JP2023092887A - Blade body, osteosynthesis implement having the same, and osteosynthesis implement set - Google Patents

Abstract

To provide a blade body and an osteosynthesis implement having the same which improve restraint of rotation of the osteosynthesis implement, increase strength against load in a varus direction and/or load in a back and forth direction, avoids complication of a structure, and has suitable operability of an operator, the blade body and the osteosynthesis implement having the same that can provide an osteosynthesis implement set, and the osteosynthesis implement set.SOLUTION: A blade body 300 is put on an osteosynthesis shaft-like member 200 for use, extends in an axis AX2 direction of the osteosynthesis axial shaft-like member 200 on an outer periphery of the osteosynthesis axial shaft-like 200 when put on the osteosynthesis shaft-like member 200, and has three or more blades 301 arranged apart from each other in a circumferential direction of the osteosynthesis shaft-like member 200.SELECTED DRAWING: Figure 7

Description

The present invention relates to a blade body that can be attached to an osteosynthesis tool used for treating bone fractures, an osteosynthesis tool having the same, and an osteosynthesis tool set.

Conventionally, as a method for treating fractures near the head of a bone having a head such as a femur and a humerus, an intramedullary nail is inserted into the bone along the axial direction, and the intramedullary nail is used. Surgical instruments with bone fasteners (lag screws) that are inserted through the bone may be used. A bone fastener (lag screw) has a shaft portion and an engaging portion (screw portion) formed with a thread groove. By screwing the engaging portion into the femoral head, the fracture site near the femoral head is fixed.

By the way, in the osteosynthesis device, the osteosynthesis device may rotate along the screw groove. When this happens, a cutout occurs in which the distal end (engagement part) of the osteosynthesis device comes out of the femur in the lateral direction, necessitating a second operation, or a poor prognosis due to a decrease in bone gripping force. be.

Therefore, in the osteosynthesis device, a hook piece protrudes on the outer periphery of the tip of the lag screw to improve the resistance to the rotational movement of the femoral head, and a triple wire is used to improve the rotational stability in the intertrochanteric fracture. A configuration for improving the performance has been developed (for example, see Patent Document 1 and Patent Document 2).

Japanese Patent No. 5937768 Japanese Patent No. 6485754

However, in the prior art, there is room for improvement in terms of resistance to load on the bone connector. Specifically, the load on the osteosynthesis device is, for example, the load in the direction from the head to the leg of the human body (the direction in which the angle between the femoral head and the bone axis becomes smaller (varus direction)) and/or The load in the front-to-back direction (back and forth direction) of the body can be mentioned, but it cannot be said that sufficient consideration has been given to resistance to these loads in the prior art.

Further, for example, the prior arts described in Patent Documents 1 and 2 both have a configuration in which a hook piece or a triple wire is led out from the inside of the shaft of the bone connector to the outside (periphery), and the structure of the bone connector is complicated. Become. As a result, there is a problem that not only the manufacturing cost of the bone connector increases, but also the operator's procedure becomes complicated and complicated.

In addition, due to the structure that leads out from the inside of the shaft of the connector to the outside (periphery), both the hook piece and the triple wire adopt a shape that is easy to rebound against the pressing force from the outside, or an elastic material. For this reason as well, it is difficult to say that this is sufficient as a countermeasure for the load associated with the bone connector.

In view of such circumstances, the present invention has been made to improve the suppression force against rotation of an osteosynthesis device, increase the strength against loads in the varus direction and/or the anteroposterior direction, avoid complication of the structure, and improve operability for the operator. To provide a good blade body, an osteosynthesis device having the same, and a osteosynthesis device set.

The present invention is a blade body to be used by being attached to an osteosynthesis shaft-like member, wherein when the blade body is attached to the osteosynthesis shaft-like member, the outer circumference of the osteosynthesis shaft-like member 2. A blade body characterized by comprising three or more blades extending in the axial direction of the osteosynthesis shaft-shaped member and spaced apart from each other in the circumferential direction of the osteosynthesis shaft-shaped member. is.

The present invention also provides an intramedullary nail having a hole, an osteosynthesis shaft-like member to be inserted into the hole of the intramedullary nail, and an osteosynthesis shaft-like member disposed on the rear end side of the osteosynthesis shaft-like member. An osteosynthesis device comprising: a fixture for fixing a member to the intramedullary nail; A plurality of recesses are provided around the axis of the osteosynthesis shaft-shaped member, and the outer peripheral surface of the osteosynthesis shaft-shaped member can accommodate a part of the blade extending in the axial direction of the osteosynthesis shaft-shaped member. wherein a plurality of blade grooves are provided around the axis of the osteosynthesis shaft-like member, and the recesses and the blade grooves are provided at different positions in the circumferential direction of the osteosynthesis shaft-like member. It is related to

The present invention also provides an intramedullary nail having a hole, an osteosynthesis shaft-like member inserted into the hole of the intramedullary nail, and a fixture for fixing the osteosynthesis shaft-like member to the intramedullary nail. , and the above-mentioned blade body, wherein the outer peripheral surface of the osteosynthesis shaft-like member is provided with a plurality of recesses around the axis of the osteosynthesis shaft-like member with which the distal end of the fastener comes into contact. wherein the recess and the blade are provided at different positions in the circumferential direction of the osteosynthesis shaft-like member.

