Intramedullary nails and bone fixation devices

Abstract

To provide an intramedullary nail and an osteosynthesis tool with improved usability.SOLUTION: An intramedullary nail includes: a cylindrical nail body 10 on whose inner peripheral surface a first female screw region 15, a second female screw region 16 disposed on a side of a base end Da with respect to the first female screw region 15, and a non-screw region 17 disposed between the first female screw region 15 and the second female screw region 16 are formed; a regulating body 20 which can be screwed into the first female screw region 15 and the second female screw region 16, and regulates relative movement and relative rotation of an osteosynthesis shaft member 2 with respect to the nail body 10 at a regulating position screwed into the first female screw region 15; and a ring body 30 in which a ring body-side male screw region 35 capable of being screwed into the second female screw region 16 is formed, and which is disposed on the side of the base end Da with respect to the regulation body 20 which is in the regulation position in the use position and in the non-screw region 17, wherein a formation range in the ring body side male screw region 35 is smaller than a formation range in the non-screw region 17.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an intramedullary nail used for osteosynthesis and an osteosynthesis device. Background Art

[0002] Conventionally, when treating fractures near the femoral head, humeral head and other bone heads, a surgical instrument called an intramedullary nail (nail) has been used. An intramedullary nail is inserted into the medullary cavity of a bone along the longitudinal direction of the bone, and a shaft-shaped member called a lag screw is inserted through the intramedullary nail and screwed into the bone, thereby firmly fixing the fractured bone from the inside together with the shaft-shaped member.

[0003] Here, as described in Patent Document 1, for example, an intramedullary nail is cylindrical because a guide wire is inserted into the medullary cavity of the bone in advance, and then the intramedullary nail is inserted into the bone with the guide wire passing through itself. A regulator called a set screw, which is also cylindrical, is provided inside such a cylindrical intramedullary nail, and this regulator regulates the relative movement and relative rotation of the shaft-shaped member (lag screw) with respect to the intramedullary nail. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese National Publication of International Patent Application No. 2014-512853 Summary of the Invention Problems to be Solved by the Invention

[0005] However, in the conventional intramedullary nail described above, there is a possibility that the above-mentioned regulator (set screw) moves from a predetermined position due to external factors such as vibration. As a result, there is a possibility that the fixation of the shaft-shaped member (lag screw) to the intramedullary nail becomes insufficient, and there is also a possibility that the regulator (set screw) falls off from the intramedullary nail during transportation. Thus, the usability is not sufficient, and improvement in this respect has been demanded.

[0006] Therefore, the present invention provides an intramedullary nail and a bone fixation device with improved usability.

[0007] An intramedullary nail according to one aspect of the present invention is an intramedullary nail that is inserted into bone when joining bones and fixes the bone from the inside together with a bone-jointing shaft member that is inserted through it, and comprises a nail body which is cylindrical and has a shaft member insertion hole formed through its outer surface at an intermediate position in the longitudinal direction for inserting the bone-jointing shaft member, and has a first female thread region located on the base end side in the longitudinal direction relative to the shaft member insertion hole, a second female thread region located on the base end side relative to the first female thread region, and a non-threaded region located between the first female thread region and the second female thread region in the longitudinal direction formed on its inner surface, and a tubular shape and has a regulating body side male thread region formed on its outer surface that can be screwed into the first female thread region and the second female thread region, and the first female thread region The device comprises: a restricting body that, in a restricted position screwed into a region, presses the bone-jointing shaft member, which is positioned in the shaft member insertion hole toward the tip side, thereby restricting the relative movement and rotation of the bone-jointing shaft member with respect to the nail body; and a ring body that is annular in shape with respect to a first axis, and has a ring-side male thread region formed on its outer circumferential surface that can be screwed into the second female thread region, and is positioned toward the base end side of the restricting body which is in the restricted position at the usage position, and at least a part of it is in the non-thread region, wherein the first female thread region and the second female thread region are formed around the second axis extending in the longitudinal direction, and the formation range in the first axial direction of the ring-side male thread region is smaller than the formation range in the second axial direction of the non-thread region.

[0008] Furthermore, in the intramedullary nail described above, the thickness dimension in the first axial direction of the ring body may be smaller than the formation range in the second axial direction of the non-threaded region.

[0009] Furthermore, in the intramedullary nail described above, the non-threaded region has a circular cross-sectional shape centered on the second axis, and the outer diameter of the threads in the male threaded region on the ring body side may be smaller than the inner diameter of the non-threaded region.

[0010] Furthermore, in the intramedullary nail described above, the inner diameter of the threads in the first female thread region and the second female thread region may be smaller than the inner diameter of the non-threaded region.

[0011] Furthermore, in the intramedullary nail described above, the male thread region on the regulating body side is formed around the third axis, and the formation range in the direction of the third axis in the male thread region on the regulating body side may be larger than the formation range in the direction of the second axis in the non-threaded region.

[0012] Furthermore, in the intramedullary nail described above, the inner circumferential surface of the ring body may have a tapered annular surface centered on the first axis, where the inner diameter gradually decreases from one end of the first axis that is the base end at the position of use toward the other end of the first axis.

