JPH0690973A - Intrabone fixing body - Google Patents

Abstract

PURPOSE:To prevent the osteodeformation to be successively generated by efficiently fixing two bones to each other. CONSTITUTION:The intrabone fixing body constituted by forming screw threads 14 for screwing of the bone part capable of fixing the two bone parts to be joined to each other on at least one point in the outer side part of a cylindrical body 11 is obtd. The cylindrical body 11 has openings 12, 13 at the top and the bottom, consists of metal, synthetic resin or composite material and has a cylindrical structure. The shape of the cross section is circular or polygon and has the screw threads 14 in a part or the whole of the outside wall thereof. The cylinder has a partition wall at its center in some cases. This fixing body is inserted into the bones to fix the two bones to each other and is used for treatment of bone diseases, such as bone fracture and osteonecrosis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intraosseous fixed body used for fixing bone in the treatment of bone diseases such as bone fracture and osteonecrosis.

[0002]

2. Description of the Related Art In the treatment of bone diseases such as fractures, screws have been frequently used to fix two bone parts to be joined. The screw is inserted into the bone and connects and fixes two or more bone parts to each other. Recently, sliding screws and cannulated screws have also been used. Here, the sliding screw is
It consists of a screw and an outer cylinder that contains the root of the screw, and the screw can slide in the outer cylinder. The screw and barrel are inserted into the bone and interconnect the two parts. The screw is movable only in the axial direction of the outer cylinder, and the screw slides in the outer cylinder to prevent a gap from being formed between the connected portions.

The cannulated screw has almost the same shape as an ordinary screw, but has a thin hole through which a steel wire is inserted in the central axis of the screw. It is used to insert into bone and connect two or more parts together. When inserting
Insert the thin steel wire first, make sure that it enters the target area, then insert the cannulated screw using the steel wire as a guide, and then remove the steel wire.

[0004]

However, the conventional screw or the like has a problem that bone deformation may occur after fixation. That is, bone is composed of hard bone tissue and soft bone marrow tissue, blood circulates inside, and each cell is nourished. Trabecular bone is a solid structure made of fine mesh-like bone tissue containing calcium in the bone.
This continuous connection maintains the mechanical strength of the bone (especially the epiphyses). In a fracture, the trabecular bone is broken at the fracture and the bone splits into two or more parts (fragments). In order for the fracture to heal, it is necessary for the trabecular bones to be reconnected by a biological repair action and to obtain continuity. The tissue involved in repair usually invades the fracture from each bone fragment. Internal fixation materials are used to immobilize bones during such repair processes.

However, since the conventional internal fixation material is a solid type, the repair process is performed only on the bone outside the internal fixation material,
The larger the inner fixing material, the smaller the part that heals. Further, in a fracture near the joint, a blood vessel that enters a bone piece on the joint surface side is damaged, the bone piece loses blood flow, and cells may die to become necrotic bone. In this case, the trabecular bone in the bone fragment (necrotic bone) on the joint surface side is in a dead state. The repaired tissue reaches the fractured portion from the bone fragment on the side opposite to the joint surface, heals the fractured bone, and further enters the necrotic bone to regenerate it. However, during the process of regenerating necrotic bone, the resorption of dead trabecular bone may occur prior to the formation of new trabecular bone, and that part may become mechanically weak. Therefore, since a structural defect surface is formed inside the fracture (necrotic bone) on the joint surface side, the joint surface may be depressed and deformed like a landslide after the fracture is fused. In this case, the compatibility of the joint surface is lost and the joint is inevitable. That is, the fracture is fused, but the joint function is impaired.

[0006] There is also a disease called osteonecrosis in which some cells of bone die to become necrotic bone. There is a boundary surface between a living bone and a necrotic bone, and repair tissue invades from the living bone into the necrotic bone to regenerate the bone. In the trabecular bone of necrotic bone, the cells are dead, but the trabecular structure is continuous with the trabecular bone of living bone and maintains the same strength as before necrosis. However, during the regeneration process, when the repaired tissue absorbs the dead trabecular bone, that part becomes mechanically weak. When this disease occurs in the vicinity of the joint, the joint surface may be depressed and deformed and the joint may be destroyed in a similar process to the case of the fracture near the joint. The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an intraosseous fixation body that efficiently fixes two bone parts to each other and prevents the occurrence of bone deformation after fixation. It is in.

[0007]

The bone anchoring body of the present invention comprises:
It has a tubular shape, and is characterized in that a screw thread for screwing in a bone portion for fixing two bone portions to each other is formed on at least a part of an outer side portion of the tubular body. That is, the intraosseous fixation body of the present invention, in the treatment of bone diseases such as bone fracture and osteonecrosis, is inserted into the bone, and at the same time fixing the two parts,
The purpose is to divide the bones of the two parts to be fixed into the inside and the outside of the cylinder so that the bones also exist inside the inner fixing material. The intraosseous fixation body is made of metal, synthetic resin, composite material, or the like. The outer shape of the cross section is circular or polygonal, and threads are carved on a part or all of the outer wall.

