CN118000877A - Degradable bone screw for promoting fracture surface healing and preparation method thereof - Google Patents
Degradable bone screw for promoting fracture surface healing and preparation method thereof Download PDFInfo
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- CN118000877A CN118000877A CN202410155792.3A CN202410155792A CN118000877A CN 118000877 A CN118000877 A CN 118000877A CN 202410155792 A CN202410155792 A CN 202410155792A CN 118000877 A CN118000877 A CN 118000877A
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- 210000000988 bone and bone Anatomy 0.000 title claims abstract description 127
- 230000035876 healing Effects 0.000 title claims abstract description 32
- 230000001737 promoting effect Effects 0.000 title claims abstract description 16
- 238000002360 preparation method Methods 0.000 title abstract description 6
- 208000010392 Bone Fractures Diseases 0.000 claims abstract description 68
- 206010017076 Fracture Diseases 0.000 claims abstract description 67
- 230000000694 effects Effects 0.000 claims abstract description 15
- 230000002441 reversible effect Effects 0.000 claims abstract description 6
- 241000587161 Gomphocarpus Species 0.000 claims abstract description 5
- 238000005553 drilling Methods 0.000 claims abstract description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 44
- 229910052749 magnesium Inorganic materials 0.000 claims description 39
- 239000011777 magnesium Substances 0.000 claims description 39
- 229910052751 metal Inorganic materials 0.000 claims description 39
- 239000002184 metal Substances 0.000 claims description 39
- 238000000137 annealing Methods 0.000 claims description 34
- 238000005096 rolling process Methods 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 13
- 238000004321 preservation Methods 0.000 claims description 12
- 230000000149 penetrating effect Effects 0.000 claims description 4
- 238000005520 cutting process Methods 0.000 claims description 3
- 230000002349 favourable effect Effects 0.000 abstract description 2
- 230000015556 catabolic process Effects 0.000 description 11
- 238000006731 degradation reaction Methods 0.000 description 11
- 238000005452 bending Methods 0.000 description 5
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 230000004060 metabolic process Effects 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000007857 degradation product Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- -1 hydroxyl ions Chemical class 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
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- Materials For Medical Uses (AREA)
- Surgical Instruments (AREA)
Abstract
The invention provides a degradable bone screw for promoting fracture healing and a preparation method thereof, wherein the bone screw comprises a screw rod and a screw cap, and the head of the screw rod is provided with a nail head for drilling into bone; the screw is provided with a first external thread, the inner side of the screw is provided with a first rotating groove, and the first rotating groove extends from the tail part of the screw to the middle part; the tail part of the screw is provided with a tail groove which is communicated with the first rotating groove; the nut is provided with a second external thread for being connected to the tail part of the screw rod; the inner side of one end of the nut far away from the screw rod is provided with a second rotating groove for driving the nut to rotate. The bone screw adopts a split structure of the screw rod and the screw cap, and can enable two bone surfaces at the fracture surface to be mutually abutted and attached under the double effects of forward screw drilling of the screw rod into the bone and reverse screw screwing of the screw cap into the screw rod, so that the healing rate of the fracture surface can be improved; and is easy to degrade and is favorable for being directly metabolized and absorbed by patients.
Description
Technical Field
The invention relates to the technical field of medical instruments, in particular to a degradable bone screw for promoting fracture surface healing and a preparation method thereof.
Background
Bone screws are internal fixation devices for bone fractures, which can be used alone to align and stabilize the fracture surface. The existing bone screw is generally made of metal materials such as pure titanium, titanium alloy, cobalt-based alloy, stainless steel and the like, and the metal materials are difficult to degrade and absorb, so that the bone screw needs to be taken out through secondary operation, even some bone screws are difficult to be taken out smoothly due to long-time contact with bones, and the burden and pain of a patient can be increased; in addition, when the existing bone screw is screwed into the fracture surface, the existing bone screw is of an integrated structure, and the whole bone screw has only one acting force on the fracture surface, so that the close fit between two bone surfaces at the fracture surface can not be ensured, and the healing rate of the fracture surface is influenced.
In addition, the degradation rate is faster because of the poor mechanical property of the easily degradable bone screw; after the bone screw is implanted into the fracture part of a patient, the bone screw cannot be guaranteed not to be obviously degraded before the fracture surface heals, and the bone screw cannot be guaranteed to provide continuous and effective fixing and pressurizing effects on the fracture surface, so that the healing of the fracture surface is affected.
