CN220109828U

CN220109828U - Lag screw

Info

Publication number: CN220109828U
Application number: CN202321004860.3U
Authority: CN
Inventors: 孙英志; 徐朋标
Original assignee: Tianjin Zhengtian Medical Instrument Co Ltd; Beijing Naton Medical Technology Holdings Co Ltd
Current assignee: Tianjin Zhengtian Medical Instrument Co Ltd; Beijing Naton Medical Technology Holdings Co Ltd
Priority date: 2023-04-28
Filing date: 2023-04-28
Publication date: 2023-12-01
Anticipated expiration: 2033-04-28

Abstract

The utility model relates to the field of orthopedic implants, in particular to a lag screw, which comprises a screw rod, wherein a guide channel is formed in the screw rod, the guide channel comprises a side hole and a central hole which are mutually communicated, the side hole is communicated with the outer wall of the screw rod and the central hole, and the axis of the central hole is coincident with the axis of the screw rod; the elastic screw penetrates through the guide channel and comprises an elastic part, a tip and a tail end, wherein the tip and the tail end are connected to two ends of the elastic part, the tip can protrude out of the outer wall of the screw rod through the guide channel, and the tail end can be locked and fixed with the screw rod. When the screw rod is matched with the elastic screw, the elastic screw is penetrated by the central hole, the tip end of the elastic screw protrudes out of the outer wall of the screw rod through the side hole of the guide channel and is pressed against cortical bone, and the protruding part of the elastic screw is matched with the screw rod at an angle; the tail end of the elastic screw continues to be extruded forwards, the elastic part is compressed, and the tail end is locked with the screw rod, so that the extrusion effect between the elastic screw and the cortical bone is kept, and the screw rod is prevented from withdrawing.

Description

Lag screw

Technical Field

The utility model relates to the technical field of orthopedic implants, in particular to a lag screw.

Background

In surgery for treating a fracture, intramedullary nails are commonly used to fix the fracture site, which require lag screws to fix it to the bone of the human body. Usually, the head of the lag screw is in a threaded structure or a spiral blade structure, and needs to be screwed into the femoral head, so that the femoral head which is reset easily rotates during operation. In addition, most patients suffering from intertrochanter fracture of femur are aged patients, osteoporosis is common, axial rotation of the femoral head and screw withdrawal cannot be effectively prevented, the postoperative movement of the patients is limited, the rotation of the femoral head prolongs the healing time of the fracture part, and malhealing is caused. Therefore, the existing lag screw is unstable in the body, and the lag screw often cuts out or penetrates out of the femoral head after operation, or the lag screw is produced to withdraw nails, so that secondary operation is caused for the patient, and pain of the patient is increased.

Therefore, a lag screw is needed to solve the above problems.

Disclosure of Invention

The utility model provides a lag screw, which solves the problems that in the prior art, the lag screw moves forwards to easily pierce a femoral head and a screwing-in mode cannot effectively prevent the axial rotation and the screw withdrawal of the femoral head for an osteoporosis patient.

The utility model is realized by adopting the following technical scheme.

A lag screw, comprising: the screw rod is internally provided with a guide channel, the guide channel comprises a side hole and a central hole which are communicated, the side hole is communicated with the outer wall of the screw rod and the central hole, and the axis of the central hole is coincident with the axis of the screw rod;

the elastic screw penetrates through the guide channel and comprises an elastic part, a tip and a tail end, wherein the tip and the tail end are connected to two ends of the elastic part, the tip can protrude out of the outer wall of the screw rod through the guide channel, and the tail end can be locked and fixed with the screw rod.

Further, the screw rod comprises a first rod section and a second rod section which are connected, wherein the first rod section is used for penetrating through the femoral head, and the outer wall of the first rod section is a cylindrical surface.

Still further, the second pole section is used for wearing to locate in the inclined hole of main nail, the outer wall of second pole section is equipped with the ridge, the ridge is on a parallel with the axis of screw pole, the ridge can with the recess joint of inclined hole lateral wall of main nail.

Further, the side hole is of a bending structure and is used for communicating the center hole with the outer wall of the first rod section.

Further, the side hole comprises a first hole and a second hole, the first hole is linear, the second hole is arc-shaped, the second hole is communicated with the first hole and the central hole, and the axis of the first hole and the axis of the central hole are at a preset angle.