[0013] Furthermore, in the intramedullary nail described above, the regulating body may have a regulating body end face that faces the proximal end side at the regulating position, and the ring body may have a ring body end face that faces the tip side at the usage position and faces the regulating body end face of the regulating body at the regulating position from the proximal end side.

[0014] Furthermore, in the intramedullary nail described above, the regulating body may be cylindrical with respect to the third axis, and with the first axis and the third axis arranged coaxially, the inner periphery of the end face of the regulating body may be positioned radially outward from the inner periphery of the end face of the ring body.

[0015] Furthermore, in the intramedullary nail described above, the end face of the restrictor body may have a circular internal bore centered on a third axis extending in the longitudinal direction in the restrictor body that is the restrictor position, and the end face of the ring body may have a circular internal bore centered on the first axis and having a smaller diameter than the internal bore of the restrictor body.

[0016] Furthermore, in the intramedullary nail described above, the regulating body and the ring body may be formed from the same metal material, and the entire area of ​​one of the end faces of the regulating body and the end face of the ring body may face a portion of the other area in the longitudinal direction.

[0017] Furthermore, in the intramedullary nail described above, the inner circumferential surface of the ring body may have an engaging portion formed thereon that is recessed radially outward or protrudes radially inward, and the ring body may be rotatable around the first axis by the tool when the engaging portion is engaged with the engaged portion of the tool.

[0018] Furthermore, a bone fixation device according to one aspect of the present invention comprises the above-mentioned intramedullary nail and a bone fixation shaft member inserted into the shaft member insertion hole in the intramedullary nail. [Effects of the Invention]

[0019] The intramedullary nail and bone fixation device described above can improve usability. [Brief explanation of the drawing]

[0020] [Figure 1] This is an overall side view showing, through the bone, how the bone fixation device according to an embodiment of the present invention is placed inside the bone of a patient. [Figure 2] This is a longitudinal cross-sectional view of the main part of the intramedullary nail of the bone fixation device described above, and is a cross-sectional view of the intramedullary nail as seen from the front of the patient's body when the bone fixation device is in use. [Figure 3] The above is a longitudinal cross-sectional view of the nail body of the intramedullary nail, where (a) is a cross-sectional view at the same cross-section as in Figure 2, and (b) is a cross-sectional view of the nail body viewed from 180 degrees opposite to (a) in the circumferential direction, i.e., from the rear of the patient's body. [Figure 4] The above is a side view showing the restrictor body of the intramedullary nail, where (a) is a view of the restrictor body from the front of the patient's body in the state of use of the bone fixation device, and (b) is a view of the restrictor body from a position rotated 90 degrees circumferentially from (a). [Figure 5]It is a longitudinal sectional view showing a state where the regulating body and the ring body of the intramedullary nail are installed in the nail body, and is a sectional view taken along the same section as FIG. 2. [Figure 6] It is a view showing the ring body of the intramedullary nail, wherein (a) is a top view seen from the proximal end side, and (b) is a view taken along arrow A in (a). [Figure 7] It is a perspective view of a dedicated tool for rotating the ring body of the intramedullary nail. Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (Overall Configuration) As shown in FIG. 1, the osteosynthesis device 100 of the present embodiment is used, for example, for treating a fracture (femoral neck fracture) in the vicinity of the femoral head B1 of a patient's femur (hereinafter simply referred to as bone) B. The osteosynthesis device 100 includes a rod-shaped intramedullary nail 1 inserted into the femur B along the extending direction of the femur B, an osteosynthesis shaft member (lag screw) 2 inserted through the intramedullary nail 1 so as to intersect the longitudinal direction D of the intramedullary nail 1, and an auxiliary shaft member 3 provided together with the osteosynthesis shaft member 2 and inserted through the intramedullary nail 1.

[0022] (Intramedullary Nail) As shown in FIG. 2, the intramedullary nail 1 includes a cylindrical nail body 10 inserted into the medullary cavity (inner cavity) of the femur B so as to extend along the extending direction of the femur B, a regulating body 20 and a ring body 30 provided inside the nail body 10, and an end cap 40 closing the upper opening 10x of the nail body 10.

[0023] (Nail Body) As shown in FIGS. 3(a) and 3(b), the nail body 10 has a proximal portion 11 disposed on the proximal end Da side in the longitudinal direction D (the upper side when the osteosynthesis device 100 is in use) and extending in the longitudinal direction D, and a distal portion 12 disposed on the distal end Db side in the longitudinal direction D relative to the proximal portion 11 (the lower side when the osteosynthesis device 100 is in use), integrated with the proximal portion 11 and extending toward the distal end Db side so as to bend (or curve) relative to the proximal portion 11.

[0024] The proximal portion 11 is cylindrical in shape, centered on the proximal axis (second axis) O1 which extends in the longitudinal direction D. The inner bore 11a of the proximal portion 11, formed by the inner circumferential surface of the proximal portion 11, has a perfectly circular cross-section centered on the proximal axis O1. Near the end of the proximal portion 11 on the side of the tip Db that connects to the distal portion 12, the diameter of the proximal portion 11 gradually decreases from one side of the proximal axis O1 (the side of the base Da) to the other side (the side of the tip Db).

