of the proximal femur, a mesh sheet laminate is bonded to the outer surface of the stem portion, and pores are regularly arranged on the outer surface of the stem portion An orthopedic implant characterized in that it has a textured surface. The orthopedic implant according to claim 1, wherein an annular groove is formed on an outer surface of the stem portion, and a mesh sheet laminate is coupled to the annular groove. The orthopedic implant according to claim 2, wherein the outer surface of the stem portion and the surface of the porous surface are flush with each other. The orthopedic implant according to any one of claims 1 to 3, wherein in the mesh sheet laminate, the pore diameter of the lower mesh sheet is large and the pore diameter of the upper mesh sheet is small. In an orthopedic implant having an inner surface in contact with the distal part of the femur, a mesh surface laminate is bonded to the inner surface of the orthopedic implant, and a porous surface in which pores are regularly arranged is formed on the inner surface. A featured orthopedic implant. The orthopedic implant according to claim 5, wherein in the mesh sheet laminate, the pore diameter of the lower mesh sheet is large and the pore diameter of the upper mesh sheet is small. An orthopedic implant having a surface in contact with bone, wherein a mesh sheet laminate is bonded to the surface of the orthopedic implant to form a porous surface in which pores are regularly arranged on the surface. Surgical implant.

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