CN211433240U - Half-thread magnesium alloy bone internal fixation screw - Google Patents
Half-thread magnesium alloy bone internal fixation screw Download PDFInfo
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- CN211433240U CN211433240U CN201922031019.3U CN201922031019U CN211433240U CN 211433240 U CN211433240 U CN 211433240U CN 201922031019 U CN201922031019 U CN 201922031019U CN 211433240 U CN211433240 U CN 211433240U
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Abstract
The embodiment of the utility model provides a half-thread magnesium alloy bone internal fixation screw, this screw include the nail body and with nail body integrated into one piece's nail cap, be equipped with the screw thread on the nail body, the length of screw thread is (0.3 ~ 0.5):1 with the proportion of the length of the nail body, is equipped with the type hole on the nail cap, the nail cap is the pressurization nail cap, the conical surface of pressurization nail cap and the contained angle of the central line of the nail body are 20 ~ 40. The utility model discloses a half thread magnesium alloy bone internal fixation screw can exert pressure to bone tissue once more after it is implanted completely, can further strengthen the fixed action of screw to bone piece and bone lamella, because the screw has higher fixed strength, when implanting hard sclerotin such as cortex bone with the screw, can avoid causing the deformation and the fracture of screw thread, avoids causing smooth silk and the twist-off of nail cap, the utility model discloses a half thread magnesium alloy bone internal fixation screw has half-thread structure, has better control effect to the great fixed position of tension, can improve the fixed strength of screw.
Description
Technical Field
The utility model belongs to the technical field of orthopedics apparatus, concretely relates to half-thread magnesium alloy bone internal fixation screw.
Background
The currently clinically used bone internal fixation screw is mainly made of inert metal materials such as stainless steel, titanium-based alloy and cobalt-based alloy, and the inert metal materials have good strength and plasticity and are easy to machine and form, but the inert metal materials are not degradable after being implanted into a body, can generate problems such as mechanical friction injury, toxic ion precipitation, local inflammatory reaction and stress shielding effect in the long-term service process, seriously affect the healing of bone tissues, can cause osteoporosis, and even can cause the risk of secondary fracture.
In view of the above, researchers have developed medical magnesium alloy screws with the following significant advantages: (1) good biological safety. Magnesium is an essential nutrient element of human body, not only can be used as an important activator of various enzymes in cell metabolism activity, but also participates in various complex physiological activities such as DNA and protein synthesis in cells, cell energy storage and transportation, nerve signal conduction, muscle expansion and contraction and the like; (2) good mechanical compatibility. The density and the elastic modulus of the magnesium alloy are closest to those of human bones, so that the stress shielding effect and the osteoporosis caused by the stress shielding effect can be effectively avoided. Meanwhile, the magnesium alloy has the specific strength and specific rigidity similar to those of stainless steel, and can provide sufficient mechanical support for the diseased part; (3) good biodegradability. The magnesium alloy screw is easy to corrode and degrade in the internal environment containing chloride ions, and the degradation product can be completely absorbed by the human body, thereby avoiding the physiological pain and the economic burden of a patient caused by taking out the magnesium alloy screw in a secondary operation; (4) good osteoblast inducibility. In recent years, a large number of research results show that magnesium ions released by the magnesium alloy screw in the degradation process can induce osteogenic differentiation and proliferation of stem cells in periosteum, can accelerate the healing of fracture parts, and is an ideal bone tissue repair device.
