JP2005152503A - Bone substitute material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bone substitute material capable of replacing the bone according to the configuration of the bone which can be displaced by the autologous bone in a short time and can be removed afterward easily. <P>SOLUTION: The bone substitute material 1 is used in osteotomy for treating joint deformation and is filled into a wedge-like opening 10W formed by opening an osteotomy section in the shin bone 10. The bone substitute material is a block-like porous material made of β-TCP (β-tricalcium phosphate) which is molded into a hexahedron having an approximate trapezoidal side view. The bone substitute material is cut to a length that fits the thickness of the cortical bone 11 at the opening 10W and is filled into the position of the cortical bone 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bone prosthetic material used in osteotomy for osteoarthritis such as knee arthropathy.

  In osteoarthritis caused by degeneration of articular cartilage represented by knee arthropathy such as so-called O-legs, the angle between the bone axes of the bones on both sides of the joint deviates from the normal state as the deformation progresses. As a result, varus deformity or valgus deformity is enhanced, and the vicious cycle of joint deformation and cartilage degeneration is repeated, and the symptoms worsen. As an effective orthopedic surgical operation for such osteoarthritis, osteotomy is performed by performing osteotomy near the joint to correct the angle of the bone axis.

As such osteotomy, for example, an opening-wedge osteotomy as described in Non-Patent Document 1 has been proposed. In this osteotomy, a cut is made in the tibia from the lateral direction to form an osteotomy, and the osteotomy is opened in a wedge shape and opened so as to have a predetermined correction angle. In this state, the upper and lower bones are temporarily fixed using a plate and a screw. A bone filling material made of porous hydroxyapatite (HAP) formed in a wedge shape corresponding to the correction angle is embedded and filled in the opening. When a predetermined period of time has passed, the bone grows and bone is also formed in the pores of the HAP, and the HAP is joined together with the cortical bone and cancellous bone of the tibia, so it is temporarily fixed. Remove plate and screw. Then, a predetermined treatment is performed on the affected part to finish the osteotomy. Thus, the bone axis is in a corrected state.
"MEDICAL OPENING-WEDGE HIGH TIBIAL OSTEOTOMY WITH USE OF POROUS HYROXYYA ATATETO TO TREAT MEDICAL COMPOTE OSTEOARTHRITIS OF THE NU J ORG, JANUARY 2003, VOLUME 85-A, NO 1, 78-85

  HAP has the advantage that it has a good affinity with bone and can be satisfactorily joined to bone tissue without inclusions, but it is not very resorbable to bone and is unlikely to be replaced with autologous bone in the future. There is a drawback. That is, the embedded HAP becomes a high-density lump in which bones are also formed inside and remains at the embedding position.

  When approximately 10 to 15 years have passed since the osteotomy has been performed, an operation for implanting an artificial joint may have to be performed. When performing such an operation, at least a part of the tibia must be excised, but if HAP remains in the bone as a high-density mass, there is a problem that it is difficult to remove. In particular, if such a mass remains in cancellous bone having a relatively low density among bones, there is a possibility that surgery becomes difficult and a long time is required. However, when HAP is used as a bone replacement material, it is difficult to replace it with autologous bone as described above, so it is necessary to secure a wide contact area with the bone. There were circumstances that had to be done.

  The present invention has been made in view of the above circumstances, can be bone replacement according to the structure of the bone, can be replaced in a short period of time after replacement, and can be easily removed thereafter An object is to provide a bone grafting material.

  The invention according to claim 1 is a bone prosthesis material used in osteotomy for joint deformation, wherein the osteotomy formed in the bone in the vicinity of the joint is supplemented in an opening that opens in a wedge shape. A block-shaped porous body of β-tricalcium phosphate formed into a hexahedron having a substantially rectangular shape in plan view and a trapezoidal shape in side view, and a length that can be accommodated within the thickness of cortical bone in the opening. And the position of the cortical bone is compensated.

  The invention according to claim 2 is the bone prosthetic material according to claim 1, wherein the length of the block-shaped porous body is set in a range of 7 to 9 mm.

  Invention of Claim 3 is the bone grafting material of Claim 1 or Claim 2, Comprising: The angle made by the back surface and upper surface of the said block-shaped porous body is set to 74-76 degrees. In addition, the angle formed by the back surface and the bottom surface is set to be substantially a right angle.