[0025] The distal portion 12 is cylindrical in shape, centered on a distal axis O2 that extends in the longitudinal direction D and intersects the proximal axis O1. The distal portion 12 also has an inner bore 12a with a perfectly circular cross-section centered on the distal axis O2. Similar to the proximal portion 11, the distal portion 12 gradually tapers in diameter near the end on the tip Db side, from one side of the distal axis O2 (the base end Da side) to the other side (the tip Db side).

[0026] The inner bore 11a of the proximal portion 11 and the inner bore 12a of the distal portion 12 are smoothly connected, and these inner bores 11a and 12a as a whole penetrate the inside of the nail body 10 in the longitudinal direction D. These inner bores 11a and 12a have the function of allowing a guide wire (not shown) inserted into the medulla cavity before the nail body 10 is inserted into the medulla cavity.

[0027] Furthermore, at an intermediate position in the longitudinal direction D of the nail body 10, a shaft member insertion hole 10y is formed in the proximal portion 11 so as to penetrate the outer surface. This shaft member insertion hole 10y extends from the outside to the inside of the patient's body, and from the outside to the inside, so as to the use state of the bone fixation device 100, it extends from the bottom to the top as it moves from the outside to the inside, so as to the femoral head B1 via the trochanter B2 of the femur B (see Figure 1), with its own central axis Oy intersecting the proximal axis O1.

[0028] In other words, the shaft member insertion hole 10y communicates with the inner hole 11a of the proximal portion 11, and penetrates the outer surface of the nail body 10 at two locations, on the inside and outside of the body, with the inner hole 11a in between, based on the usage state of the bone fixation device 100. The bone fixation shaft member 2 (see Figure 1), which will be described in detail later, is inserted through this shaft member insertion hole 10y.

[0029] Furthermore, on the proximal end Da side of the shaft member insertion hole 10y, an auxiliary shaft member insertion hole 10z is formed in the proximal portion 11, penetrating the outer surface such that its own central axis Oz extends parallel to the central axis Oy of the shaft member insertion hole 10y. Thus, the auxiliary shaft member insertion hole 10z communicates with the inner hole 11a of the proximal portion 11 and penetrates the outer surface of the nail body 10 at two locations, on the inside and outside of the patient's body, with the inner hole 11a in between, based on the usage state of the bone fixation device 100.

[0030] The auxiliary shaft member 3, which will be described in detail later, is inserted through this auxiliary shaft member insertion hole 10z. When the auxiliary shaft member 3 is inserted through the auxiliary shaft member insertion hole 10z, the auxiliary shaft member 3 and the bone joint shaft member 2 inserted through the shaft member insertion hole 10y are positioned parallel to each other (see Figure 1).

[0031] Furthermore, a fixing device insertion hole 12y is formed in the distal portion 12 on the side of the tip b beyond the shaft member insertion hole 10y, penetrating the outer surface in a direction intersecting the longitudinal direction D, that is, perpendicular to the distal axis O2. In other words, the fixing device insertion hole 12y communicates with the inner hole 12a of the distal portion 12, and penetrates the outer surface of the nail body 10 at two locations, on the inside and outside of the patient's body, with the inner hole 12a in between, based on the usage state of the bone fixation device 100. A fixing screw 13 for fixing the intramedullary nail 1 to the femur B is inserted through this fixing device insertion hole 12y (see Figure 1).

[0032] Furthermore, on the inner circumferential surface of the proximal portion 11, that is, on the inner surface of the inner hole 11a, a first female thread region 15, a second female thread region 16, and a non-threaded region 17 are formed on the side of the base end Da that is closer to the shaft member insertion hole 10y and the auxiliary shaft member insertion hole 10z.

[0033] The first female thread region 15 is formed centered on the proximal axis O1. When the bone fixation device 100 is in use, the restrictor 20, which will be described in detail later, is screwed into the first female thread region 15 (see Figure 2).

[0034] The second female thread region 16 is positioned on the base end Da side of the first female thread region 15, spaced apart in the direction of the proximal axis O1. The dimensions of the threads and grooves of the second female thread region 16, as well as the pitch and other specifications, are the same as those of the first female thread region 15. The second female thread region 16 is formed on the tip end Db side of the opening end of the inner hole 11a, which is the base end Da side of the nail body 10.

[0035] The non-threaded region 17 is located between the first female threaded region 15 and the second female threaded region 16. The non-threaded region 17 is a region on the inner surface of the inner bore 11a of the proximal portion 11 in which no female threads are formed, and is a region consisting of a hole with a perfectly circular cross-section centered on the proximal portion axis O1. The inner diameter of the non-threaded region 17 is the same as, or slightly larger than, the inner diameter of the screw grooves in the first female threaded region 15 and the second female threaded region 16, defining a space that is like an enlarged version of the first female threaded region 15 and the second female threaded region 16.

[0036] Furthermore, a guide groove 18 is formed on the inner surface of the inner hole 11a. This groove opens toward the end face on the base end Da side of the nail body 10 and recesses radially outward in the direction of the proximal axis O1, extending beyond the first female thread region 15 to the tip Db side. The guide groove 18 divides the first female thread region 15 and the second female thread region 16 at one point in the circumferential direction.

