JP2023068970A - intramedullary nail - Google Patents

Abstract

To provide an intramedullary nail capable of suppressing failure following steps of therapy with respect to bone fracture on a position on a femur proximal side, capable of being arranged at an ideal position in a femur for connecting bone pieces and firmly fixing the bone pieces.SOLUTION: There is provided an intramedullary nail 1 being one embodiment of the intramedullary nail of the invention is a member which is combined with a lag screw 2, a sub pin 3, a locking screw 4, a locking screw 5, a set screw and an end cap in use. Each member is a member forming a bone junction tool A. The intramedullary nail 1 is configured so that, in a direction viewing a distal side from a proximal side along a longitudinal direction of a femur, and in a view point viewing from a direction where a rear condyle is provided on a lower side, (confronting state), a bending direction of a curved part 110 of a shaft part 11 is an angle which is externally rotated by 5° according to an externally curved shape of the femur F.SELECTED DRAWING: Figure 13

Description

There is an application for the application of Article 30, Paragraph 2 of the Patent Law From November 16, 2020, we will start selling products to hospitals (mainly orthopedics) throughout Japan.

There is an application for the application of Article 30, Paragraph 2 of the Patent Law From November 16, 2020, we will start sales activities as product PR using product brochures, samples, procedure manuals, and explanatory materials.

There is an application for the application of Article 30, paragraph 2 of the Patent Law. Place a paper advertisement. Kurume University School of Medicine Department of Orthopedic Surgery (Society Secretariat) published on May 13, 2021 "Orthopedic Surgery and Disaster Surgery 141st Annual Meeting of the Western Japan Orthopedic and Disaster Surgery Society Abstract Volume 70" Posted a paper advertisement.

The present invention relates to intramedullary nails. Specifically, for fractures on the proximal side of the femur, it is possible to suppress problems associated with the process of surgery, and to place bone fragments in an ideal position in the femur to firmly fix them. It concerns a possible intramedullary nail.

Conventionally, in the field of bone fracture treatment requiring surgery, osteosynthesis devices are used that combine an intramedullary nail that is inserted along the longitudinal axis of the bone to be treated and a lag screw that has a male thread formed around the axis. It is used in osteosynthesis, especially for fractures of the proximal femoral site.

Intramedullary nails used for such osteosynthesis are already known in many different forms. Intramedullary nails driven into the femur from the proximal end have been proposed for repairing femoral neck base fractures (see, for example, Patent Document 1).

In addition, in this type of procedure using an intramedullary nail that is driven into the femur from the proximal end, the femur is drilled from the proximal side to the distal side with a reamer, and the intramedullary nail is inserted into the formed hole. insert.

Also, a lag screw is inserted through the screw hole formed in the proximal portion of the intramedullary nail, and the tip thereof is positioned near the center of the femoral head.

Also, the inserted lag screw is pressed and fixed via a set screw attached to the top of the intramedullary nail. In this manner, the bone fragments at the fractured site can be connected and firmly fixed via the intramedullary nail and the lag screw. In addition, by positioning the tip of the lag screw inside the head of the bone, it is possible to apply appropriate pressure to the fracture site and promote bone union.

In order to improve compatibility with the femur, the conventional intramedullary nail has a screw hole for inserting the lag screw corresponding to the anteversion angle, which is the angle at which the neck of the femur is tilted forward. Oriented structures have been proposed.

Here, the "anteversion angle" is an axis that connects the center of the femoral head F1 of the femur F and the center of the neck F2 (the position where the distance to the outer edge is equal), as shown in FIG. 1(a). The angle θ between the femoral neck axis S1 and the femoral condyle axis S2, which is the axis that connects the medial condyle F3 and the lateral condyle F4 at the distal portion of the femur F (posterior condyle).

FIG. 1(a) is a composition of the right femur viewed from the proximal side to the distal side, showing the structure of the femoral head and its periphery. Reference character H in FIG. 1(a) indicates a hip joint.

Although there are individual differences, this anteversion angle generally has a shape in which the neck of the femur is tilted forward (tilted to the upper left as viewed in FIG. 1(a)), that is, the femoral condyle axis S2. , the femoral neck axis S1 opens forward. Depending on the person, the neck of the femur may have a shape that is tilted backward (retroversion angle).

Due to this inclination of the anteversion angle, the femoral head is also inclined forward. It is

Special table 2017-535401

Here, the following problems occur in osteosynthesis using conventional intramedullary nails, including intramedullary nails in which screw holes are formed in consideration of the inclination of the anteversion angle.

First, as a premise, the shape of the femur is such that when viewed from the side, as shown in FIG. It has a forward curved shape (symbol C1, hereinafter referred to as “lordotic shape”) having a curved vertex P.

Here, FIG. 2(a) shows the shape of the right femur in a composition (side view) in which the right femur is viewed from the inside to the outside of the human body along the coronal plane of the human body. Also, FIG. 2(b) shows the shape of the right femur in a composition (front view) in which the right femur is viewed from the front to the rear of the human body along the sagittal plane of the human body.

Note that FIG. 1B shows a coronal plane K1, a sagittal plane K2, and a transverse plane K3, which are planes that traverse the human body. Here, the coronal plane K1 is a plane that bisects the body into front and back. A sagittal plane K2 is a plane passing through the body from front to back and bisecting left and right or a plane parallel thereto. A cross section K3 is a plane that bisects the body vertically. In this specification, the notation of the coronal plane, the sagittal plane, the transverse plane, and the notation of directions along these planes may be used as necessary to specify directions.

2(a) and 2(b) show the medullary canal center M extending along the longitudinal direction inside the femur, the positions M1 of both ends of the medullary canal center, and the lordotic shape of the medullary canal center. position M2 corresponding to the apex P of the marrow cavity (the position of the apex of the bend in the center of the medullary canal).

In general, this lordotic shape extends from the femur directly below the lesser trochanter (the position indicated by symbol L1 in FIG. 2(b)) to the position directly above the patella Q (see FIG. 2(b) ) is bent in the range of the position indicated by the symbol L2) (see FIG. 2(b)). In addition, the "lordotic shape" of the femur in the specification of the present application does not refer to the curvature of the entire femur, but corresponds to the position directly below the lesser trochanter and directly above the patella Q. It means the bending of the range to be secured by the intramedullary nail, which is the range to the position.

In addition, as shown in FIG. 3, the femur is viewed from the proximal side to the distal side along the longitudinal direction of the femur and viewed from the direction in which the posterior condyle is positioned downward ( Hereinafter, a viewpoint viewed from the same direction is referred to as a “front view”), and is a line that is substantially orthogonal to the reference line A connecting the posterior condyles (the medial condyle F3 and the lateral condyle F4). The bending direction of the lordotic shape is inclined with respect to the reference line B, which is a line passing through the position M1 of (in FIG. 3, the external curve shape to be described later, indicated by symbol C2).

More specifically, when viewed from the front in FIG. It is represented by the angle θ formed by the reference line C connecting the corresponding position M2 and the reference line B.

4(a), the reference line A shown in FIG. 3 is the posterior condyle of the femur (the medial condyle F3 and the lateral condyle F4) The rear side of the child) is a line located on the reference plane X, which is a plane located on the same plane. A reference line A is a line corresponding to the femoral condyle axis S2 described above. Also, the femur shown in FIG. 3 is the left femur.

FIG. 4(b) shows the positions of the posterior condyles (the medial condyle F3 and the lateral condyle F4) and the femur when the left femur is viewed from the outside to the inside of the human body along the coronal plane of the human body. FIG. 4C is a view showing the position of the posterior edge F6 of the greater trochanter of the bone, and FIG. Fig. 2 shows the position of F3 and the lateral condyle F4);

As for the shape of the femur, in general, there are many cases in which the bending direction of the lordotic shape does not match the reference line B when viewed from the front as shown in FIG. That is, the bending direction of the lordosis shape is not located in a direction (12 o'clock direction in FIG. 3) that is substantially perpendicular to the reference line A, and is either outside or inside when viewed from the reference line B. (a shape inclined clockwise or counterclockwise in FIG. 3).

Regarding the inclination of the bending direction of the lordosis with respect to the reference line B when viewed from the front, as shown in FIG. 3) is called an "external contour".

Also, unlike FIG. 3, when viewed from the front, the bending direction of the lordotic shape with respect to the reference line B is inclined inward when viewed from the reference line B (the shape inclined clockwise in FIG. 3). is called "internal curvature". In addition, the term “inner and outer” as used herein means a direction along the coronal plane of the human body.

In addition, FIG. 5 shows, as an example of an internal curve shape, a reference plane X on which the posterior condyle of the right femur (the medial condyle F3 and the lateral condyle F4) and the posterior edge F6 of the greater trochanter of the femur are located on the same plane. , shows an inclined surface Y indicating a state in which the direction of bending in the lordotic shape is inclined inward when viewed from the reference line B. FIG.

As shown in FIG. 5, the inclined plane Y is inclined with respect to the reference plane X, and the bending direction in the lordosis shape is obliquely inclined.

As described above, as a feature of the shape of the femur, the inclination of the bending direction in the lordosis shape with respect to the reference line B is often an external curve shape or an internal curve shape.

As described above, the shape of the femur has a lordotic shape when viewed from the side. In addition, when viewed from the front, the inclination of the bending direction of the lordotic shape with respect to the reference line B is often an external curve shape, and depending on the person, it may be an internal curve shape (hereinafter simply " external curvature” and “inner curvature”).

Given such a shape of the femur, conventional intramedullary nails do not have a shape corresponding to the external or internal curvature of the femur.

That is, the conventional intramedullary nail 300 in which the screw hole is formed in consideration of the inclination of the anteversion angle has, for example, shapes as shown in FIGS. 6(a) to 6(e).

6(a) and 6(b) show the shape of the intramedullary nail 300 when viewed from the front (viewpoint from the front side to the rear side when inserted into the femur). Reference numeral 300a denotes a shaft. 6(b) shows a lag screw 301 and a locking screw 302 used in combination with the intramedullary nail 300. FIG.

