Bone joint component set

Abstract

To provide an osteosynthesis member set that can securely fix a patient's fracture site and is easy for the practitioner to operate.SOLUTION: The osteosynthesis member set includes a shaft part, screw threads, a shaft hole 218, an osteosynthesis member 201 inserted through an intramedullary nail, and an injection implement 301 capable of injecting an intraosseous injection agent into the bone. The osteosynthesis member 201 includes an absence part provided on the unit screw thread so that the internal space of a pair of adjacent screw grooves faces across the unit screw thread when a 360° round of the screw thread is considered as the unit screw thread, a hole 215 provided on the shaft part so that it is connected to the absence part, and an osteosynthesis member positioning portion 212A. The injection implement 301 includes an injection nozzle 304 that can be inserted into the shaft hole 218 of the osteosynthesis member 201, an injection port 305 provided at the tip of the injection nozzle 304, and an injector-side positioning portion 309.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a bone joint member set used for bone jointing.

Background Art

[0002] Conventionally, as a method for treating a fracture near the bone head of a bone having a bone head such as the femur and the humerus, along the axial direction of the bone, an intramedullary nail (nail) inserted into the bone and a bone fixation element (lag screw) inserted through the intramedullary nail have been proposed. And a surgical instrument (bone fixation device) is used. The bone fixation element has a distal portion including a bone engagement structure such as a thread. Further, the distal portion is opened with respect to a channel extending inside, and has an opening used for allowing injection of a material (for example, a bone strengthening material) into the bone after implantation (see, for example, Patent Document 1). And the opening is provided in the thread groove between adjacent threads. The bone strengthening material extruded from the opening flows along the thread groove.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the bone fixation device of Patent Document 1, materials such as a bone strengthening material harden while filling the thread groove and spreading around the distal portion. At this time, the bone fixation element is restrained and fixed by the hardened material.

[0005] [[ID=३9]]However, if a part of the hardened material is damaged due to some factor and a gap is formed between the distal portion of the bone fixation element and the hardened material, the restraint state of the bone fixation element becomes weak, and the bone fixation element easily rotates due to vibration caused by the movement of the patient. As a result, the bone fixation element cannot sufficiently fix the fracture part of the patient.

[0006] Furthermore, when removing bone fixation elements, if they are firmly restrained by hardened material, it is necessary to apply a large rotational force to the bone fixation elements. However, applying too much rotational force may destroy the bone, making removal difficult.

[0007] In view of these circumstances, the present invention aims to provide a bone fixation member set that can reliably fix the fracture site of a patient and is easy for the practitioner to operate. [Means for solving the problem]

[0008] The bone fixation member set of the present invention comprises a bone fixation member having a shaft portion, a screw thread spirally revolving around the circumferential surface of the shaft portion, and an axial hole extending axially inside the shaft portion, and being inserted into an intramedullary nail, and an injection device capable of injecting an intraosseous injection agent into the bone, wherein the bone fixation member has a defect portion provided on the unit screw thread such that when one full rotation of the screw thread is considered as a unit screw thread, the internal spaces of a pair of adjacent screw grooves on either side of the unit screw thread face each other, and the defect portion and the shaft hole The injection device has a hole provided in the shaft portion so as to communicate with the bone joint member, and a bone joint member side positioning portion, and the injection device has an injection nozzle that can be inserted into the shaft hole of the bone joint member, an injection port provided at the tip of the injection nozzle, and an injection device side positioning portion, and the injection device is positioned relative to the bone joint member by the bone joint member side positioning portion and the injection device side positioning portion, thereby the injection port and The aforementioned hole Position them so that they overlap. It is characterized by the fact that it is possible. [Effects of the Invention]

[0009] The bone fixation member set of the present invention can reliably fix the fracture site of a patient and also provides a bone fixation member set that is easy for the practitioner to operate, thus achieving excellent effects. [Brief explanation of the drawing]