[0037] (Regulatory body) The restrictor 20 is made of a metal material such as titanium, and as shown in Figures 4(a) and 4(b), it has a restrictor body 21 that contacts the bone fixation shaft member 2 when the bone fixation device 100 is in use, and a screw portion 22 that rotates relative to the restrictor body 21. The restrictor 20 is inserted into the inner hole 11a of the proximal portion 11 of the nail body 10 from the upper opening 10x (see Figure 2).

[0038] The regulating body 21 is cylindrical in shape, centered on a regulating body axis (third axis) O3 that extends in the longitudinal direction D when the bone fixation device 100 is in use, and has a tapered shape in which the outer diameter gradually decreases towards the bottom. Furthermore, a pair of inclined planes 21a, formed by cutting out the outer circumferential surface so as to extend radially outward toward the base end, are arranged at positions offset by 180 degrees in the circumferential direction from the tip which is the lower end of the regulating body 21 when the bone fixation device 100 is in use.

[0039] A pair of roughly triangular, plate-like pressing portions 21b are formed between the inclined planes 21a. The tips (lower ends) of this pair of pressing portions 21b are positioned offset in the direction of the regulating body axis O3, and the bone-fixing shaft members 2, which will be described in detail later, are inserted through the shaft member insertion holes 10y of the nail body 10 and penetrate the nail body 10, allowing each to contact the bone-fixing shaft members 2 (see Figure 2).

[0040] Furthermore, a rectangular guide projection 21c is formed on the outer circumferential surface of the regulating body 21, projecting radially outward and extending in the direction of the regulating body axis O3. When the regulating body 21 is inserted into the inner hole 11a of the nail body 10, the guide projection 21c is positioned within the guide groove 18 of the nail body 10, thereby restricting relative rotation with respect to the nail body 10, and guiding the regulating body 21 in the longitudinal direction D within the inner hole 11a of the nail body 10 (see Figure 3(b)).

[0041] Furthermore, the regulating body 21 has a regulating body through-hole 21x that penetrates the outer surface in a direction intersecting the regulating body axis O3. When the bone fixation device 100 is in use, the auxiliary shaft member 3, which will be described in detail later, is inserted through this regulating body through-hole 21x (see Figure 2). That is, when the bone fixation device 100 is in use, it extends from the outside to the inside of the body and from bottom to top, and is positioned coaxially with the auxiliary shaft member insertion hole 10z of the nail body 10 (see Figures 3(a) and 3(b)).

[0042] The screw portion 22 is annular in shape with respect to the regulating body axis O3. The screw portion 22 supports the regulating body 21 by covering the outer circumferential surface of the regulating body 21 on the side of the base end Da of the regulating body 21, and is rotatable relative to the regulating body 21 about the regulating body axis O3. In addition, a male screw region 25 on the regulating body side is formed on the outer circumferential surface of the screw portion 22 with respect to the regulating body axis O3.

[0043] This male threaded region 25 on the regulating body side can be screwed into both the first female threaded region 15 and the second female threaded region 16 of the nail body 10 (see Figures 3(a) and 3(b)). Furthermore, the formation range of the male threaded region 25 on the regulating body side in the direction of the regulating body axis O3 is larger than the formation range of the non-threaded region 17 on the nail body 10 in the direction of the proximal axis O1. In other words, the male threaded region 25 on the regulating body side is positioned between the first female threaded region 15 and the second female threaded region 16, and can be screwed into both the first female threaded region 15 and the second female threaded region 16.

[0044] As shown in Figure 5, a hexagonal hole (or hexalobular hole, etc.) 22x is formed in a portion of the straight annular surface 22b on the regulating body side, which will be described later, inside the screw portion 22. By engaging a tool (not shown) with this hole 22x, the screw portion 22 can be rotated around the regulating body axis O3 by the tool. The male threaded region 25 on the regulating body side of the screw portion 22 is then screwed from the second female threaded region 16 into the first female threaded region 15 (see Figures 3(a) and 3(b)), and the screw portion 22 is inserted into the inner hole 11a of the nail body 10. As a result, the guide projection 21c of the regulating body 21 is guided by the guide groove 18 (see Figure 3(b)), and the regulating body 21 is inserted into the nail body 10 while the screw portion 22 rotates relative to the regulating body 21 around the regulating body axis O3, and the relative rotation of the regulating body 21 with respect to the nail body 10 is restricted.

[0045] Then, at the position where the male thread region 25 on the restrictor side of the screw portion 22 is screwed into only the first female thread region 15, the pressing portion 21b of the restrictor body 21 comes into contact with the bone joint shaft member 2, pressing the bone joint shaft member 2 toward the tip Db side in the direction of the restrictor axis O3. The position of the restrictor body 20 in which the pressing portion 21b is pressing the bone joint shaft member 2 in this manner becomes the "restriction position," and when the restrictor body 20 is positioned at this restriction position, the relative movement and relative rotation of the bone joint shaft member 2 with respect to the nail body 10 are restricted. Furthermore, when the restrictor body 20 is positioned at the restriction position, the restrictor axis O3 is positioned coaxially with the proximal axis O1 (see Figures 3(a) and 3(b)).

