JP3670677B2 - Bone prosthesis for artificial hip joint - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bone grafting material for filling a defect occurring in the hipbone during reoperation after long-term use of an artificial bone head or hip joint.
[0002]
[Prior art and its problems]
In recent years, with the prolongation of life, artificial bone heads and artificial joint replacements are often performed, and various artificial joints are put into practical use. As for the hip joint, an artificial hip joint consisting of an artificial bone head and an acetabular socket is used. However, due to infection, loosening due to long-term use, wear due to the artificial bone head sliding on the inner surface of the acetabulum, etc., it is necessary to re-operate. Often done.
[0003]
In particular, since elderly people have many patients with osteoporosis, the entire hip prosthesis often moves upward in the hipbone. In such a case, it is necessary to lower the artificial hip joint to the correct position by re-operation. However, a bone defect is generated in the hipbone by lowering. To compensate for this bone defect, it is conceivable to use autologous bone, bone cement (acrylic resin) or similar bone. However, the amount of autologous bone is not large, and in the case of a patient with low bone density, loosening occurs again, making it difficult to use. In addition, bone cement has poor affinity with surrounding bone tissue, bone resorption occurs several years later, and allogeneic bone has problems such as difficulty in obtaining and possible infection. There is a need to develop effective bone grafting materials.
[0004]
OBJECT OF THE INVENTION
It is an object of the present invention to provide a bone substitute for a hip prosthesis that can easily compensate for a defect occurring in the hipbone during reoperation after long-term use of an artificial bone head or hip prosthesis and has high strength immediately after the operation. Objective.
[0005]
SUMMARY OF THE INVENTION
The present invention achieves the above object by making the bone prosthetic material hemispherical and providing a processing adjustment portion at the bottom.
That is, the bone prosthesis material for artificial hip joints according to the present invention comprises a disk part for adjustment processing and a hemispherical part, and has a plurality of fixing screw holes provided at equal intervals from each other at an equal distance from the vertex. The outer surface portion is made of a biocompatible porous ceramic.
[0006]
The main body of the bone prosthesis material for artificial hip joints of the present invention consists of a hemispherical part, and the size of the hemispherical part is a defect part in which the hipbone is abnormally deleted, that is, a bone defect part formed after removing the artificial bone head and acetabular socket. It is preferable to have approximately the same size. By inserting the hemispherical bone filling material, it is possible to sufficiently and reliably fill a bone defect portion generated in the hipbone when the artificial hip joint that has been displaced upward is lowered and returned to the correct position.
[0007]
In the bone prosthesis material for artificial hip joints of the present invention, the adjustment disk portion is cut in order to adapt the size and shape of the defect portion when the bone prosthesis material is filled in the defect portion of the acetabular socket. Although it is provided for the purpose, there is also an effect of preventing a side slip after being embedded in a living body by providing a portion having a vertical side surface.
[0008]
The bone prosthetic material of the present invention has a plurality of fixing screw holes, and each screw hole is equidistant from the apex of the hemisphere so as to be surely fixed. is there. Moreover, it is preferable that the fixing screw holes are formed radially from the center of the bone grafting material toward the outside. This makes it possible to screw the screw at right angles to the bone and make it difficult to remove the screw. The number and dimensions of the screw holes can be appropriately determined in consideration of the size of the bone prosthetic material, and are not particularly limited. However, in the case of a bone prosthetic material having a hemispherical radius of 22 to 23 mm. Usually, it is preferable to provide four screw holes having a diameter of 2 to 10 mm.
[0009]
By constituting at least the outer surface portion of the bone prosthetic material from a biocompatible porous ceramic, the affinity with the surrounding bone tissue is good, and bone fusion is promoted by the penetration of the bone tissue into the pores. The porous ceramic preferably has continuous pores. The pore diameter and porosity are not particularly limited, but usually the pore diameter is preferably 2 to 2000 μm, and the porosity is 80% or less, preferably 70% or less.