Still further, still include the guide, the guide is used for shutoff first pole section's tip, be equipped with on the guide the second hole.

Still further, the guide includes block and main part, the block set firmly in the one end of main part, the main part inserts in the centre bore of first pole section, the block butt in the terminal surface of first pole section, be equipped with on the main part the second hole.

Still further, the outer wall of main part is equipped with the bead, the bead is parallel to the axis of main part, the bead with the slot joint of the inner wall of first pole section.

Further, the side wall of the cap is a cylindrical surface, and the outer diameter of the cap is equal to the outer diameter of the first rod section.

Further, the inner wall of the screw rod is provided with an internal thread, the tail end is provided with an external thread, and the tail end is in threaded connection with the inner wall of the screw rod.

The utility model has the following beneficial effects:

when the screw rod is matched with the elastic screw, the elastic screw is penetrated by the central hole, the tip end of the elastic screw protrudes out of the outer wall of the screw rod through the side hole of the guide channel and is pressed against cortical bone, and the protruding part of the elastic screw is matched with the screw rod at an angle; the tail end of the elastic screw is continuously extruded forwards, the elastic part is compressed, and the tail end is locked with the screw rod, so that the elastic screw and the cortical bone keep extrusion, the screw rod is prevented from withdrawing, the problem of screw withdrawing of the lag screw in the prior art is effectively solved, and the stability and the effectiveness of treatment are ensured.

Drawings

FIG. 1 is a schematic view of the construction of a lag screw of the present utility model;

FIG. 2 is a cross-sectional view of the lag screw of the present utility model;

FIG. 3 is a schematic view of the guide channel of the present utility model;

fig. 4 is a schematic view of the structure of the guide of the present utility model.

1, a screw rod; 11. a first pole segment; 12. a second pole segment; 121. a ridge; 2. an elastic screw; 21. a tip; 22. an elastic part; 23. tail end; 3. a guide channel; 31. a side hole; 311. a first hole; 312. a second hole; 32. a central bore; 4. a guide member; 41. capping; 42. a main body; 421. a rib.

Detailed Description

The utility model will be further described with reference to the drawings and examples.

As shown in fig. 1 to 4, the lag screw of the present embodiment includes a screw shaft 1 and a lag screw 2. The screw rod 1 is internally provided with a guide channel 3, the guide channel 3 comprises a side hole 31 and a central hole 32 which are mutually communicated, the axis of the central hole 32 coincides with the axis of the screw rod 1, and the side hole 31 is communicated with the outer wall of the screw rod 1 and the central hole 32. The elastic screw 2 is arranged in the guide channel 3 in a penetrating way, the elastic screw 2 comprises an elastic part 22, a tip 21 and a tail end 23 which are connected to two ends of the elastic part 22, the tip 21 can protrude out of the outer wall of the screw rod 1 through the guide channel 3, and the tail end 23 can be locked and fixed with the screw rod 1.

In this embodiment, when the elastic screw 2 is matched with the screw rod 1, the elastic screw 2 is penetrated by the central hole 32, the tip 21 of the elastic screw 2 protrudes out of the outer wall of the screw rod 1 through the side hole 31 of the guide channel 3, the tip 21 is pressed against the cortical bone, the tail end 23 of the elastic screw 2 continues to be pressed forwards, and the tail end 23 can be locked with the screw rod 1, so that the extrusion effect between the tip 21 and the cortical bone is kept, and the screw rod 1 can be prevented from withdrawing.

Specifically, referring to fig. 1, the screw rod 1 includes a first rod segment 11 and a second rod segment 12 that are connected to each other, the first rod segment 11 is used for penetrating through the femoral head, and the outer wall of the first rod segment 11 is a smooth cylindrical surface, so that the screw rod 11 is smoother when implanted in the femur, and meanwhile, the smooth cylindrical surface of the first rod segment 11 does not drive the femoral head to axially rotate. The end face of the first rod segment 11 is chamfered, so that the puncture of tissues can be avoided during implantation, and the screw rod 1 can be limited to move forwards after implantation, so that the puncture of femur can be avoided.