Further, the present invention is an osteosynthesis tool comprising an intramedullary nail having a hole, an osteosynthesis shaft-like member to be inserted into the hole of the intramedullary nail, and a blade body attached to the osteosynthesis shaft-like member. When attached to the osteosynthesis shaft-shaped member, the blade body extends in the axial direction of the osteosynthesis shaft-shaped member on the outer periphery of the osteosynthesis shaft-shaped member. The osteosynthesis shaft-shaped member has two or more blades that are circumferentially spaced apart from each other on the outer periphery of the tip side, and the osteosynthesis shaft-shaped member is fixed to the intramedullary nail by a fixture, and the bone is On the outer peripheral surface of the rear end side of the joint shaft-shaped member, a plurality of recesses with which the distal end of the fastener comes into contact is provided around the shaft of the bone joint shaft-shaped member. , when the arrangement location of the specific recess is set as a reference phase, the first blade is arranged at a position that is more than 0 degrees and less than 180 degrees with respect to the reference phase, excluding 90 degrees; Further, the second blade is arranged at a position that is more than -180 degrees and less than 0 degrees with respect to the reference phase, excluding -90 degrees. is.

The present invention also relates to an osteosynthesis tool set comprising the above osteosynthesis tool and an attachment tool for attaching the blade body to the osteosynthesis shaft member.

According to the present invention, the force for suppressing rotation of the osteosynthesis device is improved, the strength against the load in the varus direction and/or the load in the front-rear direction is also increased, the complication of the structure is avoided, and the operator's operability is improved. It is possible to provide a blade body, an osteosynthesis tool having the same, and an osteosynthesis tool set.

It is a longitudinal cross-sectional view explaining the osteosynthesis tool of this embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the blade body of this embodiment, (A) exploded front view, (B) exploded perspective view, (C) side view, (D) enlarged side view. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the lag screw of this embodiment, (A) Front view, (B) Top (planar) view, (C) Bottom view, (D) Rear view. FIG. 2 is a view for explaining the lag screw of the present embodiment, (A) an external perspective view, (B) an enlarged perspective view, (C) an enlarged perspective view, and (D) a sectional view taken along the line AA of (A). BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the lag screw with a blade body of this embodiment, (A) is an exploded front view, (B) is a front view, (C) is an external perspective view. It is an enlarged view of the lag screw with a blade body of this embodiment, (A) is a front view, (B) is a side view. It is a figure which shows the other example of the lag screw with a blade body of this embodiment, (A) is an external perspective view, (B) is a side view. FIG. 11 is a side view showing a lag screw with a blade body of another embodiment; It is a schematic diagram for describing this embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each figure below, the parts with the same reference numerals represent the same parts. In addition, in each drawing, a part of the configuration is appropriately omitted to simplify the drawing, and the size, shape, thickness, etc. of the members are appropriately exaggerated.

<Bone connector>
First, referring to FIG. 1, the overall configuration of the bone connector 10 of this embodiment will be described. FIG. 1 is a schematic longitudinal cross-sectional view showing a state in which a bone fracture site of a patient's femur 500 is fixed by an osteosynthesis device 10. As shown in FIG. In the following description, unless otherwise specified, the direction is specified based on the state in which the bone fracture site of the patient's femur 500 is fixed with the bone connector 10 . That is, the patient's ventral side is called "front", the dorsal side is called "posterior", the patient's head side is called "upper", and the patient's leg side is called "lower". FIG. 1 shows a left leg femur 500 as an example.

The osteosynthesis device 10 of this embodiment has, for example, a bone fixation device 100, an osteosynthesis shaft-like member (lag screw) 200, and a blade body 300. As shown in FIG. The lag screw 200 of this embodiment can be selectively attached to a conventionally known bone fastener 100 . That is, in this embodiment, a known bone fastener 100 can be used. The bone anchor 100 is, for example, an intramedullary nail.

The bone anchor (intramedullary nail) 100 is used by being inserted into the medullary cavity (lumen) of the femur 500 . The intramedullary nail 100 has a proximal portion 102 on the side of the proximal end (upper end T) in the direction of the axis AX1 (vertical direction in the figure) and a distal portion 103 located on the side of the tip (lower end). The intramedullary nail 100 has a shaft hole 105 that communicates with the proximal portion 102 and the distal portion 103, extends in the direction of the axis AX1, and is open at both ends. A female thread 106 is formed on the inner wall (inner surface) near the opening of the shaft hole 105 on the side of the proximal portion 102 (upper end T). Note that the shaft hole 105 may be provided only on the proximal portion 102 side of the intramedullary nail 100 and may not communicate with the distal portion 103 . That is, distal portion 103 may be solid.

The intramedullary nail 100 has a lateral hole 104 extending in a direction intersecting the axial hole 105 . The lateral hole 104 is a hole through which an osteosynthesis shaft-like member (lag screw) 200 is inserted. The axial hole 105 opens into the horizontal hole 104 in the middle of opening at both upper and lower ends of the intramedullary nail 100. At this position, the axial hole 105 and the horizontal hole 104 communicate with each other. A fixture (set screw) 451 for the lag screw 200 is inserted into this connecting portion, more specifically, into the shaft hole 105 above the horizontal hole 104 .

1, the lateral hole 104 obliquely penetrates the intramedullary nail 100 so as to have an axis AX2 inclined with respect to the direction of the axis AX1 of the intramedullary nail 100. As shown in FIG.

The inclination angle of the lateral hole 104 (its axis AX2) in FIG. In this case, the lag screw 200 is appropriately set so that the fracture site near the femoral head 502 of the femur 500 can be fixed. In this embodiment, as an example, the inclination angle is set to substantially match the angle formed by the axial direction of the femur 500 (vertical direction in the drawing) and the direction in which the femoral head 502 protrudes from the femur 500 .

Also, in this example, the intramedullary nail 100 has a fastener insertion hole 108 which penetrates the distal portion 103 and whose both ends are open on both outer peripheral surfaces of the distal portion 103 . In addition, the fixture insertion hole 108 is formed through the distal portion 103 in a direction substantially perpendicular to the direction of the axis AX1. A screw 601 or the like is inserted through the fastener insertion hole 108 , thereby fixing the intramedullary nail 100 and the femur 500 also at the distal portion 103 .

