JP2005278875A - Artificial bone and artificial joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an artificial joint capable of preventing the generation of wear powder and improving the adhesion of thigh bone to a stem at an implanting site of the artificial joint to the thigh bone. <P>SOLUTION: An artificial bone 1 comprising a caput 2, a neck 3 following the caput 2, and a stem 4 following the neck 3 is provided. The outer surface of the stem 4 is covered with composite structures 13 formed by surrounding the circumference of core materials 11 arranged regularly and made of a first ceramic material with a coating material 12 made of a material different from the first ceramic material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an artificial bone and an artificial joint that substitute for a living bone joint.

  Treatments for replacing the deformation and loss of bone joints in the human body with artificial joints are widely performed in orthopedics and the like. For example, for the femoral head necrosis, after removing the necrotic head, the stem portion of the artificial joint having the head and stem portion is embedded and fixed in the bone marrow cavity of the femur, and the cup (socket) is attached to the hip bone. Frequently, an artificial joint having a structure in which a bone head is fitted to a concave portion of the socket and is pivotably connected to the prosthesis is restored to restore the joint function.

  Such artificial joints have mechanical strength, elasticity (toughness), durability, in-vivo stability (no corrosion or deterioration against body fluids), biocompatibility (bone-promoting action and other surrounding tissues) Compatibility), safety (no toxicity, degradability, etc.), processability, and other properties are required. At present, organic resin, Alternatively, as described in Patent Document 1, metals such as stainless steel, cobalt-chromium alloy, titanium, and titanium alloy, or ceramics such as alumina and apatite are used.

  Here, when an artificial joint made of the above artificial bone is inserted between the cortical bones of the femur, the stem, which is a member embedded in the femur, is loosened due to strain, and must be replaced again. there were.

Therefore, in Patent Document 1, it is disclosed that the outer peripheral surface of the stem is covered with a resin braided fiber to reduce the deviation of the elastic coefficient between the living bone and the artificial bone, thereby preventing the problem of bone resorption. . Moreover, in patent document 2, the affinity between a stem and a living bone is improved by winding the composite fiber which coat | covered the outer periphery of the core material which consists of carbon fiber (structural fiber) with the osteogenic active fiber on the stem surface. Thus, it is disclosed that an artificial bone that can be used stably for a long period of time is suppressed.
JP-A-5-92018 Special table hei 9-505345

  However, in the method of knitting or wrapping the composite fiber around the stem surface disclosed in Patent Documents 1 and 2, since the surface of the artificial bone is entirely a skin material composition, it is not possible to suppress the wear of the surface portion, In addition, the outer peripheral surface of the fiber is likely to be dense in production, and there is a problem that the growth and growth of osteoblasts are difficult to activate due to poor liquid wetting and circulation at the interface between the artificial bone and the living bone.

  The object of the present invention is to suppress the occurrence of wear at the interface between the artificial bone and the living bone, and to improve the affinity to the living body with excellent liquid wetting and circulation, and can be used safely over a long period of time. It is to provide an artificial bone and an artificial joint.

  The present invention provides an outer shell material made of a material different from the first material on the outer periphery of the core material made of the first material regularly arranged on at least a part of the stem surface in contact with the living bone of the artificial bone. The structure covered with a composite structure that is exposed on the surface can prevent the generation of abrasion powder at the interface, and also has excellent wet and circulatory properties of blood and other liquids, thus improving safety to the living body. It is characterized by becoming an artificial joint that can be improved.

  That is, the artificial bone of the present invention includes a bone head, a neck portion that follows the bone head, and a stem portion that follows the neck portion, and is a core material made of the first ceramic material regularly arranged. It has a structure in which at least a part of the outer peripheral surface of the stem portion is covered in a state where a composite structural structure whose outer periphery is surrounded by a skin material made of a material different from the first ceramic material is exposed on the surface.

  Here, it is desirable that the thickness of the composite structure tissue is 100 to 500 μm, more preferably 300 to 450 μm, in view of good growth of osteoblasts and adhesion to the stem. Moreover, it is preferable in order to maintain the strength of the stem itself.

  The core material has a porosity of 5% or less and the outer skin material has a porosity of 25% or more and has pores that are three-dimensionally connected to each other. This is desirable because it encourages the regeneration of

  Furthermore, the average diameter of the core material of the composite structure is 10 to 1000 μm, and the area ratio of the core material on the bone head surface is 60 to 95 area%, so that the mechanical strength and the wear amount are optimal. It is desirable in that

  Furthermore, the stem portion base body is composed of a composite fiber body in which a plurality of single-core fiber bodies formed by coating the outer periphery of a long core material with a skin material, thereby maintaining the hardness of the stem portion. It is desirable in that the mechanical strength can be improved by increasing the toughness in the state.

