JP2009072397A - Nail device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nail device for bone fracture treatment where a rotation prevention mechanism has less bone-invasive and does not obstruct X-ray radiation. <P>SOLUTION: The nail device includes a nail having a lateral hole formed near a head part and inserted into the medullary cavity of a thighbone from a proximal end side, and a lag screw having a concave groove running along its surface in the axial direction and threads at the end threadedly inserted into the capital of the thighbone from the lateral hole. A lock screw, with a penetration hole formed axially in the surface from the end cap applied to the nail head, is threadedly inserted into the nail to connect the end cap with the nail. A lock pin having an end screw formed at the end is inserted through the end cap and threadedly inserted, with a penetration hole of the lock screw, used as a guide, to engage the lock pin with the concave groove of the lug screw at least for regulating the rotation of the lug screw within the lateral hole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nail device suitable for use in treatment of a long bone, particularly a femoral neck fracture of the neck.

  The basics of fracture treatment are to join and fix the fracture surface in a state of being pressed to some extent, and this is the same even for the femur. There are an internal fixture and an external fixture as devices for performing this fixation, and the former internal fixture includes a so-called nail that holds a pin body across the fracture surface in the medulla. By the way, when a fracture surface is fixed, bone masses with this surface as a boundary rotate (rotate) with each other, and the fracture surface is damaged and reduction cannot be obtained or healing is delayed. For this reason, a rotation preventing mechanism is generally employed for the nail.

  The following Patent Document 1 shows a nail used when the neck of the femur fractures, but the anti-rotation mechanism in this case is formed at the tip by extending obliquely upward from the nail and crossing the fracture surface. U-shaped fork-like blades are provided along the top and bottom of the lag screw for screwing the screw into the femoral head. Therefore, bone invasion is large and normal bones are damaged. Further, since the lag screw is generally inserted into the distal side (lower side) of the head of the bone, the lower blade is exposed from the thin neck, and sufficient strength may not be obtained.

  Although a nail is shown also in patent document 2, this anti-rotation mechanism of the prior example is screwed by overlapping a member called a compression screw on the periphery of the lug screw with a partial screw. However, since it is a screw, the bone invasion becomes large, and an operation for screwing is required, so that the treatment time becomes long. Moreover, if the lag screw is displaced to the proximal side, the space for screwing the compression screw is lost. Furthermore, since the surface of the lag screw into which the compression screw is screwed is provided only in one place on the circumference in this prior example, the lag screw may not be set at a desired position (the screw of the lag screw is upward). Because it must be located in).

In addition, in both of the preceding examples, the length from the lag screw to the head of the nail (head nail length) in the nail is long. Since the head nail length needs to have a certain length in order to obtain a desired strength, the top surface of each nail is higher than the tip of the lag screw. Whether or not the lag screw has been screwed in to the proper position is checked by irradiating X-rays during the operation, but at the site of the femoral head, X-rays are irradiated from the diagonally lower front of the nail toward the tip of the lag screw. To do. Therefore, when the head nail length is long, there is a problem that X-rays are disturbed by the nail and a clear image cannot be obtained.
JP 2000-229093 A Special table 2007-515194 gazette

  In the present invention, the member constituting the anti-rotation mechanism has a structure with little bone invasion, and a plurality of locations where the member is aligned are formed on the circumference of the lag screw so that the amount of advancement / retraction of the lag screw is small (desired The position can be aligned at a location close to the position. In addition, the head nail length is shortened so as not to interfere with X-ray irradiation.

  Under the above-described problems, the present invention provides a nail that has a lateral hole formed near the head and is inserted into the medullary cavity of the femur from the proximal end side of the femur, and a distal end. In a nail device comprising a lag screw in which a screw is formed and a groove is formed in the axial direction of the surface and the tip is screwed into a femoral head from a lateral hole, the nail device is applied to the head of the nail A lock screw with a through hole formed in the axial direction from the end cap is screwed into the nail to connect the end cap to the nail, and a lock pin with an end screw at the tip of the end cap is inserted into the through hole of the lock screw. A nail device characterized by having a lock pin engaged with a concave groove of a lag screw so as to restrict at least rotation in the lateral hole of the lag screw is inserted through a guide and screwed. That.

