Anchor with sheath

Abstract

The present invention provides a sheathed anchor, comprising an anchor rod and an expansion sheath, wherein the anchor rod passes through the tail cavity of the expansion sheath and forms a threaded connection therewith, so that the expansion sheath is squeezed and expanded, and a plurality of snap-in protrusions are arranged on the outer wall of the expansion sheath, wherein the snap-in protrusions are evenly spaced in the circumferential direction of the expansion sheath, and the snap-in protrusions are arranged in sequence in the axial direction of the expansion sheath, and the radial protrusion height of each snap-in protrusion gradually increases from the head to the tail of the anchor rod. In the above scheme, snap-in protrusions of different sizes are arranged, so that the snap-in protrusions near the tail are larger, and the snap-in protrusions at a deeper position after being nailed into the bone have a smaller snap-in part, and the snap-in protrusions at a shallower position are larger, which will also result in a larger snap-in area in the shallow layer of the bone, and when the sheathed anchor is subjected to tension, it has a larger force-bearing area in the shallow layer of the bone to increase the fixing strength, and prevent the local fragmentation of the shallow layer of the bone from causing secondary damage.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to an anchor nail with a sheath. Background Art

[0002] Different implant devices are used in clinical practice for different soft tissue injury diseases. Wire anchors are commonly used implantable soft tissue injury repair devices in clinical practice. Wire anchors are usually used to repair clinical diseases such as rotator cuff tears, knee collateral ligament injuries, and ankle and elbow soft tissue injuries. Wire anchors are very small implants. During use, a punch is used to punch a bone tunnel in the bone. The anchor is implanted under the cortical bone through an anchor inserter. Sutures are used to fix the avulsed or torn soft tissue on the bone surface to promote the healing of soft tissue and bone to achieve a repair effect.

[0003] Chinese patent CN211674388U discloses a knotless anchor, which includes a conical anchor head, an anchor body connected to the anchor head, and an anchor rod; the anchor body is provided with an expansion groove that runs through its tail end so that the tail of the anchor body forms a bifurcated structure that can move closer or farther away from each other; the anchor rod is a conical structure with a tail size larger than the head size, and the anchor body is provided with a hollow structure for inserting the anchor rod, so that when the anchor rod moves relative to the anchor body in a direction close to the anchor head, the width of the expansion groove increases; when the anchor rod moves relative to the anchor body in a direction away from the anchor head, the width of the expansion groove decreases. A plurality of small cones are provided on the outer wall of the expansion groove, and the small cones thereon are clamped into the bone to enhance the fastening force through the expansion of the expansion groove, and the shapes of the small cones thereon are basically the same. However, for patients with osteoporosis, their bones are relatively fragile, especially the superficial layer of the bone. When the anchor in this solution is embedded in the bone, the clamping force in the deep and superficial layers of the bone is basically the same, but the strength of the deep and superficial bones is different. The superficial bones are more likely to break. Therefore, when the anchor is subjected to tension, it may cause the superficial bones to break and cause secondary injury to the patient. Summary of the invention

[0004] The purpose of the present invention is to provide an anchor nail with a sheath, which can improve the clamping force on the superficial bones and avoid the superficial bones from being broken by the tensile force and causing secondary damage.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] A sheathed anchor comprises an anchor rod and an expansion sheath, wherein the anchor rod passes through a tail cavity of the expansion sheath and is threadedly connected thereto so that the expansion sheath is squeezed and expanded, and a plurality of snap-in protrusions are arranged on an outer wall of the expansion sheath, wherein the snap-in protrusions are evenly spaced in the circumferential direction of the expansion sheath, and the snap-in protrusions are arranged in sequence in the axial direction of the expansion sheath, and the radial protrusion height of the snap-in protrusions gradually increases from the head to the tail of the anchor rod.

[0007] In the above scheme, different sizes of snap-on protrusions are arranged, so that the snap-on protrusions near the tail are larger. After being nailed into the bone, the snap-on protrusions located at a deeper position have a smaller snap-on part, and the snap-on protrusions located at a shallower position have a larger snap-on area. This will also result in a larger snap-on area in the shallow layer of the bone. When the sheathed anchor is subjected to tension, it has a larger force-bearing area in the shallow layer of the bone to increase the fixing strength and prevent local fragmentation of the shallow layer of the bone from causing secondary damage.