In this embodiment, the second rod section 12 is used to be inserted into the inclined hole of the intramedullary main nail, at least one ridge 121 is provided on the outer wall of the second rod section 12, the extending direction of the ridge 121 is parallel to the axial direction of the screw rod 1, a groove is provided on the inner wall of the inclined hole of the intramedullary main nail, and the ridge 121 can be clamped with the groove on the inner wall of the inclined hole to prevent the lag screw from rotating relative to the intramedullary main nail. Preferably, the number of the two protruding ridges 121 and the number of the grooves corresponding to the inner walls of the inclined holes are two, the two protruding ridges 121 are symmetrically arranged on the outer wall of the second rod section 12, the acting force between the screw rod 1 and the main nail is uniform, the micro-motion caused by uneven stress between the screw rod 1 and the main nail is greatly reduced, and the anti-rotation effect is better.

Referring to fig. 2, the elastic screw 2 includes an elastic portion 22, and a tip 21 and a tail 23 connected to both ends of the elastic portion 22. The elastic part 22, preferably a spring, can be bent along with the structural change of the guide channel 3 when the elastic screw 2 passes through the guide channel 3, so that the advancing direction of the elastic screw 2 is changed, and the tip 21 protrudes out of the outer wall of the screw rod 1 through the guide channel 3. At the same time, the provision of the tip 21 facilitates the pressing of the elastic screw 2 against the cortical bone, forming a firm contact.

Specifically, the tail end 23 is provided with external threads, the inner wall of the screw rod 1 is provided with internal threads, and the tail end 23 is in threaded connection with the inner wall of the screw rod 1, so that the tail end 23 is locked on the screw rod 1. After the tail end 23 is locked with the proper position of the screw rod 1, the tip 21 can be kept tightly propped against the cortical bone, the acting force of the elastic screw 2 on the cortical bone is enhanced, and the screw withdrawing of the lag screw is avoided.

Referring to fig. 3, the guide passage 3 of the present embodiment includes a side hole 31 and a center hole 32 which are communicated with each other, the side hole 31 includes a first hole 311 and a second hole 312, the first hole 311 is linear, the second hole 312 is arc-shaped, and the second hole 312 communicates the first hole 311 and the center hole 32. The axis of the first bore 311 is at a predetermined angle to the axis of the central bore 32, the predetermined angle ranging from 85 ° to 150 °, and may specifically be 85 °, 90 °, 100 °, 110 °, 120 °, 130 °, 140 ° or 150 °.

Referring to fig. 4, the screw rod 1 of the present embodiment further includes a guide 4, the guide 4 including a cap 41 and a main body 42, the cap 41 being fixed to one end of the main body 42; in use, the cap 41 is abutted against the end face of the first rod section 11, the main body 42 is inserted into the central hole 32 of the first rod section 11, and the second hole 312 is machined in the main body 42, so that after the guide piece 4 is connected with the first rod section 11, the second hole 312 is communicated with the first hole 311 and the central hole 32, and the guide channel 3 is formed by combining. In this embodiment, the screw rod 1 is provided with a split structure, so that the guide channel 3 is conveniently machined, and meanwhile, the internal thread of the inner wall of the screw rod 1 is also conveniently machined.

The side wall of the cap 41 is a cylindrical surface, and the outer diameter of the cap 41 is equal to the outer diameter of the first rod section 11 of the screw rod, so that the lag screw is smoother and more labor-saving when implanted into the femur.

The interference fit between the main body 42 and the inner wall of the first rod section 11 increases the firmness of the insertion of the guide body 4 and the screw rod 1, and can prevent the guide body 4 from falling off. The outer wall of the main body 42 is provided with the convex rib 421, the inner wall of the first rod section 11 of the screw rod is provided with the corresponding groove, the convex rib 421 is clamped with the groove, the extending direction of the convex rib 421 is parallel to the axial direction of the main body 42, and the possibility that the guide body 4 rotates circumferentially relative to the screw rod 1 is limited; meanwhile, the number of the convex edges 421 is set to be one, so that the marking effect can be achieved, and the guide channels 3 can be aligned conveniently.