  The invention according to claim 4 is a bone prosthetic material used in osteotomy for joint deformation, wherein the osteotomy formed in the bone in the vicinity of the joint is supplemented in an opening that is opened in a wedge shape. It is comprised by the composite material containing the porous granule of (beta) -tricalcium phosphate, and a bone marrow, It is characterized by being filled in the position of the cancellous bone in the said opening part.

In this way, since the bone filling material is constituted by the block-like porous body of β-tricalcium phosphate, the bone resorption is considered to be extremely good, and replacement with the autologous bone after filling is performed in a short period of time. Can be done accurately. And since it is formed into a hexahedron having a substantially trapezoidal shape when viewed from the side, it is possible to make close contact with the cut surfaces on both sides in the opening that opens in a wedge shape, and to perform autologous bone replacement more accurately. .
Further, since the length can be accommodated within the thickness of the cortical bone, that is, the length that hardly enters the position of the cancellous bone, the autologous bone replacement can be performed with only the cortical bone. In other words, autologous bone replacement suitable for cortical bone, which is a dense structural part of bone, can be obtained, and there is no possibility of remaining as a massive foreign body in cancellous bone, and removal from the bone after supplementation is easy. be able to. Therefore, even when an artificial joint implantation operation is performed later, the operation can be easily and accurately performed with high efficiency.

  If the length of the block-shaped porous body is set within a range of 7 to 9 mm, the length can be almost accommodated within the thickness of the cortical bone in a general human tibia.

  Furthermore, if the angle formed between the back surface and the top surface of the block-shaped porous body is set to 74 to 76 °, and the angle formed between the back surface and the bottom surface is set to a substantially right angle, between the cut surfaces on both sides of the opening. Even when applied to an opening-wedge osteotomy or the like to which a high compressive force is applied, it is possible to obtain a structure that is unlikely to be cracked or damaged and that can maintain high durability.

  Furthermore, since the position of the cancellous bone in the opening is supplemented with a bone grafting material composed of a composite material including porous granules of β-tricalcium phosphate and bone marrow, it is relatively low among bones. Autologous bone replacement suitable for cancellous bone, which is a dense structural portion, is obtained, and removal from the bone after filling can be easily performed. Therefore, even when an artificial joint implantation operation is performed later, the operation can be easily and accurately performed with high efficiency.

Embodiments of the present invention will be described below.
The bone prosthetic materials 1 and 2 according to the present embodiment are openings in which an osteotomy portion formed in the tibia near the knee joint is opened in a wedge shape in an example in which an opening-wedge osteotomy is performed on a so-called O-leg patient. It is to be embedded and filled in the part.

  First, as a preparatory work before osteotomy, a porous body made of β-tricalcium phosphate (β-TCP) is made into a block shape in advance so as to match the desired shape, that is, the shape of the bone defect to be compensated. Mold it. This β-TCP is used as a scaffolding material that serves as a base for a bone grafting material, and is manufactured by, for example, a method disclosed in Japanese Patent No. 2597355.

  Specifically, first, an aqueous solution containing a peptizer is added to and mixed with the β-TCP fine powder to prepare a β-TCP-containing slurry. Next, a foaming slurry is prepared by adding and stirring a foaming agent to the β-TCP-containing slurry to cause foaming. Further, the foamed slurry is poured into a container having a desired shape and dried to produce a porous formed body having a skeleton bonded by a peptizer while maintaining continuous fine pores (pores). Finally, the porous body is sintered at a high temperature. In this way, a block-shaped porous sintered body of β-TCP is obtained in which fine continuous pores are distributed almost uniformly throughout and have a practically sufficient strength.

In the opening-wedge osteotomy, this block-shaped porous body is used as a bone prosthetic material 1 for embedding and filling an osteotomy portion formed in the tibia or femur into an opening that is opened like a wedge. As shown in FIG. 1, the bone grafting material 1 is formed into a hexahedron having a substantially rectangular shape in plan view and a substantially trapezoidal shape in side view. In this figure, reference numeral 1a indicates a front surface, reference numeral 1b indicates a rear surface, reference numeral 1c indicates an upper surface, reference numeral 1d indicates a lower surface, and reference numeral 1e indicates a pair of side surfaces.
The length 1 of the bone prosthetic material 1 is set to a length that can be almost completely accommodated within the thickness of the cortical bone in a general human tibia, and is specifically set within a range of 7 to 9 mm. Has been. The height t is set in the range of 10 to 13 mm, and the width w is set in the range of 9 to 11 mm.