Disclosure of Invention
In view of the above, the present invention provides a degradable bone screw for promoting fracture surface healing and a preparation method thereof, wherein the bone screw is easy to degrade, can be directly metabolized and absorbed by a patient, and can enable two bone surfaces of a fracture surface to be tightly attached, so as to accelerate the healing rate of the fracture surface.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
A degradable bone screw for promoting fracture healing, the bone screw being made of magnesium metal, the bone screw comprising a screw rod and a nut; the head of the screw is provided with a nail head for drilling into bone; the screw rod is provided with a first external thread in a penetrating way along the length direction of the screw rod, and the first external thread is used for ensuring the stability of screwing the screw rod thread into the fracture surface; a plurality of rotation stopping grooves are formed in the grooves of the first external threads and used for preventing the screw rod from reversely unscrewing relative to the bone, and each rotation stopping groove is provided with an arc-shaped surface; the arc surface extends downwards in a tilting manner in the screwing direction of the screw; the inner side of the screw is provided with a first rotating groove which extends from the tail part of the screw to the middle part, and the first rotating groove is used for being inserted into a screwing device so as to screw the screw into the bone through the screwing device; the tail part of the screw is provided with a tail groove, the inner wall surface of the tail groove is provided with an internal thread matched with the second external thread, and the tail groove is communicated with the first rotating groove; the nut is provided with a second external thread which is used for being connected to the tail part of the screw rod in a threaded manner; the second external thread is used for being connected to the tail part of the screw rod in a threaded mode; the inner side of one end of the nut far away from the screw rod is provided with a second rotating groove so as to drive the nut to rotate through a rotator.
Further, the three rotation stopping grooves are respectively positioned at the head part, the middle part and the tail part of the screw rod and used for limiting the reverse rotation of the screw rod in the bone from the three positions of the screw rod, so that the anti-loosening effect on the screw rod is better; the three rotation stopping grooves are positioned on the same straight line, the cutting depth of the rotation stopping grooves on the first external threads is 0.5mm, and one rotation stopping groove cuts at least one first external thread.
Further, in the direction from the head of the screw to the tail of the screw, namely, the tooth thickness of the first external thread positioned at the head of the screw is smaller, and the tooth thickness of the first external thread positioned at the tail of the screw is larger; the tooth thickness of the first external thread gradually increases from 0.1mm to 0.3mm from the head to the tail of the screw rod.
Further, the depth of the first rotating groove is half of the length of the whole screw rod, and the diameter of the circumscribed circle of the first rotating groove is 2mm.
Further, the depth of the tail groove is matched with the length of the portion, provided with the second external thread, of the screw cap, and the tail groove is used for enabling the second external thread to be in threaded connection with the internal thread, so that the screw cap can be fixedly arranged on the screw rod.
Further, the included angle between the arc-shaped surface and the horizontal plane is 25-35 degrees, so that the bone can rebound on a part of the arc-shaped surface, and the anti-reverse loosening effect of the anti-rotation groove on the screw rod is better; on the other hand, the screw rod screwing device is used for ensuring that the screwing stopping groove does not interfere the screw rod screwing operation into the bone, ensuring that the screw rod can be smoothly screwed into the bone, and avoiding the pain of a patient caused by the screwing stopping groove when the screw rod is screwed into the bone.
Further, the outer diameter of the portion of the nut where the second external thread is not provided is larger than the outer diameter of the screw rod, and the spiral direction of the second external thread is opposite to that of the first external thread.
A method for preparing a degradable bone screw for promoting fracture healing, which comprises the following steps:
S1: selecting a cylindrical metal magnesium bar;
S2: the metal magnesium bar in the step S1 is annealed for multiple times and rolled for multiple times, the first-stage annealing and the second-stage annealing are needed to be sequentially carried out before the metal magnesium bar is rolled each time, the metal magnesium bar is required to be rolled immediately after the second-stage annealing is carried out, and the rolling time is 10min-11min each time; the annealing and rolling sequence is that the first-stage annealing and the second-stage annealing are sequentially carried out and then the rolling is carried out; the temperature of the first-stage annealing is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second-stage annealing is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling;
S3: and (2) preparing the screw rod and the screw cap of the pressurizing degradable bone screw by adopting a core-moving processing mode for the metal magnesium bar obtained in the step (S2) to obtain the bone screw which can promote fracture healing and is degradable.