FIG. 6(c) shows the shape of the intramedullary nail 300 when viewed from the side (when inserted into the femur, viewed from the medial and lateral directions along the coronal plane of the human body). FIG. 6(d) shows the shape of the intramedullary nail 300 when viewed from the front (viewpoint from the proximal side to the distal side when inserted into the femur), and FIG. 4 shows an image diagram showing a state in which the intramedullary nail 300 is inserted straight in the longitudinal direction of the femur (front view).

As shown in FIGS. 6(a) and 6(b), the intramedullary nail 300 has a shaft 300a that extends straight in the vertical direction in the drawing.

Further, as shown in FIG. 6(c), in a side view of the intramedullary nail 300, a curved portion is formed in the shaft 300a. This curved portion is shaped to match the shape of the shaft 300a of the intramedullary nail 300 in correspondence with the above-described lordotic shape of the femur. It becomes a curved part from the front to the back along the .

Further, as shown in FIG. 6(d), in the intramedullary nail 300, the formation direction of the screw hole into which the lag screw 301 is inserted is indicated by symbol θ1 when viewed from the front, considering the inclination of the anteversion angle. formed at an angle.

Here, the intramedullary nail 300 has a curved portion on the shaft 300a corresponding to the lordotic shape of the femur. , the direction (the line labeled Y1) is perpendicular to the reference line A connecting the posterior condyles (the medial condyle F3 and the lateral condyle F4) when viewed from the front.

That is, when the intramedullary nail 300 is straightly inserted in the longitudinal direction of the femur having a curved shape (when the longitudinal direction of the shaft 300a is aligned with the longitudinal direction of the femur), The outer contour C2, that is, the reference line C and the bending direction of the curved portion of the shaft 300a (the line indicated by symbol Y1) do not match each other (see FIG. 6(e)).

In fact, as will be described later, if the intramedullary nail 300 is inserted straight into the femur having a contoured shape, the cortical bone of the femur and the intramedullary nail 300 come into contact with each other during insertion, causing further distal movement. It can be difficult to insert sideways. Therefore, FIG. 6(e) is an image diagram showing the positional relationship assuming that the intramedullary nail 300 has been inserted to a predetermined position (optimum depth) on the distal side.

Thus, the direction of bending of the curved portion of the shaft 300a of the intramedullary nail 300 is different from the direction of bending of the contoured shape of the femur.

Therefore, when the intramedullary nail 300 is used to perform surgery on a femur having a curved shape, it is necessary to extend from the proximal side to the distal side of the femur (at symbol D in FIG. 7A). direction shown), when the distal end of the intramedullary nail 300 is inserted, the direction of bending in the outer contour of the femur is different from the direction of bending in the curved portion of the shaft 300a, causing the tip to bend in the middle of the diaphysis. The tip of the intramedullary nail 300 comes into contact with the cortical bone of the femur, making insertion difficult (see FIG. 7(a)).

In order to avoid a situation in which further insertion of the intramedullary nail 300 is difficult, the intramedullary nail 300 is externally rotated (rotated outward with respect to the femur) for each target device (not shown) that supports the intramedullary nail 300. ) (rotated in the direction indicated by symbol R1 in FIG. 7(b)), and the tip of the intramedullary nail 300 is inserted further distally without contacting the cortical bone of the femur (FIG. 7 ( the direction indicated by symbol D in b)).

7A and 7B are schematic enlarged views showing the positional relationship between the tip of the intramedullary nail 300 and the cortical bone inside the femur.

Here, when the intramedullary nail 300 is externally rotated and inserted into the distal side of the femur, the formation direction of the screw hole for inserting the lag screw 301 is also rotated by externally rotating the intramedullary nail 300. become. That is, in consideration of the inclination of the anteversion angle, the formation direction of the screw hole, which is originally formed at the angle θ1 (see FIGS. 6(d) and 6(e)), is shifted further forward. tilted.

As a result, when the lag screw 301 is inserted into the rotated screw hole, the tip position of the lag screw 301 comes to the front side of the center of the femoral head F1 as shown in FIG. 8(a). In addition, in FIG. 8(a), the arrow with the symbol f indicates the direction toward the front side.

That is, originally, considering the prevention of varus or rotation of the femoral head after surgery via the lag screw 301, the tip of the lag screw 301 is positioned near the center of the femoral head F1. However, external rotation of the intramedullary nail 300 deviates the distal end position of the lag screw 301 forward from the vicinity of the desired center of the femoral head F1. In other words, with the intramedullary nail 300, there is a risk that the lag screw 301 will be installed at an inappropriate position.

In addition, against such deviation of the position where the tip position of the lag screw 301 comes forward from the vicinity of the center of the femoral head F1, the femur is compressed from the outside (in the direction indicated by P1 in FIG. 8B). Compression) A reduction operation is carried out so that the tip position of the lag screw 301 comes to the vicinity of the center of the femoral head F1. Due to this compression, the femoral head F1 is forcibly displaced forward.

When the femoral head F1 is forcibly shifted forward by compressing the femur from the outside, there is a problem that a gap is generated between the bone fragments to be fixed due to the compression. (See the part indicated by symbol P2 in FIG. 8(b)).

In addition, by compressing and shifting the femoral head forward, the diaphyseal shaft advances and retreats in an attempt to return to its original shape, causing internal rotation of the knee (rotating inward) and affecting walking, so-called excessive anteversion. There was a risk of becoming a state of

In addition, since the intramedullary nail 300 forms a screw hole at a certain angle in the direction of formation of the screw hole in accordance with the angle of anteversion, the screw hole is formed at this predetermined certain angle by compression. A change in angle is added, and this change in angle may also cause a decrease in walking ability of the user. In addition, the right femur is shown in FIG.8(a) and FIG.8(b).

As described above, the conventional intramedullary nail causes problems during insertion when it is used in a femur with a curved shape, and the intramedullary nail or lag screw is not placed in the ideal position within the femur. Therefore, it was not possible to adequately fix bone fragments and promote bone union against fractures on the proximal side of the femur.

The present invention has been devised in view of the above points. It is an object of the present invention to provide an intramedullary nail capable of connecting and firmly fixing bone fragments.

In order to achieve the above object, the intramedullary nail of the present invention is inserted from the proximal side of the femur to reduce each bone fragment when the proximal side of the femur is fractured. a proximal portion of the main body, which is used for fixation and has a cylindrical main body in which a through hole is formed, constitutes one end side of the main body, and is formed with a screw hole that intersects with the through hole; , which is connected to the proximal portion of the main body, constitutes an intermediate portion of the main body, has an outer peripheral diameter smaller than that of the proximal main body and has the same diameter, and extends toward the other end of the main body. An intramedullary nail including an extending shaft portion and a body distal portion connected to the shaft portion and constituting the other end side of the body, wherein the shaft portion extends along the medial-lateral direction of the femur. From this viewpoint, a curved portion is formed in the femur that is curved from the anterior side to the posterior side, and the curved portion extends in the longitudinal direction of the femur when the intramedullary nail is inserted into the femur. The posterior condyle of the femur and the posterior edge of the greater trochanter are on the same plane when viewed from the proximal side to the distal side along the A first reference line that is a line on a reference plane that is a surface on which the posterior condyles are located and that is a line that connects the two posterior condyles; With reference to a second reference line that is a line passing through the first axis that is the axis of the one end side of the shaft portion, the first axis on the second reference line when viewed from the front. and the apex of the curved portion, and the first angle formed by the second reference line, the curved portion of the curved portion viewed from the second reference line When the apex is positioned inward, the first angle is a predetermined inward curvature angle, or when the apex of the curved portion is positioned in the outward direction when viewed from the second reference line. , the first angle is configured to be a predetermined external curvature angle.

Note that the terms "front, back, inside, and outside" as used herein are terms defined in directions along a plane that crosses the human body. That is, the anterior-posterior direction is the direction along the sagittal plane, which is one of the planes that traverse the human body, and the medial-lateral direction is the direction along the coronal plane, which is one of the planes that traverse the human body. . In addition, in the direction along the sagittal plane, with the human body as a reference, the front side seen from the human body is called "front or front", and the rear side seen from the human body is called "back or rear". In addition, the direction along the coronal plane, with the human body as a reference, is referred to as "inner or inner", and the direction away from the center of the human body is referred to as "outer or outer". . In addition, in the notation of "proximal, distal" here, in the longitudinal direction of the bone, the direction closer to the center of the human body is called "proximal", and the direction away from the center of the human body is called "distal".

Here, the shaft portion is formed with a curved portion that curves from the anterior side to the posterior side of the femur when viewed along the medial-lateral direction of the femur, thereby allowing the intramedullary nail to be positioned at a desired position inside the femur. When the shaft is arranged in the lateral direction, the shape of the shaft portion can be easily adapted to the lordotic shape of the femur seen when the femur is viewed from the side. In addition, the "lordosis shape" of the femur here means that when the femur is viewed sideways from the medial-lateral direction along the coronal plane of the human body, the diaphysis of the femur has an apex that bends forward. It means a shape that curves forward.