  According to the present invention, a lateral groove and a convex groove parallel to the lateral hole are formed near the head, facing the lateral hole and parallel to the lateral hole. A nail to be inserted into the medullary cavity of the bone, and a lag screw having a screw formed at the tip and a groove formed in the axial direction of the surface so that the tip is screwed into the femoral head from the lateral hole In a nail device comprising a key blade inserted from the head of the lag screw into the groove of the lag screw and the upper or lower convex groove of the nail, the shaft extends from the end cap applied to the head of the nail. A lock screw with a through hole in the core direction is screwed into the nail and an end cap is connected to the nail. A lock pin with an end screw at the tip of the end cap is inserted into the guide through the through hole of the lock screw. Screwed Providing a nail and wherein the a.

  In addition, according to the present invention, in the above intramedullary nail, the lateral hole of the nail described in claim 3 is formed obliquely upward in the head direction, and the top surface of the nail is from the tip of the lag screw protruding from the nail. Means located below, means according to claim 5, wherein four or more concave grooves of the lag screw are equally formed on the circumference, and those using a key blade, key according to claim 4 Provided is a means in which the tip of the blade is pointed and formed into a streamlined shape that is taller toward the rear, and the length is shorter than the lag screw and the tip is on the screw.

  According to the first aspect of the present invention, since the end cap is connected to the nail so as to have a predetermined length for maintaining the strength (performed during the operation), the head nail length of the nail is necessarily before connection. Shorter, and does not interfere with X-ray irradiation. In addition, since the lock pin that restricts the rotation of the lag screw is inserted using the through hole of the lock screw as a guide, it is easy to insert, and even a thin pin is assisted by the lock screw and has a strong rotation regulating force .

  According to the means of claim 2, in addition to the above effects, the rotation of the head of the head can be prevented more reliably, and the nail is formed with two convex grooves, so that the key inserted along the lag screw The blade can be selected from either the upper or lower convex groove. Therefore, it can be inserted in a sufficient area of the neck, and sufficient strength can be maintained. In addition, since the key blade is one in principle, it is minimally invasive to the bone.

  According to the means of claim 3, the length of the nail is shortened more reliably, and according to the means of claim 4, the circumferential interval of the groove of the lag screw is shortened. (Screwing or unscrewing) can be reduced, and the lag screw can be set at a position close to a desired position, and the lag screw can be prevented from loosening with respect to the bone head.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, front and rear, inside and outside, and top and bottom are based on what is seen from the front of the body when a nail is loaded. FIG. 1 is a cross-sectional front view of a nail device according to the present invention. The nail device is inserted into the femoral marrow from the proximal end side of the femur, and near the head of the nail 1. A lag screw 3 to be inserted into the femoral head of the femur from the formed lateral hole 2, an end cap 5 connected to the head of the nail 1 by a lock screw 4, and the like.

  2 is a cross-sectional front view of the nail 1, and FIG. 3 is a side view. The nail 1 has a pin shape that becomes thinner toward the lower side. Is formed obliquely with the inner side facing up. Further, a fixing hole 6 for inserting a screw for fixing the nail 1 is formed substantially horizontally near the lower end of the nail 1. Further, on the upper and lower sides of the horizontal hole 2, convex grooves 7 that face the horizontal hole 2 and are narrower than the horizontal hole 2 are formed in parallel with the horizontal hole 2. However, this convex groove 7 is not absolute (it may not be formed). In addition, a screw hole 8 penetrating from the end face to the lateral hole 2 is also formed in the head of the nail 1.

  4 is a front view of the lag screw 3, and FIG. 5 is a side view. The lag screw 3 is a pin body in which a screw 9 is formed at the tip in a range of 1/5 to 1/2 of its entire length, and its outer periphery. A groove 10 is formed in the axial direction of the surface. The concave groove 10 is continuous from the portion applied to the screw 9 to the outer end, and is formed in a plurality of equal parts on the circumference (four in this example, but more than that). 6 is a cross-sectional front view of the end cap 5, and FIG. 7 is a front view. The end cap 5 is a short pin body, and has a screw hole 13 in which a first screw 11 and a second screw 12 are formed in the axial direction. Is formed. In this case, the diameter of the second screw 12 is smaller at the lower side than the first screw 11, and the diameter of the second screw 12 is larger than that of the screw hole 8 formed in the nail 1.

  The end cap 5 is connected to the head of the nail 1 by screwing the lock screw 4 into the screw hole 8 of the nail 1. 8 is a front view of the lock screw 4 and FIG. 9 is a side view. The lock screw 4 includes a screw 14 screwed into the screw hole 8 and a head 15 pressed against the lower step of the first screw 11. The through hole 16 is also formed in the shaft core. In addition, when the nail 1 and the end cap 5 are connected, a groove 17 is formed on the edge of the head of the nail 1 so that they are not displaced, and a projection 18 is formed on the joint surface of the end cap 5 and fitted. I am trying.