[0010] [Figure 1] (A) is a perspective view showing the bone fixation device according to the first embodiment of the present invention attached to a patient's fracture site. (B) is a cross-sectional view of (A). [Figure 2] (A) is a diagram showing a bone joint member in the first embodiment of the present invention. (B) is a cross-sectional view of the bone joint member cut along the axial direction. [Figure 3] (A) is an enlarged plan view of the region including the screw engagement portion of the bone joint member in the first embodiment of the present invention. (B) is a perspective view of the region including the screw engagement portion of the bone joint member in the first embodiment of the present invention. (C) is a schematic enlarged plan view of the region including the defect portion of the bone joint member in the first embodiment of the present invention. (D) is a schematic enlarged cross-sectional view of the region including the defect portion of the bone joint member in the first embodiment of the present invention. [Figure 4] (A) to (C) are schematic diagrams of enlarged cross-sections of the region including the defective portion in a modified example of the defective portion of the bone joint member in the first embodiment of the present invention. [Figure 5] (A) to (C) are schematic enlarged plan views of the region including modified examples of the bore portion of the bone joint member in the first embodiment of the present invention. (D) is a schematic cross-section of (C) taken along the arrow DD. [Figure 6] (A) is an enlarged plan view of the region including the screw engagement portion of the bone joint member in the first embodiment of the present invention. (B) is a cross-sectional view of (A) taken along the FF arrow. [Figure 7] (A) is a plan view of the bone joint member in the first embodiment of the present invention. (B) is a left side view, front view, and right side view of the bone joint member in the first embodiment of the present invention, from left to right. (C) is a bottom view of the bone joint member in the first embodiment of the present invention. (D) is a rear view of the bone joint member in the first embodiment of the present invention. (E) is a perspective view of the bone joint member in the first embodiment of the present invention. [Figure 8] This is a schematic diagram showing the intraosseous injection device of the bone fixation device set in the first embodiment of the present invention. [Figure 9](A) is a schematic diagram of the intraosseous injection device in the first embodiment of the present invention immediately before insertion into the bone fixation member. (B) is a schematic diagram of the intraosseous injection device in the first embodiment of the present invention after insertion into the bone fixation member. [Figure 10] Figures (A) to (C) are schematic diagrams of enlarged planes arranged in chronological order showing how the intraosseous injection material extruded from the intraosseous injection material insertion device in the first embodiment of the present invention begins to spread through the hole to the surface of the shaft. [Figure 11] Figures (A) to (C) are schematic diagrams of enlarged cross-sections arranged in chronological order, showing how the intraosseous injection material extruded from the intraosseous injection material insertion device in the first embodiment of the present invention begins to spread through the hole to the surface of the shaft. [Figure 12] Figures (A) to (D) are enlarged front views arranged in chronological order showing how the intraosseous injection material extruded from the intraosseous injection material insertion device in the first embodiment of the present invention begins to spread through the hole to the surface of the shaft. [Figure 13] (A) is a schematic enlarged plan view showing how the intraosseous injection material is filled in the region including the defect and hole of the bone fixation member in the first embodiment of the present invention. (B) is a schematic cross-section in the direction of arrow BB in (A). (C) is a schematic enlarged plan view showing how a gap has formed between the intraosseous injection material and the bone fixation member in the same state as in (A). (D) is a schematic enlarged cross-section showing how a gap has formed between the intraosseous injection material and the bone fixation member in the same state as in (B). [Figure 14] (A) is a schematic enlarged plan view showing the area of ​​a conventional bone fixation member, including the hole, filled with an intraosseous injection material. (B) is a schematic cross-section of (A) taken along the arrow BB. (C) is a schematic enlarged plan view showing a gap between the intraosseous injection material and the bone fixation member in the same state as (A). (D) is a schematic enlarged cross-section showing a gap between the intraosseous injection material and the bone fixation member in the same state as (B). [Figure 15] This is an enlarged plan view of a bone joint member in which, as a modified example of the bone joint member in the first embodiment of the present invention, three consecutive defects are provided in adjacent unit screw threads. [Figure 16](A) is a plan view of the bone joint member in the second embodiment of the present invention. (B) is a front view of the bone joint member in the second embodiment of the present invention. (C) is a bottom view of the bone joint member in the second embodiment of the present invention. (D) is a rear view of the bone joint member in the second embodiment of the present invention. [Figure 17] (A) is a plan view of the bone joint member in the third embodiment of the present invention. (B) is a front view of a modified example of the bone joint member in the third embodiment of the present invention. [Figure 18] It is a schematic view showing the bone joint member in the fourth embodiment of the present invention. [Figure 19] (A) is a right side view of the bone joint member in the first embodiment of the present invention. (B) is a front view of the bone joint member in the first embodiment of the present invention. (C) is a left side view of the bone joint member in the first embodiment of the present invention. (D) is a rear view of the bone joint member in the first embodiment of the present invention. (E) is a plan view of the bone joint member in the first embodiment of the present invention. (F) is a bottom view of the bone joint member in the first embodiment of the present invention. [Figure 20] (The left view of (A) is a right side view of the bone joint member in the first embodiment of the present invention. The middle view is a cross-sectional view taken along the A-A arrow of the left view, and the right view is an enlarged cross-sectional view taken along the A-A arrow of the left view. (The left view of (B) is a front view of the bone joint member in the first embodiment of the present invention. The middle view is a cross-sectional view taken along the B-B arrow of the left view, and the right view is an enlarged cross-sectional view taken along the B-B arrow of the left view. (The left view of (C) is a left side view of the bone joint member in the first embodiment of the present invention. The middle view is a cross-sectional view taken along the C-C arrow of the left view, and the right view is an enlarged cross-sectional view taken along the C-C arrow of the left view. (D) is a rear view of the bone joint member in the first embodiment of the present invention. The middle view is a cross-sectional view taken along the D-D arrow of the left view, and the right view is an enlarged cross-sectional view taken along the D-D arrow of the left view. [Figure 21] (A) is a bottom view of the bone joint member in the first embodiment of the present invention. (B) is a cross-sectional view taken along the A-A arrow of (A). (C) is a cross-sectional view taken along the B-B arrow of (A). [Figure 22](A) is a right side view of the bone joining member in the first embodiment of the present invention. (B) is a front view of the bone joining member in the first embodiment of the present invention. (C) is a left side view of the bone joining member in the first embodiment of the present invention. (D) is a rear view of the bone joining member in the first embodiment of the present invention. (E) is a plan view of the bone joining member in the first embodiment of the present invention. (F) is a bottom view of the bone joining member in the first embodiment of the present invention. When the present invention is to be separately registered as a partial design, the part is represented by a solid line and the other parts are represented by a broken line here. The dashed-dotted line shown in the drawings represents only the boundary between the part to be registered as a partial design and the other parts. [Figure 23] (A) is a bottom view of the bone joining member in the first embodiment of the present invention. (B) is a sectional view taken along the A-A arrow in (A). (C) is a sectional view taken along the B-B arrow in (A). When the present invention is to be separately registered as a partial design, the part is represented by a solid line and the other parts are represented by a broken line here. [Figure 24] (A) is a right side view of the bone joining member in the first embodiment of the present invention. (B) is a front view of the bone joining member in the first embodiment of the present invention. (C) is a left side view of the bone joining member in the first embodiment of the present invention. (D) is a rear view of the bone joining member in the first embodiment of the present invention. (E) is a plan view of the bone joining member in the first embodiment of the present invention. (F) is a bottom view of the bone joining member in the first embodiment of the present invention. When the present invention is to be separately registered as a partial design, the part is represented by a solid line and the other parts are represented by a broken line here. The dashed-dotted line shown in the drawings represents only the boundary between the part to be registered as a partial design and the other parts. [Figure 25] (A) is an enlarged view of the tip side of FIG. 25(C). (B) is a sectional view taken along the B-B arrow in (A). (C) is a sectional view taken along the A-A arrow in (A).

Mode for Carrying Out the Invention

[0011] Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following figures, parts denoted by the same reference numerals represent the same object. In addition, some components are omitted in the figures to simplify them, and the size, shape, thickness, etc. of the components are exaggerated as appropriate.

[0012] <First Embodiment> First, the overall configuration of the bone fixation device 100 of the first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic diagram showing the state in which the fracture site of the femur 500 of a patient is fixed by the bone fixation device 100. Figure 1(A) is a perspective view showing the external appearance in part, and Figure 1(B) is a longitudinal cross-sectional view showing a part of the bone fixation device 100. In the following description, unless otherwise specified, directions will be determined based on the state in which the fracture site of the femur 500 of a patient is fixed by the bone fixation device 100. That is, the ventral side of the patient will be called "anterior", the dorsal side will be called "posterior", the cranial side of the patient will be called "upper", and the leg side of the patient will be called "lower". Figure 1 shows the femur 500 of the left leg as an example.