Regarding the curved portion, when the intramedullary nail is inserted into the femur, the direction from the proximal side to the distal side along the longitudinal direction of the femur and the direction in which the posterior condyle is located downward The first reference line is a line on the reference plane, which is a plane on which the posterior condyle of the femur and the posterior edge of the greater trochanter lie on the same plane when viewed from the front, and is a line connecting the two posterior condyles. and the second reference line, which is a line substantially orthogonal to the first reference line when viewed from the front and passes through the first axis, which is the axis of one end of the shaft portion. When viewed side by side, at the first angle formed by the first curve correspondence line, which is the line connecting the first axis on the second reference line and the vertex of the curved portion, and the second reference line, When the apex of the curved portion is positioned inward as viewed from the second reference line, the first angle is the predetermined inner curvature angle, thereby making the curved portion of the shaft relative to the second reference line. This makes it easier to adapt the inclination in the direction of bending to the internal curvature of the femur. That is, when viewed from the front, the reference line B is a line that is substantially orthogonal to the reference line A that connects the posterior condyles (medial condyle and lateral condyle) of the femur and passes through the positions of both ends of the center of the medullary canal. Therefore, the bending direction of the lordotic shape of the femur is tilted inward from the reference line B, that is, the so-called "inner curved shape", and the bending direction of the curved portion of the shaft portion is inclined in the same direction. shape. As a result, the intramedullary nail can be placed at an optimum position without difficulty even for a femur having an internal curvature.
It should be noted that, hereinafter, "frontal view in the direction of viewing from the proximal side to the distal side along the longitudinal direction of the femur and from the direction in which the posterior condyle is positioned downward" is simply referred to as "frontal view It is called "sight". In addition, the first axis, which is the axis on the one end side of the shaft portion here, is the one end side of the shaft portion formed with the same diameter, that is, the position that is the boundary portion with the distal portion of the main body. It means the axis center (the center of the circular cross section) in .

Regarding the curved portion, when the intramedullary nail is inserted into the femur, the direction from the proximal side to the distal side along the longitudinal direction of the femur and the direction in which the posterior condyle is located downward The first reference line is a line on the reference plane, which is a plane on which the posterior condyle of the femur and the posterior edge of the greater trochanter lie on the same plane when viewed from the front, and is a line connecting the two posterior condyles. and the second reference line, which is a line that is substantially perpendicular to the first reference line when viewed from the front and passes through the first axis, which is the axis of one end of the shaft portion. When viewed side by side, at the first angle formed by the first curve correspondence line, which is the line connecting the first axis on the second reference line and the vertex of the curved portion, and the second reference line, When the apex of the curved portion is located in the outward direction as viewed from the second reference line, the first angle is the predetermined external curve angle, so that the curved portion of the shaft portion relative to the second reference line It becomes easy to adapt the inclination in the direction of bending of the femur to the contour shape of the femur. That is, when viewed from the front, the reference line B is a line that is substantially orthogonal to the reference line A that connects the posterior condyles (medial condyle and lateral condyle) of the femur and passes through the positions of both ends of the center of the medullary canal. The bending direction of the lordotic shape of the femur is inclined outward from the reference line B, that is, the so-called "external curve shape", and the bending direction of the curved portion of the shaft is inclined in the same direction. shape. As a result, the intramedullary nail can be placed at an optimal position without difficulty even for a femur having an external curvature.

In addition, in the first angle, when the predetermined inner curvature angle is within the range of 1° to 25°, the bending direction of the curved portion in the shaft portion is set to the inclination angle that is often seen in the inner curved shape. easier to adapt to.

Further, in the first angle, when the predetermined external curvature angle is within the range of 1° to 25°, the bending direction of the curved portion in the shaft portion is set to the inclination angle that is often seen in the external curved shape. easier to adapt to.

Further, regarding the screw hole, when the intramedullary nail is inserted into the femur, in the range of the second angle, which is the angle formed by the first reference line and the formation direction of the screw hole, when viewed from the front, the first When the direction of formation of the screw hole is tilted to the rear side with respect to the reference line of the femur, if the second angle is within the range of 0° to 2°, The formation direction of the screw hole can be matched with the shape in which the retrotwisting angle is inclined in the range of 0° to 2° toward the rear side from the first reference line. That is, it becomes easier to adapt the lag screw to the angle of the retro-twist angle. As a result, even if the femoral neck and femoral head are tilted rearward when viewed from the front, the tip of the lag screw can be easily positioned near the center of the femoral head. In addition, by setting the second angle within the range of 0° to 2°, it becomes easier to adapt to the angle of tilt that is often observed in the backward twist angle.

Further, regarding the screw hole, when the intramedullary nail is inserted into the femur, in the range of the second angle, which is the angle formed by the first reference line and the formation direction of the screw hole, when viewed from the front, the first When the direction of formation of the screw hole is tilted forward with respect to the reference line of the femur, when the second angle is within the range of 0° to 35°, the so-called The formation direction of the screw hole can be matched to a shape in which the anteversion angle is inclined in the range of 0° to 35° toward the front side from the first reference line. That is, it becomes easier to adapt the lag screw to the anteversion angle. As a result, even if the femoral neck and femoral head are tilted forward when viewed from the front, the tip of the lag screw can be easily positioned near the center of the femoral head. In addition, by setting the second angle within the range of 0° to 35°, it becomes easier to adapt to the angle of inclination that is often seen in anteversion angles.

In addition, from the point of view along the medial-lateral direction of the femur, the femur curved forward within the range of the radius of curvature of 514 mm to 1358 mm in the range from the position directly below the lesser trochanter to the position corresponding to the position directly above the patella. When the curved portion is bent in accordance with the above, it becomes easier to adapt the shape of the shaft portion to the lordotic shape of the femur seen when the femur is viewed from the side. That is, by setting the bending of the curved portion of the shaft portion in accordance with the degree of curvature in the range of the radius of curvature of 514 mm to 1358 mm for the lordotic shape of the femur, the intramedullary nail can be forced into the femur. can be placed in the optimum position.

In addition, the main body is formed to have a total length in the range of 265 mm to 400 mm, and the shaft portion is formed with a curved portion, so that it can be seen from a viewpoint along the medial-lateral direction of the femur at the second axis, which is the axis of the proximal portion of the main body. When the distance from the third reference line, which is the line corresponding to the position of the axis of the body, to the center position of the tip of the distal part of the main body is 13 mm or more, the intramedullary The position of the tip of the nail can be more easily arranged at an appropriate position inside the femur (femoral medullary canal) according to the lordotic shape of the femur. For example, the intramedullary nail may come into contact with the cortical bone while the intramedullary nail is being inserted into the femur, or the tip of the intramedullary nail may be pushed to a desired position on the distal side of the femur. When inserted, it becomes easier to prevent the tip of the intramedullary nail from protruding outside from the distal end of the femur. As a result, the compatibility of the intramedullary nail with the femoral medullary canal can be enhanced.

In addition, the curved portion is composed of four bend portions, a first bend portion, a second bend portion, a third bend portion, and a fourth bend portion, and from a viewpoint along the medial-lateral direction of the femur , the curve starting position of the first bend portion is located 120 mm from one end of the proximal portion of the main body, and the curvature of the range between the curve starting position of the first bend portion and the curve starting position of the second bend portion When the radius is 457 mm, the portion of the first bend in the process of advancing the tip of the intramedullary nail to the optimum depth beyond the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur. can be adapted to the bone shape at the beginning of flexion of the lordosis shape of the femur. As a result, contact between the intramedullary nail and the anterior cortical bone in the proximal femur is reduced, and the tip of the intramedullary nail can be smoothly inserted toward the distal direction of the femur. It also reduces the risk of fracture damage at the proximal femur and the risk of preventing intramedullary nail insertion to optimal depth. The optimum depth means the height at which the screw hole can be positioned near the center of the femoral head in the direction along the coronal plane.

In addition, the curved portion is composed of four bend portions, a first bend portion, a second bend portion, a third bend portion, and a fourth bend portion, and from a viewpoint along the medial-lateral direction of the femur , the curve start position of the second bend portion is 150 mm from one end of the proximal portion of the main body, and the curvature of the range between the curve start position of the second bend portion and the curve start position of the third bend portion When the radius is 475 mm, it is easy to obtain a shape corresponding to the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur. As a result, the intramedullary nail can be easily inserted into the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur and also into the vicinity thereof. In addition, the portion beyond the second bend portion can be easily adapted to the lordotic shape of the femur, and the intramedullary nail can be placed at the optimum position without difficulty.

In addition, the curved portion is composed of four bend portions, a first bend portion, a second bend portion, a third bend portion, and a fourth bend portion, and from a viewpoint along the medial-lateral direction of the femur , the curve start position of the third bend portion is 175 mm from one end of the proximal portion of the main body, and the curvature of the range between the curve start position of the third bend portion and the curve start position of the fourth bend portion When the radius is 637 mm, the third bend portion is shaped so as to correspond to the position (the starting point of the posterior curve) in the lordotic shape of the femur where the bone begins to descend from the anterior side to the posterior side. It becomes easier to This avoids excessive contact between the tip of the intramedullary nail and the anterior cortical bone in the femoral distal portion, making it easier to guide the intramedullary nail to the center of the medullary canal of the femur. In addition, the portion beyond the third bend portion can be easily adapted to the lordotic shape of the femur, and the intramedullary nail can be arranged at an optimum position without difficulty.

In addition, the curved portion is composed of four bend portions, a first bend portion, a second bend portion, a third bend portion, and a fourth bend portion, and from a viewpoint along the medial-lateral direction of the femur , the curvature start position of the fourth bend portion is 205 mm from one end of the proximal portion of the main body, and the curvature of the range between the curvature start position of the third bend portion and the curvature start position of the fourth bend portion In the case where the radius is 637 mm, the fourth bend portion allows the intramedullary nail to be inserted in the area distal to the apex of the lordotic shape of the femur, which is a region with a larger curvature in the lordotic shape. The tip can be prevented from protruding from the anterior cortex, and the intramedullary nail can be inserted into the center of the femoral medullary canal. As a result, in addition to insertion into the center of the medullary canal of the femur, it becomes possible to insert the lag screw at an optimal position, and to firmly fix the fractured part.