Further, the bone screw is manufactured through multiple annealing and multiple rolling, so that the grain size of the bone screw is a preset grain size, the tensile strength of the bone screw is a preset tensile strength, and the bending strength of the bone screw is a preset bending strength; so as to refine the grain size of the bone screw and improve the mechanical properties of the tensile strength and the bending strength of the bone screw.
Further, the preset grain size is matched with the healing period of the fracture surface; so as to ensure that the bone screw does not have obvious degradation phenomenon before fracture surface healing, and prolong the degradation period of the bone screw, thereby ensuring that the bone screw can always provide fixing and pressurizing effects on fracture surfaces.
Further, in the step S1, the length of the metal magnesium bar is specifically 1m, the diameter of the metal magnesium bar is 8.5mm, and the magnesium content of the metal magnesium bar is 99.98-99.99%.
Further, in step S2, the annealing temperature in the first stage is 100 ℃, the heat preservation time is 5min, the annealing temperature in the second stage is 160 ℃, and the heat preservation time is 8min.
Compared with the prior art, the invention discloses a preparation method of the degradable bone screw for promoting fracture surface healing, which has the beneficial effects that:
(1) The degradable bone screw is made of metal magnesium, namely the bone screw is made of 99.98-99.99% of pure magnesium, so that the bone screw has better biocompatibility, compared with the bone screw made of magnesium alloy, the degradable bone screw has simple components, and the degradation products are magnesium ions, hydroxyl ions and hydrogen, are less, are favorable for metabolism and absorption by patients, do not need to be taken out for secondary operation, and reduce the burden and pain of patients.
(2) The invention is characterized in that a first external thread is arranged on the screw rod of the degradation bone screw in a penetrating way along the length direction of the screw rod, namely, a full thread structure is arranged on the screw rod, and a second external thread is arranged on the screw cap, wherein the second external thread is used for being connected to the tail part of the screw rod in a threaded way, and the spiral direction of the second external thread is opposite to that of the first external thread; when the screw is screwed into the fracture surface, the screw cap is screwed to the tail part of the screw in the direction opposite to the screwing direction of the screw, so that the screw cap can provide an upward lifting force for the screw in the process of reversely screwing the screw cap; meanwhile, the screw rod can generate a downward pressing force on the fracture surface when being screwed into the fracture surface in the forward direction, so that the screw rod can push two bone surfaces at the fracture surface to be automatically close to each other and attached under the action of the upward lifting force and the downward pressing force, the two bone surfaces can be attached more tightly, the pressing attaching effect on the fracture surface is realized, and the healing rate of the fracture surface can be further accelerated; and, make the external diameter of the part not provided with the second external screw thread on the nut greater than the external diameter of the screw rod; so that the screw rod can be prevented from sinking into the bone, especially into cancellous bone, by the nut, and the use reliability of the bone screw is ensured.
(3) According to the invention, the metal magnesium bar is annealed and rolled for multiple times, namely, the metal magnesium bar is annealed for the first stage and annealed for the second stage in sequence, the temperature of the first stage is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second stage is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling, so that the metal magnesium bar subjected to multiple times of repeated annealing and repeated rolling has better mechanical compatibility, the tensile strength of the manufactured bone screw is ensured to be preset tensile strength (the preset tensile strength is 220-240N, and the preset bending strength is 280-300N), the problem that the bone screw is pulled out from a fracture surface due to movement of a patient is avoided, and the bone screw can be stably arranged at the fracture surface; meanwhile, the bending strength of the bone screw is preset, so that the problems that the compression degradable bone screw is broken and the bone screw is bent and cracked due to movement of a patient are avoided, the bone screw is prevented from being bent and damaged in the movement process of the patient, and the bone screw can be stably fixed on a fracture surface.
(4) As the crystal grains in the metal magnesium bar can be rolled when the metal magnesium bar is rolled, the crystal grains in the bone screw are smaller and more in quantity, so that the degradation rate of the bone screw in a patient body can be reduced, the degradation period of the bone screw is prolonged, and the bone screw is ensured not to be obviously degraded before fracture surface healing, so that the bone screw can provide continuous fixing and pressurizing fit effects on the fracture surface.