[0013] As shown in Figure 1(A), the bone fixation device 100 of this embodiment includes, for example, an intramedullary nail 101, a bone fixation member (lag screw) 201, and an intramedullary nail auxiliary device 10. The intramedullary nail auxiliary device 10 of this embodiment can be selectively attached to, for example, a conventionally known intramedullary nail 101. That is, in this embodiment, known intramedullary nails 101 and bone fixation members 201 can be used. The intramedullary nail auxiliary device 10 is attached to one end (upper end T (base end) side) of the intramedullary nail 101 in the axial direction AX1, which is a rod-shaped member whose overall shape is axial. In Figure 1, the axial direction AX1 of the intramedullary nail 101 is the vertical direction shown.

[0014] <Intramedullary nail> Refer to Figure 1(B) and explain the intramedullary nail 101. Note that the intramedullary nail support device 10 is not shown in Figure 1(B).

[0015] The intramedullary nail 101 is used by inserting it into the medullary cavity (lumen) of the femur 500. The intramedullary nail 101 has a proximal portion 102 which is the proximal end (upper end T) in the direction of axis AX1, and a distal portion 103 which is located on the distal end (lower end) side. The intramedullary nail 101 has an axial hole 105 that communicates with the proximal portion 102 and the distal portion 103, extends in the direction of axis AX1, and opens at both ends. Near the opening on the proximal portion 102 (upper end T) side of the axial hole 105, an internal thread 106 is formed on its inner wall (inner surface). Note that the axial hole 105 is provided only on the proximal portion 102 side of the intramedullary nail 101 and does not need to communicate with the distal portion 103. That is, the distal portion 103 may be a solid body.

[0016] The intramedullary nail 101 has a transverse hole 104 that extends in a direction intersecting the axial hole 105. The transverse hole 104 is a hole through which a bone fixation member (lag screw) 201 is inserted. The axial hole 105 opens into the transverse hole 104 midway through opening at both the upper and lower ends of the intramedullary nail 101, and at this position, the axial hole 105 and the transverse hole 104 are in communication with each other. In this connecting portion, more specifically in the axial hole 105 above the transverse hole 104, a set screw 451, which is a fixation device for the bone fixation member 201, is inserted.

[0017] In the cross-sectional view shown in Figure 1(B), the transverse hole 104 penetrates the intramedullary nail 101 at an angle, having an axis AX2 that is inclined with respect to the axis AX1 direction of the intramedullary nail 101. Hereinafter, the axis AX2 direction of the transverse hole 104 will also be referred to as the transverse hole axis direction.

[0018] The inclination angle of the transverse hole 104 (its axis AX2) in Figure 1(B) is appropriately set according to the application site of the bone fixation device 100 (such as the condition of the bone or the condition of the fracture), so that the fracture site near the femoral head 502 of the femur 500 can be fixed by the bone fixation member 201 when the intramedullary nail 101 is inserted into the medullary cavity of the femur 500. In this embodiment, as an example, the inclination angle is set to approximately coincide with the angle between the axial direction of the femur 500 (up and down direction in the figure) and the direction in which the femoral head 502 protrudes from the femur 500.

[0019] In this example, the intramedullary nail 101 penetrates the distal portion 103 and has fixation device insertion holes 108 that are open on both ends of the outer circumferential surface of the distal portion 103. The fixation device insertion holes 108 are formed to penetrate the distal portion 103 in a direction approximately perpendicular to the axis AX1 direction. Screws 601 or the like are inserted through the fixation device insertion holes 108, thereby fixing the intramedullary nail 101 to the femur 500 at the distal portion 103 as well.

[0020] <Bone joint member (lag screw)> Referring to Figures 1 to 7, the bone joint member (lag screw) 201 according to this embodiment will be described in detail. As shown in Figure 1(B), the bone joint member (lag screw) 201 is a rod-shaped member whose overall shape is axial, and is inserted into the transverse hole 104 of the intramedullary nail 101. That is, the axial direction AX2 of the bone joint member 201 coincides with the axial direction AX2 of the transverse hole 104 (the direction of the transverse hole axis).

[0021] As shown in Figure 2(A), the bone fixation member 201 has a shaft portion 211 and a screw engagement portion 221 provided in a predetermined section on the tip side of the shaft portion 211. As shown in Figure 1(B), the fracture site near the bone head 502 is fixed by screwing the screw engagement portion 221 into the bone head 502 together with the shaft portion 211. The tip side of the shaft portion 211 refers to the side that is screwed into the bone head 502. The proximal end side of the shaft portion 211 refers to the end side opposite to the tip side of the shaft portion 211.

[0022] <Shaft> The shaft portion 211 will be described below with reference to Figures 1 and 2. As shown in Figure 1(B), the shaft portion 211 is a rod-shaped cylindrical body inserted into the lateral hole 104. As shown in Figure 2(A), in this embodiment, the shaft portion 211 has different outer diameters (maximum outer diameters) or cross-sectional areas in each section along the axis AX2 direction, with a large-diameter portion 212 in the base end section S1, a tapered portion 213 in the middle section S2, and a small-diameter portion 214 in the tip end section S3. The large-diameter portion 212, the tapered portion 213, and the small-diameter portion 214 are connected in sequence along the axis AX2 direction.

[0023] The large-diameter portion 212 is the part whose outer diameter (maximum outer diameter) or cross-sectional area is larger than that of the small-diameter portion 214, and forms the base-end section S1 of the shaft portion 211, starting from the base end of the shaft portion 211. The above cross-sectional area refers to the area of ​​the cross-section obtained by cutting the shaft portion 211 in a direction perpendicular to the axis AX2 direction. The tapered portion 213 is configured such that its outer diameter decreases from the base end to the tip end of the shaft portion 211, and forms the intermediate section S2 of the shaft portion 211, starting from the boundary with the large-diameter portion 212. The small-diameter portion 214 forms the tip-end section S3 of the shaft portion 211, starting from the boundary with the tapered portion 213. Incidentally, the tapered portion 213 is continuous with the large-diameter portion 212 at the base end where the outer diameter or cross-sectional area is larger, and is continuous with the small-diameter portion 214 at the tip end where the outer diameter or cross-sectional area is smaller.