In addition, when viewed from the front and before the start of insertion of the intramedullary nail into the femur, the formation direction of the screw hole is substantially parallel to the first reference line, and the direction of formation of the screw hole is substantially parallel to the first reference line. In the range of the third angle formed by the second curve correspondence line, which is the line connecting the axis of 1 and the vertex of the curved portion, and the second reference line, the curve is curved when viewed from the second reference line. The apex of the curved portion is located inward and the third angle is in the range of 0° to 60°, or the apex of the curved portion is located in the outward direction when viewed from the second reference line and the third angle is within the range of 0° to 27°, insert the intramedullary nail into the femur, and rotate the intramedullary nail externally or internally by a predetermined angle on the way, When the intramedullary nail is placed at the desired position of the femur, the screw hole is formed while the second curve corresponding line is tilted outward or inward with respect to the second reference line when viewed from the front. can be formed in a shape inclined forward or backward with respect to the first reference line. That is, the curved portion of the shaft portion is externally curved or internally curved with respect to the external curved shape or the internal curved shape of the femur, and the lag screw is curved with respect to the anteversion angle or retroversion angle of the femur. , the intramedullary nail can be adapted to the femur. Accordingly, the intramedullary nail can be placed in an optimal position without difficulty by matching the bending direction of the lordotic shape of the femur and the angle of anteversion or retroversion. In addition, before the intramedullary nail is inserted into the femur, the formation direction of the screw hole is substantially parallel to the first reference line when viewed from the front. Since the direction of formation of the hole is not tilted by a predetermined angle in advance, even if the intramedullary nail is rotated externally or internally during insertion, it is possible to prevent the tip position of the lag screw from deviating from the vicinity of the center of the femoral head.

In addition, when the apex of the curved portion is located inwardly when viewed from the second reference line and the third angle is 7°, the intramedullary nail is inserted into the femur, and the intramedullary nail is inserted halfway. 12° externally rotates the second curve correspondence line outward by 5° with respect to the second reference line when the intramedullary nail is placed in the desired position of the femur when viewed from the front. The direction of formation of the screw holes can be inclined forward by 12° with respect to the first reference line while the shape (5° outward curve) is formed. That is, for a femur having an external curvature of 5° and an anteversion angle of 12°, the curved portion of the shaft portion is externally curved by 5°, and the orientation of the lag screw can be adapted to the anteversion angle of 12°. can. As a result, the intramedullary nail can be placed in an optimal position without difficulty by matching the lordotic shape and anteversion angle of the femur. In addition, before the intramedullary nail is inserted into the femur, the formation direction of the screw hole is substantially parallel to the first reference line when viewed from the front. Since the direction of formation of the hole is not tilted by a predetermined angle in advance, even if the intramedullary nail is externally rotated by 12° during insertion, the tip position of the lag screw can be prevented from deviating forward from the vicinity of the center of the femoral head. In the present intramedullary nail, before being inserted into the femur, the curved portion of the shaft portion is inwardly curved by 7° when viewed from the front.

In addition, when viewed from the front and before the start of insertion of the intramedullary nail into the femur, a second line connecting the first axis on the second reference line and the apex of the curved portion. In the range of the third angle formed by the curve corresponding line and the second reference line, the apex of the curved portion is positioned inward when viewed from the second reference line, and the third angle is 1°. ~ 25°, or the apex of the curved portion is positioned outward when viewed from the second reference line, the third angle is within the range of 1° to 25°, and the first reference line and the formation direction of the screw hole is located so that the formation direction of the screw hole is tilted forward with respect to the first reference line, and the fourth angle is 0 ° to 35°, or positioned so that the formation direction of the screw hole is tilted backward with respect to the first reference line, and the fourth angle is in the range of 0° to 2° , the intramedullary nail is inserted into the femur without external rotation or internal rotation, and when the intramedullary nail is placed in the desired position of the femur, the second A shape in which the direction of formation of the screw hole is inclined forward or backward with respect to the first reference line while the second curve correspondence line is inclined outward or inward with respect to the reference line. can be That is, the curved portion of the shaft portion is externally curved or internally curved with respect to the external curved shape or the internal curved shape of the femur, and the lag screw is curved with respect to the anteversion angle or retroversion angle of the femur. , the intramedullary nail can be adapted to the femur. Accordingly, the intramedullary nail can be placed in an optimal position without difficulty by matching the bending direction of the lordotic shape of the femur and the angle of anteversion or retroversion. It is also possible to insert the intramedullary nail into the femur without external or internal rotation. In addition, before the intramedullary nail is inserted into the femur, the formation direction of the screw hole is inclined forward or backward with respect to the first reference line when viewed from the front. By simply inserting the intramedullary nail straight to the desired position, the lag screw corresponds to the antetorsion angle or retrotorsion angle, and the tip position of the lag screw can be prevented from deviating from the vicinity of the center of the femoral head.

In addition, the apex of the curved portion is positioned outward when viewed from the second reference line, the third angle is 5°, and the formation direction of the screw hole is inclined forward with respect to the first reference line. and the fourth angle is 12°, the intramedullary nail is inserted into the femur without external rotation, and when the intramedullary nail is placed in the desired position on the femur, the correct alignment is achieved. Obliquely, the direction of formation of the screw hole is changed with respect to the first reference line while forming a shape in which the second curve corresponding line is inclined 5° outward (5° external curve) with respect to the second reference line. , and can be slanted forward by 12°. That is, for a femur having an external curvature of 5° and an anteversion angle of 12°, the curved portion of the shaft portion is externally curved by 5°, and the orientation of the lag screw can be adapted to the anteversion angle of 12°. can. As a result, the intramedullary nail can be placed in an optimal position without difficulty by matching the lordotic shape and anteversion angle of the femur. It is also possible to insert the intramedullary nail into the femur without external rotation. In addition, before the intramedullary nail is inserted into the femur, the direction in which the screw hole is formed is inclined forward by 12° with respect to the first reference line when viewed from the front. By simply inserting the intramedullary nail straight to the desired position, the lag screw can handle an anteversion angle of 12°, and the tip position of the lag screw can be prevented from deviating forward from the vicinity of the center of the femoral head. In the present intramedullary nail, before being inserted into the femur, the curved portion of the shaft portion has a 5° outward curvature when viewed from the front.

INDUSTRIAL APPLICABILITY The intramedullary nail according to the present invention is capable of suppressing problems associated with the treatment process for fractures on the proximal side of the femur. It can be firmly fixed.

(a) is a schematic diagram showing the anteversion angle of the femur, viewed from the proximal side to the distal side of the femur; (b) is a plane across the human body, coronal; 1 is a schematic diagram showing plane, sagittal and transverse planes; FIG. (a) is a schematic side view showing the shape of the right femur in a composition (side view) in which the femur is viewed from the inside to the outside in the medial-lateral direction along the coronal plane of the human body; (b) is a schematic side view; 2 is a schematic front view showing the shape of the right femur in a composition (front view) in which the femur is viewed from front to back in the front-rear direction along the sagittal plane of the human body; FIG. FIG. 4 is a schematic diagram for showing the contour shape of the femur; (a) is a diagram showing a state in which the posterior condyle of the femur and the posterior edge of the greater trochanter of the femur are positioned on the same plane (reference plane), and (b) is a diagram showing the state from the outside to the inside along the medial-lateral direction. FIG. 10C shows the position of the posterior condyle and the position of the posterior edge of the greater trochanter of the femur, as viewed from the distal side to the proximal side along the longitudinal direction of the femur. FIG. 11 shows the position of the posterior condyles in the folded state. FIG. 4 is a schematic diagram for showing the internal curvature of the femur; (a) to (d) are diagrams showing the shapes of conventional intramedullary nails, and (e) is a diagram showing the positional relationship between the external curvature of the femur and the bending direction of the curved portion of the shaft. is. (a) is a schematic diagram showing a state in which a conventional intramedullary nail is inserted into the femur and its tip is in contact with the femoral cortical bone; FIG. 11 is a schematic diagram showing a state of trying to insert to the distal side; (a) is a conventional intramedullary nail, and is a schematic diagram showing a state in which the tip position of the lag screw is forward of the center of the femoral head; FIG. 4 is a schematic diagram showing a state in which a gap is generated between bone fragments to be fixed. FIG. 1(a) is a front view of an osteosynthesis device having an intramedullary nail according to the first embodiment of the present invention, as viewed from the front to the rear, and FIG. is a side view from the outside to the inside. FIG. 10 is a diagram showing a state in which the osteosynthesis device is inserted into the desired position of the femur; (a) is a front view of the intramedullary nail viewed from the front to the rear, and (b) is a side view of the intramedullary nail viewed from the inside to the outside. Fig. 10 is a schematic view of the intramedullary nail viewed from the proximal side toward the distal side immediately before inserting the intramedullary nail into the femur; Fig. 10 is a schematic diagram showing a state in which the intramedullary nail is inserted into the femur and externally rotated by 12° when viewed from the front; FIG. 2A is a diagram showing the positions of four bends in the shaft of the intramedullary nail, where (aa) is a front view of the intramedullary nail viewed from the front to the rear, and (b) is the intramedullary nail. It is the side view which looked toward the inside from the outside. It is a schematic enlarged view showing four bend portions. FIG. 4 is a diagram showing the correspondence relationship between the bending start point of the bone in the lordotic shape of the femur and the bending start position of the first bend portion of the intramedullary nail. FIG. 10 is a diagram showing the correspondence relationship between the vertex of bending of the bone in the lordotic shape of the femur and the bending start position of the second bend portion of the intramedullary nail. FIG. 10 is a diagram showing the correspondence relationship between the anterior cortical bone of the femur and the curve starting position of the third bend portion of the intramedullary nail. FIG. 10 is a diagram showing the correspondence relationship between a range of greater bending in the lordotic shape of the femur and the bending start position of the fourth bend portion of the intramedullary nail. FIG. 2(a) is a front view of an osteosynthesis device having an intramedullary nail according to a second embodiment of the present invention, viewed from the front to the rear, and FIG. is a side view from the outside to the inside. (a) is a front view of the intramedullary nail viewed from the front to the rear, and (b) is a side view of the intramedullary nail viewed from the outside to the inside.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below for understanding of the present invention.
In addition, the notation of "front (front)", "back (rear)", "inner (inner)", and "outer (outer)" used below are all on the plane that crosses the human body as described above. A term used to denote each direction along In addition, hereinafter, regarding the intramedullary nail (or shaft), the part of the intramedullary nail that is proximal to the trunk of the person to be treated is referred to as the “proximal side”, and The portion of the intramedullary nail that is distal is referred to as the "distal side."