The osteosynthesis shaft-shaped member (lag screw) 200 has a shaft portion 221 and an engaging portion (screw portion) 211 and is inserted through the horizontal hole 104 . That is, the direction of the axis AX2 of the lag screw 200 coincides with the direction of the axis AX2 of the lateral hole 104 . The engaging portion 211 is located on the distal end side of the lag screw 200 and is a portion formed with a thread groove, and the shaft portion 221 is a portion extending from the engaging portion 211 to the proximal end side. The lag screw 200 fixes the fracture site near the femoral head 502 by screwing the engaging portion 211 into the femoral head 502 .

The lag screw 200 is also fixed to the intramedullary nail 100 by a set screw 451 . The set screw 451 has a screw shape consisting of a head portion and a threaded portion having a male thread. The threaded portion of the set screw 451 is configured to be screwed into. Further, the lag screw 200 is formed with a plurality of recesses 222 extending in the direction of the axis AX2 on the outer peripheral surface of the shaft portion 221 at regular intervals around the axis. The tip of the set screw 451 contacts and presses (fits) in, for example, the recess 222 on the rear end side of the lag screw 200, so that the lag screw 200 is prevented from rotating while being inserted into the horizontal hole 104. and fixed to the intramedullary nail 100 . The concave portion 222 is here, as an example, a groove extending in the longitudinal direction of the axis AX2. By forming the recessed portion 222 as a long groove portion, it is possible to fix the recessed portion 222 at any position in the longitudinal direction according to the degree of penetration of the lag screw 200 into the femur 500 . However, the shape of the recess 222 may not be a long groove as long as the tip of the set screw 451 can be fitted therein. good.

When the bone fracture site of the patient's femur 500 is fixed with the osteosynthesis device 10, the lag screw 200 mainly receives a component in a direction from above to below (hereinafter referred to as "varus direction IV"). and a load having a component in the direction from the front to the rear (hereinafter referred to as "front-back direction AP") have a great influence. Hereinafter, for convenience of explanation, a load having a component in the varus direction IV will simply be referred to as a "load in the varus direction IV", and a load having a component in the longitudinal direction AP will simply be referred to as a "load in the longitudinal direction AP".

<Blade body>
The blade body 300 of this embodiment will be described with reference to FIG. The blade body 300 of this embodiment is used by being attached to the lag screw 200 . 2A and 2B are views showing an example of the blade body 300, FIG. 2A is an exploded front view of the appearance, FIG. 2B is an exploded perspective view of the appearance, and FIG. 2D is an enlarged side view of the portion marked with a dashed line in FIG.

The blade body 300 has a plurality of blades 301 , a blade support portion 302 and a blade body fixture (lock screw) 303 . Each of the plurality of blades 301 is an elongated, substantially flat plate-like (substantially flat prismatic) member whose longitudinal direction is the direction of the axis AX2 of the lag screw 200. are spaced apart. The number of blades 301 in one blade body 300 is, for example, 2 to 4, preferably 3 or 4, more preferably 3. FIG. 2 illustrates a case where the blade body 300 has three blades 301 . Each blade 301 extends in the direction of the axis AX2 of the lag screw 200 with a connecting portion to the blade support portion 302 as a base end.

The blade support portion 302 integrally supports a plurality of (here, three) blades 301, and is made of, for example, an annular member having a diameter approximately equal to that of a lag screw. One end of a plurality of blades 301 is connected to one peripheral edge of the blade supporting portion 302, and the plurality of blades 301 are spaced apart from each other in the circumferential direction. are arranged (FIGS. 2(B) and 2(C)).

Each blade 301 has substantially the same shape, and is substantially rectangular in a side view (FIG. 2(C)) from the tip direction. Specifically, in a side view (FIG. 2(C)), a curved surface (outer peripheral surface 3012) located radially outward of the blade support portion 302 and three substantially U-shaped planes (two side surfaces 3013 and an inner It has a peripheral surface 3014).

The height of the blade 301 (blade height H; length in the radial direction of the blade support portion 302) is substantially constant along the direction of the axis AX2 (the blade height H does not vary substantially), but the height of the blade 301 is substantially constant in the direction of the axis AX2. ), and as indicated by the broken line circle in FIG. . The width of the blade 301 (blade width W; the length in the circumferential direction of the blade support portion 302) is substantially constant along the direction of the axis AX2 (the width does not vary substantially). A thread groove (female screw) 3021 is formed in the inner wall of the blade support portion 302 .

The blade body fixture 303 has a screw shape consisting of a head and a threaded portion with a male screw formed therein. is configured as

<Lag screw>
Next, the lag screw 200 of this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3(A) is a front view of the appearance of the lag screw 200, FIG. 3(B) is a top (plan) view of the appearance of the lag screw 200, FIG. 3(C) is a bottom view, and FIG. 3(D) is a rear view. is. 4A is an external perspective view of the lag screw 200, FIGS. 4B and 4C are enlarged perspective views of the vicinity of the engaging portion 211, and FIG. It is an A line sectional view.

As shown in FIG. 3, the lag screw 200 of this embodiment is provided with a plurality of blade grooves 250 on its outer peripheral surface. Each blade groove 250 extends in the direction of the axis AX2 of the lag screw 200 and is spaced apart from each other around the axis (in the circumferential direction). The blade groove 250 is provided in a substantially U-shape in a cross-sectional view perpendicular to the axis AX2, and can accommodate and hold a part of the blade 301. As shown in FIG. For example, the number of blade grooves 250 is equal to or greater than the number of blades 301 of the blade body 300 used in combination. Here, as an example, the blade grooves 250 are three grooves of the same number as the number (three) of the blades 301 of the blade body 300 used in combination, and are arranged at approximately equal intervals around the axis of the lag screw 200 (in the circumferential direction). will be described.