  In the artificial joint of the present invention, the bone head of the artificial bone is fitted in a recess of a socket so as to be rotatable.

  In the artificial bone and artificial joint of the present invention, the stem surface in contact with the living bone of the artificial bone is formed on the outer periphery of the core material made of the first material regularly arranged, from a material different from the first material. The composite structure surrounded by the outer skin material is coated so that it is exposed on the surface, so that generation of abrasion powder at the interface can be prevented, and the wetness and circulation of liquids such as blood can be prevented. It becomes an artificial joint that can improve safety.

  Hereinafter, the artificial bone and artificial joint of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

    1 is a front view showing a configuration example of an artificial joint according to the present invention, FIG. 2 is a schematic cross-sectional view of a composite structural tissue 13 included in FIG. 1, and FIG. 3A is a view of a bone head in the artificial joint of FIG. The principal part enlarged view about the surface, (b) is a perspective view of a single core fiber body, (c) is a perspective view of a composite fiber body.

  As shown in FIG. 1, the artificial joint 1 has an artificial bone 5 composed of a bone head 2, a neck portion 3 that follows the bone head 2, and a metal stem portion 4 that follows the bone portion 2 at a predetermined position of the pelvis A. These are fitted in a recess 7 of a socket 6 provided as a separate body, and these are rotatably connected.

  The bone head 2 is a member having a substantially spherical curved surface, and the stem portion 4 is a portion that is embedded and fixed in the bone marrow cavity 8 of the femur B, and has a stem base portion 9 on the neck portion 3 side. It is comprised with the stem front-end | tip part 10. FIG. Since the outer periphery of the stem base 9 and the bone marrow cavity are in close contact with each other, the stem base 9 is thicker than the neck part 3 and the stem tip part 10, and the shape thereof matches the shape of the bone marrow cavity to be implanted. Molded. Moreover, since the stem tip portion 10 is inserted to the back of the bone marrow cavity, it has a tapered shape.

  On the other hand, the neck portion 3 is a member that connects the bone head 2 and the stem portion 4 and has a substantially cylindrical shape. The neck portion 3 is preferably formed integrally with the stem portion 4 continuously. The axis of the stem tip 10 is inclined with respect to the axis of the neck 3 by, for example, about 15 to 35 degrees.

  According to the present invention, as described in FIGS. 2 and 3 (a), at least a part of the surface of at least the stem tip 10 of the stem 4 (in FIGS. 2, 3 (a), the stem tip 10 to the stem). A composite structural structure in which a region up to the base 9) surrounds the outer periphery of a core material 11 made of a first ceramic material regularly arranged with a skin material 12 made of a material different from the first ceramic material. It is a great feature that it is covered with the surface 13 exposed on the surface, which can prevent generation of abrasion powder at the interface between the stem 4 and the femur B, and can prevent the liquid such as blood from flowing. It is excellent in wetness and circulation and can improve safety to living bodies.

  According to the present invention, since the nuclear materials 11 are regularly arranged, there is an advantage that there is no local wear bias and the generation of osteoblasts is uniform compared to the irregular arrangement. Further, since the core material 11 is surrounded by the skin material 12 having high biocompatibility, there is little risk of loss even when an impact is applied to the surface of the bone head 2.

  The core material 11 has, for example, a hexagonal cross-sectional shape in FIG. 3, but the present invention is not limited to this, and has a circular shape or other polygonal shape, or an elongated shape that is long in one direction. May be.

  As a constituent material of the core material 11, the same kind of material containing the same components as the base material can be used because of its adhesion to the base material. On the other hand, as the constituent material of the outer skin material 12, it is desirable to use a material having higher toughness or biocompatibility than the core material 11, for example, a ceramic material such as zirconia or a calcium phosphate compound, or a metal or an organic resin is also used. be able to.

  Here, when the bone head 2 and the socket 6 are also made of artificial bone, the inner surface of the concave portion 7 of the bone head 2 and the socket 6 is composed of the composite structural tissue 13 in the sliding portion of the bone head 2 and the socket 6. It is desirable in that it can prevent wear.