Also, when the femur is viewed from the side with reference to FIG. 2(a), the diaphyseal shaft has a forward curved shape with an apex P of the curve toward the front side, which is referred to as a "lordotic shape".

Also, with reference to FIG. 3, the direction viewed from the proximal side to the distal side along the longitudinal direction of the femur and the direction viewed from the direction in which the posterior condyle is located downward is referred to as "frontal view". . 3, the line connecting the posterior condyles (the medial condyle F3 and the lateral condyle F4) when viewed from the front is referred to as a "reference line A". A line passing through positions M1 of both ends of the center is referred to as a "reference line B".

Also, with reference to FIG. 3, regarding the inclination of the bending direction of the lordotic shape with respect to the reference line B when viewed from the front, the bending direction of the lordotic shape is tilted outward when viewed from the reference line B. It is called "external curvature shape".

Further, regarding the inclination of the curve of the lordosis with respect to the reference line B when viewed from the front, a shape in which the direction of the curve of the lordosis is inclined inward when viewed from the reference line B is referred to as an "inner curve".

[First embodiment of the present invention]
As shown in FIGS. 9(a) and 9(b), an intramedullary nail 1, which is an example of an intramedullary nail to which the present invention is applied, includes a lag screw 2, a sub-pin 3, a locking screw 4, and a locking screw 5 during operation. , a set screw (not shown) and an end cap (not shown). Further, each member is a member that constitutes the bone connector A. As shown in FIG.

FIG. 9(a) is a front view of the osteosynthesis device A viewed from the front to the rear. Moreover, FIG.9(b) is the side view which looked at the osteosynthesis tool A from the outer side toward the inner side.

In the present embodiment, each constituent member of the bone connector A is preferably made of a titanium alloy, but is not limited to this. , alloys such as vanadium, stainless steel, and various engineering plastics. Moreover, each member constituting the bone connector may be made of a different material.

In addition, the intramedullary nail 1 is inserted toward the distal side of the femur from its tip side, and until the fracture site heals, the bone fragments are displaced, fused together, or separated. It is a member that connects bone fragments to prevent them from collapsing. The intramedullary nail 1 is also a member for inserting and holding the lag screw 2 or the like in the bone.

Moreover, the intramedullary nail 1 is a member for the left femur. Although the following description is based on the intramedullary nail 1, the intramedullary nail to which the present invention is applied can also be applied to the intramedullary nail for the right femur. In addition, the intramedullary nail for the right femur has a shape corresponding to the lordotic shape, anteversion angle (retroversion angle) and external curvature shape (internal curvature shape) of the right femur. , intramedullary nail 1 .

Also, the lag screw 2 is a member that connects bone fragments so that the bone fragments do not shift, fuse together, or separate until the fractured site is healed.

Further, the sub-pin 3 is a member that protrudes to the fracture site and connects the fractured bone fragments. In addition, the sub-pin 3 is a portion that bites into the cancellous bone and produces resistance to the rotational force applied to the bone fragment of the bone to be treated, and cooperates with the lag screw 2 to obtain the effect of preventing rotation of the bone fragment. is a member of

The locking screw 4 and the locking screw 5 are members for fixing the lower end of the intramedullary nail 1 to the bone to be treated. In this embodiment, only two locking screws 4 and 5 are used. A necessary number can be used as appropriate according to the requirements.

Moreover, the bone connector A has a set screw (not shown). The set screw is a member provided above and inside the long axis hole of the intramedullary nail 1, and by engaging with the lag screw 2, holds the lag screw 2 so that it does not move backward and fall off. Together, it is a member that suppresses rotation of the lag screw 2 .

FIG. 10 is a diagram showing a state in which the osteosynthesis device A is inserted into the femur F at a desired position (optimal depth). FIG. 10 is a front view of the femur F and the osteosynthesis device A viewed from the front to the rear. Also, the femur shown in FIG. 10 is the left femur.

As shown in FIG. 10, the tip of the intramedullary nail 1 is inserted at a position near the femoral distal portion F7 in the femoral shaft F5. Further, the tip of the lag screw 2 is inserted at a position near the center position of the femoral head F1 in the femoral proximal portion F8.

The shape of the intramedullary nail 1 will be described in detail.

11(a) and 11(b) show only the intramedullary nail 1. FIG. 11(a) is a composition corresponding to FIG. 9(a), and FIG. It is a composition corresponding to (b). 11(a) and 11(b), reference numeral 2a schematically shows the position of the tip of the lag screw 2 when the intramedullary nail 1 is inserted into the lag screw 2. As shown in FIG.

As shown in FIGS. 11( a ) and 11 ( b ), the intramedullary nail 1 is composed of a proximal body portion 10 , a shaft portion 11 and a distal body portion 12 . In addition, the intramedullary nail 1 is a tubular body having a long axis hole (not shown) extending through the inside thereof along the longitudinal axis.

Also, the main body proximal portion 10 is a member that constitutes the proximal end portion side of the intramedullary nail 1 . A screw hole 100 through which the lag screw 2 is inserted and a pin hole 101 through which the sub-pin 3 is inserted are formed in the main body proximal portion 10 . The direction in which the screw holes 100 are formed will be described later.

Further, the screw hole 100 and the pin hole 101 are formed so as to intersect with a long axis hole penetrating through the intramedullary nail 1 .

In addition, a set screw (not shown) is incorporated inside the proximal end portion side of the main body proximal portion 10 .

The body proximal portion 10 has a same-diameter portion 10a formed to have substantially the same outer diameter, and a diameter-reduced portion 10b having an outer peripheral diameter that gradually decreases toward the shaft portion 11. As shown in FIG. The axial center of the end of the shaft portion 11 connected to the diameter-reduced portion 10b of the main body proximal portion 10 (the axial center of the starting position of the shaft portion 11), which constitutes a part of this cylindrical body, is the This is the portion corresponding to "the first axis which is the axis on the one end side of the shaft portion" in the above item.

Also, the shaft portion 11 is a portion extending along the longitudinal direction of the intramedullary nail 1 . A curved portion 110 is formed on the shaft portion 11 (see FIG. 11(b)).

This curved portion 110 serves as a portion for arranging the intramedullary nail 1 along the lordotic and lateral curves of the femur when the intramedullary nail 1 is inserted to a predetermined position in the femur. Become. The details of the bending of the curved portion 110 will be described later.

Two cross-stopping holes 111 and 112 are formed on the shaft portion 11 on the side of the main body distal portion 12 . Each hole is a hole for inserting a locking screw 4 and a locking screw 5, respectively, and is formed to intersect with a long axis hole penetrating the interior of the intramedullary nail 1. As shown in FIG.

Moreover, the formation direction of the lateral stop hole 111 and the formation direction of the lateral stop hole 112 are formed in different directions.

Here, the formation direction of the cross-stop hole 111 and the formation direction of the cross-stop hole 112 do not necessarily have to be formed in different directions. However, since the direction in which the two locking screws 4 and 5 are inserted can be changed to more firmly fix the osteosynthesis device A to the bone to be treated, the formation direction of the cross-stop hole 111 and the cross-stop hole 112 are different. is preferably formed in a direction different from the formation direction of .

Further, the body distal portion 12 is a member that constitutes the tip portion side of the intramedullary nail 1 . The body distal portion 12 is formed such that the outer diameter gradually decreases toward its tip. Further, the distal end of the main body distal portion 12 is an opening 120 of a long shaft hole penetrating through the intramedullary nail 1 .

Next, the formation direction of the screw hole 100 corresponding to the anteversion angle of the femur and the bending direction of the curved portion 110 of the shaft portion 11 corresponding to the external curvature of the femur will be described.

First, the formation direction of the screw hole 100 through which the lag screw 2 is inserted in the intramedullary nail 1 is such that the intramedullary nail 1 is formed from the proximal side toward the distal side immediately before the intramedullary nail 1 is inserted into the femur. It is formed in the left-right direction from the point of view when viewed from above (the point of view corresponding to the above-mentioned front view) (see FIG. 12).

More specifically, when viewed in FIG. 12, the screw hole 100 is formed in the left-right direction in the figure (the direction connecting 3 o'clock and 9 o'clock in the circumferential direction of the clock). Assuming that there is a horizontal plane below the intramedullary nail 1, the angle formed by the horizontal plane and the formation direction of the screw hole 100 is 0° (substantially parallel).

In addition, the direction of bending of the curved portion 110 of the shaft portion 11 is determined from the point of view of the intramedullary nail 1 from the proximal end side to the distal end side (see above) in the state immediately before the intramedullary nail 1 is inserted into the femur. ), the “vertical line L3” passing through the axis of the starting position of the shaft portion 11 and the “curve Regarding the corresponding line L4, the curve corresponding line L4 is located inside the vertical line L3 as viewed from the femur, and the angle formed by the vertical line L3 and the curve corresponding line L4 is 7°. , the bending direction of the curved portion 110 is formed (see FIG. 12). The bending direction of the curved portion 110 is called a "7° internal curve".

Note that FIG. 12 is for making it easy to imagine the direction of formation of the screw hole 100 and the direction of bending of the curved portion 110 of the shaft portion 11 in the state immediately before the intramedullary nail 1 is inserted into the femur. , an intramedullary nail 1 is shown with a lag screw 2, a locking screw 4 and a locking screw 5 attached.

In the actual operation, as will be described later, the intramedullary nail 1 is inserted into the femur, the intramedullary nail 1 is externally rotated, and with the intramedullary nail 1 placed at a predetermined position, the lag screw 2 and the locking screw 4 are inserted. and the locking screw 5 is inserted, each member is not inserted through the intramedullary nail 1 before inserting the femur.