A plurality of recesses 222 are formed around the axis of the shaft portion 221 on the outer peripheral surface of the shaft portion 221 with which the tip of the set screw 451 (see FIG. 1) can come into contact. The recess 222 and the blade groove 250 are provided at different positions in the circumferential direction of the lag screw 200 . More specifically, in this example, three recesses 222 and three blade grooves 250 are alternately arranged around the axis of the shaft portion 221 at substantially equal intervals.

In addition, the blade groove 250 is continuously provided from the shaft portion 221 to the engaging portion (screw portion) 211 in the direction of the axis AX2. More specifically, the blade groove 250 has a first blade groove 251 provided in the shaft portion 221 and a second blade groove 252 provided in the engaging portion 211, and the first blade groove 251 and the second blade groove 252 are continuous. are doing. Here, as an example, the first blade groove 251 extends from the proximal end of the shaft portion 221 to its distal end (boundary with the engaging portion 211), and the second blade groove 252 extends from the proximal end of the engaging portion 211 (shaft portion 221) to its tip (tip thread). Each of the plurality of blade grooves 250 has a similar shape.

Referring to FIG. 4A, in each blade groove 250, the first blade groove 251 is an elongated groove communicating from the proximal end to the distal end of the shaft portion 221. As shown in FIG. The first blade groove 251 is substantially U-shaped in the cross-sectional view shown in FIG. Dg1 (the length in the radial direction of the shaft portion 221) is approximately equal to the blade height H.

The second blade groove 252 is a groove that is continuous with the first blade groove 251 and accommodates (holds) one blade 301, and is an aggregate of a plurality of cutouts 2522 aligned in the direction of the axis AX2.

As shown in FIGS. 4(B) and 4(C), the engaging portion 211 has a screw thread 2112 provided in a helical shape on the outer periphery of a screw shaft portion 2110 coaxial with the shaft portion 221 and having a small diameter. Configuration. The second blade groove 252 is formed by forming a notch portion 2522 in a portion of the screw shaft portion 2210 and a portion of a plurality of screw threads 2112 linearly aligned in the direction of the axis AX2. As shown in FIGS. 4(B) to 4(D), the notch 2522 is also substantially U-shaped in cross section, and its groove width Wg is the same as that of the first blade groove 251, but the Depth Dg2 gradually becomes shallower toward the tip of engaging portion 211 .

In addition, a screw groove (female screw) 2211 is formed on the inner wall of the proximal end of the shaft portion 221 (see FIGS. 3(A) and 3(B)) so that it can be screwed with the screw portion of the blade body fixture 303. )).

The lag screw with blade body 200B will be described with reference to FIGS. 5 to 7. FIG.
5(A) is an exploded front view of the lag screw with blade body 200B, FIG. 5(B) is a front view of the appearance of the lag screw with blade body 200B, and FIG. 5(C) is the appearance of the lag screw with blade body 200B. is a perspective view of the.

Referring to FIG. 5A, blade body 300 is configured to be detachable from lag screw 200 . When attaching the blade body 300 to the lag screw 200, after inserting the lag screw 200 into the lateral hole 104 of the intramedullary nail 100 embedded in the femur 500, the blade body 300 is inserted from the proximal end side thereof. . That is, on the proximal side of the blade groove 250 (first blade groove 251) of the lag screw 200, the tip of each blade 301 is aligned with the blade groove 250 (first blade groove 251), and the blade body 300 is moved to the lag screw. Slide towards the tip of 200. This causes blades 301 to be inserted into and engage respective blade grooves 250 . Then, the screw portion of the blade body fixture 303 is screwed into the screw groove 3021 of the blade support portion 302 . A screw groove (female screw) 2211 is also provided at the proximal end of the shaft portion 221 , and the blade body fixture 303 is screwed into the screw grooves 3021 and 2211 .

Thereby, the blade body 300 is fixed to the lag screw 200 as shown in FIGS. 5(B) and 5(C). The three blades 301 extend in the direction of the axis AX2 on the outer circumference of the lag screw 200 and are arranged apart from each other (at equal intervals) in the circumferential direction of the lag screw 200 . In addition, this also causes the recess 222 and the blade 301 to be arranged at different positions in the circumferential direction of the lag screw 200 . More specifically, in this example, three recesses 222 and three blades 301 are alternately arranged around the axis of the shaft portion 221 at approximately equal intervals (see FIG. 4D).

When removing the blade body 300 from the lag screw 200 , the fixation by the blade body fixture 303 is released, and the blade body 300 is slid in the direction from the distal end to the proximal end to separate from the lag screw 200 .

6A and 6B are views showing the vicinity of the engaging portion 211 of the lag screw with blade body 200B. FIG. 6A is a front view showing the vicinity of the engaging portion 211, and FIG. is a side view as viewed from the distal end side. In FIG. 6(A), the direction from the top to the bottom in the drawing is shown as an inversion direction IV, and the direction from the back to the front in the drawing is shown as an anterior-posterior direction AP. The reverse direction IV and the direction from right to left in the drawing are shown as the front-back direction AP (see FIG. 1).

As shown in FIG. 6A, when the blade body 300 is attached to the lag screw 200, the blade 301 is accommodated and held in the blade groove 250 (first blade groove 251, second blade groove 252).