However, the conventional medical magnesium alloy screw is a standard screw, as shown in fig. 1 or fig. 2. In fig. 1 and 2, 3 is a standard nail cap and 5 is bone tissue. The head of the standard screw in fig. 1 is of a flat head design, without angular inclination, so that the fixation to the bone tissue is only achieved by means of a thread. The head of the standard screw in fig. 2 is of round design, without angular inclination, so that the fixation to the bone tissue is only achieved by means of the thread. The standard screw has the problems that the holding force of the screw body is insufficient, the pressurizing force is insufficient after the screw cap is screwed in, the screw is deformed and broken due to the fact that the force cannot be uniformly transmitted, and the like. These conditions not only add additional difficulty to the surgical operator, but can even affect the post-operative recovery.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a half-thread magnesium alloy bone internal fixation screw, this screw and magnesium alloy have good biosafety, mechanical compatibility, biodegradability and osteoblast inductivity.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, including the nail body and with nail body integrated into one piece's head of a nail, be equipped with the screw thread on the nail body, the length of screw thread with the proportion of the length of the nail body is (0.3 ~ 0.5):1, be equipped with the type hole on the head of a nail, the head of a nail is the pressurization head of a nail, the conical surface of pressurization head of a nail with the contained angle of the central line of the nail body is 20 ~ 40.
The utility model provides a half-thread magnesium alloy bone internal fixation screw, wherein "half-thread" indicates that the ratio of the length of screw thread and the length of the nail body is (0.3-0.5): 1. When the ratio of the length of the thread to the length of the nail body is 1:1, the nail is a full thread. Compared with a full-thread screw, the actual inner diameter of the half-thread screw is larger than that of the full-thread screw, so that the strength of the half-thread screw is far higher than that of the full-thread screw on the premise of adopting the same preparation material. The actual inner diameter range of the half-thread screw is 60-90% of the diameter of the screw body.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw has following technological effect at least:
the semi-thread magnesium alloy bone internal fixation screw provided by the embodiment of the utility model can apply pressure to bone tissues again after being completely implanted, and can further strengthen the fixation effect of the screw on bone blocks and bone flaps;
the half-thread magnesium alloy bone internal fixation screw provided by the embodiment of the utility model has the advantages that as the screw has higher fixation strength, when the screw is implanted into hard sclerotin such as cortical bone and the like, the deformation and fracture of the thread can be avoided, and the slipping and twisting of the screw cap are avoided;
when the half-thread magnesium alloy bone internal fixation screw is implanted into hard bone such as cortical bone and the like, the force of the half-thread magnesium alloy bone internal fixation screw can uniformly reach the conical screw tip, so that the deformation and the fracture of the screw are avoided;
the half-thread magnesium alloy bone internal fixation screw provided by the embodiment of the utility model has a half-thread structure, has better holding effect on a fixed position with larger tension, and can improve the fixation strength of the screw;
the utility model discloses half-thread magnesium alloy bone internal fixation screw has good biosafety, mechanical compatibility, biodegradability and osteoblast inducibility, can accelerate the healing that promotes the fracture position, is the bone tissue repair apparatus of ideal.
The pressurizing screw cap can be embedded into surrounding bone tissues again under pressure at a certain angle through the structural characteristics of the pressurizing screw cap after the screw is implanted into hard sclerotin such as cortical bone and the like, and the fixing effect of the screw on bone blocks and bone flaps can be further strengthened.
The screw cap and the screw thread of the standard screw are structurally designed in a conventional mode, after the standard screw is implanted into hard sclerotin such as cortical bone and the like, the screw and bone tissues can reach mechanical balance under the fixing effect of the screw thread, and the lower edge of the screw cap is designed in a horizontal structure, so that the effect of applying pressure again after the standard screw is implanted cannot be achieved. And the cap of a nail and the screw thread of screw adopt unique structural design in this application, make it implant hard sclerotin such as cortex bone completely after, not only can reach the balance of mechanics through the fixed action of screw thread, but also can carry out the embedding effect that pushes down of certain angle to bone tissue through the tapering design of cap of a nail for the screw of this application can exert pressure to bone tissue again after implanting completely, can further strengthen the fixed action of screw to bone piece and bone lamella.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the length of the nail body is 15 ~ 40 mm.