[0008] Preferably, the head of the expansion sheath is a conical structure, and a thread hole for inserting sutures is provided in the conical structure and passes through in the radial direction.

[0009] Preferably, the expansion sheath comprises a plurality of elastic rods evenly spaced in the circumferential direction, one end of the elastic rods is connected to the bottom surface of the conical structure, and the other end is suspended, the inner side of the elastic rods is an outwardly concave arc and is provided with threads, the snap-in protrusions are arranged on the outer side of the elastic rods, and the inner side walls of all the elastic rods enclose an insertion cavity for the anchor rod to be screwed into.

[0010] Preferably, the snap-fitting protrusion is a wedge-shaped structure with the tip facing the head of the expansion sheath, the inclined surface of the wedge-shaped structure is located on the side of the snap-fitting protrusion away from the axis of the expansion sheath, the width and length of each snap-fitting protrusion are the same, and the angle between the inclined surface of each snap-fitting protrusion and the axis gradually increases from the head to the tail of the anchor rod.

[0011] Preferably, the angle between the inclined surface of the first snap-fitting protrusion close to the expansion sheath head and the axis is 2-5°, and the angle between the inclined surfaces 211 of the two adjacent snap-fitting protrusions 21 in the axial direction and the axis differs by 2-5°.

[0012] Preferably, the inner diameter of the insertion cavity gradually increases from a position close to the head of the expansion sheath to a position far away from the head of the expansion sheath.

[0013] Preferably, the width of the outer wall of the elastic rod gradually increases from a position close to the expansion sheath head to a position far away from the expansion sheath head.

[0014] Preferably, the anchor rod is in the shape of a threaded cone.

[0015] Preferably, the anchor rod is provided with a plum blossom hole arranged along the axis for tool screwing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the three-dimensional structure of the expansion sheath;

[0018] Figure 3 is a cross-sectional view of the expansion sheath;

[0019] Figure 4 is a schematic diagram of the elastic rod structure;

[0020] Figure 5 is a schematic diagram of the anchor rod structure;

[0021] Explanation of the reference numerals: 10, anchor rod; 11, plum blossom hole; 20, expansion sheath; 21, snap-fit ​​protrusion; 211, inclined surface; 22, conical structure; 23, wire hole; 24, elastic rod; 25, insertion cavity. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as "bottom", "outside", and "front and back" are based on the orientations or positional relationships shown in the use state of the present invention, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] A sheathed anchor comprises an anchor rod 10 and an expansion sheath 20, wherein the anchor rod 10 passes through a tail cavity of the expansion sheath 20 and is threadedly connected thereto so that the expansion sheath 20 is squeezed and expanded, and a plurality of snap-in protrusions 21 are arranged on an outer wall of the expansion sheath 20, wherein the snap-in protrusions 21 are evenly spaced in the circumferential direction of the expansion sheath 20, and the snap-in protrusions 21 are sequentially arranged in the axial direction of the expansion sheath 20, and the radial protrusion height of the snap-in protrusions 21 gradually increases from the head to the tail of the anchor rod 10.

[0026] In the above scheme, the clamping protrusions 21 of different sizes are arranged, so that the clamping protrusions 21 near the tail are larger, and the clamping parts of the clamping protrusions 21 located at a deeper position after being nailed into the bone are smaller, and the clamping protrusions 21 located at a shallower position are larger. This will also result in a larger clamping area in the shallow layer of the bone. When the sheath anchor is subjected to tension, it has a larger force-bearing area in the shallow layer of the bone to increase the fixing strength and prevent the local fragmentation of the shallow layer of the bone from causing secondary damage. When in use, a hole is first opened in the bone, and then the anchor rod 10 and the expansion sheath 20 are connected end to end and placed in the hole. The expansion sheath 20 has a thread matching the anchor rod 10 inside. The anchor rod 10 squeezes the expansion sheath 20 during the screwing process, and the clamping protrusions 21 around the expansion sheath 20 are squeezed into the cancellous bone, which effectively increases the bone contact area and improves the fixing strength. The problem of weak fixation in patients with osteoporosis is solved.