The groove width Wg of the first blade groove 251 is slightly larger than the blade width W, and the groove depth Dg1 of the first blade groove 251 is equivalent to the blade height H (Fig. 2(C), Fig. 4(D )). In addition, the curvature of the outer peripheral surface 3012 of the blade 301 is substantially the same as the curvature of the peripheral surface of the shaft portion 221 of the lag screw 200 . Therefore, the side surface 3013 and the inner peripheral surface 3014 of the blade 301 are substantially in close contact with the inner wall of the first blade groove 251, and the peripheral surface of the shaft portion 221 and the outer peripheral surface 3012 are accommodated in the first blade groove 251 with substantially no level difference.

On the other hand, the groove depth Dg2 of the second blade groove 252 (notch portion 2522 aligned on a straight line in the direction of the axis AX2) is equivalent to the groove depth Dg1 of the first blade groove 251 at the proximal end of the engaging portion 211. However, it gradually becomes shallower toward its tip (to the right in FIG. 6A) and becomes smaller (shallower) than the blade height H of the blade 301 . Therefore, the blade 301 gradually protrudes from the outer peripheral edge of the thread 2112 of the engaging portion 211 (indicated by the large broken line in FIG. 6A) in the vicinity of the tip of the engaging portion 211 . That is, the blade protrusion amount P shown in FIG. 6B increases from the proximal end of the engaging portion 211 toward the distal end.

It is preferable that the blade protrusion amount P and the blade height H satisfy the formula of P=1/4H to 3/4H in order to increase the anti-rotation force and the like. More preferably, it satisfies the formula P=1/3H to 2/3H.

The blade 301 projecting from the thread 2112 functions as a wedge when the lag screw with blade body 200B tries to rotate around the axis AX2 in the femur 500. FIG. Therefore, compared with the case without the blade 301, the force for suppressing rotation (rotation suppression force) can be increased.

Also, by projecting the three blades 301, the outer circumference of the engaging portion 211 gradually expands from the proximal end toward the distal end. As a result, as shown in FIG. 6B, the area receiving the load in the inversion direction IV (the area formed by projecting the engaging portion 211 onto a plane orthogonal to the inversion direction IV, the front surface in the inversion direction IV ( Anterior) projected area) can be increased. Similarly, the area that receives the load in the front-rear direction AP (the area formed by projecting the engaging portion 211 onto a plane orthogonal to the front-rear direction AP, the front (front) projected area in the front-rear direction AP) can be increased. Therefore, compared to the case where the blade 301 is not arranged, the resistance to the load in the inversion direction IV and the resistance to the load in the longitudinal direction AP can be increased.

Specifically, the front projected area includes a portion of the blade 301 arranged between the threads 2112 in the direction of the axis AX2 of the engaging portion 211 and the outer peripheral edge of each thread 2112 in the radial direction of the engaging portion 211. (large dashed line) is increased by a portion of the blade 301 protruding radially outward.

Furthermore, the three blades 301 are arranged such that the normal direction of the outer peripheral surface 3012 of each blade 301 is shifted from both the inversion direction IV and the front-rear direction AP. If a large load is applied from the normal direction to the outer peripheral surface 3012 of the blade 301 protruding from the thread 2112 of the engaging portion 211, the cancellous bone of the femur 500 may be broken by the knife effect, and the head 502 may be damaged. be.

In this embodiment, the blade 301 can be placed in a position that is least affected by both the load in the varus direction IV and the load in the anteroposterior direction AP, thereby minimizing the risk of cancellous bone breakage. At the same time, it is possible to increase the rotation restraining force, the resistance to the load in the inversion direction IV, and the resistance to the load in the front-back direction AP.

In this embodiment, such arrangement of the blades 301 can be performed easily and reliably. That is, the lag screw 200 is fixed to the intramedullary nail 100 by the set screw 451 , but the recess 222 with which the set screw 451 abuts and the blade 301 are provided at different positions in the circumferential direction of the lag screw 200 . More specifically, regarding the arrangement of the lag screw 200 in the circumferential direction, one of the blades 301 (first blade 301a) is , is arranged at a position that is more than 0 degrees and less than 180 degrees in the clockwise direction with respect to the reference phase and is excluding 90 degrees (the position of 60 degrees in the example of FIG. 6), and another one The blade (second blade 301b) is more than -180 degrees to less than 0 degrees in the counterclockwise direction with respect to the reference phase, except for -90 degrees (-60 degrees in the example of FIG. 6 position). In this example, the phase difference between the first blade 301a and the second blade 301b is 120 degrees. When three blades 301 are provided as shown in FIG. 6(B), since these are arranged at approximately equal intervals, the remaining blades (third blade 301c) are arranged, for example, 180 degrees with respect to the reference phase. position.

The recesses 222 are provided in the same number as the blades 301 (blade grooves 250), and both are arranged alternately in the circumferential direction of the lag screw 200 (FIG. 4(D)).

As described above, in this embodiment, a plurality of blades 301 are arranged at predetermined positions with reference to the recess 222 . Therefore, by fixing the lag screw 200 with reference to the recessed portion 222, each blade 301 can improve the rotation restraining force and the resistance to the load in the inversion direction IV and the load in the front-back direction AP. , can be easily and reliably placed in a suitable position with less risk of fracture of the femur 500.

In addition, since the blade groove 250 and the recessed portion 222 are also provided at different positions in the circumferential direction of the lag screw 200, the local decrease in strength of the lag screw 200 due to the thinning of the lag screw 200 can be dispersed. In addition, the shape of the blade 300 and the blade groove 250 is not limited to the shape shown in FIG.

7A and 7B are diagrams showing other examples of the blade 300 and the blade groove 250. FIG. 7A is an external perspective view of the lag screw with blade body 200B, and FIG. It is the side view seen from the tip direction.