[0024] Furthermore, as shown in Figures 2(A) and (B), the large-diameter portion 212 is provided with grooves 216 that are recessed in the radial direction R of the shaft portion 211, starting from the outer circumferential surface. Multiple grooves 216 are provided at intervals in the circumferential direction around the axis of the shaft portion 211. In this embodiment, four grooves 216 are provided at equal intervals (every 90 degrees) in the circumferential direction around the axis of the shaft portion 211. As shown in Figure 1(B), the grooves 216 are contacted, fitted, and / or pressed by the tip 451A of the set screw 451, thereby preventing the bone joint member 201 from rotating while it is inserted into the transverse hole 104 and fixing it to the intramedullary nail 101.

[0025] Furthermore, as shown in Figures 2(A) and (B), an engagement recess 212A is provided at the base end of the large-diameter portion 212 for fitting a device for rotating the shaft portion 211. The engagement recess 212A is recessed in the direction of axis AX2, starting from the base end 212C of the cylindrical peripheral wall 212B that constitutes the large-diameter portion 212. Four engagement recesses 212A are provided at intervals along the circumferential direction of the large-diameter portion 212. In this embodiment, it is preferable that the intervals are equal (every 90 degrees).

[0026] The shaft portion 211 is not limited to the above configuration; it may have the same diameter throughout its entire length, or it may have sections with different diameters mixed together in other ways.

[0027] Furthermore, as shown in the cross-sectional view of Figure 2(B), the shaft portion 211 has an internal shaft hole 218 extending in the direction of axis AX2. In this embodiment, the shaft hole 218 penetrates the shaft portion 211 (large diameter portion 212, tapered portion 213, small diameter portion 214), but is not limited to this. For example, the shaft hole 218 may extend from the opening 211D on the base end side of the shaft portion 211 to partway down the small diameter portion 214. The diameter of the shaft hole 218 is substantially the same from the base end to the tip of the shaft portion 211, but is not limited to this.

[0028] Furthermore, the small-diameter portion 214 has a cylindrical circumferential wall 214A surrounding the shaft hole 218. As shown in Figure 2(B), the small-diameter portion 214 has a hole 215 that penetrates the circumferential wall 214A. The hole 215 is preferably provided near the missing portion 223, which will be described later. The hole 215 is provided in one or more locations. In this embodiment, four holes 215 are provided at equal intervals (every 90 degrees) in the circumferential direction around the axis of the shaft portion 211. In other words, since the shaft hole 218 needs to communicate with the outside through the holes 215, the length of the shaft hole 218 extends from the opening 211D on the base end side to at least the position where the holes 215 are provided. Details of the holes 215 will be described later.

[0029] <Screw engagement part> The screw engagement portion 221 will be described below with reference to Figures 2 to 4. As shown in Figures 2(A) and 3(A) and (B), the screw engagement portion 221 has a plurality of unit screw threads 222 that are spirally connected around the outer circumferential surface of the shaft portion 211 around its axis. As a result, identical spiral screw grooves 224 are formed between adjacent unit screw threads 222 in the direction of axis AX2. A unit screw thread 222 is a tapered (sawtooth-shaped) screw thread that gradually decreases in width from the surface 211A of the shaft portion 211 outward in the radial direction R of the shaft portion 211, as shown in the cross-section along the direction of axis AX2 in Figure 2(B), and spirals around the circumferential surface of the shaft portion 211 in a full circle (360 degrees). As shown in Figure 2(A), nine unit screw threads 222 are provided in this embodiment. Of these, the fourth unit thread 222A from the tip of the shaft portion 211 (hereinafter referred to as the specific unit thread) has a missing portion 223. Note that the specific unit thread can be any unit thread 222. In other words, the nth unit thread from the tip can be defined as the specific unit thread.

[0030] As shown in Figures 3(A) to (C), the missing portion 223 is a part of a specific unit screw thread 222A that is missing. As shown in the schematic diagram of Figure 3(C), the internal spaces of a pair of adjacent screw grooves 224A and 224B that are flanking the specific unit screw thread 222A face each other (oppose each other) through the missing portion 223. In other words, from one screw groove 224A side, the 5th (n+1th) unit screw thread 222D can be seen through the missing portion 223, and from the other screw groove 224B side, the 3rd (n-1st) unit screw thread 222C can be seen through the missing portion 223. Furthermore, as shown in the schematic diagram of Figure 3(D), in this embodiment, the missing portion 223 has a first missing region B1 that is notched or punctured, due to the absence of at least a part of a section (missing section) A along the circumferential direction of the 4th (nth) specific unit screw thread 222A. In other words, the first defect region B1 is formed in the defect section A in at least a portion of the area from the base (bottom position of the screw groove) to the top 222B of a specific unit screw thread 222A. This first defect region B1 allows the internal spaces of the pair of screw grooves 224A and 224B to communicate in the axial direction. The circumferential direction refers to the direction in which the unit screw thread revolves around the circumferential surface of the shaft portion 211 (helical direction).

[0031] Furthermore, the defective region of the defective portion 223 is not limited to the configuration of the first defective region B1. In the defective section A of the specific unit screw thread 222A, a portion of it may be configured to maintain the continuity of the specific unit screw thread 222A while the rest is defective. For example, the second defective region B2 of the defective portion 223 in Figure 4(A) is a portion of the defective section A, starting from the base (bottom position of the screw groove) of the specific unit screw thread 222A and extending to just before the top 221B of the specific unit screw thread 222A (a portion of the screw thread in the height direction H). Also, for example, the third defective region B3 of the defective portion 223 in Figure 4(B) is a portion of the defective section A, starting from the top 221B of the specific unit screw thread 222A and extending to just before the base (bottom position of the screw groove). Furthermore, for example, the fourth defective region B4 of the defective portion 223 in Figure 4(C) is located in the defective section A, starting from below the top 221B of the specific unit screw thread 222A in the height direction H, and extending to above the base (bottom position of the screw groove) in the height direction H. Moreover, the defective portion 223 may be composed of a mixture of the embodiments shown in Figures 4(A) to (C). In any defective portion 223, the internal spaces of a pair of adjacent screw grooves 224A and 224B, which are separated by the specific unit screw thread 222A, face each other (oppose each other) through the defective portion 223. Although the first defective region B1 to the fourth defective region B4 are all rectangular (or partially fan-shaped), they are not limited to this and may take any shape.

[0032] Furthermore, as shown in Figures 3(A) and (C), the third (n-1)th unit thread 222C and the fifth (n+1)th unit thread 222D adjacent to the specific unit thread 222A in the direction of axis AX2 do not have a defect in the region (opposing region) facing the defect 223 of the fourth (n)th specific unit thread 222A. Note that the third (n-1)th unit thread 222C and the fifth (n+1)th unit thread 222D may have defects in regions other than the above-mentioned opposing region.