  Further, the angle θ1 formed between the back surface 1b and the upper surface 1c is set within a range of 74 to 76 °, and the angle θ2 formed between the back surface 1b and the lower surface 1d is within a range of 89 to 91 °, that is, approximately. It is set at a right angle. Thus, the reason why the upper surface 1c and the lower surface 1d are made non-parallel is to allow close contact with the cut surfaces on both sides when they are filled in the wedge-shaped opening. Therefore, the angle θ1 on one side (here, the upper side) is appropriately set in accordance with the opening angle of the opening, that is, the correction angle. In addition, the reason why the angle θ2 on the other side (here, the lower side) is set to a substantially right angle is to maintain a high strength in the opening to which a high compressive force is applied.

Next, an example in which an opening-wedge osteotomy is performed on a patient using such a bone grafting material 1 will be described with reference to FIGS.
First, the X-ray fluoroscopy or external examination of the entire lower limbs of the patient is performed in advance to confirm the correction angle of the tibia in advance. This correction angle is normally set within a range of 14 to 16 °, more preferably 15 to 16 °.

  After confirming the correction angle, cut the knee and perform osteotomy. Before performing osteotomy, a diagnostic arthroscopy or the like is performed to check the state of the articular cartilage and the meniscus. If debridement and excision are necessary, do so at this time.

  The patient's knee joint is shown in FIG. In this patient, the inner side of the articular cartilage (left side in the figure) has been deformed due to wear or the like, and the bone axis of the tibia 10 is tilted inward from the bone axis of the femur 20. For this reason, as shown in the same figure, using a jig for osteotomy or the like, a straight cut is made from the lateral direction inside the vicinity of the joint of the tibia 10 to form an osteotomy portion 10C. Specifically, the inner side, the front side, and the rear side of the cortical bone of the tibia 10 are excised to the maximum depth, and the outer part is left without being excised. At this time, since it is necessary to take care not to damage the cancellous bone of the tibia 10 unnecessarily, for example, the X-ray fluoroscopic image is carefully removed while being confirmed.

  Next, as shown in FIG. 3, a bone cutting wedge G having a wedge shape with the distal end set at a predetermined angle is inserted into the bone cutting part 10 </ b> C, and the bone cutting part 10 is opened. The “predetermined angle” on the distal end side needs to be set to an opening angle that matches the correction angle of the tibia 10. That is, as described above, the bone cutting wedge 1G that is normally set within the range of 14 to 16 °, more preferably 15 to 16 ° is used. Thus, an opening 10W is formed on the inner side of the tibia 10 in a state where the cut surface 10f1 and the cut surface 10f2 are opened up and down in a wedge shape.

  Then, the plates P shown in FIG. 4 are placed between the upper and lower tibias 10 sandwiching the opening 10 and fixed. As an operation, the opening angle of the opening 10W is maintained by the bone cutting wedge 10, and the upper side of the plate P is firmly fixed to the upper tibia 10 with the screw S, and the plate P is fixed to the lower tibia 10 The lower side is firmly fixed with the screw S, and then the osteotomy wedge G is removed. FIG. 4 shows this state. As shown in this figure, since the upper and lower tibias 10 are firmly fixed by the plate P, the opening 10W is held in a state of being opened in a wedge shape by the correction angle.

Here, the bone grafting material 2 is adjusted.
The bone grafting material 2 is composed of a composite material including β-TCP porous granules and bone marrow. The β-TCP porous granule used here is preferably a granule obtained by finely pulverizing a product produced by the same method as the bone grafting material 1. The particle diameter of the β-TCP porous granule is preferably set in the range of 0.01 μm to 3 mm.
The bone marrow used here is collected from the cancellous bone 12 (shown in FIG. 5B) in the opening 10W. The bone marrow is mixed with the β-TCP porous granule to obtain a mixture of bone marrow and β-TCP porous granule. At this time, it is more preferable if the bone marrow is sufficiently distributed in the pores of the β-TCP porous granule.