[0027] Preferably, the head of the expansion sheath 20 is a conical structure 22, and a thread hole 23 for inserting a suture is provided on the conical structure 22. The thread hole 23 is inserted with a suture, and the suture is generally connected to the tendon part. The suture is pulled and stressed at the head of the expansion sheath 20, so that the entire expansion sheath 20 can withstand the tension instead of the local tension, thereby avoiding local damage to the expansion sheath 20. In addition, the suture can be led out from the side of the expansion sheath 20.

[0028] Preferably, the expansion sheath 20 includes a plurality of elastic rods 24 evenly spaced in the circumferential direction, one end of the elastic rod 24 is connected to the bottom surface of the conical structure 22, and the other end is suspended, the inner side of the elastic rod 24 is an outwardly concave arc and provided with threads, the clamping protrusion 21 is provided on the outer side of the elastic rod 24, and the inner side walls of all the elastic rods 24 are combined to form an insertion cavity 25 for the anchor rod 10 to be screwed into. When the anchor rod 10 is screwed into the insertion cavity 25, the elastic rod 24 can bend outward around the connection between it and the conical structure 22 to form an expansion effect.

[0029] Preferably, the clamping protrusion 21 is a wedge-shaped structure with the tip facing the head of the expansion sheath 20. The inclined surface 211 of the wedge-shaped structure is located on the side of the clamping protrusion 21 away from the axis of the expansion sheath 20. The width and length of each clamping protrusion 21 are the same. From the head to the tail of the anchor rod 10, the angle between the inclined surface 211 of each clamping protrusion 21 and the axis gradually increases. After the elastic rod 24 is bent and deformed, the wedge-shaped structure can form a barb that penetrates into the bone, further improving the clamping force.

[0030] Preferably, the angle between the inclined surface 211 of the first clamping protrusion 21 near the head of the expansion sheath 20 and the axis is 2-5°, and the angle between the inclined surface 211 and the axis increases successively to 2-5°. That is, the angle between the inclined surface 211 and the axis changes linearly, because the distance between the inclined surface 211 and the head of the expansion sheath 20 also changes linearly.

[0031] Preferably, the inner diameter of the insertion cavity 25 gradually increases from the position close to the head of the expansion sheath 20 to the position far from the head of the expansion sheath 20. Since the head size of the anchor rod 10 is fixed, the deeper the anchor rod 10 is screwed, the greater the expansion of the tail of the expansion sheath 20.

[0032] Preferably, the width of the outer wall of the elastic rod 24 gradually increases from the position close to the head of the expansion sheath 20 to the position far from the head of the expansion sheath 20. Since the tail of the expansion sheath 20 is far away from the conical structure 22, the corresponding elastic rod 24 is suspended, and the expansion degree of the tail of the expansion sheath 20 is greater than that of the position close to the head, so the tail needs a higher structural strength, so the elastic rod 24 is set wider near the tail.

[0033] Preferably, the anchor rod 10 is in the shape of a threaded cone. The maximum outer diameter of the threaded cone is larger than the inner diameter of the insertion cavity 25, while the minimum outer diameter of the threaded cone is smaller than the inner diameter of the insertion cavity 25, so that when the anchor rod 10 and the expansion sheath 20 are connected end to end in the initial state, it does not cause the expansion sheath 20 to expand, making it easier to insert the anchor rod 10 and the expansion sheath 20 connected end to end into the drilled bone hole.

[0034] Preferably, the anchor rod 10 is provided with a plum blossom hole 11 arranged along the axis for tool screwing, thereby increasing the torque bearing capacity of the anchor rod 10 and reducing the probability of the anchor rod 10 being damaged during the screwing process.

[0035] The anchor rod 10 and the expansion sheath 20 in the present application are made of biocomposite materials such as PLGA / β-TCP, PLGA / HA, PLGA / β-TCP / CS, PLLA / β-TCP, PLLA / HA, PLLA / β-TCP / CS, PLLA / PLGA / β-TCP, PLLA / PLGA / HA, etc. The biocomposite materials are molded at 140°C-160°C to obtain sheets and rods, and a large number of fiber structures appear inside the composite materials. These fiber structures significantly improve the mechanical properties of the material, and the bending strength is increased by 100%-150%. At the same time, the tensile strength of the rod will also be significantly improved with molding.