As shown in FIG. 7, the blade width W is smaller and the blade height H is larger than the blade 301 shown in FIG. You can make it bigger. Note that the blade groove 250 is also shaped to match the blade 301 .

Compared to the shape of the blade 301 shown in FIG. 6, by reducing the blade width W and increasing the blade height H and the blade protrusion amount P, the blade 301 against the load in the inversion direction IV and the front-back direction AP Strength can be increased. In this case, the overall length of the lag screw 200 in the direction of the axis AX2 may be shorter than that shown in FIG.

<Other embodiments>
FIG. 8 is a diagram showing an example of another embodiment of the present invention, and is a side view corresponding to FIG. In this embodiment, when the lag screw with blade body 200B is embedded in the femur 500, the blades 301 are arranged at a plurality of positions other than the varus direction IV and the anteroposterior direction AP. Just do it. That is, the number of blades 301 in one blade body 300 may be four or two. Also in this case, the recess 222 and the blade 301 of the lag screw 200 are provided at different positions in the circumferential direction of the lag screw 200 .

FIG. 8A shows the case where the number of blades 301 is four. Regarding the arrangement of the lag screw 200 in the circumferential direction, when the arrangement location of a specific recess 222 (for example, a recess 222a) is set as a reference phase, one of the blades 301 (first blade 301a) is positioned relative to the reference phase. For example, it is more than 0 degrees and less than 180 degrees in the clockwise direction, and is arranged at a position other than 90 degrees (for example, a position of +45 degrees), and another blade (second blade 301b) It is arranged at a position between -180 degrees and less than 0 degrees in the counterclockwise direction with respect to the reference phase and excluding -90 degrees (for example, -45 degrees). In this case, the phase difference between the first blade 301a and the second blade 301b is 90 degrees. When four blades 301 are provided as shown in FIG. 8(A), they are arranged at approximately equal intervals, so the remaining third blade 301c is positioned at, for example, -135 degrees with respect to the reference phase. , and the fourth blade 301d are arranged at a position of, for example, +135 degrees with respect to the reference phase. The recesses 222 are provided in the same number as the blades 301 , are spaced apart at approximately equal intervals in the circumferential direction of the lag screw 200 , and are alternately arranged with the blades 301 .

FIG. 8B shows the case where the number of blades 301 is two. Regarding the arrangement of the lag screw 200 in the circumferential direction, when the arrangement location of a specific recess 222 (for example, a recess 222a) is set as a reference phase, one of the blades 301 (first blade 301a) is positioned relative to the reference phase. For example, it is more than 0 degrees and less than 180 degrees in the clockwise direction, and is arranged at a position other than 90 degrees (for example, a position of +45 degrees), and another blade (second blade 301b) It is arranged at a position between -180 degrees and less than 0 degrees in the counterclockwise direction with respect to the reference phase and excluding -90 degrees (for example, -135 degrees). In this case, the phase difference between the first blade 301a and the second blade 301b is 180 degrees. The recesses 222 are provided in the same number as the blades 301 and arranged alternately with the blades 301 .

FIG. 9 is a schematic diagram of a case where a load in the inverse direction IV is applied to the lag screw 200 (hereinafter, the same applies to the lag screw with blade body 200B in the description of FIG. 9). The lag screw 200, which is firmly fixed to the intramedullary nail 100 and in which a load in the varus direction IV is applied to the vicinity of the engaging portion 211, is modeled as a simple cantilever structure as shown in FIG. can.

In this case, assuming that the lag screw 200 is a cylinder, a tensile stress is generated on the upper surface side and a compressive stress is generated on the lower surface side with the neutral plane including the center line (indicated by the dashed line) along the axis AX2 as a boundary. . In this case, since the fatigue limit is greater for compressive stress than for tensile stress, it is not desirable to provide blade grooves 250 on the upper surface side to increase tensile stress. Further, considering the risk of cancellous bone breakage as described above, it is desirable that the normal direction of the outer surface of the blade 301 should not overlap with the varus direction IV and the front-back direction AP.

For these reasons, in this embodiment, the lightening on the upper surface side is only the minimum recess 222, and the blade 301 is arranged at a position other than ±90 degrees with respect to the recess 222 (reference phase). .

As a result, regardless of whether the number of blades 301 is two, three, or four, it is possible to prevent the normal direction of the outer surface of the blades 301 from overlapping with the varus direction IV and the front-to-back direction AP. can minimize the risk of

Moreover, when the number of blades 301 is two or four, the position of the blade groove 250 can be shifted from the inversion direction IV, which is advantageous in terms of stress. Note that when there are three blades, one blade groove 250 is positioned on the lower surface side in the inverse direction IV, but on the compression side, the blade groove 250 accommodates the blade 301, The risk of fatigue can be reduced (minimized) compared to the case of providing on the top side.

By the way, the lag screw 200 is inserted into the femur 500 to a depth determined by the screwing amount (rotation amount) of the engaging portion 211 , but fixing to the intramedullary nail 100 is limited to the position of the recess 222 .

As an example, when the lag screw 200 is rotated once around its axis AX2, the amount of movement (advance and retreat) is 3 mm (the amount of movement per rotation is a pitch of 3 mm). If three locations are arranged at approximately equal intervals, the amount of movement of the lag screw 200 for each recess 222 is 1 mm (pitch control is possible by 1 mm).

That is, when there are three recesses 222 (three blades 301), pitch control can be performed by 1 mm as the amount of movement of the lag screw 200, and when there are four recesses 222, the amount of movement of the lag screw 200 is It is possible to control the pitch by 0.75 mm, and if there are two concave portions 222, the amount of movement of the lag screw 200 can be controlled by 1.5 mm.