[0046] As shown in Figure 5, the inner circumferential surface of the screw portion 22 has a tapered annular surface 22a centered on the regulating body axis O3, where the inner diameter gradually decreases from one side in the direction of the regulating body axis O3 (the side of the base end Da at the regulating position) to the other side (the side of the tip Db at the regulating position), and a straight annular surface 22b connected to the other side in the direction of the regulating body axis O3 relative to the tapered annular surface 22a, forming a perfect annular shape centered on the regulating body axis O3. The screw portion 22 also has a planar end surface 22c facing one side of the regulating body axis O3.

[0047] (Ring-shaped body) As shown in Figures 6(a) and 6(b), the ring body 30 is a perfect annular shape centered on the ring body axis (first axis) O4. The ring body 30 is made of the same material as the regulating body 20. A ring body-side male thread region 35 is formed on the outer circumferential surface of the ring body 30. This ring body-side male thread region 35 is formed centered on the ring body axis O4 and can be screwed into the second female thread region 16 of the nail body 10 (see Figures 3(a) and 3(b)). When the ring body-side male thread region 35 is screwed into the second female thread region 16, the ring body axis O4 coincides with the regulating body axis O3 (see Figure 5).

[0048] Furthermore, the length dimension of the ring body 30 in the direction of the ring body axis O4 is smaller than the formation range in the direction of the proximal axis O1 of the non-threaded region 17. In this embodiment, for example, the thickness dimension t of the ring body 30 in the direction of the ring body axis O4 is 13 mm, and the formation range (formation length) L in the direction of the proximal axis O1 of the non-threaded region 17 is 15 mm (see Figures 3(a) and 3(b)). Also, the maximum outer diameter of the male threaded region 35 on the ring body side, i.e., the outer diameter of the threads, is smaller than the inner diameter of the non-threaded region 17. As a result, the ring body 30 can be housed within the non-threaded region 17.

[0049] Here, the ring body 30 is inserted into the nail body 10 after the regulating body 20 so that it is housed within the non-threaded area 17 with the regulating body 20 positioned in the regulating position (see Figure 2). The position in which the ring body 30 is positioned within the non-threaded area 17 is defined as the "use position," and when the bone fixation device 100 is in use, the ring body 30 is positioned in this use position.

[0050] Returning to Figure 5, the inner circumferential surface of the ring body 30 has a ring body side tapered annular surface 30a centered on the ring body axis O4, where the inner diameter gradually decreases from one side in the direction of the ring body axis O4 (the side of the base end Da in the position of use) to the other side (the side of the tip Db in the position of use), and a ring body side straight annular surface 30b connected to the ring body side tapered annular surface 30a on the other side in the direction of the ring body axis O4, forming a perfect annular shape centered on the ring body axis O4. The ring body 30 also has a ring body end surface 30c that is planar and faces the other side of the ring body axis O4.

[0051] When the ring body axis O4 and the regulating body axis O3 are arranged coaxially, the ring body end face 30c of the ring body 30, which is in the usage position, faces the regulating body end face 22c of the regulating body 20, which is in the regulating position, in the longitudinal direction D. Furthermore, when the ring body axis O4 and the regulating body axis O3 are arranged coaxially, the entire area of ​​the regulating body end face 22c can contact a portion of the ring body end face 30c, facing it in the longitudinal direction D. More specifically, in this embodiment, the tapered annular surface 22a of the regulating body end face 22c, which is in the inner circumferential direction, is located radially outward from the ring body side straight annular surface 30b, which is in the inner circumferential direction of the ring body end face 30c. In other words, the inner diameter of the inner hole (internal hole of the ring body) of the ring body end face 30c is smaller than the inner diameter of the inner hole (internal hole of the regulating body) of the regulating body end face 22c.

[0052] As shown in Figure 6(a), an engagement groove (engagement portion) 30x is formed on the inner circumferential surface of the ring body 30, opening on one side in the direction of the ring body axis O4 and recessed radially outward. Two engagement grooves 30x are formed at equal intervals (180-degree intervals) in the circumferential direction. The engagement projection Kx of the special tool K, as shown in Figure 7, can be engaged with these engagement grooves 30x. By rotating the special tool K with the engagement projection Kx of the special tool K engaged with the engagement groove 30x, the ring body 30 can be screwed into the second female thread region 16 and inserted into the nail body 10, thereby guiding the ring body 30 into the non-threaded region 17 of the nail body 10.

[0053] (End cap) Returning to Figure 2, the end cap 40 prevents tissue from flowing into the inner holes 11a and 12a of the nail body 10 (see Figures 3(a) and 3(b)). It is inserted into the inner hole 11a of the proximal part 11 from one side of the proximal axis O1 and is screwed into the second female threaded area 16 of the nail body 10. The end cap 40 has an axial region 41 that is inserted inside the regulating body 20 and the ring body 30, and a screwed region 42 that is provided on the base end Da side of the nail body 10 relative to the axial region 41 when the bone fixation device 100 is in use, and has a male thread 42a formed on its outer circumference.