  Next, a method for performing the above intramedullary nail will be described. FIG. 10 is a front view thereof, and FIG. 11 is a cross-sectional front view of the main part. First, the nail 1 is inserted into the medulla from the proximal side of the femur T at the waist. At this time, the nail 1 is inserted to a predetermined depth so as to cross the fracture surface F (if necessary, the nail 1 is fixed to the fixing hole 6 through a screw). Next, the lag screw 3 is inserted from the outer end of the lateral hole 2 and the screw 9 at the tip is screwed into the bone head T ′. At this time, it is confirmed by irradiating X-rays whether or not the screw 9 portion is normally inserted into the bone head. The X-rays are irradiated obliquely upward from the nail 1 toward the screw 9.

  By the way, since the end cap 5 is not connected at this time, the length (head nail length) h from the side hole 2 to the head of the nail 1 is the side from the side hole 2 to the tip of the lag screw 3. The projection length is smaller than H (h <H). Therefore, the X-ray R can be irradiated over the head of the nail 1 and there is no case where a clear image is not obtained due to the nail 1 being obstructed.

  When the screw 9 of the lag screw 3 is properly screwed into the head T ′ of the femur T, the end cap 5 is connected. The operation is performed by aligning the groove 17 and the protrusion 18, applying the end cap 5 to the head of the nail 1, screwing the screw 14 of the lock screw 4 into the screw hole 8 of the nail 1, and inserting the head 15 of the end cap 5. The nail 1 and the end cap 5 are firmly integrated with each other by pressing strongly against the step below the first screw 11. At this time, the head 15 of the lock screw 4 is embedded deeper than the second screw 12. Thus, the nail 1 is extended by the end cap 5 and has sufficient strength. When the above operation is completed, the end screw 19 is screwed into the end cap 5 to fill the opening above the head 15 of the lock screw 4.

  12 is a cross-sectional front view of the end screw 19, FIG. 13 is a side view, and FIG. 14 is a cross-sectional view taken along the line AA of FIG. 11. The end screw 19 is screwed to the second screw 12 of the end cap 5 at the bottom. And a lock pin 22 projecting from the tip of the head. The lock pin 22 is inserted into the lock screw 4 with the through hole 16 as a guide. is there. At this time, the lock pin 22 and the through-hole 16 do not have a tight fitting, but have a fitting tolerance that restricts a lateral force applied to the lock pin 22. In addition, when the end screw 19 is fitted to the second screw 12 of the end cap 5, the tip of the lock pin 22 has a length and a thickness so as to enter the concave groove 10 of the lag screw 3.

  In this state, the nail 1 is inserted into the femur T across the fracture surface F and the necessary length is secured by the end cap 5. The lag screw 3 is inserted into the nail 1 and screwed into the bone head T ′. Therefore, the fracture surface F is fixed in a state of being pressed to some extent, and is suitable for fracture treatment. The rotating force acting on the bone head T ′ when the patient takes a standing posture or the like is restricted by the end screw 19 being locked in the concave groove 10 of the lag screw 3. In this respect, the lock pin 22 of the end screw 10 has only to enter the concave groove 10 and restrict its rotation, and does not need to be completely tightened.

  Therefore, the fracture surface F is rubbed by the rotational force, and the reduction position can be lost, and the delay or inability of healing can be prevented. Further, when the end screw 19 is completely screwed into the end cap 5 and the lag screw 3 is pressed by the lock pin 22, the movement of the lag screw 3 in the axial direction in the lateral hole 2 can be restricted, and the fracture surface F is loosened. It can also prevent over-compression due to body movement. In addition, since the outer end of the lag screw 3 is uneven due to the formation of the concave groove 10 or the like, the lid with the lag end screw 23 prevents rubbing against the skin or the like to cause pain. it can.

  15 is a cross-sectional front view of a nail 1 showing another example of the present invention, and FIG. 16 is a cross-sectional view taken along the line BB of FIG. The key blade 24 is inserted across the groove 7 and the concave groove 10 of the lag screw 3. The key blade 24 is loaded before the end screw 19 is screwed in. The key blade 24 is inserted from the outer end of the lag screw 3 with the phase of the convex groove 7 and the concave groove 10 aligned, and a downward projecting portion formed at the rear part. 25 is dropped into a pocket 26 formed at the outer end of the groove 10 and fixed.