In other words, from the viewpoint of pitch control of the lag screw 200 (high degree of freedom in manipulation), it can be said that a larger number of recesses 222 (for example, four) is desirable because it facilitates fine adjustment. However, especially when the recessed portions 222 are formed in a long groove shape along the axis AX2, the larger the number of recessed portions 222, the greater the amount of hollowing out of the shaft portion 221, and the strength of the lag screw 200 is reduced. . Conversely, from the viewpoint of the strength of the lag screw 200, it is more advantageous to have a smaller number of recesses 222 (for example, two). less, which is disadvantageous in terms of resistance to loads in these directions.

That is, when comprehensively considering the performance of the lag screw with blade body 200B (rotation restraining force, resistance to loads in the varus direction IV and the longitudinal direction AP), rigidity, ease of control in the procedure, etc., the recess 222 The number is three, and the number of blades 301 in one blade body 300 is preferably three, which is the same as the number of recesses 222 and can be arranged alternately with them.

The blade width W of the blade groove 250, the blade height H, the blade protrusion amount P and the length of the lag screw 200 in the direction of the axis AX2 are determined by the bending rigidity of the lag screw 200B with the blade body (geometrical moment of inertia in the direction of the axis AX2 ) and others are appropriately selected so as not to cause a decrease in rigidity.

The intramedullary nail 100 of the osteosynthesis device 10 can use the conventionally known lag screw and the lag screw with blade body 200B of the present embodiment. In other words, without changing the specifications of one (current) intramedullary nail 100, a conventionally known lag screw and a lag screw with a blade body 200B with improved performance are selected (selectively adding functions). can do.

Further, as described above, the operator's procedure is to insert the lag screw 200 into the intramedullary nail 100 and fix the lag screw 200 to the intramedullary nail 100 with the set screw 451 . After that, the blade body 300 is slid and inserted from the proximal end of the lag screw 200 , and the blade body 300 is fixed by the lock screw 303 . Thereby, the blade 301 can be arranged at an appropriate position based on the concave portion 222 (the position of the reference phase). In other words, the attachment/removal of the blade body 300 can be performed easily and reliably, and a function for enhancing the performance can be added without complicating the procedure itself as compared with the normal (conventional) procedure.

Also, although not shown, the blade body 300 is held by a mounting tool for mounting the blade body 300 on the lag screw 200 and is inserted into the outer circumference of the lag screw 200 .

<Surgical method using osteosynthesis device>
The osteosynthesis device 10 of this embodiment is applied, for example, to treat fractures near the head of the femur (femoral neck fractures). An example of a surgical method (procedure) using the osteosynthesis device 10 will now be described with reference to the respective drawings.

First, referring to FIG. 1(B), an entry hole is formed in an upper end portion 501 of the femur 500 on the femoral head 502 side using an awl or the like, and then a boring tool such as a drill and a reamer is used to make the entry hole. Enlarge the entry hole and open the cortical bone. As a result, an opening is formed at the end 501 . The opening in the cortical bone communicates with the medullary canal of the femur 500 .

Next, the intramedullary nail 100 is inserted along the axis of the femur 500 into the internal medullary cavity by introducing the distal end of the intramedullary nail 100 through the opening formed in the end portion 501 .

Next, an intramedullary nail attachment device (target device) (not shown) is connected to the upper end T (top, proximal end) of the intramedullary nail 100 exposed from the femur 500 . After the tip (holding portion) of the intramedullary nail attaching device is engaged with the notch portion (not shown) provided at the upper end T of the intramedullary nail 100, a fixing bolt (not shown) is screwed into the female screw 106. Thus, the intramedullary nail attaching device and the intramedullary nail 100 are connected. Then, a guide pin (not shown) is inserted from outside the body along the axis of the lateral hole 104 according to a guide provided in advance in the intramedullary nail attaching device. The guide pin tip traverses the fracture line 505 until the tip reaches the cortical bone of the head 502 .

The guide pin is then used to guide a drilling tool such as a drill and reamer. The punch creates a bone hole 503 in the femur 500 along the axis of the transverse hole 104 .

Next, after removing the punch, the guide pin is used to guide the osteosynthesis shaft-like member (lag screw) 200 . As a result, the lag screw 200 passes through the lateral hole 104 and is screwed into the bone hole 503 formed in the femur 500 . At this time, the engaging portion 211 of the lag screw 200 crosses the fracture line 505 and reaches the cortical bone of the femoral head 502 .

As a result, the lag screw 200 is fixed to the femoral head 502, and the lag screw 200 is pulled toward the intramedullary nail 100 side. Reduce so that the abutting fracture sites on both sides are in close contact with each other.

Next, in this state, the set screw 451 is screwed into the shaft hole 105 from the proximal end of the intramedullary nail 100 to bring the tip of the set screw 451 into contact with the lag screw 200 . The lag screw 200 is thereby fixed to the intramedullary nail 100 .

After that, the blade body 300 is held by the fixture 350, and the blade body 300 is aligned from the proximal end of the lag screw 200 so that the blade 301 engages the blade groove 250 of the lag screw 200, and is inserted into the blade groove 250. Slide to insert. Then, the lock screw 303 fixes the blade body 300 . Thereby, the blade 301 can be arranged at an appropriate position based on the concave portion 222 (the position of the reference phase). In other words, the attachment/removal of the blade body 300 can be performed easily and reliably, and a function for enhancing the performance can be added without complicating the procedure itself as compared with the normal (conventional) procedure.

The lag screw with blade body 200B is allowed to slide with respect to the intramedullary nail 100, and whether or not to allow the sliding (to lock the sliding) is selected according to the symptoms.

