CN215839413U - Internal support fixing system for femoral neck fracture - Google Patents

Abstract

The utility model discloses an internal support fixing system for femoral neck fracture, which belongs to the technical field of orthopedic implants and comprises an external fixing plate, a power rod and an anti-rotation screw, wherein the inner side of the upper end of the external fixing plate is provided with a sliding sleeve which is used for inserting femoral bone moment and allowing the power rod to penetrate through, the tail end of the power rod is provided with an anti-rotation screw mounting hole, the rod part of the power rod is provided with an anti-rotation screw penetrating groove communicated with the anti-rotation screw mounting hole, the sliding sleeve is provided with a groove for allowing the anti-rotation screw to penetrate through, and the head part of the power rod is provided with a first pressurizing thread. The internal support fixing system for femoral neck fracture does not cause fracture line displacement and is not easy to loosen in the dynamic pressurization process.

Description

Internal support fixing system for femoral neck fracture

Technical Field

The utility model relates to the technical field of orthopedic implants, in particular to an internal support fixing system for femoral neck fracture.

Background

Torsion and shear stress of the femoral neck fracture part are main stress for preventing fracture healing, axial compression stress is stress for facilitating fracture healing, and the torsion and shear stress are eliminated therapeutically, and the axial compression stress is reserved for facilitating fracture healing. Pauwels type is to classify the fracture into three types according to the angle between the fracture line of the femoral neck and the horizontal line: type I is less than 30 degrees, type II is 30-50 degrees, and type III is more than 50 degrees; the larger the included angle, i.e. the more vertical the fracture line, the larger the shear stress on the fracture end, the more unstable the fracture, and the non-healing rate is increased.

The Femoral Neck dynamic cross nail System (FNS) is a newer special product for Femoral Neck fracture at present. The FNS system usually includes sliding sleeve, power stick and prevents revolving screw etc. and the structural design of this system is more stable, and the reduction that can be fine is turned over and is collapsed and twist reverse the inefficacy, reduces mechanics unstability, reduces to cut and exposes the area, can prevent to shorten the painful problem that the protruding side that leads to of preventing revolving screw after.

At present, in clinical use, the conventional FNS system has a plurality of defects, the power rod of the FNS system is fixed on the central axis of the femoral neck, the firmness is insufficient, the fracture line can be shifted in the dynamic pressurization process of unstable femoral neck fracture, the power rod of the FNS system has weak holding effect on the femoral head, and the loosening phenomenon is easy to occur particularly in the case of poor bone quality.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem of providing an internal support fixing system for femoral neck fracture, which can not cause fracture line displacement and is not easy to loosen in the dynamic pressurization process.

In order to solve the technical problems, the utility model provides the following technical scheme:

the utility model provides a support fixing system in femoral neck fracture, includes external fixation plate, power stick and prevents revolving screw, the upper end inboard of external fixation plate is equipped with and is used for inserting the thighbone moment and supplies the sliding sleeve that the power stick passed, the tail end of power stick is equipped with prevents revolving screw mounting hole, the pole portion of power stick be equipped with prevent revolving screw mounting hole UNICOM prevent revolving screw and wear out the groove, the last confession that is equipped with of sliding sleeve prevent the fluting that the revolving screw passed, the head of power stick is equipped with first pressure thread.

Further, the outer diameter of the first pressing thread of the head of the power rod is equal to the outer diameter of the rod of the power rod;

and/or the head of the power rod comprises a straight rod section positioned at the front part and a conical rod section positioned at the rear part of the straight rod section.

Further, the tail end of the power rod is provided with a nail holding groove;

and/or the inner side of the middle part of the power rod is provided with a screw thread for holding the screw;

and/or the first pressure thread on the straight rod section of the power rod is provided with a self-tapping groove;

and/or the first pressurizing thread on the taper rod section of the power rod is provided with a screw withdrawing groove.

Furthermore, a first internal thread is arranged in the anti-screwing screw mounting hole, and a first external thread matched with the first internal thread is arranged at the tail part of the anti-screwing screw.

Furthermore, a first anti-rotation plane is arranged in the sliding sleeve, and a second anti-rotation plane matched with the first anti-rotation plane is arranged at the rod part of the power rod;

and/or the length of the sliding sleeve is 8-12 mm.