  The porosity of the core material 11 of the composite structure 13 is 5% or less, particularly 2% or less, and the porosity of the outer skin material 12 is 25% or more, particularly 40 to 90%, and further 45 to 70%. It is desirable to have pores that communicated with each other in terms of excellent mechanical strength, enhanced biocompatibility, and promoted osteoblast proliferation and bone regeneration. Here, there is an effect that the pores in the outer skin material 12 can be filled with a lubricating liquid to improve the slidability of the bone head 2 surface.

  The bone head 2 can be entirely composed of the composite structure tissue 13, but since the bone head surface has a curved surface, the inside of the bone head 2 has a composite structure in terms of surface tissue control. It is desirable to be composed of an organization different from the organization 13.

  In addition, as a constituent material of the bone head 2 and the neck part 3, for example, stainless steel (for example, SUS316, SUS316L), cobalt-chromium alloy, cobalt-chromium-nickel alloy, titanium, titanium alloy (for example, Ti-6% Al) −4% V) or other metals, alloys, or materials having excellent strength and hardness such as ceramics such as alumina, zirconia, silicon nitride, and silicon carbide can be used. The inside of the portion 2 is composed of a uniform tissue formed of the first material that forms the core material 11 described above, and the hardness of the bone head 11 itself is high, and the inside of the bone head 11 and the surface tissue ( This is desirable in terms of enhancing the adhesion with the composite structure 13). Further, the inside of the bone head 2 may be hollow or solid.

  Moreover, as a constituent material of the stem 4, for example, stainless steel (for example, SUS316, SUS316L), cobalt-chromium alloy, cobalt-chromium-nickel alloy, titanium, titanium alloy (for example, Ti-6% Al-4% V) It is possible to use metals and alloys having excellent corrosion resistance such as, or strength and materials such as ceramics such as alumina, zirconia, silicon nitride, silicon carbide, etc., but in consideration of corrosion resistance and mechanical properties, it may be made of a titanium alloy. desirable.

  In the present invention, as shown in FIGS. 3B and 3C, from a composite fiber body 18 in which a plurality of single core fiber bodies 17 formed by covering the outer periphery of a long core material 15 with a skin material 16 are converged. As a result, the hardness of the neck portion 3 can be maintained and the wear of the neck portion 3 at the connecting portion between the bone head 2 and the stem portion 4 can be suppressed, and the toughness of the member can be increased to generate a sudden load. It is desirable in that it can improve the durability.

  On the other hand, it is desirable that the thickness of the composite structure 13 is 100 to 500 μm, while the new bone can sufficiently enter the composite structure 13 that is a surface tissue to ensure adhesion with the stem.

  Furthermore, the average diameter of the core material 11 of the composite structure 13 is 10 to 1000 μm, and the area ratio of the core material 11 on the surface of the bone head 2 is 60 to 95 area%. Is desirable.

  Here, when the area ratio c1 / s1 between the area c1 of the core material 11 and the area s1 of the outer skin material 12 in the cross section of the composite structure 13 is between 1 and 10, the wearability is excellent and the biocompatibility is high. It is preferably 1 to 5, and more preferably 1 to 3.

  In the present invention, the skin material 12 (or the skin material 16 of the composite fiber body 18) and the core material 11 (or the core material 15 of the composite fiber body 18) in the cross section of the composite structure 13 (or the composite fiber body 18 described later). For example, the sum of the cross-sectional areas of the respective core materials 11 observed in a scanning electron microscope (SEM) photograph in an arbitrary cross section of the composite structure 13 is calculated as c. The area s of the outer skin 12 can be calculated by subtracting the area c of the core material 11 from the total cross-sectional area of the arbitrary cross section of the structural structure 13. It can be easily obtained by an image analysis method or the like.

As the skin material 16 of the composite fiber body 18 used in the present invention, a calcium phosphate compound generally known as a biocompatible porous ceramic is suitable, for example, tricalcium phosphate TCP (Ca ₃ (PO ₄ ) ₂ ). , tetracalcium phosphate _{(Ca 4 (PO 4) 2} O), octacalcium phosphate _{(Ca 8 H 2 (PO 4} ) 6 · 5H 2 O), calcium hydrogen phosphate (CaHPO _4), dihydrogen phosphate Inorganic materials such as calcium (Ca (H ₂ PO ₄ ) · H ₂ O), hydroxyapatite HAP (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ), zirconia (ZrO ₂ ), or polyether ketone, polyether Ketone resins such as ether ketone and polyallyl ether ketone, polyphenylene sulfide, polysulfone, etc. It includes thermoplastic resins. In the present invention, one or more of these can be used in any combination. Various additives such as stabilizers and reinforcing materials may be added to the biomedical resin material 8.