  If bone marrow is left as it is after it is collected, a coagulation reaction takes place inside, so that its viscosity gradually increases and gradually solidifies. That is, the mixture of bone marrow and β-TCP porous granule gradually changes its form and is allowed to stand for a predetermined time to finally obtain a solid consisting of bone marrow / β-TCP composite material. This composite material is used as the bone grafting material 2.

  In addition, although such a mixture may be left as it is for a predetermined time to obtain a composite material, thrombin may be added and mixed as a coagulant to this mixture. Since thrombin clots whole blood, plasma, etc. in the bone marrow, the viscosity of this fluid can be increased, and the time until the coagulation reaction is completed (coagulation time) can be shortened. That is, the coagulation time can be controlled by appropriately setting the amount of thrombin added. Therefore, the manufacturing time of the bone prosthetic material 2 can be set as appropriate according to the surgical condition and the like.

  Furthermore, if platelet-rich plasma (PRP) is added to and mixed with this mixture, the coagulation reaction can be activated so that the viscosity can be easily controlled. That is, if the amount of plasma in the bone marrow increases, the coagulation reaction rate changes accordingly, so that it can be finely controlled by using it together with thrombin.

  In addition, PRP contains various natural formation factors (autologous growth factors) such as TGF-β1, PDGF, and IGF-1, and activation of osteoblasts and the like is promoted by these formation factors. I know that. Therefore, if β-TCP containing such PRP is used as a bone grafting material to fill a bone defect part, osteoblasts and the like around the bone grafting material are immediately activated and quickly penetrate into the pores of β-TCP. As a result, cell adhesion to β-TCP is realized at an early stage, and bone formation is promoted.

  The PRP collects blood from the patient during surgery and extracts it from the blood. This extraction of PRP is performed, for example, by a known centrifugation method. Then, the extracted PRP is added to and mixed with the mixture. At this time, PRP should be sufficiently distributed in the pores of β-TCP.

  By mixing PRP with β-TCP together with bone marrow, the behavior of β-TCP, such as osteoblasts contained in the bone marrow, is activated in-vitro by the action of PRP-forming factors. The When β-TCP containing PRP and bone marrow is used as a bone grafting material to fill a bone defect, as described above, the osteoblasts around the bone grafting material are immediately affected by the action of the PRP forming factor. It is activated and rapidly penetrates into the pores of β-TCP, and cell adhesion to β-TCP is realized at an early stage. At this time, since osteoblasts and the like on β-TCP are in an activated state in advance, these cells try to quickly start activities in β-TCP. As a result, cell adhesion to β-TCP is realized more quickly and accurately.

  As shown in FIGS. 5 (a) and 5 (b), the bone prosthetic material 2 thus adjusted and mixed is embedded and supplemented at the position of the cancellous bone 12 in the opening 10W. Then, the bone grafting material 1 is embedded and filled in the position of the cortical bone 11 in the opening 10W. The bone filling material 2 in a mixed state is solidified by being left for a predetermined time after filling, becomes a solid made of bone marrow / β-TCP composite material, and comes into close contact with the upper and lower cut surfaces 10f1 and 10f2 of the cancellous bone 12 respectively. . The upper surface 1c of the bone grafting material 1 is in close contact with the upper cut surface 10f1 of the cortical bone 11, and the lower surface 1d is in close contact with the lower cut surface 10f2 of the cortical bone 11.

  Thereafter, the bone substitute material 1 is replaced with cortical bone 11, and the bone substitute material 2 is replaced with cancellous bone 12. When the bone replacement progresses and the tibia 10 can secure a predetermined strength, the screw S and the plate P are removed. Then, a predetermined treatment is performed on the affected part to finish the osteotomy. Thus, the bone axis is in a corrected state.

