JP3325986B2 - Artificial bone substitute - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial bone substitute,
Specifically, a relatively large load such as a human femur or tibia is applied, and a rod-shaped bone (hereinafter, also simply referred to as a femur) is resected as if it were affected by a bone tumor or the like and resected. The present invention relates to an artificial bone filling material (hereinafter, also simply referred to as a bone filling material) used for filling (treating) damaged bone.

[0002]

2. Description of the Related Art When performing an orthopedic surgery by excision of a site (affected part) affected by a bone tumor, a part of the excised bone is replaced with a bone filler. As a bone replacement material used for such treatment, a material having a structure as shown in FIG. 7 is used. Since this bone replacement material is subjected to a considerable load on the femur, a center member (a rod-shaped body called an intramedullary nail) S having a circular cross section having both ends tapered to be able to withstand the load. Has a structure in which a cylindrical side member G having an inner diameter (hollow portion C) slightly larger than the outer diameter of the concentric material is externally fitted. At the time of treatment, a filler or an adhesive (hereinafter simply referred to as bone cement) for bone treatment called bone cement is applied to the outside (peripheral surface) of the core material S, and the side member G is extrapolated ( The core material S is inserted into the center (cancellous bone) of the end of the living bone K by widening the interval between the bone parts L from which both ends of the core material S have been cut, and the end face F of the side member G and the living bone K
Is filled or joined with bone cement.

[0003]

However, the above-mentioned conventional bone substitute has the following problems. That is, since both the hollow section C of the side member G and the cross section of the core material S are circular,
That is, the side member G has a fitting structure in which the side member G idles with respect to the core material S for the clearance fitting of the circular cross section. For this reason, although it is adhered by the bone cement, the side member G rotates around the axis J of the core material S under some influence when the femoral bone is supplemented and repaired in the operation. When subjected to the action, the adhesion may be removed and the side member G may rotate. As described above, in the conventional bone filling material, the side member G may be separated from the bone or the core material S although it has been bonded (adhered) to the bone and the core material S, so that the bonding property with the bone and the repair thereof can be improved. It was pointed out that there was a problem with the durability (life) of the affected part.

The present invention has been devised in view of such a problem, and an object of the present invention is to provide an artificial bone having a structure in which a core member and a side member do not relatively idle around an axis. An object of the present invention is to provide a filling material, and to improve the bonding property with the living bone and the durability after the operation.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an artificial bone replacement material used for treating a rod-shaped bone such as a femur, and the like. core
And a side member which is externally fitted to the material in a clearance-fitting manner , wherein both ends of the core material protrude from an end surface of the side member.
Has a length that, when the externally fitted to the side member to the core member,
In a state where both ends of the core material are projected from the end surface of the side member
Wherein the side member has an axis of the core with respect to the core.
And a fitting structure that does not idle around the axis of the core material . In this case, the fitting structure in which the core member and the side member are fitted in a substantially square cross-sectional shape in a cross section substantially perpendicular to the axis of the concentric member is preferable from the viewpoint of manufacturing and use. Further, in these artificial bone filling materials, the side member may be formed in a cylindrical shape, or may be one whose one side is opened so as to be able to be fitted to the core material from the radial direction. It is preferable that both side members are made of hydroxyapatite from the viewpoint of biocompatibility.

According to the artificial bone substitute according to the present invention, since the side member has a fitting structure in which the side member does not idle with respect to the core material,
Even if a rotational force is applied to the side member externally fitted to the fixed core member around the axis, the side member moves only by the gap of the fitting and therefore does not rotate. Thus, the bonding or fixing property of the bone substitute to living bone is improved, and the durability (life) of the repaired affected part is improved. In addition,
In the artificial bone substitute according to the present invention, both ends of the core material are fixed ends.
(Supporting end) can be supplemented to the affected area.
Inside, the side member can slide in the axial direction of the core material
Therefore, it is easy to align the side member with the affected part,
It becomes easy to take measures according to the situation. Therefore, intraoperative
The burden on the physician is also reduced.

[0007]

Next, a first embodiment of the present invention will be described in detail with reference to FIG.
In the figure, reference numeral 1 denotes a rod-shaped core material, which in this example is made of stainless steel and has tapered portions 2 and 2 having a circular cross section at both ends, and the intermediate portion 3 is substantially square (square). Is formed in a rectangular shape having a constant cross section. On the other hand, the side member 4 has a hollow portion (through hole) 5 having a substantially square cross section so that the intermediate portion 3 of the core material 1 can be inserted with a small gap at the center, and is formed in a cylindrical shape. ing.
The length L and the outer diameter D of the side member 4 are set so as to substantially match the length L and the thickness D of the living bone (affected part) to be cut. However, the length of the core member 1 is longer than the length of the side member 4 as shown in FIG.
When the tape is inserted into the side member, the tapered portions 2 at both ends and the substantially square cross-sectional portion (intermediate portion 3) in the vicinity thereof project from the end surface 6 of the side member 4, and this portion is driven into the living bone. The connection is made while maintaining the bending strength. In the present example, the entire ridge line (corner) of both the core material 1 and the side member 4 is rounded by about R1 mm.
Thus, in this example, the side member 4 is externally fitted to the core member 1 from the direction of the axis J. When the core member 1 is fixed thereunder, the side member 4 slides in the direction of the axis J.
The fitting structure does not rotate around the axis J.