The length of the nail body is in a proper range of 15-40 mm, the nail body is insufficient in holding force when the length of the nail body is shorter than 15mm, the nail body is excessively high in holding force when the length of the nail body is longer than 40mm, and the fixing effect of the screw on bone tissue is influenced in both cases.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the width of screw thread is 0.4 ~ 0.8mm, the interval of screw thread is 0.45 ~ 0.85 mm.
The width and spacing of the threads are suitably selected to be below a range that would result in excessive compression of the shank and above a range that would result in insufficient compression of the shank, both of which would affect the fixation of the screw in bone tissue.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the degree of depth of screw thread does 10 ~ 30% of the diameter of the nail body.
The depth of the screw thread is 10-30% of the diameter of the nail body, so that the fixing strength of the nail body is improved, and deformation and breakage of the screw thread are avoided.
According to the utility model discloses half thread magnesium alloy bone internal fixation screw, the lead angle of screw thread is 5 ~ 30, the flank angle of screw thread is 20 ~ 60.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the type hole includes a word hole, a mouthful word hole, cross hole and hexagonal hole.
The design of the straight hole, the square hole, the cross hole and the hexagonal hole can prevent the screw cap from sliding and twisting off when the magnesium alloy screw is implanted into hard sclerotin such as cortical bone and the like, and improve the fixing strength of the magnesium alloy screw.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the thickness of nail cap is 2.0 ~ 4.5 mm.
The design can ensure that the strength of the magnesium alloy screw can uniformly reach the conical screw tip when the magnesium alloy screw is implanted into hard sclerotin such as cortical bone and the like, thereby avoiding the deformation and the fracture of the magnesium alloy screw.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the nail body is kept away from the one end of nail cap is conical screw point, the apex angle of conical screw point is 40 ~ 120.
According to the utility model discloses half-thread magnesium alloy bone internal fixation screw, the length of conical screw point is 1.0 ~ 2.5 mm.
According to the utility model discloses a magnesium alloy for preparing half thread magnesium alloy bone internal fixation screw of second aspect embodiment, including the following composition by mass percent:
Nd 0.1～8.0％，
Zn 0.1～6.0％，
Ca 0.1～6.0％，
Zr 0.1～5.0％，
the balance being Mg.
In the magnesium alloy, the total amount of impurity elements is less than 0.05%.
The utility model discloses half-thread magnesium alloy bone internal fixation screw, magnesium alloy include high-purity magnesium material, magnesium zinc alloy, magnesium calcium alloy, magnesium manganese alloy, magnesium tin alloy, magnesium lithium alloy, magnesium neodymium alloy, magnesium yttrium alloy and magnesium gadolinium in the arbitrary one in the alloy. Compare with the screw of inert metal material preparation, the embodiment of the utility model provides a half-thread magnesium alloy bone internal fixation screw of magnesium alloy processing takes place corrosion degradation easily in the internal environment that contains chloride ion to degradation product can be absorbed by the human body completely. According to the corrosion degradation condition of the prior medical magnesium alloy material, after the medical magnesium alloy material is prepared into the in-bone fixing screw and implanted into a human body, the medical magnesium alloy material can be completely degraded and absorbed and discharged by the human body within about 3-4 months.
Drawings
Fig. 1 is a schematic view of a standard screw of the prior art with a flat head design.
Fig. 2 is a schematic view of a standard prior art screw with a round head design.
Fig. 3 is a schematic view of the thread width of a half-thread magnesium alloy bone internal fixation screw.
Fig. 4 is a schematic view of the thread depth of a half-thread magnesium alloy endosseous fixation screw.
Fig. 5 is a schematic view of the lead angle of a half-thread magnesium alloy bone internal fixation screw.
Fig. 6 is a schematic view of the actual inner diameter of a half-thread magnesium alloy bone internal fixation screw.
Fig. 7 is a schematic view of the diameter of the nail body of a half-thread magnesium alloy bone internal fixation screw.
Fig. 8 is a side schematic view of a half-thread magnesium alloy endosseous fixation screw.