  The role of the key blade 24 is to prevent the lag screw 3 from rotating, and the deterring force is greater than that due to the end screw 19. FIG. 17 is a front view of the key blade 24, and FIG. 18 is a plan view. The key blade 24 is formed in a streamlined shape with a sharp tip and a tall back toward the rear, and the tip is a concave groove 10 applied to the screw 9. It is set to be shorter than the lag screw 3. This is to reduce the resistance during insertion and suppress bone invasion.

  By the way, since the convex groove 7 is formed above and below the horizontal hole 2, the key blade 24 may be inserted into the convex groove 7 on the preferred side. In general, since the lag screw 3 is screwed into the lower part of the neck of the bone head, the upper convex groove 7 having a lot of room is usually selected. However, depending on the case, the lower portion may be screwed into the upper portion and the lower portion may have more room. In such a case, the lower convex groove 7 is selected. However, in general, both convex grooves 7 are not used to avoid bone invasion.

  Even when the key blade 24 is used, the end screw 19 is used. This is because if the end screw 19 is lightly tightened and the lock pin 22 is applied to the top surface of the key blade 24, arbitrary movement of the lag screw 3 in the axial direction can be restricted. Moreover, if it tightens tightly, it can lock completely. At this time, a concave groove 27 may also be formed on the top surface of the key blade 24. The end screw 19 also has a meaning of filling the recessed portion of the end cap 5. Therefore, when it is only necessary to fill, a lid (not shown) having no lock pin 22 or the like may be screwed into the first screw 11.

It is a section front view of a nail device. It is a section front view of a nail. It is a side view of a nail. It is a front view of a lag screw. It is a side view of a lag screw. It is a section front view of an end cap. It is a front view of an end cap. It is a front view of a lock screw. It is a side view of a lock screw. It is a front view of a nail device. It is a principal part cross-sectional front view of a nail apparatus. It is a section front view of an end screw. It is a side view of an end screw. It is AA sectional drawing of FIG. It is a cross-sectional front view of the nail apparatus which shows another example. It is BB sectional drawing of FIG. It is a front view of a key blade. It is a top view of a key blade.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nail 2 Horizontal hole 3 Lug screw 4 Lock screw 5 End cap 6 Fixing hole 7 Convex groove 8 Screw hole 9 Screw 10 Concave groove 11 First screw 12 Second screw 13 Screw hole 14 Screw 15 Head 16 Through-hole 17 Groove 18 Protrusion 19 End screw 20 Screw 21 Head 22 Lock pin 23 Lug end screw 24 Key blade 25 Downward projecting portion 26 Pocket 27 Concave groove

Claims (5)

  A lateral hole is formed near the head, a nail inserted into the medullary cavity of the femur from the proximal end of the femur, a screw is formed at the tip, and a concave groove is formed in the axial direction of the surface In a nail device comprising a lag screw whose tip is screwed into the femoral head from the lateral hole, a nail lock screw having a through-hole formed in the axial direction from the end cap applied to the head of the nail The end pin is connected to the nail by screwing into the end cap, and a lock pin formed with an end screw at the tip of the end cap is inserted into the guide through the through hole of the lock screw, and at least within the lateral hole of the lag screw. A nail device characterized in that a lock pin is engaged with a concave groove of a lag screw so as to restrict rotation of the lug screw.   A nail that is inserted into the medullary cavity of the femur from the proximal end side of the femur, with a lateral hole near the head and a convex groove parallel to the lateral hole that faces the lateral hole above and below the lateral hole, and the tip A lag screw in which a groove is formed in the axial direction of the surface and the tip is screwed into the femoral head from the lateral hole, and the lag screw groove from the head side of the lag screw And a key blade inserted over the upper or lower convex groove of the nail, the nail lock screw having a through hole in the axial direction from the end cap applied to the head of the nail The nail device is characterized in that an end cap is connected to the nail by being screwed into the end cap, and a lock pin having an end screw formed at the tip of the end cap is inserted into the guide through the through hole of the lock screw.   The nail device according to claim 1 or 2, wherein a lateral hole of the nail is formed obliquely above the head of the head, and a top surface of the nail is located below a tip of a lag screw protruding from the nail.   The nail device according to claim 2 or 3, wherein the key blade is formed in a streamlined shape with a sharp tip and a taller back, and is shorter than a lag screw and has a tip on the screw.   The nail device according to any one of claims 1 to 4, wherein four or more concave grooves of the lag screw are equally divided on the circumference.