(5) The healing period of the fracture surface can be specifically within 3-6 months, the preset grain size is matched with the healing period of the fracture surface, that is, the preset grain size is matched with the degradation period of the pressurizing degradable bone screw, correspondingly, the degradation period of the pressurizing degradable bone screw is more than 3-6 months, that is, the pressurizing degradable bone screw does not have obvious degradation within 3-6 months; in the healing period of the fracture surface, the pressurized degradable bone screw does not have obvious degradation phenomenon; after the healing period of the fracture surface has elapsed, the pressurized degradable bone screw begins to undergo significant degradation until it is completely degraded to be absorbed by the patient's metabolism.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of the structure of the pressurized degradable bone screw provided by the present invention;
FIG. 2 is a cross-sectional view taken along the A-A plane of FIG. 1;
FIG. 3 is a schematic view of the structure of the screw provided by the invention;
FIG. 4 is a cross-sectional view taken along the B-B plane of FIG. 3;
FIG. 5 is a schematic view of a nut according to the present invention;
FIG. 6 is a front view of a nut provided by the present invention;
FIG. 7 is a cross-sectional view of the C-C plane of FIG. 6;
FIG. 8 is a flow chart of a method of manufacturing a compression degradable bone screw according to the present invention;
wherein 1: screw rod, 11: first external thread, 111: tooth thickness, 12: spin-stop groove, 121: arced face, 13: first rotating groove, 14: tail groove, 15: internal thread, 2: nut, 21: second external threads, 22: and a second rotating groove.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements.
Example 1
A degradable bone screw for promoting fracture healing, as shown in fig. 1, the bone screw comprises a screw rod 1 and a screw cap 2; the screw rod 1 is provided with a first external thread 11 in a penetrating manner along the length direction, namely, the screw rod 1 is provided with a full thread structure so as to ensure the stability of screwing the screw rod 1 into a fracture surface; and the head of the screw rod 1 is provided with a nail head for drilling into the bone, so that the screw rod 1 is driven by the nail head to be smoothly screwed into the fracture surface.
As shown in fig. 1 to 3, a plurality of rotation stopping grooves 12 are formed on the first external thread 11, wherein the rotation stopping grooves 12 are used for preventing the screw 1 from reversely unscrewing relative to the bone, namely, the rotation stopping grooves 12 are specifically a section of groove on the first external thread 11, when the screw 1 is screwed and fixed in a fracture surface, as the bone has certain extrusion in the process of screwing in through the screw 1, the bone can rebound in a part of the groove at the rotation stopping grooves 12 due to the existence of the groove, so that the problem of preventing the screw 1 and the whole pressurizing degradable bone screw from reversely rotating in the bone can be solved through the rotation stopping grooves 12, and the fixation effect of the screw 1 in the bone is ensured; and due to the arrangement of the rotation stopping groove 12, the screw 1 can not rotate reversely when the screw cap 2 is screwed into the tail part of the screw 1, the reliability of the screw 1 in the screwing process of the screw cap 2 is ensured, and the problem that the screw 1 loosens in a bone surface can not occur.
The rotation stopping groove 12 is provided with an arc-shaped surface 121, the arc-shaped surface 121 extends downwards in an inclined mode towards the screwing direction of the screw 1, the included angle between the arc-shaped surface 121 and the horizontal plane is 25 degrees to 35 degrees, on one hand, the bone can be guaranteed to rebound on a part of the arc-shaped surface 121, and the reverse loosening prevention effect of the rotation stopping groove 12 on the screw 1 is guaranteed to be good; on the other hand, the screw 1 can be smoothly screwed into the bone by ensuring that the rotation stopping groove 12 does not interfere the operation of screwing the screw 1 into the bone, so that the pain of a patient caused by the rotation stopping groove 12 when the screw 1 is screwed into the bone can be avoided. In this embodiment, the angle between the arc-shaped surface 121 and the horizontal plane is 35 °.
As shown in fig. 1 to 3, the number of the rotation stopping grooves 12 is three, and the three rotation stopping grooves 12 are respectively positioned at the head, the middle and the tail of the screw 1 so as to limit the reverse rotation of the screw 1 in the bone from three positions of the screw 1, thereby having better anti-loosening effect on the screw 1. Wherein, three anti-rotation grooves 12 are positioned on the same straight line, the cutting depth of the anti-rotation grooves 12 on the first external thread 11 is 0.5mm, and one anti-rotation groove 12 cuts at least one first external thread 11.