[0010]
As the biocompatible porous ceramics, glass ceramics or calcium phosphate compounds having a Ca / P ratio of 1.0 to 2.0 are preferable. Examples of calcium phosphate compounds having a Ca / P ratio of 1.0 to 2.0 that can be used in the present invention include various types of apatite such as hydroxyapatite and fluorine apatite, primary calcium phosphate, dicalcium phosphate, tricalcium phosphate, and phosphoric acid. Tetracalcium and the like can be mentioned, and these can be used alone or as a mixture. After the slurry of the raw material compound is dried, calcined at 500 to 800 ° C. and then calcined at 800 to 1400 ° C., and the obtained block-like body is processed into a desired shape and size, or the calcium phosphate compound A green compact having a desired shape and size is produced from the powder, and this is fired in the same manner as described above.
[0011]
The central portion may be composed of dense or porous ceramics, and examples of usable ceramics include calcium phosphate compounds having a Ca / P ratio of 1.0 to 2.0, alumina, titania, zirconia, and the like. Of these, calcium phosphate compounds are preferred. There is no particular limitation on the method of providing a porous biocompatible material layer on the surface of the central part made of dense ceramics, and any known method can be adopted, for example, thermal spraying, sputtering, impregnation. Method, spray coating method and the like.
The bone prosthetic material of the present invention is only required to be composed of a biocompatible porous ceramic at least on the outer surface portion as described above, but it is preferable that the whole is made of a porous ceramic having biocompatibility.
[0012]
It is preferable to provide one or more recesses in the hemispherical portion of the bone grafting material of the present invention. The surrounding tissue enters the recess, and a stronger bond than the pores of the porous material is performed, and the movement of the bone prosthetic material can be prevented.
Such a recess may be a recess or a groove through which the recess passes. In the case of the depression, it is preferably a substantially circular depression having a diameter of 2 to 15 mm and a depth of 1 to 8 mm, and the groove is preferably a groove having a width of 2 to 15 mm and a depth of 1 to 8 mm.
[0013]
Furthermore, it is preferable to make the surface uneven in addition to the pores (porous pores) and the recesses as described above. As a result, the surface area of the bone prosthetic material is increased, so that the area in contact with the bone is increased, and the initial fixation between the bone prosthetic material and the bone is improved.
[0014]
【Example】
Next, the present invention will be described more specifically based on examples with reference to the drawings, but the present invention is not limited thereto.
[0015]
FIG. 1 is a plan view of a bone grafting material showing a first embodiment of the present invention, and FIG. 2 is a side view thereof. 1 and 2, the bone prosthetic material 1 includes a hemispherical portion 2 having a radius of 22.0 mm and a processing adjustment disc portion 3 having a thickness of 3.0 mm, and four fixing screw holes having a diameter of 5 mm. 4 and one depression 5 (diameter 10.0 mm, depth 3.0 mm) at the apex of the hemisphere, and four depressions 6 (equal distance (12.0 mm) from this depression 5 at equal intervals from each other ( Diameter 5.2 mm, depth 3.0 mm). The recesses 5 and 6 may have the same or different sizes and depths.
[0016]
FIG. 3 is a plan view of a bone grafting material showing a second embodiment of the present invention, and FIG. 4 is a side view thereof. 3 and 4 includes a hemispherical portion 7 having a radius of 22.0 mm and a disc portion 8 having a thickness of 3.0 mm. The hemispherical portion 7 has four fixing screw holes 9 ( Two grooves 10 (width: 10 mm, depth: 3 mm) passing through the apex of the hemisphere and orthogonal to each other in order to achieve a stronger bond with the surrounding tissue. ) Is provided.
[0017]
FIG. 5 is an explanatory view showing a use state of the bone grafting material of the present invention. In FIG. 5, the artificial bone head 12 and the acetabular socket 13 are placed at appropriate positions, and the bone defect material 15 of the present invention in which the bone defect portion generated in the hipbone 14 is processed into the shape thereof is compensated.