Furthermore, the anti-rotation screw penetrates out of the groove and is positioned on the side face of the power rod, so that the anti-rotation screw and the power rod are horizontally arranged.

Furthermore, the rear part of the anti-rotation screw is provided with an avoiding conical surface which gradually narrows from the tail part to the head part of the anti-rotation screw, so that a step is formed at the front part of the avoiding conical surface.

Furthermore, an included angle between the axis of the anti-rotation screw and the axis of the power rod is 8-10 degrees;

and/or the rear part of the anti-rotation screw is provided with a rotating interface, and a second pressurizing thread is arranged in the rotating interface.

Furthermore, a locking screw hole is formed in the outer fixing plate below the sliding sleeve, and a locking screw is arranged in the locking screw hole;

and/or the included angle between the plane of the outer fixing plate and the axis of the sliding sleeve is 120-160 degrees;

and/or both sides of the inner surface of the outer fixing plate are provided with plate holding grooves.

Furthermore, a second internal thread is arranged in the locking screw hole, and a second external thread matched with the second internal thread is arranged at the head of the locking screw;

and/or the number of the locking screw holes is at least two, and the locking screw holes are arranged along the length direction of the external fixing plate.

The utility model has the following beneficial effects:

the internal support fixing system for femoral neck fracture comprises an external fixing plate, a power rod and an anti-rotation screw, wherein a sliding sleeve for inserting a femoral bone moment and allowing the power rod to penetrate is arranged on the inner side of the upper end of the external fixing plate; the head of the power rod is provided with a first pressurizing thread, and the power rod is a pressurizing screw, so that the holding and supporting effects on femoral head sclerotin are improved, and the phenomenon of looseness is not easy to occur in the case of slightly poor sclerotin.

Drawings

FIG. 1 is a schematic view of the overall structure of the internal support fixation system for femoral neck fractures of the present invention;

FIG. 2 is a schematic structural diagram of an external fixation plate in the internal support fixation system for femoral neck fracture according to the present invention;

FIG. 3 is a schematic structural view of a power bar in the internal support fixation system for femoral neck fractures of the present invention, wherein (a) is a front view and (b) is a cross-sectional view;

FIG. 4 is a schematic cross-sectional view of an anti-rotation screw of the internal support fixation system for femoral neck fractures according to the present invention;

FIG. 5 is a schematic structural view of a locking screw in the internal support fixation system for femoral neck fractures according to the present invention;

FIG. 6 is a graph comparing the compressive stiffness of the internal support fixation system of the present invention and a prior FNS system.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The utility model provides an internal support fixing system for femoral neck fracture, which comprises an external fixing plate 1, a power rod 2 and an anti-rotation screw 3, wherein a sliding sleeve 11 for inserting femoral bone moment and allowing the power rod 2 to penetrate is arranged on the inner side of the upper end of the external fixing plate 1, an anti-rotation screw mounting hole 21 is arranged at the tail end of the power rod 2, an anti-rotation screw penetrating groove 22 communicated with the anti-rotation screw mounting hole 21 is arranged at the rod part of the power rod 2, a slotted groove 111 for allowing the anti-rotation screw 3 to penetrate is arranged on the sliding sleeve 11, and a first pressurizing thread 23 is arranged at the head part of the power rod 2.

When the external fixation system is used, firstly, the external fixation plate 1 can be held and taken by using a surgical tool and is attached to the femoral bone matrix, then the power rod 2 is held and taken by using the surgical tool and is implanted along the sliding sleeve 11 on the inner side of the upper end of the external fixation plate 1, and then the anti-rotation screw 3 is held and taken by using the surgical tool and is implanted along the anti-rotation screw mounting hole 21 at the tail end of the power rod 2, the anti-rotation screw penetrating groove 22 at the rod part of the power rod 2 and the open groove 111 on the sliding sleeve 11, so that the implantation of the whole internal fixation system is completed.

The inventor finds that the power rod of the conventional FNS system is fixed on the central axis of the femoral neck, the internal support is not realized by utilizing a femoral rectangular structure, and the fracture line can be displaced in the dynamic pressurization process for unstable femoral neck fractures.

The internal support fixing system for femoral neck fracture comprises an external fixing plate, a power rod and an anti-rotation screw, wherein a sliding sleeve for inserting a femoral bone moment and allowing the power rod to penetrate is arranged on the inner side of the upper end of the external fixing plate; the head of the power rod is provided with a first pressurizing thread, the power rod is a pressurizing screw, the first pressurizing thread improves the holding and supporting effect of the power rod on femoral head sclerotin, and the phenomenon of looseness is not easy to occur in the case of poor sclerotin.