[0033] <Positional relationship between the missing part and the hole> Referring to Figures 4 and 5, the positional relationship between the defect 223 and the hole 215 will be explained. As shown in Figure 5(A), the hole 215 in this embodiment includes a pair of screw grooves 224A and 224B, and an elongated hole region 228 that spans the defect 223, where the hole 215 is the elongated hole itself with the axis AX2 direction as the longitudinal direction. Because the hole 215 is an elongated hole, the intraosseous injection material can be quickly inserted in the axial direction even with a small number and arrangement of holes, and the strength of the lag screw can be maintained. As shown in Figure 5(A), when the defect 223 and the hole 215 are viewed in plan from the radial direction R (direction perpendicular to the plane of the paper) of the shaft 211, the region corresponding to the defect 223 is defined as the defect-exclusive region R1, the region of the screw groove 224A adjacent to the defect-exclusive region R1 is defined as the first screw groove region R2, and the region of the screw groove 224B adjacent to the defect-exclusive region R1 is defined as the second screw groove region R3. In this case, the elongated hole region 228 spans the first screw groove region R2, the defective area-occupied region R1, and the second screw groove region R3. The defective area-occupied region R1 includes any of the first defective areas B1 to the fourth defective areas B4 described above, or any combination thereof. The first screw groove region R2 and the second screw groove region R3 are located near the defective area-occupied region R1 in the direction of axis AX2. Furthermore, it is preferable that the extension direction (longitudinal direction) of the elongated hole region 228 is approximately parallel to the direction of axis AX2.

[0034] Furthermore, as shown in Figure 5(A), when the hole 215 becomes an elongated hole region 228, this elongated hole region 228 has a structure that is connected to (continuous with) the first defective region B1 or the second defective region B2 shown in Figures 3(D) and 4(A).

[0035] Furthermore, the hole portion 215 does not necessarily have to have a pair of screw grooves 224A, 224B and an elongated hole region 228 that spans the missing portion 223. For example, as shown in Figure 5(B), the hole portion 215 may consist of multiple holes provided in the first screw groove region R2 and the second screw groove region R3, respectively, without spanning the region R1 occupied by the missing portion.

[0036] Furthermore, as shown in Figures 5(C) and 5(D), the hole 215 may span the defective area R1 and the first screw groove area R2, or it may span the defective area R1 and the second screw groove area R3. In Figures 5(C) and 5(D), this is combined with the configuration of the third defective area B3 shown in Figure 4(B). In this case, it is preferable to form a concave surface 219 in the specific unit screw thread 222A that is recessed in the thickness direction E (approximately parallel to the axis AX2 direction) so that the entire defective area R1 of the hole 215 is open to the outside. It is preferable that the concave surface 219 extends from the surface 211A of the shaft portion 211 to the third defective area B3, as shown in Figure 5(D). The same applies to the fourth defective area B4.

[0037] <Defects and holes in the shaft portion> Referring to Figures 6 and 7, the arrangement of the missing portion 223 and the hole portion 215 in the shaft portion 211 will be described. Figure 6(A) is an enlarged view of the screw engagement portion 221 provided on the small diameter portion 214 of the bone joint member (lag screw) 201. Figure 6(B) is a cross-sectional view taken along the FF arrow in Figure 6(A).

[0038] As shown in Figure 6(B), in this embodiment, four missing portions 223 and holes 215 are provided at intervals in the circumferential direction C of the shaft portion 211. Preferably, the intervals between the missing portions 223 and holes 215 are equal. In this embodiment, the multiple missing portions 223 and holes 215 are provided such that adjacent missing portions 223 and holes 215 have a phase difference of 90 degrees in the circumferential direction C of the shaft portion 211. The circumferential direction C is the direction around the axis of the shaft portion 211.

[0039] The number of missing portions 223 and holes 215 may be one or more. Furthermore, if there are multiple missing portions 223 and holes 215, they may be spaced unequally, or a mixture of equal and unequal spacing, as long as they are spaced apart in the circumferential direction C of the shaft portion 211.

[0040] Furthermore, in this embodiment, the four missing portions 223 are provided on a single specific unit screw thread 222A. Each hole 215 is provided at a position corresponding to each missing portion 223. Therefore, the four missing portions 223 and the four holes 215 are provided at approximately the same position in the direction of the axis AX2. More precisely, since the single specific unit screw thread 222A is provided spirally on the shaft portion 211, the positions of each missing portion 223 and each hole 215 are offset from each other in the direction of the axis AX2 due to the lead of the helix.

[0041] When the bone joint member (lag screw) 201 is configured as described above, the six-view drawings of the bone joint member (lag screw) 201 are shown in Figures 7(A) to (E). Incidentally, Figure 7(A) is a plan view of the bone joint member (lag screw) 201. Figure 7(B) shows, from left to right, the left side view, front view, and right side view of the bone joint member (lag screw) 201. Figure 7(C) is a bottom view of the bone joint member (lag screw) 201. Figure 7(D) is a rear view of the bone joint member (lag screw) 201. Figure 7(E) is a perspective view of the bone joint member (lag screw) 201.

[0042] As shown in Figure 7, the circumferential arrangement of the four holes 215 of the bone joint member 201 is 45 degrees in phase with respect to the circumferential arrangement of the four engagement recesses 212A formed at the base end of the shaft portion 211. Understanding this relative relationship allows the engagement recesses 212A to serve as a guide for the arrangement of the holes 215.

[0043] <Surgical methods using bone fixation devices> The bone fixation device 100 of this embodiment is applied, for example, to the treatment of fractures near the femoral head (femoral neck fracture). An example of a surgical method (technique) using the bone fixation device 100 will be described below with reference to the preceding figures, Figure 8, and Figure 9.

[0044] First, as shown in Figure 1(B), an entry hole is formed in the upper end 501 of the femur 500 on the side of the femoral head 502 using an awl or similar tool. Then, this entry hole is enlarged using drilling tools such as a drill and reamer to create an opening in the cortical bone. As a result, an opening is formed in the end 501. The opening in the cortical bone is made to communicate with the medullary cavity of the femur 500.

[0045] Next, the tip of the intramedullary nail 101 is introduced through the opening formed in the end portion 501, thereby inserting the intramedullary nail 101 into the internal medullary cavity along the axis of the femur 500.