[0054] In the state of use of the bone fixation device 100, with the male screw 42a screwed into the second female screw region 16 of the nail body 10, the shaft-shaped region 41 is inserted inside the regulating body 20, which is the regulating position, and the ring body 30, which is the usage position, and contacts the outer circumferential surface of the auxiliary shaft member 3, which is inserted through the auxiliary shaft member insertion hole 10z of the nail body 10 and the regulating body through hole 21x of the regulating body 20, pressing the auxiliary shaft member 3 toward the tip Db side of the nail body 10.

[0055] (Axial member for bone fixation) Returning to Figure 1, the bone-fixing shaft member 2 is inserted into the shaft member insertion hole 10y of the nail body 10 (see Figures 3(a) and 3(b)) when the bone-fixing device 100 is in use, and is provided on the nail body 10. The bone-fixing shaft member 2 is positioned toward the femoral head B1 via the trochanter B2 of the femur B, that is, it is positioned within the femur B so as to extend from the outside to the inside of the patient's body and from bottom to top.

[0056] A male screw 2a is formed on the outer circumferential surface of the tip of the bone-fixing shaft member 2, and this male screw 2a is installed so as to be screwed into the femur B. A pressure groove 2b extending in the axial direction of the bone-fixing shaft member 2 is formed on the outer circumferential surface of the bone-fixing shaft member 2 on the proximal end side of the male screw 2a. When the bone-fixing device 100 is in use, a pair of pressing parts 21b (see Figures 4(a) and 4(b)) on the restrictor body 20 are arranged side by side in the axial direction of the bone-fixing shaft member 2, with the tips of each pressing part 21b positioned in the pressure groove 2b, and the bone-fixing shaft member 2 is pressed by the pressing parts 21b toward the tip Db side of the nail body 10, thereby restricting the relative movement and rotation of the bone-fixing shaft member 2 relative to the nail body 10.

[0057] (Auxiliary shaft member) The auxiliary shaft member 3 is inserted into the auxiliary shaft member insertion hole 10z (see Figures 3(a) and 3(b)) of the nail body 10 when the bone fixation device 100 is in use, and is provided on the nail body 10. When the bone fixation device 100 is in use, the auxiliary shaft member 3 is positioned above the bone fixation shaft member 2 and parallel to the bone fixation shaft member 2, that is, it is positioned inside the femur B toward the femoral head B1 via the trochanter B2 of the femur B. A male screw 3a is formed on the outer peripheral surface of the tip of the auxiliary shaft member 3, and this male screw 3a is provided so as to be screwed into the femur B. The tip of the axial region 41 (see Figure 2) of the end cap 40 contacts the outer peripheral surface of the auxiliary shaft member 3 on the proximal end side of the male screw 3a, and the auxiliary shaft member 3 is pressed toward the tip Db side of the nail body 10, thereby restricting the relative movement and rotation of the auxiliary shaft member 3 with respect to the nail body 10.

[0058] (Effects and Benefits) When using the bone fixation device 100 of this embodiment described above for the treatment of a fracture, first, an entry hole is formed at the upper end of the femur B using an awl or the like. Then, the entry hole is widened with a drill or the like to form an opening Ba that communicates with the medullary cavity of the femur B. After inserting a guide wire (not shown) through the opening Ba, the nail body 10 is inserted through the opening Ba with the regulating body 20 and ring body 30 provided on the inside of the nail body 10, so that the guide wire is inserted inside the nail body 10, the regulating body 20, and the ring body 30.

[0059] Subsequently, bone holes for inserting the bone-fixing shaft member 2 and bone holes for inserting the auxiliary shaft member 3 are formed using a drilling tool, and the bone-fixing shaft member 2 and the auxiliary shaft member 3 are screwed in. Then, the regulating body 20 is further screwed onto the nail body 10 to press down on and fix the bone-fixing shaft member 2, and finally, the end cap 40 is screwed onto the nail body 10 to complete the installation of the bone-fixing device 100.

[0060] As described above, in the bone fixation device 100 of this embodiment, a first female thread region 15 and a second female thread region 16 are formed on the inside of the nail body 10 of the intramedullary nail 1, and a non-threaded region 17 without female threads is formed between these female thread regions 15 and 16. Therefore, after inserting the regulating body 20 into the nail body 10 and positioning it in a regulating position that screws only into the first female thread region 15, the ring body 30 is inserted into the inside of the nail body 10 while screwing it into the second female thread region 16 and accommodated in the non-threaded region 17. Even if the ring body 30 rotates in the non-threaded region 17 due to external factors, the male thread region 35 on the ring body side will rotate freely in the non-threaded region 17 without screwing into the first female thread region 15 or the second female thread region 16.

[0061] Therefore, the ring body 30 will not fall out of the nail body 10 and will remain in the non-threaded area 17. As a result, even if the regulating body 20, which is in the regulating position, rotates due to external factors and tries to move towards the base end Da in the longitudinal direction D (upward when the bone fixation device 100 is in use) within the nail body 10, the ring body 30 will restrict such movement, preventing the regulating body 20 from falling off and preventing the regulating body 20 from moving significantly from its regulating position.

