A magnesium alloy hollow bone screw

Abstract

The utility model relates to the field of medical equipment, in particular to a magnesium alloy hollow bone nail, which includes an integrally formed ball head and a nail body, a through hole is arranged inside the ball head and the nail body, the ball head and the nail body are made of magnesium alloy, and the outer surface of the ball head and the nail body and the inner surface of the through hole are coated with a calcium phosphate coating; the nail body includes a straight section and a tapered section, and a self-tapping blade is arranged at the end of the tapered section; the end of the ball head is recessed inward to form a driving hole, and a cortical bone thread is arranged on the surface of the straight section close to the ball head, and a cancellous bone thread is arranged on the surface of the straight section close to the tapered section and the surface of the tapered section, and the pitch of the cortical bone thread is smaller than the pitch of the cancellous bone thread. The utility model adopts magnesium alloy material to make bone nails, and realizes the degradation function of the bone nail; by coating the calcium phosphate coating on the outer surface of the nail body and the inner surface of the through hole, the degradation rate of the bone nail is slowed down, and the bone injury can be fully healed.

Description

Technical Field

[0001] The utility model relates to the field of medical equipment, in particular to a magnesium alloy hollow bone screw. Background Art

[0002] AO hollow bone screws are mostly used in orthopedic surgeries on toe bones, radius, ulna, tibia and fibula, metacarpal bones, etc. The anchor materials used in the past were titanium alloys or polyetheretherketone, etc. After implantation, anchors and bone screws made of these materials are non-absorbable or degradable, and always exist in the human body, which will cause different degrees of rejection reactions in the human body, and still exist after the body tissue heals, and even require a second surgery to remove them. Magnesium alloys are gradually being widely used in implantable medical devices due to their biodegradability, biocompatibility and appropriate mechanical properties. Bone screws and anchors made of magnesium alloys can gradually degrade in the human physiological environment after implantation, which can avoid the need for a second surgery to remove them. However, the excessively fast degradation rate of magnesium alloys in the human physiological environment will cause premature failure of the implant, which may result in the patient's body not healing but the anchor has been completely degraded, which is not conducive to the patient's rehabilitation treatment. Utility Model Content

[0003] The utility model aims to solve the above problems and provides a magnesium alloy hollow bone screw, the technical solution of which is as follows:

[0004] A magnesium alloy hollow bone nail comprises an integrally formed ball head and a nail body, wherein a through hole is arranged inside the ball head and the nail body, the ball head and the nail body are made of magnesium alloy, and the outer surfaces of the ball head and the nail body and the inner surface of the through hole are coated with a calcium phosphate coating; the nail body comprises a straight tube section and a tapered section, and a self-tapping blade is arranged at the end of the tapered section; the end of the ball head is recessed inward to form a driving hole, a cortical bone thread is arranged on the surface of the straight tube section close to the ball head, and a cancellous bone thread is arranged on the surface of the straight tube section close to the tapered section and the surface of the tapered section, and the pitch of the cortical bone thread is smaller than the pitch of the cancellous bone thread.

[0005] Based on the above solution, the cortical bone thread and the cancellous bone thread are continuously arranged.

[0006] Preferably, the driving hole is in the shape of an equilateral triangle or a hexagonal plum blossom.

[0007] Preferably, the number of the self-tapping blades is 2 or 3, and they are evenly distributed around the axis of the nail body.

[0008] Preferably, the thread angle of the cortical bone thread is 25°-30°, and the thread angle of the cancellous bone thread is 20°-50°.

[0009] Preferably, the pitch of the cortical bone thread is 0.3 mm-2 mm, and the pitch of the cancellous bone thread is 0.5 mm-3.5 mm.

[0010] Preferably, a ball head gasket is arranged on the side of the ball head close to the straight tube section.

[0011] Preferably, the ball head has a thickness of 4 mm-10 mm.

[0012] Preferably, the angle between the generatrix of the tapered section and the axis of the nail body is 30°-60°.

[0013] The beneficial effects of the utility model are as follows: the bone nail is made of magnesium alloy material, and the degradation function of the bone nail is realized; by coating the outer surface of the nail body and the inner surface of the through hole with a calcium phosphate coating, the degradation rate of the bone nail is slowed down, ensuring that the bone injury can be fully healed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 : Schematic diagram of the structure of the utility model;

[0015] Figure 2 : A cross-sectional view of the internal structure of the utility model;

[0016] Figure 3 : Schematic diagram of the ball head structure of the utility model. DETAILED DESCRIPTION

[0017] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between 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.