As shown in fig. 1 to 3, the tooth thickness 111 of the first external thread 11 gradually increases in the longitudinal direction of the screw 1 and in the direction from the head of the screw 1 to the tail of the screw 1, that is, the tooth thickness 111 of the first external thread 11 at the head of the screw 1 is smaller and the tooth thickness 111 of the first external thread 11 at the tail of the screw 1 is larger. In this embodiment, the tooth thickness 111 of the first external thread 11 gradually increases from 0.1mm to 0.3mm from the head to the tail of the screw 1. By forming the first external thread 11 into a gradual tooth thickness configuration, the first external thread 11 having the smaller tooth thickness 111 can be more easily screwed into the bone when the compression degradable bone screw is gradually screwed into the bone; on the other hand, as the tooth thickness 111 of the first external thread 11 at the tail part of the screw rod 1 is larger, even if the first external thread 11 with larger tooth thickness 111 gradually applies larger pressurizing force to the fracture surface, the first external thread 11 can gradually pressurize the fracture surface, so that the fracture surface can be driven to be mutually extruded and closed, the two bone surfaces are ensured to be better mutually attached, and the healing rate of the fracture surface is further improved; and can ensure a good fixing effect between the screw 1 and the bone.
As shown in fig. 2 and 4, a first rotating groove 13 is arranged at the inner side of the screw 1, the first rotating groove 13 extends from the tail part of the screw 1 to the middle part, and a matched screwing device is inserted into the first rotating groove 13 so as to screw the screw 1 into a bone through the screwing device, thereby leading the screw 1 to be screwed into a fracture surface with simple and convenient operation; in order to ensure the stability of the screwing of the screw 1 by the screwing device, in this embodiment, the depth of the first rotary groove 13 is half of the length of the entire screw 1, and the diameter of the circumscribed circle of the first rotary groove 13 is 2mm. The cross-sectional shape of the first rotating groove 13 is quadrangular, and the cross-sectional shape of the first rotating groove 13 may be circular or other shapes, which is not limited herein, so long as the screwing device is ensured to be capable of being inserted into the first rotating groove 13 in a matching manner.
As shown in fig. 2 and 4, a tail groove 14 is formed on the inner side of the tail of the screw 1, an inner thread 15 matched with a second outer thread 21 is formed on the inner wall surface of the tail groove 14, and the depth of the tail groove 14 is matched with the length of the part of the nut 2 provided with the second outer thread 21; the second external thread 21 is in threaded connection with the internal thread 15, so that the nut 2 can be fixedly arranged on the screw 1; the tail groove 14 is communicated with the first rotating groove 13, and the inner diameter of the tail groove 14 is larger than that of the first rotating groove 13. Wherein the arrangement depth of the tail groove 14 in the screw 1 is 4mm.
As shown in fig. 1, a second external thread 21 is provided on the nut 2, the second external thread 21 is used for being connected to the tail part of the screw rod 1 in a threaded manner, the external diameter of the part of the nut 2, where the second external thread 21 is not provided, is larger than the external diameter of the screw rod 1, so that the screw rod 1 can be prevented from sinking into bones, particularly cancellous bones, through the nut 2, and the use reliability of the pressurized degradable bone screw is ensured; and the spiral direction of the second external thread 21 is opposite to the spiral direction of the first external thread 11, the depth of the first external thread 11 relative to the outer wall surface of the screw 1 is 0.5mm, and the pitch is specifically 1mm.
As shown in fig. 5 to 7, a second rotating groove 22 is provided on the inner side of one end of the nut 2 far away from the screw 1, and the second rotating groove 22 is used for plugging in a matched instrument, so that the nut 2 is driven to rotate by rotating the instrument, and the nut 2 is simply and conveniently rotated. The cross section of the second rotating groove 22 is in a hexagonal quincuncial shape, so that the insertion between the instrument and the second rotating groove 22 is relatively tight, and the instrument cannot rotate in the second rotating groove 22 in the screwing process. Here, the specific shape of the second whirling groove 22 is not limited.
Specifically, when the fracture surface is fixed, the matched screw-in device is inserted into the first rotating groove 13 of the screw rod 1, and the screw rod 1 is screwed into the bone clockwise by screwing the screw-in device, and at the moment, the screw rod 1 penetrates through the whole fracture surface; after that, the screwing device is taken out again, and the screw cap 2 is screwed anticlockwise, so that the screw cap 2 is screwed into the tail groove 14 at the tail part of the screw rod 1, and the connection between the screw cap 2 and the screw rod 1 is realized. Wherein the length of the whole screw cap 2 is 7mm.