On the other hand, the material of the core material 15 is a material that is not harmful to the living body and is preferably a dense ceramic or metal having biocompatibility. For example, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), silica ( SiO ₂ ) and titania (TiO ₂ ). These ceramics may contain auxiliary agents such as Ti, Mg, Zr, Hf, and Y as appropriate. Examples of the metal include stainless steel (for example, SUS316, SUS316L), cobalt-chromium alloy, cobalt-chromium-nickel alloy, titanium, titanium alloy (for example, Ti-6% Al-4% V, Ti-49 to 51%). A metal having excellent corrosion resistance such as Ni) can be used. Among them, it is particularly preferable to use a shape memory alloy (Ti-49 to 51% Ni). Since this shape memory alloy has excellent followability to repeated loads, resilience, and fatigue characteristics, stability and durability are improved during long-term embedding.

  The core material 11 of the composite structure 13 and the core material 15 of the composite fiber body 18, and the skin material 12 of the composite structure 13 and the skin material 16 of the composite fiber body 18 may be formed of the same material. In this case, it is desirable in that the composite structure 13 and the composite fiber body 18 can be produced by the same manufacturing method halfway.

  Here, when the area ratio c / s between the area c of the core material 15 and the area s of the skin material 16 in the cross section of the composite fiber body 18 is between 1 and 10, strength and biocompatibility suitable as a bone grafting material. And preferably 1 to 5 and more preferably 1 to 3. When the area ratio c / s is less than 1, the proportion of the dense body is reduced, and the strength of the composite structure itself is reduced, which may cause damage. On the other hand, when the area ratio c / s exceeds 10, the strength is sufficient, but since the density of pores in the composite structure is low, the growth of osteoblasts is suppressed and a long time is required for healing. It comes to be.

  Furthermore, the Young's modulus of the composite structure can be adjusted by controlling the area ratio between the core material c and the skin material s of the present invention and the porosity of each, and for example, the Young's modulus of living bone is controlled to about 30 GPa. As a result, it becomes more suitable as a bone filling material.

  The composite fiber body 18 may be either a short fiber or a long fiber, and may be linear or have a bent portion as in bulky processing. In addition, the aggregate form of the composite fiber body 18 is not particularly limited, and the single core fiber body 17 may be simply bundled, but may be a woven fabric, a knitted fabric, or a net (mesh) of the single core fiber body 17. . This increases the strength, particularly the strength in the axial direction of the stem portion 4 and the direction perpendicular thereto.

  Although the suitable range of the diameter of the single core fiber body 17 is based also on the kind of the constituent material, it is preferable that it is 0.01-2.0 mm normally, and it is 0.1-1.0 mm. More preferred. When the diameter of the metal fiber 7 is less than 0.01 mm, mixing with the powder becomes difficult at the time of sintering, and when it exceeds 2.0 mm, the strength as a composite with the resin decreases. In addition, the number of single-core fiber bodies 17 in the composite fiber body 18 is not particularly limited, but in the case of the single-core fiber bodies 17 having the above-mentioned diameter, it is preferably 1 to 4 million, particularly 400 to 40000.

The arrangement density of the single-core fiber bodies 7 in the stem part 4, particularly the stem base part 9 is not particularly limited, but is preferably 1 million to 20 pieces / cm ² , particularly preferably 10,000 to 100 pieces / cm ² . Note that the arrangement density of such metal fibers 7 may be different between the central portion and the peripheral portion of the stem portion 4.

  When the artificial joint 1 is embedded and fixed in, for example, the femur, the stem distal end portion 10 is inserted up to a dense portion (compact bone), and the upper stem base portion 9 is located in the cancellous bone portion. In the cancellous bone, since the bone marrow cavity is enlarged by reaming, the contact area with the outer periphery of the stem base 9 is increased, and therefore, the balance of the bending elastic modulus between the artificial joint 1 and the living bone becomes important. In order to prevent bone destruction and resorption (particularly resorption of the bone in the calcar part) due to excessive bending elastic modulus as seen in the metal stem part, it is above the little trochanter at the time of artificial joint implantation. It is particularly effective to improve the bending elastic modulus of the stem base 9.

  The artificial joint of the present invention is not limited to the above-mentioned artificial bone head, for example, an artificial knee joint, an artificial shoulder joint, an artificial elbow joint, an artificial finger joint, an artificial hip joint, or a part of an acetabular cup embedded in a hipbone It can also be applied to.