In the artificial bone filling material of this embodiment, predetermined bone cement is applied to the side surface of the core material 1 and the like, and the two are assembled by inserting the cement into the hollow portion 5 of the side member 4. However, in the operation, the tapered portions 2 at both ends of the core material 1 and the portions near the tapered portions 2 are fixed to the end surfaces of the living bones (femurs) K, K which are left after excision. Thereby, the substantially square cross-section near the tapered portion 2 stops rotation of the living bone K. Then, a predetermined bone cement is interposed to fill the gap, and a treatment is performed so that the end face 6 of the side member 4 comes into contact with the end face of the living bone K.

After the operation, since the side member 4 does not rotate around the axis J with respect to the core 1, the living bone K and the core 1 are not rotated.
Joining is performed smoothly and the durability after joining (operation) is excellent. In this example, since the cross-sectional shape of the intermediate portion 3 of the core material 1 and the hollow portion 5 of the side member 4 is substantially square, the corner of the side surface of the core material 1 Can be easily assembled (outside fitting) by adjusting the angle to fit the corner angle of. In addition, since the side member 4 is formed in a cylindrical shape, reliable fitting can be obtained. The core material 1 may be selected and used from appropriate materials such as stainless steel having biocompatibility and high strength. The material of the side member 4 is ceramic,
In particular, hydroxyapatite is preferable because of its high mechanical strength and excellent adhesion to living bone K.

A second embodiment will be described with reference to FIGS. 2 and 3. The previous example illustrates a case where the side members are cylindrical and the core material is inserted in the axial direction and fitted. In the example, one side of the side member 24 is opened so that the side member 24 is externally fitted (fitted) to the core member 21 from the radial (lateral) direction. Since it is basically common to the previous example, only the differences will be described. That is, in this example, the core material 21 is provided with tapered portions 22, 22 each having a circular cross section and tapered at both ends as in the previous example, and the intermediate portion 23 is formed into a square having a substantially square (quadrangle) cross section. Is formed. However, two through holes 27 are formed in the middle. The side member 24 has a tapered cylindrical body set to correspond to the outer shape of the living bone K of the affected part, and has one side opened so that the cross section thereof is substantially U-shaped when viewed from the axial direction. The three side surfaces of the core 21 are formed along the inner surface of the groove 25 so as to be accommodated in a fitted state with a slight gap. However, the width W of the concave groove 25 near the opening edge is slightly wider in a stepped manner than the width of the concave groove 25 in which the core material 21 is accommodated, so that fitting in the radial direction is easy. Further, in this example, when the core 21 is fitted, two similar through holes 28 are formed at the same pitch at the same position as the through holes 27 formed in the core 21.

In this embodiment, a predetermined bone cement is applied to the core 21 fixed to the living bone K, and the concave groove 25 of the side member 24 is fitted from the side. The side member 24
The opening side of the concave groove 25 is supplemented with autogenous bone (bone of another part of the self) or bone cement as appropriate. Also in this example, as in the previous example, the side member 24 does not idle around the core 21. In this example, since the side member 24 can be externally fitted to the core member 21 from the side, it is suitable for a case where the portion of the bone to be cut is long.

In this embodiment, since the through holes 27 and 28 are formed in the core member 21 and the side member 24, they can be fixed as follows. That is, as shown in FIG. 4, the autogenous bone Ka is positioned on the opening side and is attached to the core material 21, and a screw member (tap for bone treatment called a bone screw called a bone screw) is inserted through the through hole 28 outside the side member 24. The screw T is screwed into the autogenous bone Ka. By doing so, the fixability is further improved, and therefore, earlier repair is expected. Also, the through holes 27 and 2
Since the wire 8 can be wound around the side member 24 or around the autogenous bone Ka through a wire (not shown), the wire 8 can also be used as such a fixing means. The through-holes 27 and 28 provided in the side member 24 and the core member 21 in this example have a circular cross section, however, as shown in FIG.
Medium, as shown by the two-dot chain line, it is good to have a long hole such as a so-called oval shape that is long in the axial direction. This allows fine adjustment of the position of the side member 24 in the axial direction with respect to the core member 21.