As shown in fig. 3, the outer diameter of the first pressing thread 23 on the head of the power rod 2 is preferably equal to the outer diameter of the rod of the power rod 2, so as to avoid bone void around the rod of the power rod 2, enable the rod to be close to the femoral distance, and better improve the inner supporting effect of the power rod 2. The head of the power rod 2 can comprise a straight rod section 24 at the front part and a taper rod section 25 at the rear part of the straight rod section 24, and the strength of the power rod 2 can be improved due to the fact that the head part of the power rod 2 adopts a taper transition form.

In order to conveniently hold and take the power rod 2, the tail end of the power rod 2 can be provided with a nail holding groove 26, and the inner side of the middle part of the power rod 2 can be provided with a nail holding thread 27. The first press thread 23 on the straight shank section 24 of the power rod 2 may be provided with a self-tapping groove 231 to facilitate implantation of the power rod 2. The first pressing thread 23 on the taper rod section 25 of the power rod 2 may be provided with a nail withdrawing groove 232 to facilitate the taking out of the power rod 2. The self-tapping groove 231 and the nail-removing groove 232 are preferably adjusted with the taper to ensure the sharpness of the first pressing thread 23 and the strength of the thread, and the first pressing thread 23 can be partially in a positive-negative combination form to better improve the holding force on the femoral head.

The fixing between the anti-rotation screw 3 and the power rod 2 can be performed in various conventional manners in the art, however, in order to improve the firmness of the system, it is preferable that a first internal thread is provided in the anti-rotation screw mounting hole 21, and a first external thread 31 matched with the first internal thread is provided at the tail of the anti-rotation screw 3.

As shown in fig. 2-3, in order to prevent the power rod 2 and the sliding sleeve 11 from rotating relatively, a first anti-rotation plane 112 may be provided in the sliding sleeve 11, and a second anti-rotation plane 28 matching with the first anti-rotation plane 112 may be provided at the rod portion of the power rod 2. The number of the first anti-rotation planes 112 may be one or more, and the number of the corresponding second anti-rotation planes 28 may also be one or more, in the illustrated embodiment, the number of the first anti-rotation planes 112 is two and is oppositely disposed, and correspondingly, the number of the second anti-rotation planes 28 is two and is disposed on both sides of the power rod 2.

The length of the sliding sleeve 11 may be 8-12mm, preferably 10mm, and compared to the prior art, the present invention changes the slidable distance of the prior art, which is typically 20mm, to 10mm, which can reduce the over-shortening of the femoral neck, thereby reducing the over-shortening problem.

The inventor also finds that the anti-rotation screw and the power rod are locked up and down in the FNS system in the prior art, the power rod and the anti-rotation screw are positioned in the same vertical shaft after being fixed and are in series relation with the bearing direction, the section area of a fixed object vertical to the load is small, the contact stress is increased, and therefore the risk that the anti-rotation screw cuts trabecula inside the femoral head and even cuts out the femoral head is increased.

In order to solve the problem, the anti-rotation screw through groove 22 is preferably arranged on the side surface of the power rod 2, so that the anti-rotation screw 3 and the power rod 2 are horizontally arranged, the transverse contact area between the implant and the bone is increased, the anti-displacement capacity of the fracture line is improved, the contact area with cancellous bone in the direction of resisting compression load can be effectively increased, the contact surface stress is reduced, the cutting of the anti-rotation screw 3 on the trabecula bone in the femoral head when the femoral head is subjected to compressive stress is reduced, the risk of cutting from the femoral head is reduced, and the integral system rigidity is improved.

As shown in fig. 4, in order to avoid the side wall of the sliding sleeve 11, the rear portion of the anti-rotation screw 3 may be provided with an avoiding tapered surface 32 which gradually narrows from the tail portion to the head portion of the anti-rotation screw 3, so that a step 33 is formed at the front portion of the avoiding tapered surface 32, and the step 33 is matched with the bottom of the slot 111 on the sliding sleeve 11, so as to prevent the anti-rotation screw 3 from being removed, and further, the relative position of the power rod 2 and the sliding sleeve 11 can be effectively controlled. The head of the anti-rotation screw 3 can be designed into a thread or a non-thread, and the thread design can improve the holding and supporting effect on femoral head sclerotin; the non-thread design can reduce the cutting to near cortex position, avoids screwing in the in-process and splits the cortex bone. In the embodiment shown in the figures, the head of the anti-rotation screw 3 is provided with a thread 36 to increase the holding force on the femoral head.