[0062] In particular, in this embodiment, since the outer diameter of the threads in the male thread region 35 on the ring body side is smaller than the inner diameter of the non-thread region 17, the ring body 30 can rotate smoothly in the non-thread region 17. Also, since a gap is formed between the ring body 30 and the non-thread region 17, the ring body 30 can move radially in the non-thread region 17. As a result, the ring body axis O4 of the ring body 30 is misaligned with the proximal axis O1 which is the center of the first female thread region 15 and the second female thread region 16, and the ring body 30 can be reliably prevented from falling out of the non-thread region 17.

[0063] Furthermore, since the inner diameter of the threads in the first female thread region 15 and the second female thread region 16 is smaller than the inner diameter of the non-thread region 17, a step is formed between the first female thread region 15 and the non-thread region 17, and between the second female thread region 16 and the non-thread region 17. The ring body 30 comes into contact with this step, preventing it from falling out of the non-thread region 17 in both directions D.

[0064] Furthermore, the formation range in the direction of the regulating body axis O3 in the regulating body side male thread region 25 is larger than the formation range in the direction of the proximal axis O1 in the non-threaded region 17. Therefore, when screwing the regulating body 20 into the nail body 10 and attempting to move it from a state where the regulating body side male thread region 25 is screwed only into the second female thread region 16 to a state where it is screwed only into the first female thread region 15 (for example, the regulating position), the regulating body side male thread region 25 can be screwed into both the second female thread region 16 and the first female thread region 15 when passing through the non-threaded region 17. Thus, the regulating body side male thread region 25 can pass through the non-threaded region 17 smoothly, and the regulating body 20 can be easily and reliably installed in the predetermined position.

[0065] Furthermore, since the inner circumferential surface of the ring body 30 has a ring body side tapered annular surface 30a, when inserting the axial region 41 of the end cap 40 into the inside of the ring body 30, the axial region 41 can be guided by this ring body side tapered annular surface 30a, thereby facilitating the installation of the end cap 40.

[0066] Furthermore, the tapered annular surface 22a, which forms the inner periphery of the regulating body end face 22c, is located radially outward from the straight annular surface 30b, which forms the inner periphery of the ring body end face 30c. Therefore, when the ring body 30 is viewed from above with the nail body 10 installed in the femur B, the inner periphery of the regulating body end face 22c is hidden by the ring body 30. When inserting the axial region 41 of the end cap 40 from the inside of the regulating body 20 toward the inside of the ring body 30, the axial region 41 can be guided smoothly without getting caught between the ring body 30 and the regulating body 20.

[0067] Incidentally, the intramedullary nail 1 may be transported with a restrictor 20 and a ring body 30 installed inside the nail body 10, and the restrictor end face 20c and the ring body end face 30c in contact, thereby fixing the restrictor end face 20c and the ring body end face 30c in place while generating internal forces on each of them. In this embodiment, since the restrictor end face 22c is in contact with a portion of the ring body end face 30c, even if the ring body 30 and the restrictor 20 are made of the same metal material, the effect of adhesion between the ring body 30 and the restrictor 20 can be minimized.

[0068] Therefore, when using the bone fixation device 100, even if the restrictor 20 and the ring body 30 are fused together, it is possible to easily detach the restrictor 20 from the ring body 30 and push the restrictor 20 to the restricted position.

[0069] Furthermore, the contact between the end face 30c of the ring body and the end face 22c of the restrictor body causes interference between the ring body 30 and the restrictor body 20. Therefore, the ring body 30 prevents the restrictor body 20 from moving towards the base end Da side of the ring body 30, thus preventing the restrictor body 20 from falling off.

[0070] Furthermore, since the ring body 30 can be rotated using only the special tool K, it is possible to prevent a third party from accidentally removing the ring body 30 from the nail body 10.

[0071] Herein, 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. For example, in the case of the ring body 30, the overall thickness dimension of the ring body 30 in the direction of the ring body axis O4 does not necessarily have to be smaller than the formation range in the direction of the proximal axis O1 in the non-threaded region 17. At least the formation range in the direction of the ring body axis O4 in the male threaded region 35 on the ring body side must be smaller than the formation range in the direction of the proximal axis O1 in the non-threaded region 17. In this case, at least the ring body 30 located in the non-threaded region 17 will rotate freely in the non-threaded region 17 without being screwed into the first female threaded region 15 and the second female threaded region 16, thereby avoiding significant relative movement of the regulating body 20 with respect to the nail body 10.

[0072] Alternatively, the ring body 30 may have an engagement projection instead of an engagement groove 30x. In this case, the special tool K will have an engagement groove instead of an engagement projection Kx.