In this way, the intramedullary nail 1 has the above-described formation direction of the screw hole 100 (0° substantially parallel to the horizontal plane) and the bending direction of the curved portion 110 of the shaft portion 11 (7° internal curvature). are doing.

Then, during the operation, the intramedullary nail 1 is inserted into the femur from its distal end, and the operator externally rotates the intramedullary nail 1 by 12° (at the starting position of the shaft portion 11) when viewed from the front. By rotating the intramedullary nail outward about the center, the direction of formation of the screw hole 100 forms an angle of 12° with the reference line A. Further, the curve corresponding line L4 forms an angle of 5° with the reference line B, and the direction of bending of the curved portion 110 of the shaft portion 11 is the direction curved 5° (see FIG. 13). In FIG. 13, G denotes the axis of the starting position of the shaft portion 11, and E denotes the apex of the curved portion 110. As shown in FIG.

That is, by inserting the intramedullary nail 1 into the femur and externally rotating it by 12°, the intramedullary nail 1 can be placed in a manner suitable for the femur having an anteversion angle of 12° and an external curvature of 5°. .

That is, the intramedullary nail 1 can place the tip of the lag screw 2 near the center of the femoral head F1 of the femur having an antetorsion angle of 12°. In addition, it is possible to prevent the position of the tip of the lag screw 2 from moving toward the front side of the femoral head F1.

In addition, the intramedullary nail 1 can match the bending direction of the curved portion 110 of the shaft portion 11 with respect to the femur having an external curvature of 5°. Thereby, the adaptability of the shaft portion 11 to the femur can be enhanced.

Here, in the intramedullary nail to which the present invention is applied, the angle formed by the horizontal plane and the formation direction of the screw hole 100 is necessarily set to 0° (substantially parallel) when viewed from the front. It is not limited to placing an intramedullary nail in the femur with 12° external rotation. This point can be designed and positioned to match the anteversion angle of the femur. Here, preferably, the horizontal plane and the formation direction of the screw hole 100 are in the range of -2° to 35° with respect to the reference line A, which is a numerical range often seen in the anteversion angle and the posttwist angle. The angle and the angle to externally (or internally) rotate the intramedullary nail can be set.

Further, in the intramedullary nail to which the present invention is applied, the direction of bending of the curved portion 110 is necessarily curved 7° inward when viewed from the front, and after being inserted into the femur, the nail is externally rotated 12°. It is not limited to placing an intramedullary nail in the femur. This point can be designed and positioned for the lateral or medial contour of the femur and its angle. Here, preferably, the direction of curvature of the curve 110 is in the range of 1° to 25° internal curvature or 1° to 25° external curvature, which are typical numerical ranges for femurs. The orientation and angle and the angle to externally (or internally) rotate the intramedullary nail can be set.

Thus, in the intramedullary nail 1, the direction of formation of the screw hole 100 (0° substantially parallel to the horizontal plane) and the direction of bending of the curved portion 110 of the shaft portion 11 (7° internal curvature) are characterized. It is constructed to fully conform to the femur, which has a constant anteversion angle and valvus shape.

Further, for the intramedullary nail to which the present invention is applied, for example, the intramedullary nail is designed by combining the numerical values shown in Tables 1 to 6 below, inserted into the femur, and antetwisted at a desired angle. The conforming placement can be on a femur with a corner or retroversion angle and an external or internal curve shape.

Here, in the combinations of numerical values shown in Tables 1 to 6, first, the formation direction of the screw hole 100 is substantially parallel to the horizontal plane when viewed from the front in the state immediately before the intramedullary nail 1 is inserted into the femur. 0°.

Further, for example, in Table 1, if the bending of the curved portion of the shaft portion 11 before insertion into the femur is 0° (no external curve or internal curve), this is inserted into the femur and 1° external curve Rotation results in an intramedullary nail with an anteversion angle of 1° and a femoral curvature of 1°.

Further, for example, in Table 3, if the bending of the curved portion of the shaft portion 11 before insertion into the femur is 2° internal curvature, inserting it into the femur and externally rotating it by 1° results in an anterior curvature. The intramedullary nail has a torsion angle of 1° and is compatible with a femur with a 1° inward curvature.

Furthermore, for example, in Table 5, if the bending of the curved portion of the shaft portion 11 before insertion into the femur is 3° external curvature, by inserting this into the femur and internally rotating it by 2°, the posterior The intramedullary nail has a torsion angle of 2° and corresponds to a femur with a 1° curve.

Thus, with the intramedullary nail of the present invention, the intramedullary nail is inserted into the femur to obtain the desired anteversion angle or retroversion angle and external curvature or internal curvature. A conformal placement on the femur can be taken.

The combinations of numerical values in Tables 1 to 3 are applicable not only to the intramedullary nail for the left femur but also to the intramedullary nail for the right femur.

Further, it is not always necessary that the direction of formation of the screw hole 100 is 0° substantially parallel to the horizontal plane when viewed from the front immediately before the intramedullary nail 1 is inserted into the femur. For example, by changing the angle formed with the horizontal plane, the bending direction of the curved portion of the shaft portion 11 is adjusted according to the anteversion angle or retroversion angle, external curvature shape, or internal curvature shape of the target femur. and angle, and the direction and angle of rotation after insertion can be set as appropriate.

Next, the bending direction of the curved portion 110 of the shaft portion 11 corresponding to the lordotic shape of the femur will be described.

First, the intramedullary nail 1 is formed with a length of 265 mm from its proximal end 13 to its distal end 14 . In addition, the curved portion 110 of the shaft portion 11 is provided with bend portions (bends) at four locations along the longitudinal direction, and the entire curve is formed.

14(a) and 14(b), the first bend, second bend, third bend, and fourth bend start positions are indicated by symbols A to . It is indicated by D. FIG. 14(a) is a front view of the intramedullary nail 1 viewed from the front to the rear. FIG. 14(b) is a side view of the intramedullary nail 1 viewed from the outside toward the inside.

As shown in FIG. 14(b), the curved portion 110 of the shaft portion 11 of the intramedullary nail 1 is curved from the left side to the right side in the figure as a whole. corresponds to the bending from the front to the rear in 14(a) and 14(b) show the intramedullary nail for the left femur, the intramedullary nail for the right femur also has a curved portion of the shaft portion as in the case of the left femur. , corresponds to the anterior-to-posterior bend in the lordotic shape of the femur.

In addition, the intramedullary nail 1 is formed with the curved portion 110 so that, when viewed from the side, the reference line L5 corresponding to the extension of the axis of the proximal body portion 10 and the center position of the distal end 14 are aligned. is 15 mm.

Further, the bending start position A of the first bend portion is 120 mm from the proximal end 13 of the intramedullary nail 1 . Further, the bending start position B of the second bend portion is 150 mm from the proximal end 13 of the intramedullary nail 1 . Further, the curve starting position C of the third bend portion is 175 mm from the proximal end 13 of the intramedullary nail 1 . Further, the bending start position D of the fourth bend portion is 205 mm from the proximal end 13 of the intramedullary nail 1 .

In the intramedullary nail 1, as shown in FIG. 15, the radius of curvature between positions AB is 457.2055 mm, the radius of curvature between positions BC is 475.1435 mm, and the radius of curvature between positions CD is 637.797 mm. there is Also, the radius of curvature between positions AC is 439.8625 mm, and the radius of curvature between positions BD is 543.8545 mm.

Thus, in the intramedullary nail 1, four bend portions are formed to configure the bending of the curved portion 110 as a whole. Further, by forming these four bend portions, the distance h between the reference line L5 and the center position of the distal end 14 of the intramedullary nail 1 becomes 15 mm.

Here, the length of the intramedullary nail 1 from the proximal end 13 to the distal end 14 is not necessarily limited to 265 mm, and the length can be set as appropriate. Further, it is preferable that the intramedullary nail to which the present invention is applied has a total length in the range of 265 mm to 400 mm. In addition, by setting the total length to 265 mm, it becomes easier to adapt to the approximately average length of the femur of Japanese elderly people, especially women.

In addition, it is not necessary that the curved portion 110 of the shaft portion 11 of the intramedullary nail 1 is provided with bend portions (curved portions) at four locations along the longitudinal direction, and the entire curve is formed. can be set appropriately. In addition, in the range from the position directly below the lesser trochanter to the position corresponding to the position directly above the patella, which is a general numerical range of the lordosis shape of the femur, the curvature radius corresponds to the bending within the range of 514 mm to 1358 mm, Preferably, a bend of the curved portion is formed.

Moreover, the intramedullary nail 1 does not necessarily have the bending of the curved portion 110 so that the reference line L5 corresponding to the extension of the axis of the proximal body portion 10 and the center of the distal end 14 in a side view. The distance h to the position is not limited to 15 mm, and can be set as appropriate. However, by setting the total length of the intramedullary nail 1 to 265 mm and the distance h to 15 mm, the intramedullary nail 1 can be adjusted according to the approximately average length and lordotic shape of the femur of Japanese elderly people, especially women. It becomes much easier to place the tip of the nail at an appropriate position inside the femur (femoral medullary canal). Further, in the present invention, it is preferable that the distance h between the center position of the distal end and the reference line corresponding to the extension of the axis of the proximal portion of the main body is set to 13 mm or more according to the total length of the intramedullary nail.

In addition, the relationship between the total length of the intramedullary nail and the distance h between the reference line L and the central position of the tip of the intramedullary nail can be set as follows according to the length of the femur of the subject. is. For example, setting the total length of the intramedullary nail to 300 mm to 320 mm and the distance h to 17 to 22 mm, or setting the total length of the intramedullary nail to 340 mm to 360 mm and the distance h to 22 to 25 mm can be considered.

Further, the distance from the proximal end of the intramedullary nail 1 to each bending start position and the value of the curvature radius can be appropriately set for the four bend portions in the curved portion 110 of the shaft portion 11 . However, the design of the intramedullary nail 1 described above produces the effects described below.