In the invention, the bone screw is provided with a split structure comprising a screw rod 1 and a screw cap 2; when the screw 1 is screwed into the fracture surface, the screw cap 2 is screwed to the tail of the screw 1 in the direction opposite to the screwing direction of the screw 1, so that the screw cap 2 can provide an upward lifting force for the screw 1 in the process of reversely screwing the screw cap 2; simultaneously, because screw rod 1 can produce a decurrent pressure to the fracture face when forward screw in fracture face to can make screw rod 1 can promote two bone faces of fracture face department and draw close the laminating each other voluntarily under the effect of ascending pulling force and decurrent pressure, so that two bone faces can laminate comparatively closely, and then realize the pressurization laminating effect to the fracture face, and then can accelerate the healing rate of fracture face. In this embodiment, the screw 1 is screwed into the fracture surface in the forward direction, and correspondingly, the nut 2 is screwed into the tail of the screw 1 in the reverse direction.
Example 2
A method of manufacturing a degradable bone screw for promoting fracture healing, comprising the steps of:
S1: selecting a cylindrical metal magnesium bar with the length of 1m, the diameter of 8.5mm and the magnesium content of 99.98-99.99%;
S2: and (2) sequentially carrying out first-stage annealing with the annealing temperature of 100 ℃ and the heat preservation time of 5min and second-stage annealing with the annealing temperature of 160 ℃ and the heat preservation time of 8min on the metal magnesium bar in the step (S1), and carrying out first rolling on the metal magnesium bar by a stand-up horse for 10min after the second-stage annealing is finished, and rolling the diameter of the metal magnesium bar from 8.5mm to 8.2mm so as to finish the first annealing and the first rolling. Then sequentially carrying out first-stage annealing and second-stage annealing on the metal magnesium bar subjected to the first rolling, carrying out second rolling on the metal magnesium bar by a vertical horse for 10min after the second-stage annealing is finished, and rolling the diameter of the metal magnesium bar from 8.2mm to 7.8mm so as to finish the second annealing and the second rolling; repeating the above process until the diameter of the metal magnesium bar is rolled to 7 mm;
s3: and (2) manufacturing the metal magnesium bar obtained in the step (S2) into a bone screw by adopting a core-moving processing mode, namely processing the annealed and rolled metal magnesium bar into a screw rod 1 and a screw cap 2 with split structures.
The deformation rate of the metal magnesium bar is calculated according to a formula (S1-S2)/S1, wherein S1 is the maximum cross-sectional area of the metal magnesium bar, and S2 is the minimum cross-sectional area of the metal magnesium bar.
The number of times of annealing and rolling the metal magnesium rod is not limited, and it is only necessary to ensure that the screw 1 and the nut 2 made of the metal magnesium rod can meet the grain size and mechanical properties by annealing and rolling.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A degradable bone screw for promoting fracture healing, wherein the bone screw comprises a screw rod and a screw cap; the head of the screw is provided with a nail head for drilling into bone; the screw rod is provided with a first external thread in a penetrating way along the length direction of the screw rod, and the first external thread is used for ensuring the stability of screwing the screw rod thread into the fracture surface; a plurality of rotation stopping grooves are formed in the grooves of the first external threads and used for preventing the screw rod from reversely unscrewing relative to the bone, and each rotation stopping groove is provided with an arc-shaped surface; the arc surface extends downwards in a tilting manner in the screwing direction of the screw; the inner side of the screw is provided with a first rotating groove which extends from the tail part of the screw to the middle part, and the first rotating groove is used for being inserted into a screwing device so as to screw the screw into the bone through the screwing device; the tail part of the screw is provided with a tail groove, the inner wall surface of the tail groove is provided with an internal thread matched with the second external thread, and the tail groove is communicated with the first rotating groove; the nut is provided with a second external thread which is used for being connected to the tail part of the screw rod in a threaded manner; the second external thread is used for being connected to the tail part of the screw rod in a threaded mode; the inner side of one end of the nut far away from the screw rod is provided with a second rotating groove so as to drive the nut to rotate through a rotator.
2. The degradable bone screw for promoting fracture healing according to claim 1, wherein the number of the rotation stopping grooves is three, and the rotation stopping grooves are respectively positioned at the head part, the middle part and the tail part of the screw rod and are used for limiting the reverse rotation of the screw rod in the bone from three positions of the screw rod, so that the anti-loosening effect on the screw rod is better; the three rotation stopping grooves are positioned on the same straight line, and the cutting depth of the rotation stopping grooves on the first external thread is 0.5mm.