[0073] Conversely to the above case, the entire area of ​​the ring body end face 30c may be able to contact a portion of the regulating body end face 22c in the longitudinal direction D. [Industrial applicability]

[0074] The intramedullary nail and bone fixation device of the present invention can improve usability. [Explanation of Symbols]

[0075] 1…Intramedullary nail 2…Axial member for bone jointing 3…Auxiliary shaft member 10… Nail body 10x…Top opening 10y… Shaft member insertion hole 10z...Auxiliary shaft member insertion hole 11…Proximal part 11a...Inner hole 12…Distal part 12a...Inner hole 15…First female thread area 16…Second female thread area 17…Non-screw area 20… Regulatory body 20c…Regulator end face 22a... Regulator side tapered annular surface 22c…Regulator end face 25... Regulator side male thread area 30... Ring body 30a... Tapered annular surface on the side of the ring body 30b...Ring body side straight annular surface 30c... End face of the ring body 30x…Engagement groove 35... Male thread area on the ring body side 100…Bone joint device B…femur B1…Female head B2... Trochanter D... Long direction Da…Proximal end Db…Tip K... Specialized tool Kx…Engagement protrusion O1…Proximal axis (second axis) O2...Distal axis O3…Regulator axis (third axis) O4…Ring body axis (first axis)

Claims

1. When joining bones, it is inserted into the bone and, together with the bone-jointing shaft member that is inserted through itself, the bone is moved inward. An intramedullary nail for fixation, It is cylindrical in shape, and the bone-jointing shaft member is inserted through its outer surface at an intermediate position in the longitudinal direction. A shaft member insertion hole is formed, and the longitudinal base is formed relative to the shaft member insertion hole. A first female thread region located at the end, and a first female thread region located at the base end relative to the first female thread region. A second female thread region, and the first female thread region and the second female thread region in the longitudinal direction A nail body having a non-threaded region positioned between it and its inner surface, A tubular regulating body that can be screwed into the first female thread region and the second female thread region. A male thread region is formed on its outer circumferential surface, and in a regulated position where it is screwed into the first female thread region, The bone-jointing shaft member is positioned in the shaft member insertion hole toward the tip side in the longitudinal direction. Restriction that restricts the relative movement and rotation of the bone-fixing shaft member with respect to the nail body by pressing it. Body and, A ring-shaped male thread on the ring side that forms an annular shape centered on the first axis and can be screwed into the second female thread region. A region is formed on its outer circumferential surface, and the restricting body that becomes the restricting position at the usage position is A ring body is positioned on the base end side, and at least a portion of it is located in the non-threaded region, Equipped with, The first female thread region and the second female thread region are located along the second axis extending in the longitudinal direction. It is formed around, When the ring body is positioned in the usage position, the male thread region on the ring body side However, the range formed along the first axial direction is such that the non-threaded region is in the second axial direction An intramedullary nail smaller than the area formed along the nail.

2. The thickness dimension in the first axial direction of the ring body is the same as the non-threaded region The intramedullary nail according to claim 1, which is smaller than the formation range in the biaxial direction.

3. The non-threaded region has a circular cross-sectional shape centered on the second axis. The outer diameter of the threads in the male thread region of the ring body is smaller than the inner diameter of the non-thread region. The intramedullary nail according to claim 1 or 2.

4. The inner diameter of the threads in the first female thread region and the second female thread region is the non-ne An intramedullary nail according to claim 1 or 2, which is smaller than the inner diameter of the region.

5. The male screw region on the regulating body side is formed around the third axis, which is the central axis of the regulating body. , The male thread region on the regulating body side is formed along the third axial direction, and the non-threaded portion is the same as the non-threaded portion. The claim 1 or 2 states that the region is larger than the range formed along the second axial direction. Intramedullary nail.

6. The inner circumferential surface of the ring body is one of the first axes that is on the base end side at the usage position. From the end of the side, the inner diameter gradually decreases toward the other side of the first axis, with the first axis as the center. An intramedullary nail according to claim 1 or 2, having a tapered annular surface.

7. The regulating body has a regulating body end face that faces the base end side at the regulating position, The ring body faces the longitudinal end side at the usage position and the restriction The end face of the ring body facing the end face of the regulating body, which is the position of the regulating body, from the base end side An intramedullary nail having the characteristics of claim 1 or 2.

8. The regulating body is cylindrical with respect to the third axis, With the first axis and the third axis arranged coaxially, at the end face of the restrictor The inner periphery is positioned radially outward from the inner periphery on the end face of the ring body, as described in claim 7. Intramedullary nail.

9. The end face of the restricting body has a third extending in the longitudinal direction in the restricting body that is the restricting position. A circular internal cavity is formed centered on the three axes. The end face of the ring body has a circular shape centered on the first axis and within the regulating body The intramedullary nail according to claim 7, wherein a bore is formed inside the ring that is smaller in diameter than the hole.

10. The regulating body and the ring body are formed from the same metal material. The entire area of ​​one of the end faces of the regulating body and the end face of the ring body is on the other side The intramedullary nail according to claim 7, which is opposed in the longitudinal direction to a portion of the region.

11. The inner circumferential surface of the ring body has a recess toward the radially outward direction, or a recess toward the radially inward direction. A protruding engagement portion is formed, With the engaging portion engaged with the engaged portion of the tool, the ring body is subjected to the tool. The intramedullary nail according to claim 1 or 2, which is rotatable about a first axis.

12. An intramedullary nail according to claim 1 or 2, A bone-fixing shaft member inserted into the shaft member insertion hole in the intramedullary nail, A bone fixation device equipped with the following features.

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