[0046] Next, an intramedullary nailing device (target device), not shown, is connected to the upper end T (apex, proximal end) of the intramedullary nail 101 exposed from the femur 500. The tip (holding part) of the intramedullary nailing device is engaged with a notch 1012 provided on the upper end T of the intramedullary nail 101, and then a fixing bolt (not shown) is screwed into the female thread 106 to connect the intramedullary nailing device and the intramedullary nail 101. Then, following the guide provided in the intramedullary nailing device, a guide pin (not shown) is inserted from outside the body along the axis of the transverse hole 104. The tip of this guide pin crosses the fracture line 505 and reaches the cortical bone of the femoral head 502.

[0047] Next, this guide pin is used to guide drilling tools such as drills and reamers. These drilling tools then create bone holes 503 in the femur 500 that are aligned with the axis of the transverse hole 104.

[0048] Next, after removing the drilling tool, the guide pin is used to guide the bone fixation member (lag screw) 201. As a result, the bone fixation member 201 passes through the transverse hole 104 and is screwed into the bone hole 503 formed in the femur 500. At this time, the screw engagement portion 221 of the bone fixation member 201 crosses the fracture line 505 and reaches the cortical bone of the femoral head 502.

[0049] As a result, the bone fixation member 201 is fixed to the femoral head 502, and the bone fixation member 201 is further pulled toward the intramedullary nail 101. At this time, the area around the fracture line 505 of the femur 500 is aligned, and the fracture sites on both sides that abut at the fracture line 505 are reduced so that they come into close contact with each other.

[0050] In this state, the set screw 451 is screwed into the axial hole 105 from the base end of the intramedullary nail 101, and the tip 451A of the set screw 451 is brought into contact with the groove 216 of the bone fixation member 201. This fixes the bone fixation member 201 to the intramedullary nail 101.

[0051] Next, using the injection device 301 shown in Figure 8, the intraosseous injection material is injected into the femoral head 502 through the bone fixation member (lag screw) 201. In this invention, the injection device 301 and the bone fixation device 100 together are referred to as the bone fixation device set. The intraosseous injection material is a material used in bone treatment, such as reinforcing bone tissue, and a paste-like form is preferred. Examples of intraosseous injection materials include calcium phosphate-based bone graft materials and bone cement made of polymethyl methacrylate.

[0052] The injection device 301 is capable of injecting an intraosseous injection agent into the bone, and as shown in Figure 8, comprises a syringe 302 having a material-filling space 302A inside, a plunger 303, and an injection nozzle 304 connected to the syringe 302. The injection nozzle 304 has an outer diameter that can be inserted into the axial hole 218 and has an injection port 305 near its tip. The plunger 303 has a movable body 306 and a pressing part 307 that presses the movable body 306 to move the movable body 306 in the axial direction of the syringe 302.

[0053] The movable body 306 has a tip portion 306A that is held by the syringe 302 so as to be movable in the axial direction of the syringe 302, with the outer surface of the movable body 306 in contact with the inner surface of the syringe 302, and a base portion 306B that is continuous with the tip portion 306A. The base portion 306B faces the pressing portion 307 in the axial direction of the syringe 302.

[0054] The pressing portion 307 has a threaded portion 307A and a threaded engagement portion 307B. The threaded portion 307A is screwed into the threaded engagement portion 307B. When the threaded portion 307A is rotated forward, the threaded portion 307A moves along the axial direction of the syringe 302 toward the movable body 306 (base end portion 306B). When the threaded portion 307A is rotated backward, the threaded portion 307A moves away from the movable body 306 (base end portion 306B) along the axial direction of the syringe 302.

[0055] When the threaded portion 307A is rotated forward with the material-filling space 302A filled with the intraosseous injection material, the threaded portion 307A approaches the proximal end portion 306B. When the threaded portion 307A presses against the proximal end portion 306B, the tip portion 306A moves together with the proximal end portion 306B in a direction that presses against the intraosseous injection material. As a result, the intraosseous injection material is pushed out into the injection nozzle 304 and then pushed out to the outside through the injection port 305.

[0056] To inject the intraosseous injection material into the femoral head 502 using the injection device 301 configured as described above, as shown in Figure 9(A), first, the injection nozzle 304 is inserted into the axial hole 218 of the bone fixation member 201 fixed to the intramedullary nail 101. It is preferable that the outer diameter of the injection nozzle 304 is approximately the same as or slightly smaller than the diameter of the axial hole 218. This is to prevent the intraosseous injection material from entering the gap between the axial hole 218 and the injection nozzle 304.

[0057] Then, as shown in Figure 9(B), the entire injector 301 is rotated in the circumferential direction C to align the injection port 305 with the hole 215 of the bone fixation member 201. It is preferable to provide markers on both the bone fixation member 201 and the injector 301 so that the relative positions (relative phase difference in the circumferential direction C) of the hole 215 of the bone fixation member 201 and the injection port 305 of the injector 301 can be recognized from the outside. In this embodiment, the marker on the hole 215 of the bone fixation member 201 is the engagement recess 212A of the large diameter portion 212 of the shaft portion 211, as shown in Figures 8 and 9(B). On the other hand, the marker on the injector 301 is the marking 309 provided on the outer circumferential surface of the injection nozzle 304 (or syringe 302), as shown in Figures 8 and 9(B). Furthermore, the shaft portion 211 may have a stopper 217 inside that contacts the tip of the injection nozzle 304 near its tip to position the injection nozzle 304 in the axial direction AX. After the practitioner inserts the injection nozzle 304 until it hits the stopper 217, the injection tool 301 is rotated and positioned so that the marking 309 is located at the midpoint (45-degree phase difference) between a pair of adjacent engagement recesses 212A, so that the position of the hole 215 of the bone fixation member 201 and the position of the injection port 305 coincide. In this state, when the syringe 302 filled with the intraosseous injection material is pressed with the plunger 303, the intraosseous injection material is pushed into the femoral head 502 in order through the injection nozzle 304, the injection port 305, and the hole 215. This process is repeated for all the holes 215. Furthermore, as shown in Figure 9(B), it is also preferable to provide a marking 310 on the injection device 301 side that indicates the depth of penetration of the hole 215 into the bone joint member 201 in the axial direction AX2.