The included angle between the axis of the anti-rotation screw 3 and the axis of the power rod 2 can be 8-10 degrees, preferably 9 degrees, the anti-inversion and anti-rotation effects can be increased, and a better anti-rotation effect can be obtained for a short femoral neck, and the diameter distance of the femoral neck is matched. To facilitate the implantation of the anti-rotation screw 3, the rear portion of the anti-rotation screw 3 may be provided with a rotation port 34, and the rotation port 34 may be provided with a second pressing thread 35.

As shown in fig. 1-2, to fix the external fixation plate 1, a locking screw hole 12 may be provided on the external fixation plate 1 below the sliding sleeve 11, and a locking screw 4 is provided in the locking screw hole 12. The included angle between the plane of the external fixation plate 1 and the axis of the sliding sleeve 11 is preferably 120 degrees and 160 degrees, which is convenient for the femur to fit. Both sides of the inner surface of the outer fixing plate 1 can be provided with a plate holding groove 13, which is convenient for holding and taking the outer fixing plate 1.

As shown in fig. 5, in order to improve the firmness between the locking screw hole 12 and the external fixation plate 1, a second internal thread may be provided in the locking screw hole 12, and a second external thread 41 matching with the second internal thread may be provided at the head of the locking screw 4. For better firmness improvement, the number of the locking screw holes 12 is at least two, and the locking screw holes 12 are arranged along the length direction of the external fixation plate 1. In the embodiment shown in the figures, the number of locking screw holes 12 is 2. The head of the locking screw 4 may be provided with a screw interface 42 to facilitate manipulation of the locking screw 4. The rod part of the locking screw 4 can be provided with an external thread 43, so that the holding force of the locking screw 4 can be increased, and the external fixing plate 1 can be firmly fixed. The head of the locking screw 4 may be provided with a self-tapping groove 44 to facilitate implantation of the locking screw 4.

In conclusion, the internal support fixing system for femoral neck fracture provided by the utility model adopts the power rod which is driven along the femoral moment, so that the internal support below the unstable femoral neck fracture line is realized, the fracture end displacement in the unstable femoral neck pressurization process is obviously reduced, the limited dynamic pressurization is realized, the excessive shortening of the femoral neck is reduced, the relative rotation of the head and the neck is prevented, the transverse contact area of an implant and a bone is increased, the anti-displacement capability of the fracture line is improved, meanwhile, the lower fixation close to the femoral moment is realized, the space for driving a hollow nail can be reserved in the upper area of the femoral head, the rotation and the excessive shortening can be prevented better, an environment with initial mechanical stability superior to that of the traditional product is provided for the rehabilitation of unstable femoral neck fracture, and the effect of fracture healing is realized.

The anti-rotation screw and the power rod are vertically placed instead of being horizontally placed, the whole body after being changed is fixed downwards as close to the femoral moment as possible in the use process, the internal support is realized by fully utilizing the femoral moment structure, the support of an internal fixture to the femoral head is increased, the contact area with cancellous bone in the direction of resisting a compression load can be effectively increased, the contact surface stress is reduced, the cutting of the anti-rotation screw to a trabecula in the femoral head when the femoral head is subjected to a compression stress is reduced, and the rigidity of the whole system is improved.

Research shows that the most important performance index of the femoral neck fracture product is the immediate stability after operation, theoretically, the rigidity can be characterized by the integral system rigidity index of the proximal femur after internal fixation, the rigidity means the slope of a load-deformation curve before the yield point appears when the system is deformed by external load, the larger the slope value is, the higher the system rigidity is, and the better the deformation resistance of the internal fixation is. From the femoral neck fracture internal fixation system, the meaning of the yield point on the curve is not that the internal fixation object is subjected to plastic deformation, but the internal fixation object and bone tissues are cut to cause the displacement between the screw and the cancellous bone, and macroscopically the displacement or the separation of the femoral head and the fracture section is reflected. When metal and bone tissue contact, the bone tissue can be damaged at the position of stress concentration, the shape factor of the contact surface is directly related to the stress concentration, the larger the contact area is, the smaller the stress is, and the larger the stress is. Therefore, if the contact area of the implant and the cancellous bone can be increased, the system rigidity after proximal femur fixation can be greatly improved, and the risk of internal fixation failure before fracture healing can be reduced. Therefore, the fixing ability of different fixtures can be numerically evaluated by using the integral system rigidity index immediately after the operation.