First, the bending start position A of the first bend portion was set at a distance of 120 mm from the proximal end 13 of the intramedullary nail 1, and the radius of curvature between the positions AB was set at 457.2055 mm in side view. , in the process of advancing the tip 14 of the intramedullary nail to the optimum depth beyond the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur, the portion of the first bend is brought into contact with the lordotic curve of the femur. It can be adapted to the shape of the bone at the beginning of the bending of the shape.

This reduces the contact between the intramedullary nail 1 and the anterior cortical bone F9 in the proximal femur, and allows smooth insertion with the tip 14 of the intramedullary nail 1 directed toward the distal femur. It also reduces the risk of fracture damage at the proximal femur and the risk of preventing the intramedullary nail from being inserted to the optimal depth.

In this regard, in FIG. 16, A indicates the starting position of the first bend and F9 indicates the anterior cortex of the proximal femur.

Further, the bending start position B of the second bend portion is 150 mm from the proximal end 13 of the intramedullary nail 1, and the radius of curvature between positions BC in side view is set to 475.1435 mm. , it becomes easier to form a shape corresponding to the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur.

As a result, the intramedullary nail can be easily inserted into the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur and also into the vicinity thereof. In addition, the portion beyond the second bend portion can be easily adapted to the lordotic shape of the femur, and the intramedullary nail 1 can be arranged at an optimum position without difficulty.

In this regard, in FIG. 17, B indicates the bending start position of the second bend portion, and M2 indicates the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur.

Further, the curve starting position C of the third bend portion is 175 mm from the proximal end 13 of the intramedullary nail 1, and the radius of curvature between the positions CD is set to 637.797 mm in side view. , the third bend portion can be easily formed into a shape corresponding to the position where the bone begins to descend from the anterior side toward the posterior side (the starting point of the posterior curve) in the lordotic shape of the femur.

This avoids excessive contact between the tip 14 of the intramedullary nail 1 and the anterior cortical bone F10 at the distal portion of the femur, making it easier to guide the intramedullary nail to the center of the medullary canal of the femur.

In this regard, in FIG. 18, reference character C indicates the bending start position of the third bend portion, and reference character F10 indicates the anterior cortical bone.

Further, the bending start position D of the fourth bend portion is 205 mm from the proximal end 13 of the intramedullary nail 1, and the radius of curvature between positions CD is set to 637.797 mm in side view. , a region distal to the apex of the lordotic shape of the femur, which is a region T in which the curvature is greater in the lordotic shape, the fourth bend portion causes the tip 14 of the intramedullary nail 1 to be brought into contact with the anterior cortex. In addition, it is possible to insert the intramedullary nail into the center of the femoral medullary cavity.

As a result, in addition to insertion into the center of the medullary canal of the femur, it becomes possible to insert the lag screw at an optimal position, and to firmly fix the fractured part.

In this regard, in FIG. 19, D indicates the bending start position of the fourth bend portion, M2 indicates the position corresponding to the apex of the lordotic shape at the center of the medullary canal of the femur, and T indicates It shows the range of greater curvature in the lordotic shape, which is the area distal to the apex of the lordotic shape in the femur.

Thus, in the intramedullary nail 1, by setting the positions and bends of the four bend portions in the curved portion 110 of the shaft portion 11, the intramedullary nail can be adjusted to match the curved shape of the lordosis of the femur. 1 can be fully adapted.

Next, a brief description will be given of the procedure for inserting the intramedullary nail 1 to which the present invention is applied into the femur.

(1) A reamer is used to perforate the femur from the proximal side of the trunk to the distal side, and the intramedullary nail 1 is inserted into the formed hole.

(2) Insert the tip of the intramedullary nail 1 to a predetermined position inside the femur (femoral medullary canal), and externally rotate the intramedullary nail 1 by 12° together with the target device to which the intramedullary nail 1 is attached. When viewed from the front, the formation direction of the screw hole 100 is aligned with the anteversion angle of the femur, and the bending direction of the curved portion 110 of the shaft 10 is externally rotated by 5°. Also, the position of the screw hole 100 of the inserted intramedullary nail 1 is finely adjusted using an X-ray imaging device.

(3) A hole is drilled in the lateral side of the femur, where the lag screw 2 is to be inserted, and the lag screw 2 is inserted into the formed hole. , insert until the tip of the lag screw 2 reaches.

(4) After the tip of the lag screw 2 has reached the vicinity of the center of the femoral head F1, the fitting protrusion of the set screw built into the long shaft hole of the intramedullary nail 1 is inserted into the long groove of the lag screw 2. The lag screw 2 is fixed by fitting and pressing from above.

(5) A hole is drilled in the lateral side of the femur for the planned insertion site of the sub-pin 3, the sub-pin 3 is inserted into the formed hole, and the pin hole 101 of the intramedullary nail 1 and the set screw arranged in the intramedullary nail 1 are inserted. Insert it through the pin hole.

(6) An end cap is further attached from the upper part of the inserted set screw to make it difficult for the sub-pin 3 to come off from the intramedullary nail 1 .

According to the above flow, the osteosynthesis device A having the intramedullary nail 1 can be inserted into the femur to be treated, and the bone fracture site on the proximal side of the femur can be firmly fixed with the osteosynthesis device A. .

Effects of the present embodiment include the following main effects.

First, in the intramedullary nail 1, the direction of bending of the curved portion 110 of the shaft portion 11 can be externally rotated by 5° in accordance with the external curved shape of the femur F when viewed from the front. Thereby, the intramedullary nail 1 can be adapted to the contour shape of the femur F.

Further, when inserting the intramedullary nail 1 into the femur F from the distal end 14, the intramedullary nail 1 can be externally rotated by 12 degrees to facilitate insertion. In addition, by this 12° external rotation operation, the bending direction of the curved portion 110 of the shaft portion 11 can take a 5° externally curved angle when viewed from the front.

Furthermore, by this 12° external rotation operation, the angle formed with the reference line A is set to 12° so that the formation direction of the screw hole 100 corresponds to the anteversion angle of the femur F when viewed from the front. can be done.

In addition, in this 12° external rotation work, the direction in which the screw hole 100 is formed is such that the tip of the lag screw 2 is positioned near the center of the femoral head F1. It is possible to suppress the state of being positioned on the front side of the.

In addition, as a result, it is possible to avoid the work of compressing the femur from the outside and reducing the position of the tip of the lag screw 2 so that it is near the center of the femoral head F1. can. Therefore, it is possible to prevent gaps from forming between the bone fragments to be fixed due to compression, and excessive anteversion due to internal rotation of the knee.

In addition, in the intramedullary nail 1, the curved portion 110 of the shaft portion 11 is formed by four bent portions, and the position and curvature of each bent portion are set to match the curved shape of the lordosis of the femur. , the intramedullary nail 1 can be well adapted.

[Second embodiment of the present invention]
Next, an intramedullary nail 1a, which is a second embodiment of the present invention, will be described. In the following description, features different from those of the above-described first embodiment of the present invention will be described, and members that overlap with those of the first embodiment will be assigned the same reference numerals, and detailed description thereof will be omitted. do.

As shown in FIGS. 20(a) and 20(b), an intramedullary nail 1a, which is an example of an intramedullary nail to which the present invention is applied, includes a lag screw 2, a sub-pin 3, a locking screw 4, and a locking screw 5 during operation. , setscrews and end caps. Further, each member is a member that constitutes the bone connector B. As shown in FIG.

In addition, Fig.20 (a) is the front view which looked at the bone connector B from the front toward the back. Moreover, FIG.20(b) is the side view which looked at the osteosynthesis tool B from the outer side toward the inner side.

21(a) and 21(b) show only the intramedullary nail 1a, and FIG. 21(a) is a composition corresponding to FIG. 20(a), and FIG. It is a composition corresponding to FIG.20(b). 21(a) and 21(b), reference numeral 20a schematically shows the position of the tip of the lag screw 2 when the lag screw 2 is inserted through the intramedullary nail 1a.

As shown in FIGS. 21( a ) and 21 ( b ), the intramedullary nail 1 a is composed of a proximal body portion 7 , a shaft portion 8 and a distal body portion 9 . In addition, the intramedullary nail 1a is a tubular body having a long axis hole (not shown) extending through the inside thereof along its longitudinal axis.

Further, a screw hole 100a for inserting the lag screw 2 and a pin hole 101 for inserting the sub-pin 3 are formed in the proximal portion 7 of the main body. The formation direction of the screw holes 100a will be described later.

Further, the screw hole 100a and the pin hole 101 are formed so as to intersect with a long axis hole passing through the inside of the intramedullary nail 1a.

In addition, a set screw (not shown) is incorporated inside the proximal end portion side of the main body proximal portion 7 .

A curved portion 110a is formed on the shaft portion 8 (see FIG. 21(b)).

This curved portion 110a serves as a portion for arranging the intramedullary nail 1a along the lordotic and lateral curves of the femur when the intramedullary nail 1a is inserted to a predetermined position in the femur. Become. Details of the bending of the curved portion 110a will be described later.

Two cross-stopping holes 111 and 112 are formed in the shaft portion 8 on the side of the main body distal portion 9 .

Next, the direction of formation of the screw hole 100a corresponding to the anteversion angle of the femur and the direction of bending of the curved portion 110a of the shaft portion 8 corresponding to the external curvature of the femur will be described.

First, the formation direction of the screw hole 100a through which the lag screw 2 is inserted in the intramedullary nail 1a is such that the intramedullary nail 1a is formed from the proximal side toward the distal side immediately before the intramedullary nail 1 is inserted into the femur. When it is assumed that there is a horizontal plane below the intramedullary nail 1a from a perspective (corresponding to the above-mentioned front view), the angle formed by the horizontal plane and the formation direction of the screw hole 100a is 12°. (It faces upward at an angle of 12° to the horizontal plane, not shown).