[0008]

According to the intraosseous fixed body of the present invention,
First, the area of bone involved in healing is increased. Second, the bone inside the tube also contributes to the fixation, thus increasing the stability of fixation. Thirdly, when there is necrotic bone due to a fracture or osteonecrosis in the vicinity of the joint, depression and deformation of the joint surface can be prevented. That is, by inserting the tubular intraosseous fixation body into the boundary surface between the living bone and the necrotic bone, the living bone, the boundary surface (fracture surface), and the necrotic bone are respectively divided into the inside and outside of the intraosseous fixation body. It On this occasion,
By the operation of inserting the intraosseous fixed body, the blood flow inside the intraosseous fixed body is blocked. Therefore, the bone in the inner part of the intraosseous fixation body among the living bones becomes necrotic bone. Therefore,
The boundary between the living bone and the necrotic bone is different from that before the insertion, and has a mushroom-like shape by adding a columnar extending portion to the side of the living bone. Therefore, the fragile portion formed inside the necrotic bone during the repair process is not a simple surface as in the case where the intraosseous fixing body is not inserted, and depression or deformation such as landslide is less likely to occur. Also, during the repair process, the fragile portion generated on the outer side of the intraosseous fixation body is supported by the fixing force of the intraosseous fixation body and the necrotic bone inside the intraosseous fixation body. By such an action, the mechanical strength of the necrotic bone in the repair process is maintained, and the depression and deformation of the joint surface are prevented.

[0009]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. An embodiment of the tubular intraosseous fixation body of the present invention is shown in FIG. In the figure, the intraosseous fixed body 11 has a tubular shape, and upper and lower ends 12 and 13 are open, and a screw thread 14 is provided on the outer side portion along the entire length. Next, an example of treating a bone fracture using the intraosseous fixation body according to the present embodiment will be described. That is, when connecting two bone parts, first, a groove 5 corresponding to the intraosseous fixation body 11 is dug from the fracture surface 4 side with a cylinder drill or cylinder chisel on one of the bone pieces 2 of the fracture (FIG. 2). . Then, a similar groove 5 is dug in the other bone piece 3 from the fracture surface 4 side (FIG. 3). Next, the tubular intraosseous fixation body 11 is screwed or driven into the groove 5 of the one bone piece 2 from the fracture surface 4 (FIG. 4). Finally, the tubular bone anchor 11 is screwed or driven into the groove 5 of the other bone piece 3 from the fracture surface 4,
Fix the bone fragments 2 and 3 on both sides (Fig. 5). In the case where the bone necrosis 6 occurs (hatched portion in FIG. 6), a hole is drilled from the outside of the bone piece 7 (direction of arrow 9 in FIG. 7), passes through the normal bone, crosses the boundary surface 8, and is a necrotic bone. Dig the groove 5 up to 6 (FIG. 7). Then, the tubular intraosseous fixation body is screwed in or driven in the direction of the arrow 9 to be fixed so as to straddle the bones 6 and 7 on both sides of the boundary surface 8 (FIG. 8). FIG. 9 shows an intraosseous fixed body 1 according to this embodiment.
1 shows a state in which the bone fragments 2 and 3 are joined and fixed. It is also possible to have the partition wall 10 inside the cylinder of the fixed body 11 (FIG. 10).

[Brief description of drawings]

FIG. 1 is a perspective view of a tubular intraosseous fixation material according to the present invention.

FIG. 2 is a schematic perspective view showing a state in which a groove corresponding to an internal fixation material is dug in one bone fragment of a fracture.

FIG. 3 is a perspective view showing a state in which a groove corresponding to an internal fixation material is dug in the other fracture of the fracture.

FIG. 4 is a perspective view showing a state in which an intraosseous fixing material is inserted into one bone fragment of a fracture.

FIG. 5 is a perspective view showing a state in which a bone fracture is fixed with a tubular intraosseous fixing material.

FIG. 6 is a perspective view of an osteonecrotic bone.

FIG. 7 is a perspective view showing a state in which a groove crossing the boundary surface of osteonecrosis is cut from the outside (lower surface) of the bone.

FIG. 8 is a perspective view when an intraosseous fixation body is used for osteonecrosis.

9 is a schematic diagram showing a state in which a bone fragment is fixed using the intraosseous fixing body shown in FIG. 1. FIG.

FIG. 10 is a perspective view of an intraosseous fixing body having a partition wall therein.

[Explanation of symbols]

 2 …… One bone fragment of the fracture 3 …… The other bone fragment of the fracture 4 …… The fracture surface 5 …… The groove dug inside the bone 6 …… Necrotic bone (diagonal line) 7 …… Normal bone 8 …… Boundary surface 9 ・ ・ ・ Arrow indicating the direction of digging the groove 10 ・ ・ ・ Partition wall 11 ・ ・ ・ Cylindrical bone anchor

Claims (1)

[Claims] 1. A tubular shape is formed, and a screw thread for screwing in a bone portion capable of fixing two bone portions to be joined to each other is formed at least at one location on an outer side portion of the tubular body. An intraosseous fixed body characterized by being formed.