[0058] As shown in Figures 10(A), 11(A), and 12(A), when the intraosseous injection material is pushed out from the hole 215, it spreads from the elongated hole region 228 into the defect-exclusive region R1, the first screw groove region R2, and the second screw groove region R3. As the pressure continues, as shown in Figures 10(B), (C), 11(B), (C), and 12(B), the intraosseous injection material spreads beyond the first screw groove region R2 and the second screw groove region R3, along the screw grooves 224A and 224B, and also in the height direction H of the screw grooves 224A and 224B. At this time, as shown in Figures 10(B), (C), when the defect 223 and the hole 215 are viewed in plan from the radial direction (direction perpendicular to the plane of the paper) of the shaft 211, the intraosseous injection material spreads in an H shape. The viscous resistance as the intraosseous injection material spreads in an H-shape increases the pressure of the injection material.

[0059] Finally, as shown in Figure 12(C), the thread grooves 224A and 224B are filled with the intraosseous injection material, and at the same time as shown in Figure 12(D), the intraosseous injection material moves radially outward from the thread grooves 224A and 224B, and enters the interior of the femoral head 502 adjacent to the screw engagement portion 221. The intraosseous injection material then spreads further along the (unit) thread grooves 224A and 224B, and gradually spreads to the (unit) thread groove 224C which is continuous with respect to the (unit) thread groove 224A towards the tip in the axial AX2 direction, and to the (unit) thread groove 224D which is continuous with respect to the thread groove 224B towards the proximal end. The same applies to the other thread grooves.

[0060] Furthermore, because multiple holes 215 and defects 223 are concentrated in the specific unit screw thread 222A, the intraosseous injection material does not spread unnecessarily. As a result, the intraosseous injection material spreads mainly around the specific unit screw thread 222A, and as the intraosseous injection material hardens, the bone fixation member 201 and the femoral head are firmly fixed to each other.

[0061] Furthermore, as shown in Figures 13(A) and (B), the intraosseous injection material filled in the region corresponding to the defect 223 (the region dedicated to the defect R1) contacts two opposing surfaces 229 of the specific unit screw thread 222A, which are on either side of the defect 223, when the bone fixation member 201 rotates in the circumferential direction C, thereby restricting the rotation of the bone fixation member 201. In other words, the intraosseous injection material filled in the region corresponding to the defect 223 (the region dedicated to the defect R1) functions as a rotation limiting unit that restricts the rotation of the bone fixation member 201.

[0062] <Advantages of bone joint members> As shown in the comparative examples in Figures 14(A) and (B), we consider the case where the intraosseous injection material is extruded through the holes 215 provided in the screw grooves 224, does not cross the unit screw threads 222, but fills along the screw grooves 224, thereby restraining the bone fixation member 201 with the femoral head. In this case, as shown in Figures 14(C) and (D), if for some reason a gap region 900 is created between the intraosseous injection material and the screw grooves 224, or between the intraosseous injection material and the shaft portion 211, the restraining force on the bone fixation member 201 weakens. As a result, when vibration is applied to the bone fixation member 201 due to the patient's movements, the bone fixation member 201 rotates relative to the femoral head 502, and the fixing force on the fracture site weakens.

[0063] On the other hand, according to the bone fixation member 201 of this embodiment, as shown in Figures 13(C) and (D), even if a gap region 900 occurs between the intraosseous injection material and the screw grooves 224A and 224B, or between the intraosseous injection material and the shaft portion 211, the intraosseous injection material filled in the region corresponding to the defect portion 223 functions as a rotation limiter. Therefore, even if vibration is applied to the bone fixation member 201 due to the patient's movements, the relative rotation between the bone fixation member 201 and the femoral head 502 is limited, and the fixation force of the fracture site is maintained.

[0064] Furthermore, as shown in the reference examples in Figures 14(A) and (B), when the intraosseous injection material is filled along the screw groove 224 and firmly fixed with the femoral head, attempting to remove the bone fixation member 201 requires rotating the bone fixation member 201 in the loosening direction so that it slides against the solidified intraosseous injection material along the screw groove 224. This frictional force could potentially damage the femoral head.

[0065] On the other hand, as shown in Figures 13(A) and (B), when attempting to remove the bone fixation member 201 of this embodiment, the rotation of the bone fixation member 201 allows the surface 229 of the specific unit screw thread 222A to apply strong localized pressure to the intraosseous injection material solidified within the defect 223, thereby destroying that portion. When a portion of the intraosseous injection material is destroyed, the cracks and other damage spread throughout the entire intraosseous injection material, allowing the bone fixation member 201 to be easily rotated and removed.

[0066] Furthermore, as shown in Figure 15, which is a modified example of this embodiment, it is also possible to provide a defect 223 in each of the specific unit screw threads 222F and 222G adjacent to the specific unit screw thread 222A, such that the defect 223 is in the same phase as the defect 223 of the specific unit screw thread 222A. In other words, multiple adjacent defect portions 223 in the direction of axis AX2 are provided continuously in the direction of axis AX2 opposite to each other. In this case, the intraosseous injection material pushed out from the hole 215 flows in both the continuous direction P of the defect portions 223 and in the direction along the screw groove 224. Compared to Figure 13, the number of paths through which the intraosseous injection material spreads is increased, so a larger volume of liquid and filling time are required for the intraosseous injection material to sufficiently diffuse from the screw groove 224 to the radially outward (femoral head side), but there is also the advantage that the diffusion of the intraosseous injection material in the axial direction AX2 is easier.

[0067] On the other hand, in the bone fixation member 201 shown in Figures 12 and 13, the region (opposing region) facing the defect 223 of the specific unit screw thread 222A is not missing in the unit screw threads 222C and 222D adjacent to the specific unit screw thread 222A in the axial AX2 direction. In other words, the path through which the intraosseous injection material diffuses is actively limited to the pair of screw grooves 224A and 224B. As a result, the intraosseous injection material flows along the screw grooves 224A and 224B of the bone fixation member 201, and also has the advantage that the bone fixation member 201 diffuses radially outward at an early stage, reaching the surrounding femoral head tissue sufficiently. Since the bone fixation member 201 solidifies locally within the femoral head, the strength of the femoral head is also easily increased.

[0068] <Second Embodiment> Next, with reference to Figure 16, a bone fixation device of a second embodiment of the present invention will be described. In this embodiment, the bone fixation device differs from that of the first embodiment in the arrangement of the missing portion 223 and the hole portion 215 in the shaft portion 211.