After that, the intramedullary nail 100 is fixed to the femur 500 by screwing a screw (distal screw) 601 into the fixture insertion hole 108 of the intramedullary nail 100 . As described above, the bone fracture site near the femoral head 502 of the femur 500 is fixed using the osteosynthesis device 10 .

As described above, in the present embodiment, the intramedullary nail 100 embedded in the femur is used as a bone fastener, but the lag screw with blade body 200B is also applicable to bone fasteners other than the intramedullary nail 100. It is possible. The bone fastener 100 is, for example, arranged longitudinally on the surface of the femur, with a lag screw holder provided on the proximal side of the femur and a fixing hole provided on the distal side of the femur. It may be a plate.

Further, for example, the positions of the blades 301 may not be evenly spaced in the circumferential direction of the blade support portion 302 (the same applies to the positions of the corresponding blade grooves 250). For example, when the placement location of a specific recess 222 (for example, recess 222a) is the reference phase, the first blade 301a is arranged at a position 45 degrees clockwise with respect to the reference phase, and the second The blade 301b is arranged at a position of -45 degrees in the counterclockwise direction with respect to the reference phase (the phase difference between the first blade 301a and the second blade 301b is 90 degrees). One blade 301a is positioned at, for example, 70 degrees in the clockwise direction with respect to the reference phase), and the second blade 301b is positioned at −70 degrees in the counterclockwise direction with respect to the reference phase. Arranged (the phase difference between the first blade 301a and the second blade 301b is 140 degrees).

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

10 Bone connector 100 Bone anchor (intramedullary nail)
104 Lateral hole 105 Axial hole 106 Female screw 107 Female screw 108 Fixing tool insertion hole 200 Osteotomy shaft-like member (lag screw)
200B lag screw with blade body 211 engagement portion (screw portion)
221 shaft portion 222 recessed portion 250 blade groove 251 first blade groove 252 second blade groove 300 blade body 301 blade 302 blade support portion 303 blade body fixture (lock screw)
350 osteosynthesis tool set 451 fixture (set screw)
500 Femur 501 End 502 Head 503 Bone hole 505 Fracture line 2011 Tip 2110 Screw shaft 2112 Thread
2210 screw shaft portion 2211 screw groove (female screw)
2522 notch 3012 outer peripheral surface 3013 side surface 3014 inner peripheral surface 3021 thread groove (female screw)
AP Front-back direction IV Varus direction AX1 axis AX2 axis

Claims (7)

A blade body to be attached to an osteosynthesis shaft-shaped member for use,
When attached to the osteosynthesis shaft-shaped member, the blade body extends in the axial direction of the osteosynthesis shaft-shaped member on the outer periphery of the osteosynthesis shaft-shaped member, and extends in the circumferential direction of the osteosynthesis shaft-shaped member. having three or more blades spaced apart from each other in
A blade body characterized by: 2. The blade body according to claim 1, wherein the three or more blades are arranged at approximately equal intervals around the axis of the osteosynthesis shaft-like member. 3. The blade body according to claim 2, wherein the number of said blades is three. an intramedullary nail having a hole;
an osteosynthesis shaft-like member inserted into the hole of the intramedullary nail;
a fixture for fixing the osteosynthesis shaft-shaped member to the intramedullary nail;
A bone connector having a blade body according to any one of claims 1 to 3,
The outer peripheral surface of the osteosynthesis shaft-shaped member is provided with a plurality of recesses around the axis of the osteosynthesis shaft-shaped member with which the tip of the fixture contacts,
The outer peripheral surface of the osteosynthesis shaft-shaped member is provided with a plurality of blade grooves extending in the axial direction of the osteosynthesis shaft-shaped member and capable of accommodating a portion of the blade around the shaft of the osteosynthesis shaft-shaped member. be
The recess and the blade groove are provided at different positions in the circumferential direction of the osteosynthesis shaft-shaped member,
An osteosynthesis device characterized by: an intramedullary nail having a hole;
an osteosynthesis shaft-like member inserted into the hole of the intramedullary nail;
a fixture for fixing the osteosynthesis shaft-shaped member to the intramedullary nail;
A bone connector having a blade body according to any one of claims 1 to 3,
The outer peripheral surface of the osteosynthesis shaft-shaped member is provided with a plurality of recesses around the axis of the osteosynthesis shaft-shaped member with which the tip of the fixture contacts,
The recess and the blade are provided at different positions in the circumferential direction of the osteosynthesis shaft-shaped member,
An osteosynthesis device characterized by: an intramedullary nail having a hole;
an osteosynthesis shaft-like member inserted into the hole of the intramedullary nail;
An osteosynthesis device having a blade body attached to the osteosynthesis shaft-shaped member,
When attached to the osteosynthesis shaft-shaped member, the blade body extends in the axial direction of the osteosynthesis shaft-shaped member on the outer periphery of the osteosynthesis shaft-shaped member, and extends toward the distal end of the osteosynthesis shaft-shaped member. having two or more blades circumferentially spaced apart from each other on the outer periphery of the
The osteosynthesis shaft-shaped member is fixed to the intramedullary nail by a fixture,
The outer peripheral surface of the rear end side of the osteosynthesis shaft-shaped member is provided with a plurality of recesses around the shaft of the osteosynthesis shaft-shaped member, with which the tip of the fixture contacts,
With respect to the circumferential arrangement of the osteosynthesis shaft-shaped member, the first blade is at an angle of more than 0 degrees to less than 180 degrees with respect to the reference phase when the location of the specific concave portion is set as the reference phase. , and the second blade is more than -180 degrees and less than 0 degrees with respect to the reference phase, and is arranged at a position other than -90 degrees ,
An osteosynthesis device characterized by: a bone connector according to any one of claims 4 to 6;
an attachment for attaching the blade body to the osteosynthesis shaft;
Bone fastener set with.

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