FIG. 9 is a cross-sectional view of a half-thread magnesium alloy bone internal fixation screw.
FIG. 10 is a schematic view of the working principle of a pressurizing nut of a half-thread magnesium alloy bone internal fixation screw.
FIG. 11 is a schematic view of a half-thread magnesium alloy bone internal fixation screw.
FIG. 12 is a schematic view of an implant of a half-thread magnesium alloy bone internal fixation screw.
Detailed Description
The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the embodiments, but the present invention is not limited to these embodiments.
In order to facilitate accurate understanding of the "width of the thread", "depth of the thread", "lead angle of the thread", "actual inner diameter of the half-thread screw" and "nail body diameter" referred to in the embodiments of the present invention, the description will be made with reference to the drawings. The width W of the thread is referred to as the distance shown in fig. 3. The depth H of the thread refers to the distance as shown in fig. 4. The lead angle a of the thread is indicated as shown in fig. 5. The actual inner diameter C of the half-thread screw is shown in fig. 6. The shank diameter D is shown in fig. 7.
Example 1
The embodiment provides a half-thread magnesium alloy bone internal fixation screw, as shown in fig. 8 and 9, which comprises a screw body 1 and a screw cap 2 integrally formed with the screw body 1, wherein a thread 11 is arranged on the screw body 1, the ratio of the length of the thread 11 to the length of the screw body 1 is (0.3-0.5): 1, a hole 21 is arranged on the screw cap 2, the screw cap 2 is a pressure screw cap, and the included angle between the conical surface of the pressure screw cap and the central line of the screw body 1 is 20-40 degrees.
The pressurizing screw cap can be embedded into surrounding bone tissues again under pressure at a certain angle through the structural characteristics of the pressurizing screw cap after the screw is implanted into hard sclerotin such as cortical bone and the like, and the fixing effect of the screw on bone blocks and bone flaps can be further strengthened. As shown in fig. 10, 5 is a bone tissue. The pressure head is of a conical design, inclined at an angle, so that the fixation to the bone tissue 5 can be achieved not only by means of the thread 11, but also by means of a press-fit.
According to the half-thread magnesium alloy bone internal fixation screw, the length of the screw body 1 is 15-40 mm.
The width of the thread 11 is 0.4-0.8 mm, and the distance between the threads 11 is 0.45-0.85 mm.
The depth of the thread 11 is 10-30% of the diameter of the nail body 1.
The lead angle of the thread 11 is 5-30 degrees, and the flank angle of the thread 11 is 20-60 degrees.
The profile hole 21 includes a straight hole 211, a square hole 212, a cross hole 213, and a hexagonal hole 214, as shown in fig. 11.
The thickness of the nail cap 2 is 2.0-4.5 mm.
One end of the nail body 1, which is far away from the nail cap 2, is a conical screw tip 12, and the vertex angle of the conical screw tip 12 is 40-120 degrees.
The length of the conical screw tip 12 is 1.0-2.5 mm.
Example 2
The working principle of the half-thread magnesium alloy bone internal fixation screw is explained in the embodiment.
As shown in fig. 12, the present embodiment provides a half-thread structure in a half-thread magnesium alloy endosseous fixation screw, so that the thread 11 is positioned in two fixed objects, the holding force of the screw is from the space between the thread 11 and the nut 2 and the holding force of the nut body 1, the design can have better holding effect on a fixed position with larger tension, and the fixation strength of the screw can be improved.
In the use process of the magnesium alloy screw, a measuring device is needed to select the screw with the proper length after drilling, the channel is expanded in a tapping mode so as to be matched with the thread 11, and then the screw is installed and used through a surgical tool. Because the magnesium alloy screw has low strength and is easy to deform, the magnesium alloy screw does not have self-tapping capability, and therefore, a tapping mode with matched size needs to be selected to expand the hole.