Next, still another embodiment will be described with reference to FIG. 5. In this embodiment, the cylindrical side member 4 shown in the first embodiment is formed by a plane including the axis J thereof. It is divided into two parts, and should be called a modification of the previous example. That is, in this example, the side member 34
Is divided by a line connecting the centers of opposing sides of the hollow portion 5 which is substantially square when viewed from the axial direction in the first embodiment, and by joining the two members 35, 35,
The hollow portion is constituted by each concave portion 36. Thus, in this example, the side member 34
Is divided into two parts, so that it can be fitted to the core material 31 from both sides (sideways). This one is
The one component member 35 of the side member can be made thin (thin) by the division. Therefore, it is suitable when the affected part cannot be opened widely.

FIG. 6 shows still another modification. In this example, the side member 44 is divided into two members 45, 45 in a diagonal direction connecting corners of a square cross section when viewed from the axial direction. In this case, since the concave portions 46, 46 forming the hollow portion have a V-groove shape, the concave portions 46, 46 can be easily applied to the core material 41 and can be easily fitted. FIGS. 5 and 6 illustrate the case of dividing into two parts, but the number of divisions should be prepared in advance as appropriately set according to the condition of the affected part (bone to be treated) or symptoms. I just need.

In the above embodiment, the case where the core material is fitted to the side member with a substantially square cross section has been exemplified. However, in the present invention, this can be made substantially rectangular (rectangular), It is not limited to such a square.
Consists of a rod-shaped core material and a side member externally fitted to the core material, and when the side member is externally fitted to the core material, the side member does not idle around the axis of the core material with respect to the core material. What is necessary is just a fitting structure.

In the above-mentioned embodiment, the case where the side member is made of hydroxyapatite is exemplified. However, it is sufficient that the side member has strength and biocompatibility, and the invention is not particularly limited to this. It may be made of other appropriate materials such as ceramics or human body compatible metals (stainless steel, titanium alloy). The same applies to the core material. Further, the artificial bone replacement material according to the present invention can be widely applied to the replacement of a rod-shaped bone such as a femur or a tibia.

[0017]

As is apparent from the above description, the artificial bone filling material according to the present invention has a structure in which the side members do not idle with respect to the core material. Even if a rotational force acts on the side member around the axis, the side member moves only by the gap of the fitting and therefore does not rotate. That is, the fitting structure serves to stop the side member around the axis and prevent rotation. Therefore, when the bone member is supplemented with the bone substitute material according to the present invention, the joint property with the living bone after the operation is obtained. And has the effect of improving the durability of the repaired affected part. Therefore, it is good news for patients. In addition, the artificial bone replacement material according to the present invention
To fix the affected area with both ends of the core material as fixed ends (supporting ends)
During the operation, the side member can be
Because it can slide in the axial direction, the position of the side member to the affected area
Easy alignment and easy treatment according to the condition of the affected area
It becomes. Therefore, the burden on the doctor during surgery is also reduced.
It is.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view and a cross-sectional view showing a first embodiment of an artificial bone substitute according to the present invention.

FIG. 2 is an exploded perspective view illustrating a second embodiment of the artificial bone substitute according to the present invention.

FIG. 3 shows side members used in the second embodiment,
Is a front view as viewed from the opening side, B is a bottom view thereof, and C is a central longitudinal sectional view in the front view.

FIG. 4 is a partially broken vertical cross-sectional view when screwed using a screw member in the second embodiment.

FIG. 5 shows another embodiment of the side member, and is a view of the side member externally fitted to a core member and viewed from an axial direction.

FIG. 6 is a view showing still another embodiment of the side member, wherein the side member is externally fitted to a core member and viewed from an axial direction.

FIG. 7 is a partially cutaway front view and a cross-sectional view illustrating an example of a conventional artificial bone substitute for a femur.

[Explanation of symbols]

 1,21,31,41 Core material 4,24,34,44 Side member K Living bone J axis

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shozo Higaki 2-43-35, Kikunodai, Chofu-shi, Tokyo (56) References JP-A-54-27295 (JP, A) JP-A-5-305132 (JP, A) Actual opening 555-154009 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61L 27/00 A61F 2/28

Claims (5)

(57) [Claims] 1. An artificial bone replacement material used for treating a rod-shaped bone such as a femur, which comprises a rod-shaped core material and side members which are fitted around the core material in a gap-fitting manner. Wherein the core material has both ends
A length protruding from an end surface of the side member, and when the side member is externally fitted to the core, both ends of the core
Is projected from the end surface of the side member.
The member slides in the axial direction of the core with respect to the core.
An artificial bone filling material , which is made possible and has a fitting structure that does not idle around the axis of the core material. 2. The artificial bone replacement according to claim 1, wherein the core member and the side member are fitted with a substantially square cross-sectional shape in a cross section substantially perpendicular to the axis of the core material. Wood. 3. The artificial bone substitute according to claim 1, wherein the side member is formed in a cylindrical shape. 4. The artificial bone prosthesis according to claim 1, wherein the side member has an opening on one side so that the side member can be externally fitted to the core material in a radial direction. 5. The artificial bone substitute according to claim 1, wherein the side member is made of hydroxyapatite.