(Production method)
Next, a method for producing the artificial joint of the present invention will be described with a suitable example.

    First, a method for producing a composite surface structure that forms the surface of the stem portion will be described with reference to the schematic diagram of FIG. 4 taking as an example the case where the core material is titanium and the outer skin material is hydroxyapatite.

  First, an auxiliary agent is appropriately added to and mixed with titanium powder having an average particle size of 0.01 to 3.5 μm, and paraffin wax, polystyrene, polyethylene, ethylene-ethyl acrylate, ethylene-vinyl acetate, polybutyl methacrylate, polyethylene are added thereto. An organic binder such as glycol or dibutyl phthalate is added and kneaded to produce a core material molding 21 in a cylindrical shape by a molding method such as press molding, extrusion molding or casting.

  On the other hand, a hydroxyapatite raw material powder having an average particle size of 0.1 to 100 μm is appropriately added with a dispersant, a foaming agent, and an antifoaming agent in addition to the above-mentioned binder and kneaded, and press molding, extrusion molding, or cast molding. Two molded bodies 22 for the outer skin material are produced by a molding method such as the above.

  According to the present invention, when the raw material for the outer shell material molding 22 is mixed in order to control the porosity of the outer skin material 12 to 25% or more, the amount of the organic binder added is 100 to 200 parts by volume, particularly It is desirable to set it as 120-150 volume parts. The hydroxyapatite raw material powder is preferably granulated to have a secondary particle size of 20 to 400 μm, particularly 50 to 200 μm, in terms of producing a uniform pore size and structure.

  Next, a composite molded body 23 in which two outer shell material molded bodies 22 are arranged on the outer periphery of the core material molded body 21 is produced, and the composite molded body 23 is co-extruded (core material molded body 21, And the outer shell material molded body 22 are simultaneously extruded) to produce a single core molded body 24 in which the outer shell material molded body 22 is coated on the outer periphery of the core material molded body 21 and is elongated to a thin diameter (step (step (step)). b)). Further, in order to produce a multi-fiber (filament) type multi-core molded body 25, a plurality of the co-extruded long single-core molded bodies 24 may be converged and co-extruded again. According to this, it is possible to obtain stronger adhesion between the single-core molded bodies 24 in the molded body. (See FIG. 4 (c)).

  In the co-extrusion molding, the elongated single-core molded body 24 or the multi-core molded body 25 has a cross-sectional shape such as a circle, a triangle, a quadrangle, or a hexagon by changing the die. It is also possible to mold into a desired shape.

  In addition, according to the present invention, as shown in FIG. 3C, when the composite fiber body 18 or the composite fiber body 18 in which the single-core fiber bodies 17 are gathered into a sheet shape is formed, as described above. The composite fiber body 18 or the single-core fiber body 17 produced as described above is bundled to form an aggregate molded body. Furthermore, when producing a sheet-like molded body, when a single-core molded body 24 or a multi-core molded body 25 is aligned, it is molded into a desired complex shape in advance using a molding method such as a known rapid prototyping method. It is also possible to do.

  And the said assembly molded object is cut | disconnected in the direction orthogonal to the fiber direction of the said fiber body, and it is set as a sheet-like molded object. In that case, an adhesive such as the above binder is interposed between the aggregated molded body or the single-core fiber body 17 as desired, and pressure is applied to the sheet-shaped molded body by a cold isostatic press (CIP) or the like. However, if necessary, it is possible to roll-roll the sheet-like formed body using a roll or the like.

  Then, after preparing a base material stem part separately and carrying out a binder removal process in the state which stuck the molded object on the surface, the said bone head can be produced by baking. As the firing method, vacuum or atmosphere firing, gas pressure firing, hot press, discharge plasma sintering, or the like is used depending on the core material and the skin material. The firing temperature is desirably 750 ° C to 1300 ° C.

  Further, the artificial joint of the present invention can be manufactured by separately manufacturing a bone head, a neck portion, and a socket and assembling them together with the stem portion.

  After adding and kneading a binder and a lubricant in a total proportion of 85 parts by mass to titanium powder having an average particle size of 0.3 μm, a cylindrical shaped core material was produced by press molding. On the other hand, after adding and kneading a binder and a lubricant in a ratio of 120 parts by mass in total to a hydroxyapatite powder having an average particle size of 0.2 μm, a half-cylindrical molded body for outer skin material is formed by press molding. Two were prepared, and a composite molded body in which the outer core material molded body was covered as shown in FIG. 4 was manufactured around the core material molded body.