The lag screw implantation process of the present embodiment includes: the guide body 4 is inserted into the end part of the first rod section 11, the combined screw rod 1 is implanted into the femur, the convex ridge 121 on the screw rod 1 is clamped with the pre-implanted main intramedullary nail of the femur, and the screw rod 1 can be prevented from rotating relative to the main nail; the elastic screw 2 is threaded into the guide channel 3 from the end of the second rod section 12, the tip 21 passes through the guide channel 3 to be tightly propped against the cortical bone, and the external thread at the tail end 23 of the elastic screw 2 is locked with the internal thread on the inner wall of the screw rod 1, so that the tip 21 is kept to be extruded towards the cortical bone, and the screw rod 1 is prevented from withdrawing.

The screw rod 1 and the femoral intramedullary main nail do not axially rotate after operation, the locking part of the screw rod 1 is cortical bone, the screw holding cannot be affected by osteoporosis, and the elastic screw 2 and the screw rod 1 are matched at an angle, so that the screw cannot be retracted. When the elastic screw is taken out, the tail end 23 of the elastic screw 2 is reversely rotated, and the tip 21 is retracted into the screw rod 1, so that the screw rod 1 can be taken out conveniently and quickly.

The embodiments of the present utility model are all preferred embodiments of the present utility model, and are not intended to limit the scope of the present utility model in this way, therefore: all equivalent changes in structure, shape and principle of the utility model should be covered in the scope of protection of the utility model.

Claims

1. Lag screw, its characterized in that includes:

the screw rod (1) is internally provided with a guide channel (3), the guide channel (3) comprises a side hole (31) and a central hole (32) which are communicated with each other, the side hole (31) is communicated with the outer wall of the screw rod (1) and the central hole (32), and the axis of the central hole (32) is coincident with the axis of the screw rod (1);

elastic screw (2), it wears to establish in guide way (3), elastic screw (2) include elasticity portion (22), and connect in tip (21) and tail end (23) at elasticity portion (22) both ends, tip (21) can warp guide way (3) protrusion in screw pole (1) outer wall, tail end (23) can with screw pole (1) locking is fixed.

2. A lag screw according to claim 1, wherein: the screw rod (1) comprises a first rod section (11) and a second rod section (12) which are connected with each other, wherein the first rod section (11) is used for penetrating through a femoral head, and the outer wall of the first rod section (11) is a cylindrical surface.

3. A lag screw as claimed in claim 2, wherein: the second pole section (12) is used for penetrating through the inclined hole of the main nail, a convex ridge (121) is arranged on the outer wall of the second pole section (12), the convex ridge (121) is parallel to the axis of the screw rod (1), and the convex ridge (121) can be clamped with the groove on the side wall of the inclined hole of the main nail.

4. A lag screw as claimed in claim 2, wherein: the side hole (31) is of a bending structure and is used for communicating the central hole (32) with the outer wall of the first rod section (11).

5. A lag screw according to claim 1, wherein: the side hole (31) comprises a first hole (311) and a second hole (312), the first hole (311) is linear, the second hole (312) is arc-shaped, the second hole (312) is communicated with the first hole (311) and the central hole (32), and the axis of the first hole (311) and the axis of the central hole (32) are at a preset angle.

6. A lag screw according to claim 2 or 5, wherein: the screw rod (1) further comprises a guide (4), wherein the guide (4) is used for blocking the end part of the first rod section (11), and the guide (4) is provided with the second hole (312).

7. A lag screw as claimed in claim 6, wherein: the guide piece (4) comprises a cap (41) and a main body (42), the cap (41) is fixedly arranged at one end of the main body (42), the main body (42) is inserted into the central hole (32) of the first rod section (11), the cap (41) is abutted to the end face of the first rod section (11), and the main body (42) is provided with the second hole (312).

8. A lag screw as claimed in claim 7, wherein: the outer wall of main part (42) is equipped with bead (421), bead (421) are parallel to the axis of main part (42), bead (421) with the slot joint of the inner wall of first pole section (11).

9. A lag screw as claimed in claim 7, wherein: the side wall of the cap (41) is a cylindrical surface, and the outer diameter of the cap (41) is equal to the outer diameter of the first rod section (11).

10. A lag screw according to claim 1, wherein: the inner wall of the screw rod (1) is provided with an internal thread, the tail end (23) is provided with an external thread, and the tail end (23) is in threaded connection with the inner wall of the screw rod (1).