[0069] Figures 16(A) to (D) are, in order, a plan view of a modified example of the bone joint member (lag screw) 201 in this embodiment, a front view of the bone joint member (lag screw) 201 in this embodiment, a bottom view of the bone joint member (lag screw) 201 in this embodiment, and a rear view of the bone joint member (lag screw) 201 in this embodiment. In the bone joint member (lag screw) 201 shown in Figures 16(A) to (D), each missing portion 223 is provided on a separate specific unit screw thread 222A. As with the first embodiment, the multiple missing portions 223 are arranged at positions that do not face each other in the axial direction (positions with a phase shift in the circumferential direction).

[0070] When each missing portion 223 and hole 215 is provided on a separate specific unit screw thread 222A, as in this bone joint member (lag screw) 201, there is an advantage in that the strength of the shaft portion 211 and the surrounding screw engagement portion 221 can be homogenized in the direction of the axis AX2.

[0071] In the second embodiment, an example was given in which one missing portion 223 and one hole 215 are provided for each specific unit screw thread 222A, but the number of missing portions 223 and holes 215 is not particularly limited.

[0072] <Third Embodiment> Next, with reference to Figure 17, a bone fixation device of a third embodiment of the present invention will be described. The bone fixation device in this embodiment differs from that of the first embodiment in the configuration of the missing portion 223 and the hole portion 215. In this embodiment, the multiple holes 215 and missing portions 223 are arranged at positions that are in phase with each other in the circumferential direction and at positions that are separated in the direction of axis AX2, as shown in Figure 17(A). Two holes 215 and corresponding missing portions 223 arranged in series form a set and are provided at intervals in the circumferential direction of the shaft portion 211.

[0073] As shown in Figure 17(A), at least one unit screw thread 222 is interposed between the two missing portions 223 (and the hole portion 215) that are in phase in the circumferential direction, with the region in phase with the two missing portions 223 being unmissing. In Figure 17(A), there is only one unit screw thread 222 with the region opposite the two missing portions 223 being unmissing, but as shown in Figure 17(B), multiple unit screw threads 222 may be interposed. Also, compared to Figure 17(A), the circumferential width of the shaft portion 211 of the hole portion 215 and the missing portion 223 (circumferential width) is set to be larger in Figure 17(B), but this width is not particularly limited. The region (phase width) occupied by one missing portion 223 in the circumferential direction is preferably 40 degrees or less, more preferably 30 degrees or less, and more preferably 20 degrees or less.

[0074] <Fourth Embodiment> Next, with reference to Figure 18, a bone fixation device of the fourth embodiment of the present invention will be described. In the bone fixation device of this embodiment, a hole 215 and a defect 223 are formed for each of the multiple (in this case, three) specific unit screw threads 222A, 222C, and 222D adjacent to each other in the direction of axis AX2. The defect 223 formed in the specific unit screw threads 222 (222C, 222D) is located in a region shifted in the circumferential direction from the region facing the defect 223 of the intermediate specific unit screw thread 222A.

[0075] The hole 215 formed in the specific unit screw thread 222A spans the screw groove 224A (first screw groove region R2), 224B (second screw groove region R3), and the defect-dedicated region R1 corresponding to the specific unit screw thread 222A. Similarly, the hole 215 formed in the specific unit screw thread 222C spans the screw groove 224C (third screw groove region R4), 224A (first screw groove region R2), and the defect-dedicated region R1 corresponding to the specific unit screw thread 222C. Furthermore, the hole 215 formed in the specific unit screw thread 222D spans the screw groove 224D (fourth screw groove region R5), 224B (second screw groove region R3), and the defect-dedicated region R1 corresponding to the specific unit screw thread 222D. In this way, multiple defects 223 are formed in a labyrinthine pattern on multiple adjacent (in this case, three) specific unit screw threads 222A, 222C, and 222D.

[0076] In the bone fixation device of the present invention, the example shown is one in which the screw engagement portion 221 is a single-start screw, but the present invention is not limited to this and can also be applied to multi-start screws with two or more starters.

[0077] Furthermore, the bone fixation device of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. In addition, various combinations of the components of each embodiment are also included within the scope of the present invention. [Explanation of symbols]

[0078] 10 Intramedullary nail aid 100 Osteosynthesis 101 Intramedullary nail 104 Horizontal hole 201 Bone joint member (lag screw) 211 Shaft 212A Engaging recess 215 Hole 216 Groove 218 shaft hole 221 Screw engagement part 222, 222C, 222D Unit screw thread 222A, 222E Specific Unit Screw Thread 223 Defective area 224, 224A~224D Screw groove 228 Long hole area 301 Injection tool 302 Syringe 303 Plunger 304 Injection nozzle 305 Inlet

Claims

1. A bone joint member having a shaft portion, a screw thread spirally encircling the circumferential surface of the shaft portion, and an axial hole extending axially inside the shaft portion, which is inserted into an intramedullary nail, A bone fixation member set comprising an injection device capable of injecting an intraosseous injection agent into the bone, The bone joint member is When a 360° rotation of the aforementioned screw thread is considered as a unit screw thread, a defect is provided in the unit screw thread such that the internal spaces of a pair of adjacent screw grooves on either side of the unit screw thread face each other, A hole provided in the shaft portion so as to communicate with the missing portion and the shaft hole, It has a bone joint member side positioning portion, The aforementioned injector is An injection nozzle that can be inserted into the axial hole of the bone joint member, One inlet is provided at the tip of the injection nozzle, It has an injection device side positioning part, By positioning the injection device relative to the bone joint member using the bone joint member side positioning portion and the injection device side positioning portion, it is possible to position the injection port and the hole portion so that they overlap. A bone joint member set characterized by the following features.

2. The aforementioned holes are provided at multiple locations in the circumferential direction of the shaft portion. The bone joint member side positioning portion is provided at multiple locations corresponding to the hole portion in the circumferential direction of the shaft portion. The bone joint member set according to feature 1.

3. The aforementioned holes are provided at four locations along the unit screw threads, at approximately 90° intervals around the axis of the shaft. The bone joint member set according to feature 2.

4. The bone joint member has an engagement recess at the base end of the shaft portion into which a device for rotating the bone joint member is fitted, and the engagement recess functions as a positioning portion on the bone joint member side. A bone joint member set according to any one of claims 1 to 3.

5. The injection port is an elongated hole that extends in the axial direction of the injection nozzle so as to cover the hole. A bone joint member set according to any one of claims 1 to 4.

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