[0018]
Bone prosthetic materials each having the shape shown in the first and second embodiments, and having a pore diameter of 2 to 2000 μm and a porosity of 50%, are manufactured, respectively, for hip replacement of osteoporotic patients. When the defect was compensated for during the reoperation, a good course was observed.
[0019]
【The invention's effect】
The bone prosthesis of the present invention is an acetabular socket in patients with osteoporosis having low bone density, such as an intraosseous upward dislocation of the artificial bone head due to abnormal deletion of the acetabular bone by the artificial bone head, which is seen in patients who have been using an artificial hip joint for a long time When the acetabular socket and the artificial bone head are lowered to an appropriate position in the case where an upward dislocation of the artificial bone head occurs in the hip bone, it is suitable for filling the bone defect portion generated in the hip bone at that time. Is usually hemispherical and therefore very easy to fill. In addition, since at least the outer surface part is made of a biocompatible material, the surrounding tissue is not harmed, and the disk part is adjusted to fit the shape and dimensions of the defect part to be compensated. It is useful for processing and has an effect of preventing displacement such as side slip after compensation.
If the bone grafting material of the present invention is used, it is not necessary to collect autologous bones, and there is no concern about infectious diseases. Bone filling with excellent fixation and strength can be performed immediately after surgery.
[Brief description of the drawings]
FIG. 1 is a plan view of a bone grafting material showing a first embodiment of the present invention.
FIG. 2 is a side view of a bone prosthesis material showing a first embodiment of the present invention.
FIG. 3 is a plan view of a bone grafting material showing a second embodiment of the present invention.
FIG. 4 is a side view of a bone grafting material showing a second embodiment of the present invention.
FIG. 5 is an explanatory view showing a usage state of the bone grafting material of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bone prosthetic material 2 Hemisphere part 3 Disk part 4 Fixing screw hole 5 Groove 6 Groove 7 Hemispherical part 8 Disk part 9 Fixing screw hole 10 Groove 11 Bone prosthesis 12 Artificial head 13 Acetabular socket 14 Hipbone 15 Bone Supplementary material

Claims (8)

Consists of a adjusting machining disc portion and the hemispherical portion has a plurality of fixing screw holes provided at equal intervals from one another from the apex at equal distances, at least the outer surface is made of a biocompatible porous ceramic The bone prosthesis for a hip prosthesis , wherein the hemispherical part has a size substantially equal to that of the acetabular part . The bone prosthesis material for artificial hip joints according to claim 1, comprising four screw holes having a diameter of 2 to 10 mm as fixing screw holes . Consists of a adjusting machining disc portion and the hemispherical portion has a plurality of fixing screw holes provided at equal intervals from one another from the apex at equal distances, at least the outer surface is made of a biocompatible porous ceramic A bone prosthetic material for artificial hip joints , wherein the hemispherical portion has one or more recesses. The bone prosthesis for a hip prosthesis according to claim 3, wherein the hemispherical part has substantially the same size as the acetabular part. The bone prosthesis for a hip prosthesis according to claim 3 , wherein the recess is a recess having a diameter of 5 to 15 mm and a depth of 1 to 8 mm. The bone prosthesis for an artificial hip joint according to claim 3 , wherein the recess is a groove passing through the apex. The bone substitute material for artificial hip joints according to claim 5 , wherein the groove is a groove having a width of 2 to 15 mm and a depth of 1 to 8 mm. It consists of a disk part for adjustment processing and a hemispherical part, has a plurality of fixing screw holes equidistant from each other at equal distances from the apex, and at least the outer surface part is made of biocompatible porous ceramics. , the biocompatibility of porous artificial hip joint bone substitute material, wherein the ceramic is a calcium phosphate-based compound of the Ca / P ratio 1.0 to 2.0.

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