In order to verify that the compressive stiffness of the utility model is actually superior to that of the conventional FNS system, simulation verification of simulated implantation and experimental verification of simulated bones are carried out, and the results after comparison are as follows:

as shown in FIG. 6, through calculation and comparison, the DAS system of the present invention has a compressive stiffness of 454.18N/mm, the FNS system of the present invention has a compressive stiffness of 421.93N/mm, and the DAS system of the present invention has a compressive stiffness greater than that of the FNS system of the present invention.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the utility model as defined in the appended claims.

Claims (10)

1. The utility model provides a support fixing system in femoral neck fracture, its characterized in that includes external fixation board, power stick and prevents revolving screw, the upper end inboard of external fixation board is equipped with and is used for inserting the thighbone moment and supplies the sliding sleeve that the power stick passed, the tail end of power stick is equipped with prevents revolving screw mounting hole, the pole portion of power stick be equipped with prevent revolving screw mounting hole UNICOM's prevent revolving screw and wear out the groove, the last confession that is equipped with of sliding sleeve prevent the fluting that the screw passed, the head of power stick is equipped with first pressure screw thread.

2. The internal support fixation system for femoral neck fractures according to claim 1, wherein the first compression thread of the head portion of the power rod has an outer diameter equal to the outer diameter of the shaft portion of the power rod;

and/or the head of the power rod comprises a straight rod section positioned at the front part and a conical rod section positioned at the rear part of the straight rod section.

3. The internal support fixing system for femoral neck fractures according to claim 2, wherein the tail end of the power rod is provided with a nail holding groove;

and/or the inner side of the middle part of the power rod is provided with a screw thread for holding the screw;

and/or the first pressure thread on the straight rod section of the power rod is provided with a self-tapping groove;

and/or the first pressurizing thread on the taper rod section of the power rod is provided with a screw withdrawing groove.

4. The internal support and fixation system for femoral neck fractures according to claim 1, wherein the anti-rotation screw mounting hole is internally provided with a first internal thread, and the tail portion of the anti-rotation screw is provided with a first external thread matched with the first internal thread.

5. The internal support and fixation system for femoral neck fractures according to claim 1, wherein a first anti-rotation plane is provided in the sliding sleeve, and a second anti-rotation plane matched with the first anti-rotation plane is provided on the rod portion of the power rod;

and/or the length of the sliding sleeve is 8-12 mm.

6. The internal support fixation system for femoral neck fractures according to any one of claims 1-5, wherein the anti-rotation screw through slot is located on a lateral side of the power bar such that the anti-rotation screw is horizontally disposed with the power bar.

7. The support and fixation system in femoral neck fracture according to claim 6, wherein the back portion of the anti-rotation screw is provided with an avoiding cone surface that gradually narrows from the tail portion to the head portion of the anti-rotation screw, thereby forming a step in front of the avoiding cone surface.

8. The internal support fixation system for femoral neck fractures according to claim 6, wherein the angle between the axis of the anti-rotation screw and the axis of the power rod is 8-10 degrees;

and/or the rear part of the anti-rotation screw is provided with a rotating interface, and a second pressurizing thread is arranged in the rotating interface.

9. The internal support fixation system for femoral neck fractures according to claim 6, wherein a locking screw hole is provided in the external fixation plate below the sliding sleeve, and a locking screw is provided in the locking screw hole;

and/or the included angle between the plane of the outer fixing plate and the axis of the sliding sleeve is 120-160 degrees;

and/or both sides of the inner surface of the outer fixing plate are provided with plate holding grooves.

10. The internal support fixation system for femoral neck fractures according to claim 9, wherein a second internal thread is provided in the locking screw hole, and a second external thread matching the second internal thread is provided on the head of the locking screw;

and/or the number of the locking screw holes is at least two, and the locking screw holes are arranged along the length direction of the external fixing plate.

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