In the present embodiment, since the bone grafting material 1 is constituted by the block-shaped porous body of β-TCP, the resorption to the tibia 10 is considered to be extremely good, and replacement with the autologous bone after the filling is performed in a short time. Can be done accurately. And since this bone prosthetic material 1 is formed into a hexahedron having a substantially trapezoidal shape when viewed from the side, it can be brought into close contact with the cut surfaces 10f1 and 10f2 on both the upper and lower sides in the opening 10W opened in a wedge shape. Thus, autologous bone replacement can be performed more accurately.
In addition, the length l of the bone grafting material 1 is set to a length that is almost within the thickness of the cortical bone 11, that is, a length that hardly enters the position of the cancellous bone 12. Bone replacement can be performed. That is, autologous bone replacement suitable for the cortical bone 11, which is a dense structural portion of the bone, is obtained, and there is no possibility of remaining as a massive foreign body in the cancellous bone 12, and removal from the tibia 10 after filling is also possible. It can be done easily. Therefore, even when an artificial joint implantation operation is performed later, the operation can be easily and accurately performed with high efficiency.

  If the length of the block-shaped porous body is set within a range of 7 to 9 mm, the length can be almost accommodated within the thickness of the cortical bone in a general human tibia.

  Further, the angle θ1 formed between the back surface 1b and the top surface 1c is set to 74 to 76 °, and the angle θ2 formed between the back surface 1b and the bottom surface 1d is set to be substantially a right angle. Even when applied to an opening-wedge osteotomy or the like in which a high compressive force is applied between the surfaces 10f1 and 10f2, cracks, defects and the like are hardly generated and a structure capable of maintaining high durability can be obtained.

  Furthermore, the position of the cancellous bone 12 in the opening 12W is supplemented with the bone grafting material 2 composed of a composite material including β-TCP porous granule and bone marrow, so that it is relatively low among bones. Autologous bone replacement suitable for the cancellous bone 12 which is a dense structural part is obtained, there is no possibility of remaining as a lump-like foreign body in the cancellous bone 12, and removal from the tibia 10 after filling can be easily performed. . Therefore, even when an artificial joint implantation operation is performed later, the operation can be easily and accurately performed with high efficiency.

  Furthermore, since the bone prosthetic material 2 is manufactured by using bone marrow and PRP that can be directly collected from the patient, the bone prosthetic material can be manufactured within a short time such as during osteotomy. Once completed, it can be quickly implanted and filled into the patient's body. Then, since both PRP and bone marrow are collected from the patient and returned to the same patient's body, there is no risk of rejection and the like, and an extremely reliable osteotomy can be performed accurately.

It is a perspective view which shows schematic structure of the bone grafting material which concerns on one Embodiment of this invention. It is a schematic side view which shows the state which formed the osteotomy part in the tibia. It is a schematic side view which shows the state which opened the osteotomy part of the tibia shown in FIG. 2 in the shape of a wedge. It is a schematic perspective view which shows the state which fixed the upper and lower tibia shown in FIG. 3 with the plate. It is a figure which shows the state which supplemented the bone grafting material to the opening part shown in FIG. 4, Comprising: (a) is a cross-sectional view of a tibia, (b) is a longitudinal cross-sectional view of a tibia.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bone prosthetic material 1b Back surface 1c Upper surface 1d Lower surface 2 Bone prosthetic material 10 Tibia (bone)
10C osteotomy part 10W opening part 11 cortical bone 12 cancellous bone θ1, θ2 angle

Claims (4)

A bone prosthesis material used in osteotomy for joint deformation, wherein the osteotomy formed in the bone in the vicinity of the joint is supplemented in an opening that opens in a wedge shape,
It is constituted by a block-like porous body of β-tricalcium phosphate, which is formed into a hexahedron having a substantially rectangular shape in plan view and a substantially trapezoidal shape in side view,
A bone prosthetic material that has a length that can be accommodated within the thickness of the cortical bone in the opening and is supplemented to the position of the cortical bone.   The bone grafting material according to claim 1, wherein a length of the block-shaped porous body is set within a range of 7 to 9 mm.   The angle formed between the back surface and the top surface of the block-shaped porous body is set within a range of 74 to 76 °, and the angle formed between the back surface and the bottom surface is set to be substantially a right angle. The bone prosthetic material described in 1. A bone prosthesis material used in osteotomy for joint deformation, wherein the osteotomy formed in the bone in the vicinity of the joint is supplemented in an opening that opens in a wedge shape,
A bone grafting material comprising a composite material comprising β-tricalcium phosphate porous granules and bone marrow, and being supplemented at the position of cancellous bone in the opening.

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