[0019] In the description of the present utility model, it should be understood that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model 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 utility model. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0020] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0021] like Figures 1 to 3As shown, a magnesium alloy hollow bone nail includes an integrally formed ball head 1 and a nail body, and a through hole is arranged inside the ball head 1 and the nail body, and the through hole is used to install a guide pin. The ball head 1 and the nail body are made of magnesium alloy, and the outer surface of the ball head 1 and the nail body and the inner surface of the through hole are coated with a calcium phosphate coating. Since the degradation rate of calcium phosphate is slow, the degradation rate of the nail body is reduced, ensuring that the hollow nail is degraded layer by layer after achieving a rehabilitation effect in the human body. The nail body includes a straight tube section 3 and a tapered section 4, and a self-tapping blade 7 is arranged at the end of the tapered section 4, so that the bone nail is more convenient and labor-saving during implantation. The number of the self-tapping blades 7 is 2 or 3, and they are evenly distributed along the circumference. The end of the ball head 1 is recessed inward to form a drive hole 2, and the shape of the drive hole 2 is an equilateral triangle or a hexagonal plum blossom. Different shapes are selected according to the convenience of operation and the stability of the contact between the drive hole and the nail implanter. A cortical bone thread 5 is provided on the surface of the straight section 3 close to the ball head 1, and a cancellous bone thread 6 is provided on the surface of the straight section 3 close to the tapered section 4 and the surface of the tapered section 4. The pitch of the cortical bone thread 5 is smaller than the pitch of the cancellous bone thread 6. Preferably, the cortical bone thread 5 and the cancellous bone thread 6 are provided continuously. Specifically, the tooth angle of the cortical bone thread 5 is 25°-30°, and the tooth angle of the cancellous bone thread 6 is 20°-50°; the pitch of the cortical bone thread 5 is 0.3mm-2mm, and the pitch of the cancellous bone thread 6 is 0.5mm-3.5mm. Different lengths of the cortical bone thread 5 and the cancellous bone thread 6 are selected according to the screw specifications to achieve effective pressure on the bone to meet the relevant mechanical performance requirements. The angle between the generatrix of the tapered section 4 and the axis of the nail body is 30°-60°.

[0022] A ball head gasket is arranged on one side of the ball head 1 close to the straight tube section 3 to play a role of pressurizing and stabilizing the bone screw after installation. According to the size of the bone screw, the thickness of the ball head 1 can be selected in the range of 4mm-10mm.

[0023] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A magnesium alloy hollow bone screw, characterized in that: The invention comprises an integrally formed ball head (1) and a nail body, wherein a through hole is arranged inside the ball head (1) and the nail body, the ball head (1) and the nail body are made of magnesium alloy, and the outer surfaces of the ball head (1) and the nail body and the inner surface of the through hole are coated with a calcium phosphate coating; the nail body comprises a straight section (3) and a tapered section (4), and a self-tapping blade (7) is arranged at the end of the tapered section (4); the end of the ball head (1) is recessed inward to form a driving hole (2), a cortical bone thread (5) is arranged on the surface of the straight section (3) close to the ball head (1), and a cancellous bone thread (6) is arranged on the surface of the straight section (3) close to the tapered section (4) and the surface of the tapered section (4), and the pitch of the cortical bone thread (5) is smaller than the pitch of the cancellous bone thread (6).

2. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The cortical bone thread (5) and the cancellous bone thread (6) are arranged continuously.

3. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The shape of the driving hole (2) is an equilateral triangle or a hexagonal plum blossom.

4. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The number of the self-tapping blades (7) is 2 or 3, and they are evenly distributed around the axis of the nail body.

5. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The tooth angle of the cortical bone thread (5) is 25°-30°, and the tooth angle of the cancellous bone thread (6) is 20°-50°.

6. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The pitch of the cortical bone thread (5) is 0.3 mm to 2 mm, and the pitch of the cancellous bone thread (6) is 0.5 mm to 3.5 mm.

7. The magnesium alloy hollow bone screw according to claim 1, characterized in that: A ball head gasket is arranged on one side of the ball head (1) close to the straight tube section (3).

8. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The thickness of the ball head (1) is 4 mm-10 mm.

9. The magnesium alloy hollow bone screw according to claim 1, characterized in that: The included angle between the generatrix of the tapered section (4) and the axis of the nail body is 30°-60°.

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