  Next, after the composite molded body is extruded and stretched, the single core formed bodies are arranged in parallel to form an aggregate molded body and subjected to CIP pressing, and then the aggregate molded body is 0.4 mm thick in a direction perpendicular to the fiber direction. Then, it was sliced to obtain a sheet-like molded body.

  Then, this sheet-like molded body is separately bonded to the surface of a stem base made of a titanium alloy, and the binder removal treatment is performed by raising the temperature to 300 to 700 ° C. in 72 hours. Firing was carried out at 1200 ° C. for 10 minutes by the kneading method.

The polished cross section of the obtained composite structure was observed with a metal microscope or a scanning electron microscope, and the area ratio c / s between the core material and the skin material was calculated by an image analysis method. s was 5. Moreover, when the area ratio of the pores contained in the core material was measured from the structure observation photograph to calculate the porosity in the core material, it was 0.2%. Furthermore, the porosity was calculated by mercury porosimetry, and the porosity of the outer skin material was calculated together with the area ratio of the core material and the outer skin material and the estimation of the porosity of the core material. Was 27%.

  The adhesion was evaluated by the following tensile test. The test piece was produced in the shape shown in FIG. 5, and a sheet-like molded body was attached to both sides as shown in the figure and fired to obtain a test body. The sintered body produced in the same manner as described above was embedded in the patellas of the left and right femurs of a beagle dog (10-15 kg adult dog), and an animal experiment was conducted after one month had passed (see FIG. 5). The average stress value was 5.2 MPa.

(conditions)

Crosshead speed: 2.0mm / min

n = 8
(Comparative Example 1)
A titanium alloy test piece was prepared without bonding the sheet-like molded body of Example 1 to the surface of the test piece. As a result of evaluation in the same manner as in Example 1,
The average stress value was 0.1 MPa.

(Comparative Example 2)
A test piece having a porosity of the outer skin material of 20% (other conditions are the same as in Example 1) was prepared, and a tensile test was performed. When an animal experiment was conducted in the same manner as in Example 1 to conduct a tensile test, the average stress value was 2.9 MPa.

(Comparative Example 3)
A test piece having a thickness of 0.1 mm for the outer skin material (other conditions were the same as in Example 1) was prepared, and a tensile test was performed. When the tensile test was conducted, the average stress value was 2.5 MPa.

It is a schematic perspective view which shows the example of a suitable embodiment of the artificial joint of this invention. It is a schematic sectional drawing of the stem surface part of FIG. (A) is a principal part enlarged view which shows the surface of the stem surface part of FIG. 1, (b) is a perspective view of a single core fiber body, (c) is a perspective view of a composite fiber body. It is process drawing for demonstrating the manufacturing method of the composite structure of this invention. It is a schematic diagram for demonstrating the adhesiveness test (peeling test) performed in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Artificial joint 2 Bone head 3 Neck part 4 Stem part 5 Artificial bone 6 Socket stem front-end | tip part 7 Recessed part 9 Stem base part 10 Stem front-end | tip part 11 Core material 12 Outer skin material 13 Composite fiber structure 14 Stem base material 15 Core material 16 Skin material 17 Single Core fiber body 18 Composite fiber body 21 Core material molded body 22 Outer skin material molded body 23 Composite molded body 24 Single-core molded body 25 Multi-core molded body

Claims (6)

An artificial bone comprising a bone head, a neck portion following the bone head, and a stem portion following the neck portion, wherein the outer periphery of the core material made of the first material regularly arranged is An artificial bone in which at least a part of the outer peripheral surface of the stem portion is covered in a state where a composite structure surrounded by an outer skin material made of a material different from the material of 1 is exposed on the surface. The artificial bone according to claim 1, wherein the thickness of the composite structure tissue is 100 to 500 µm. The artificial bone according to claim 1 or 2, wherein the core material has a porosity of 5% or less, and the skin material has a porosity of 25% or more and has pores communicating in three dimensions. The artificial bone according to any one of claims 1 to 3, wherein an average diameter of the core material of the composite structure is 10 to 1000 µm, and an area ratio of the core material on the surface of the bone head is 60 to 95 area%. The artificial bone according to any one of claims 1 to 4, wherein the base body of the stem portion is composed of a composite fiber body in which a plurality of single-core fiber bodies formed by covering an outer periphery of a long core material with a skin material. . The artificial joint which connected the said bone head of the said artificial bone in any one of Claim 1 thru | or 5 in the recessed part of a socket so that rotation was possible.

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