In addition, the direction of bending of the curved portion 110a of the shaft portion 8 is determined from the point of view of the intramedullary nail 1a from the base end side to the distal end side in the state immediately before the intramedullary nail 1a is inserted into the femur (see above). ), a “vertical line L6 (not shown)” passing through the axis of the starting position of the shaft part 8, the axis of the starting position of the shaft part 8 and the apex of the bend of the curved part 110a Regarding the "curve corresponding line L7 (not shown)" connecting The bending direction of the curved portion 110a is formed so that the angle formed is 5°. The bending direction of the curved portion 110a is called a 5° external curve.

In this way, the intramedullary nail 1a has the above-described formation direction of the screw hole 100a (12° with respect to the horizontal plane) and the bending direction of the curved portion 110a of the shaft portion 8 (5° external curvature). ing.

During the operation, the intramedullary nail 1a is inserted straight into the femur from its tip, and the operator does not rotate the intramedullary nail 1 externally when viewed from the front. , the angle formed with the reference line A is 12°. Further, the curve corresponding line L7 forms an angle of 5° with the reference line B, and the direction of bending of the curved portion 110a of the shaft portion 8 is the direction curved 5°.

In other words, the intramedullary nail 1a can be inserted into the femur and placed in a position adapted to the femur having an anteversion angle of 12° and an external curvature of 5° without external rotation.

That is, the intramedullary nail 1a can place the tip of the lag screw 2 near the center of the femoral head F1 of the femur having an antetorsion angle of 12°. In addition, it is possible to prevent the position of the tip of the lag screw 2 from moving toward the front side of the femoral head F1.

Further, the intramedullary nail 1a can match the direction of bending of the curved portion 110a of the shaft portion 8 with respect to the femur having an external curve of 5°. Thereby, the adaptability of the shaft portion 8 to the femur can be enhanced.

Thus, in the intramedullary nail 1a, the formation direction of the screw hole 100a (12° with respect to the horizontal plane) and the bending direction of the curved portion 110a of the shaft portion 8 (5° external curvature) are characterized, It has a structure that sufficiently enhances the conformity to the femur with a anteversion angle and valvus shape.

Here, in the second embodiment of the present invention, the angle formed by the horizontal plane and the formation direction of the screw hole 100a must be 12 degrees when viewed from the front immediately before the intramedullary nail 1 is inserted into the femur. , and the bending direction of the curved portion 110a does not need to be curved 5°. According to the anteversion angle or retroversion angle of the target femur and the shape of external curvature or internal curvature, for example, the angle formed by the horizontal plane and the formation direction of the screw hole when viewed from the front is - It is set within the range of 2° to 35°, and the bending direction of the curved part is to take an externally curved shape in the range of 1° to 25° or an inwardly curved shape in the range of 1° to 25°. can also

As described above, the intramedullary nail according to the present invention can prevent problems associated with the treatment process for fractures in the proximal side of the femur, and can be placed at an ideal position in the femur to It is possible to connect the pieces and sufficiently fix them.

The invention made by the present inventor has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say.

A Bone connector 1 Intramedullary nail 10 Proximal portion of main body 10a Same diameter portion 10b Reduced diameter portion 11 Shaft portion 110 Curved portion 12 Distal portion of main body 120 Opening (of long axis hole) 13 Proximal end (of intramedullary nail) 14 tip (of intramedullary nail) 100 screw hole 101 pin hole 2 lag screw 3 sub pin 4 locking screw 5 locking screw F femur F1 (femoral) head F2 (femoral) neck F3 medial condyle F4 lateral condyle F5 (femur) Diaphysis F6 Posterior margin of greater trochanter F7 Distal (femur) F8 Proximal (femur) F9 Cortical bone (anterior side of femur) S1 Femoral neck axis S2 Femoral condyle axis M Medullary canal Center M1 Both ends of the center of the medullary canal M2 The position corresponding to the apex of the lordosis shape in the center of the medullary canal L1 The position just below the lesser trochanter (of the femur) L2 The position just above the patella (of the femur) L3 Vertical line L4 Curve corresponding line L5 A line corresponding to the extension of the axis of the proximal portion of the main body in side view G The axis of the starting position of the shaft portion

B Bone connector 1a Intramedullary nail 7 Proximal part of main body 8 Shaft part 9 Distal part of main body 100a Screw hole 110a Curved part

Claims (10)

When the proximal side of the femur is fractured, it is inserted from the proximal side of the femur to reduce and fix each bone fragment, and has a cylindrical shape with a through hole. and a proximal portion of the main body that constitutes one end side of the main body and has a screw hole that intersects the through hole, and an intermediate portion of the main body that is connected to the proximal portion of the main body and a shaft portion formed with an outer peripheral diameter smaller than the outer peripheral diameter of the proximal portion of the main body and having the same diameter and extending toward the other end portion side of the main body; An intramedullary nail comprising a body distal portion constituting an end portion side,
The shaft portion has a curved portion that curves from the front side to the rear side of the femur when viewed along the medial-lateral direction of the femur,
The curved portion is
When inserting the intramedullary nail into the femur,
The posterior condyle and the greater trochanter of the femur when viewed from the proximal side to the distal side along the longitudinal direction of the femur and viewed from the direction in which the posterior condyle is located downward A first reference line that is a line on a reference plane that is a surface whose edges are located on the same plane and that connects the two posterior condyles, and a line that is substantially orthogonal to the first reference line when viewed from the front. Based on a second reference line that is a line passing through a first axis that is the axis of the one end side of the shaft portion,
In the front view,
At the first angle formed by the second reference line and the first curve correspondence line, which is a line connecting the first axis on the second reference line and the vertex of the curved portion,
When the apex of the curved portion is positioned inward when viewed from the second reference line, the first angle is a predetermined inner curvature angle, or
In the intramedullary nail, the first angle is a predetermined lateral curvature angle when the apex of the curved portion is located in the lateral direction as viewed from the second reference line. at the first angle,
the predetermined internal curvature angle is in the range of 1° to 25°; or
2. The intramedullary nail of claim 1, wherein the predetermined external curvature angle is in the range of 1[deg.] to 25[deg.]. The screw hole is
When the intramedullary nail is inserted into the femur,
In the front view,
In the range of the second angle, which is the angle formed by the first reference line and the formation direction of the screw hole,
When the direction of formation of the screw holes is tilted toward the rear side with respect to the first reference line, the second angle is in the range of 0° to 2°, or
The second angle is in the range of 0° to 35° when the direction of formation of the screw hole is tilted forward with respect to the first reference line. Or an intramedullary nail according to claim 2. From the point of view along the medial-lateral direction of the femur, the femur is curved forward with a radius of curvature in the range of 514 mm to 1358 mm in the range from the position directly below the lesser trochanter to the position corresponding to the position directly above the patella. 4. The intramedullary nail according to claim 1, 2 or 3, wherein the curvature of the curved portion is formed to match the bone. The main body has a total length in the range of 265 mm to 400 mm,
By forming the curved portion in the shaft portion, the second axis, which is the axis of the proximal portion of the body, corresponds to the position of the second axis from the point of view along the medial-lateral direction of the femur. 5. The intramedullary nail according to claim 1, 2, 3, or 4, wherein the distance from the reference line 3 to the center position of the distal end of the body distal portion is 13 mm or more. The curved portion is composed of four vents, a first vent, a second vent, a third vent, and a fourth vent,
From a viewpoint along the medial-lateral direction of the femur,
a position where the bending of the first vent portion starts is a position 120 mm from one end of the proximal portion of the main body;
A curve starting position of the second vent portion is a position 150 mm from one end of the proximal portion of the main body,
A curve starting position of the third vent portion is a position 175 mm from one end of the proximal portion of the main body,
A curve starting position of the fourth vent portion is a position 205 mm from one end of the proximal portion of the main body,
The radius of curvature of the range between the curve start position of the first vent portion and the curve start position of the second vent portion is 457 mm,
The radius of curvature of the range between the curve start position of the second vent portion and the curve start position of the third vent portion is 475 mm,
1, 2, 3, 4 or claim 1, claim 2, claim 3, claim 4, or claim 1, claim 2, claim 3, claim 4, or claim 1, claim 2, claim 3, claim 4, or claim 1, claim 2, claim 3, claim 4 or claim 5. Intramedullary nail according to 5. When viewed from the front and before starting insertion of the intramedullary nail into the femur,
the formation direction of the screw hole is substantially parallel to the first reference line,
A third angle range that is an angle formed by a second curve corresponding line that is a line that connects the first axis on the second reference line and the vertex of the curved portion and the second reference line in
The apex of the curved portion is located inward when viewed from the second reference line, and the third angle is in the range of 0° to 60°, or
The apex of the curved portion is positioned outward when viewed from the second reference line, and the third angle is within the range of 0° to 27°. Intramedullary nail according to claim 4, claim 5 or claim 6. The intramedullary nail according to claim 7, wherein the apex of the curved portion is positioned inwardly when viewed from the second reference line, and the third angle is 7°. When viewed from the front and before starting insertion of the intramedullary nail into the femur,
A third angle range that is an angle formed by a second curve corresponding line that is a line that connects the first axis on the second reference line and the vertex of the curved portion and the second reference line in
The apex of the curved portion is positioned inward when viewed from the second reference line, and the third angle is in the range of 1° to 25°, or
The apex of the curved portion is positioned outward when viewed from the second reference line, and the third angle is in the range of 1° to 25°,
In the range of the fourth angle, which is the angle formed by the first reference line and the formation direction of the screw hole,
With respect to the first reference line, the direction of formation of the screw hole is positioned so as to be inclined forward, and the fourth angle is in the range of 0° to 35°, or
With respect to the first reference line, the direction of formation of the screw hole is positioned so as to incline toward the rear side, and the fourth angle is within a range of 0° to 2°. 2. An intramedullary nail according to claim 3, claim 4, claim 5 or claim 6. The apex of the curved portion is positioned outward when viewed from the second reference line, and the third angle is 5°,
10. The intramedullary nail according to claim 9, wherein the direction of formation of the screw hole is inclined forward with respect to the first reference line, and the fourth angle is 12[deg.].

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