Example 3
The embodiment provides a magnesium alloy for preparing a full-thread magnesium alloy bone internal fixation screw, which comprises the following components in percentage by mass:
Nd 0.1～8.0％，
Zn 0.1～6.0％，
Ca 0.1～6.0％，
Zr 0.1～5.0％，
the balance of Mg, and the balance of Mg,
in the magnesium alloy, the total amount of impurity elements is less than 0.05%.
The utility model discloses half-thread magnesium alloy bone internal fixation screw, magnesium alloy include high-purity magnesium material, magnesium zinc alloy, magnesium calcium alloy, magnesium manganese alloy, magnesium tin alloy, magnesium lithium alloy, magnesium neodymium alloy, magnesium yttrium alloy and magnesium gadolinium in the arbitrary one in the alloy. Compare with the screw of inert metal material preparation, the embodiment of the utility model provides a half-thread magnesium alloy bone internal fixation screw of magnesium alloy processing takes place corrosion degradation easily in the internal environment that contains chloride ion to degradation product can be absorbed by the human body completely. According to the corrosion degradation condition of the prior medical magnesium alloy material, after the medical magnesium alloy material is prepared into the in-bone fixing screw and implanted into a human body, the medical magnesium alloy material can be completely degraded and absorbed and discharged by the human body within about 3-4 months.
The above description has been made of specific embodiments of the present invention. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by those skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (9)
1. The half-thread magnesium alloy bone internal fixation screw is characterized by comprising a screw body (1) and a screw cap (2) integrally formed with the screw body (1), wherein a thread (11) is arranged on the screw body (1), the ratio of the length of the thread (11) to the length of the screw body (1) is (0.3-0.5): 1, a shaped hole (21) is formed in the screw cap (2), the screw cap (2) is a pressurizing screw cap, and the included angle between the conical surface of the pressurizing screw cap and the central line of the screw body (1) is 20-40 degrees.
2. The half-thread magnesium alloy bone internal fixation screw according to claim 1, wherein the length of the screw body (1) is 15-40 mm.
3. The half-thread magnesium alloy bone internal fixation screw according to claim 2, wherein the width of the thread (11) is 0.4-0.8 mm, and the distance between the threads (11) is 0.45-0.85 mm.
4. The half-thread magnesium alloy bone internal fixation screw according to claim 2, wherein the depth of the thread (11) is (10-30)% of the diameter of the nail body (1).
5. The half-thread magnesium alloy bone internal fixation screw according to claim 2, wherein the lead angle of the thread (11) is 5-30 °, and the flank angle of the thread (11) is 20-60 °.
6. The half-thread magnesium alloy endosseous fixation screw according to claim 2, characterized in that the hole pattern (21) comprises a straight hole (211), a square hole (212), a cross hole (213) and a hexagonal hole (214).
7. The half-thread magnesium alloy bone internal fixation screw according to claim 2, wherein the thickness of the screw cap (2) is 2.0-4.5 mm.
8. The half-thread magnesium alloy bone internal fixation screw according to claim 2, wherein one end of the screw body (1) far away from the screw cap (2) is a conical screw tip (12), and the vertex angle of the conical screw tip (12) is 40-120 degrees.
9. The half-thread magnesium alloy bone internal fixation screw according to claim 8, wherein the length of the conical screw tip (12) is 1.0-2.5 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922031019.3U CN211433240U (en) | 2019-11-21 | 2019-11-21 | Half-thread magnesium alloy bone internal fixation screw |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922031019.3U CN211433240U (en) | 2019-11-21 | 2019-11-21 | Half-thread magnesium alloy bone internal fixation screw |
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| Publication Number | Publication Date |
|---|---|
| CN211433240U true CN211433240U (en) | 2020-09-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922031019.3U Active CN211433240U (en) | 2019-11-21 | 2019-11-21 | Half-thread magnesium alloy bone internal fixation screw |
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| CN (1) | CN211433240U (en) |
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