3. The degradable bone screw according to claim 1, wherein the first external thread at the head of the screw has a smaller tooth thickness and the first external thread at the tail of the screw has a larger tooth thickness; the tooth thickness of the first external thread gradually increases from 0.1mm to 0.3mm from the head to the tail of the screw rod.
4. The degradable bone screw according to claim 1, wherein the depth of the first turning groove is half of the length of the entire screw, and the diameter of the circumscribed circle of the first turning groove is 2mm.
5. The degradable bone screw for promoting healing of fracture surfaces according to claim 1, wherein an included angle between the arc-shaped surface and the horizontal plane is 25 ° -35 °, so as to ensure that the bone can rebound on a part of the arc-shaped surface, and ensure that the anti-reverse loosening effect of the anti-rotation groove on the screw rod is better.
6. The degradable bone screw according to claim 1, wherein the portion of the nut not provided with the second external thread has an outer diameter larger than an outer diameter of the screw rod, and the second external thread has a screw direction opposite to a screw direction of the first external thread.
7. A method for preparing a degradable bone screw for promoting fracture healing, which is characterized by comprising the following steps:
S1: selecting a cylindrical metal magnesium bar;
S2: the metal magnesium bar in the step S1 is annealed for multiple times and rolled for multiple times, the first-stage annealing and the second-stage annealing are needed to be sequentially carried out before the metal magnesium bar is rolled each time, the metal magnesium bar is required to be rolled immediately after the second-stage annealing is carried out, and the rolling time is 10min-11min each time; the annealing and rolling sequence is that the first-stage annealing and the second-stage annealing are sequentially carried out and then the rolling is carried out; the temperature of the first-stage annealing is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second-stage annealing is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling;
S3: and (2) preparing the screw rod and the screw cap of the pressurizing degradable bone screw by adopting a core-moving processing mode for the metal magnesium bar obtained in the step (S2) to obtain the bone screw which can promote fracture healing and is degradable.
8. The method for preparing a degradable bone screw for promoting fracture healing according to claim 7, wherein in the step S1, the length of the metal magnesium rod is specifically 1m, the diameter is 8.5mm, and the magnesium content of the metal magnesium rod is 99.98-99.99%.
9. The method for preparing a degradable bone screw for promoting fracture healing according to claim 7, wherein in the step S2, the annealing temperature in the first stage is 100 ℃, the heat preservation time is 5min, the annealing temperature in the second stage is 160 ℃, and the heat preservation time is 8min.
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| CN202410155792.3A CN118000877A (en) | 2023-08-08 | 2023-08-08 | Degradable bone screw for promoting fracture surface healing and preparation method thereof |
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| CN202310987773.2A CN116687540A (en) | 2023-08-08 | 2023-08-08 | Pressurized degradable bone screw and manufacturing method thereof |
| CN202410155792.3A CN118000877A (en) | 2023-08-08 | 2023-08-08 | Degradable bone screw for promoting fracture surface healing and preparation method thereof |
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| CN202410155792.3A Pending CN118000877A (en) | 2023-08-08 | 2023-08-08 | Degradable bone screw for promoting fracture surface healing and preparation method thereof |
| CN202310987773.2A Pending CN116687540A (en) | 2023-08-08 | 2023-08-08 | Pressurized degradable bone screw and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5498265A (en) * | 1991-03-05 | 1996-03-12 | Howmedica Inc. | Screw and driver |
| CN2640426Y (en) * | 2003-06-24 | 2004-09-15 | 中南大学湘雅医院 | Locking partially threaded screw for spongy bone |
| CN104328318B (en) * | 2014-10-20 | 2016-04-20 | 东北大学 | A kind of preparation method of high anti-corrosion biodegradable magnesium alloy |
| CN210749453U (en) * | 2017-07-25 | 2020-06-16 | 江苏百易得医疗科技有限公司 | Hollow bone screw |
| CN109022843B (en) * | 2018-08-01 | 2020-01-10 | 郑州大学第一附属医院 | Medical implantable degradable composite bar and preparation method thereof |
| CN109938818B (en) * | 2019-01-11 | 2021-01-08 | 中国医学科学院北京协和医院 | Degradable magnesium alloy patella claw and preparation method thereof |
| FR3109075B1 (en) * | 2020-04-09 | 2023-06-30 | Lock In Sa | Cortical Stabilization Bone Anchor Implant |
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