[0036] Biocomposite materials have obvious advantages: they can be completely degraded in the human body within 2 to 3 years and do not need to be removed again; their mechanical properties are equivalent to those of osteoblasts and there is no stress shielding; components such as β-TCP and HA have osteoconductive effects and are beneficial to bone healing; they are easy to revise and facilitate surgical operations.

[0037] Heat-forming biocomposites such as PLGA / β-TCP, PLGA / HA, PLGA / β-TCP / CS, PLLA / β-TCP, PLLA / HA, PLLA / β-TCP / CS, PLLA / PLGA / β-TCP, PLLA / PLGA / HA into blanks;

[0038] The parison is subjected to orientation molding at 100°C-160°C to obtain sheets and rods;

[0039] Process the rods or sheets through machine tools to obtain products with different structures;

[0040] Clean by ultrasonication at 40°C for 10 minutes.

[0041] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A sheathed anchor, characterized in that: The invention comprises an anchor rod (10) and an expansion sheath (20), wherein the anchor rod (10) passes through a rear cavity of the expansion sheath (20) and is threadedly connected thereto so that the expansion sheath (20) is squeezed and expanded, and a plurality of clamping protrusions (21) are arranged on the outer wall of the expansion sheath (20), and the clamping protrusions (21) are evenly spaced in the circumferential direction of the expansion sheath (20), and the clamping protrusions (21) are arranged in sequence in the axial direction of the expansion sheath (20), and the radial protrusion height of each clamping protrusion (21) gradually increases from the head to the tail of the anchor rod (10); The anchor rod (10) and the expansion sheath (20) are both made of PLGA / β-TCP, PLGA / HA, PLGA / β-TCP / CS, PLLA / β-TCP, PLLA / HA, PLLA / β-TCP / CS, PLLA / PLGA / β-TCP, PLLA / PLGA / HA biocomposite materials, and the biocomposite materials are molded at 140° C.-160° C. to obtain sheets and rods, so that a fiber structure appears inside the composite material.

2. The sheathed anchor according to claim 1, characterized in that: The head of the expansion sheath (20) is a conical structure (22), and a thread hole (23) for inserting a suture and penetrating in the radial direction is provided on the conical structure (22).

3. The sheathed anchor according to claim 2, characterized in that: The expansion sheath (20) comprises a plurality of elastic rods (24) evenly spaced in the circumferential direction, one end of the elastic rod (24) is connected to the bottom surface of the conical structure (22), and the other end is suspended, the inner side of the elastic rod (24) is an outwardly concave arc and is provided with a thread, the clamping protrusion (21) is arranged on the outer side of the elastic rod (24), and the inner side walls of all the elastic rods (24) are combined to form an insertion cavity (25) for the anchor rod (10) to be screwed into.

4. The sheathed anchor according to claim 3, characterized in that: The clamping protrusion (21) is a wedge-shaped structure with its tip facing the head of the expansion sheath (20); the inclined surface (211) of the wedge-shaped structure is located on the side of the clamping protrusion (21) away from the axis of the expansion sheath (20); the width and length of each clamping protrusion (21) are the same; and the angle between the inclined surface (211) of each clamping protrusion (21) and the axis gradually increases from the head to the tail of the anchor rod (10).

5. The sheathed anchor according to claim 4, characterized in that: The inclined surface (211) of the first clamping protrusion (21) close to the head of the expansion sheath (20) has an angle of 2-5° with the axis, and the inclined surfaces (211) of two adjacent clamping protrusions (21) in the axial direction have an angle difference of 2-5° with the axis.

6. The sheathed anchor according to claim 3, characterized in that: The inner diameter of the insertion cavity (25) gradually increases from a position close to the head of the expansion sheath (20) to a position far from the head of the expansion sheath (20).

7. The sheathed anchor according to claim 3, characterized in that: The width of the outer wall of the elastic rod (24) gradually increases from a position close to the head of the expansion sheath (20) to a position far from the head of the expansion sheath (20).

8. The sheathed anchor according to claim 1 or 2 or 3 or 4 or 5 or 6 or 7, characterized in that: The anchor rod (10) is in the shape of a threaded cone.

9. The sheathed anchor according to claim 8, characterized in that: The anchor rod (10) is provided with a plum blossom hole (11) arranged along the axis and used for tool screwing.

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