CN109875667B - Flexible nail and system for internal fixation of proximal humerus fracture - Google Patents
Flexible nail and system for internal fixation of proximal humerus fracture Download PDFInfo
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- CN109875667B CN109875667B CN201910159946.5A CN201910159946A CN109875667B CN 109875667 B CN109875667 B CN 109875667B CN 201910159946 A CN201910159946 A CN 201910159946A CN 109875667 B CN109875667 B CN 109875667B
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Abstract
The embodiment of the invention relates to a flexible nail for internal fixation of proximal humerus fracture, which comprises: the flexible nail comprises a flexible nail body, wherein the head part of the flexible nail is of a conical structure and is arranged at one end of the flexible nail body; the tail part of the flexible nail is of an arc-shaped structure, is arranged at the other end of the flexible nail body and is used for bending the flexible nail in the nail feeding process; and the anti-skid part is arranged on the flexible nail body and close to the tail part of the flexible nail and is used for applying pressure to the humerus to prevent nail withdrawal. Therefore, the flexible nail for internal fixation of proximal humerus fracture provided by the invention solves the problems of screw falling, joint damage caused by humerus head puncturing and the like in the operation, can obtain good holding force, has no risk of humerus head puncturing, has small damage to bone, and improves the success rate of the operation; the tail of the flexible nail is arranged to be arc-shaped, so that the flexible nail can be bent in the nail feeding process, the wall-adhering fixation is realized, and the pull-out resistance of the flexible nail is increased.
Description
Technical Field
The invention relates to a screw for orthopedic surgery, in particular to a flexible nail and a system for internal fixation of proximal humerus fracture.
Background
Proximal humeral fractures are common fractures in clinic, and the incidence rate of the proximal humeral fractures accounts for about 4-5% of the total fractures. The locking plate, in combination with the screws, has many advantages in treating proximal humeral fractures, and thus is the most common treatment. However, the bone inside the humeral head of the elderly is loose, the nail-grasping capability is obviously reduced, and the dropped screw is easy to fall off, which leads to the failure of the operation. In clinic, longer screws are sometimes used to drive the edges of the inner walls of opposite sides of the humerus head to improve holding force, but the humerus head is easily driven through to damage the articular surface, which results in failure of the operation, so that doctors with poor experience rarely adopt the method. Another method is to use a larger number of screws for fixation, but the number of nails to be driven is limited due to the limited internal space of the humeral head, and the excessive number of nails is not recommended because the nails are likely to cause more damage to the internal bone of the humeral head and do not conform to the biological fixation principle of BO.
Therefore, an internal fixation nail is needed at present, and the problems that the stability of the internal fixation nail of the humerus is low, the bone is seriously damaged and the like in the prior art are solved.
Disclosure of Invention
In order to solve the above problems, the present invention provides a flexible nail and a system for internal fixation of proximal humerus fracture, which can be driven in an arc shape along the edge of the inner wall of the humerus head according to a certain weaving rule, and since the bone near the inner wall of the humerus head is obviously denser than the bone at the center of the humerus head, the flexible nail driven in this way can obtain a good holding force, and has no risk of driving through the humerus head, little damage to the bone, high stability, and an improved success rate of the operation.
In a first aspect, the present invention provides a flexible nail for internal fixation of a proximal humerus fracture, comprising: a flexible nail body, wherein:
the flexible nail head part is of a conical structure and is arranged at one end of the flexible nail body;
the tail part of the flexible nail is of an arc-shaped structure, is arranged at the other end of the flexible nail body and is used for bending the flexible nail in the nail feeding process;
and the anti-skid part is arranged on the flexible nail body and close to the tail part of the flexible nail and is used for applying pressure to the humerus to prevent nail withdrawal.
In one possible embodiment, the anti-slip part comprises four sets of anti-slip protrusions arranged on the surface of the flexible nail body at equal intervals, and projections of every two adjacent sets of anti-slip protrusions on a plane perpendicular to the flexible nail body are crossed.
In a possible embodiment, two sets of the anti-slip protrusions which are arranged at intervals are positioned on the same plane, and the projection area on the same plane is gradually reduced towards the tail part of the flexible nail.
In a possible embodiment, the cross-sectional profile of the anti-slip bulge is a curve, a nail feeding angle and a nail pulling angle are arranged at the joint of the anti-slip bulge and the flexible nail body, the nail feeding angle is 23 degrees, and the nail pulling angle is 67 degrees.
In one possible embodiment, the flexible tack body has a cross-section in the shape of a rounded rectangle with an aspect ratio of 5: 2.
In one possible embodiment, the curved arc of the tail of the flexible nail has a diameter of 38mm and a length of 6.6 mm.
In a second aspect, the present invention provides an internal humerus fixation system in which one end of a flexible nail is connected to a locking steel plate via a tapered structure to be fixed in the humerus.
The invention has the beneficial effects that:
1. the flexible nail for internal fixation of proximal humerus fracture provided by the invention solves the problems of screw falling off, joint damage caused by humerus head puncturing and the like in the operation, can obtain good holding force, has no risk of humerus head puncturing, has small damage to sclerotin, and improves the success rate of the operation.
2. According to the invention, the tail part of the flexible nail is arranged to be of an arc-shaped structure, so that the flexible nail can be bent in the nail feeding process, the wall-adhering fixation is realized, and the pull-out resistance of the flexible nail is increased.
3. According to the invention, the cross section of the flexible nail is designed into a rounded rectangle, so that the flexible nail can be effectively prevented from rotating in the humerus, and the flexible nail can be bent towards a direction with small moment of inertia.
4. By arranging the anti-skid protrusions, on one hand, the holding force of the flexible nail body is increased by 2 times, and the stability of internal fixation of the humerus is effectively improved. On the other hand, through advancing nail angle and nail pulling angle, realized the function of can extracting of flexible nail, realize the auto-lock to automatic exerting pressure to the humerus, make it be difficult for moving back the nail.
Drawings
Fig. 1 is a schematic structural view of a flexible nail for internal fixation of a proximal humerus fracture, provided by the invention;
FIG. 2 is a schematic view of an anti-slip bump structure according to an embodiment of the present invention;
FIG. 3 is a schematic view of a nail pulling angle and a nail feeding angle in the anti-skid protrusions provided by the embodiment of the invention;
FIG. 4 is a schematic cross-sectional view of a flexible nail for internal fixation of a proximal humerus fracture according to the present invention;
fig. 5 is a schematic structural view of an internal fixing system for a proximal humerus fracture according to an embodiment of the present invention;
notation of the reference numerals: 1-a flexible nail head, 2-a flexible nail body, 3-an anti-slip component, 4-a flexible nail tail, 5-an anti-slip bulge, 6-an anti-slip bulge, 7-an anti-slip bulge, 8-an anti-slip bulge, 9-a cross section of the flexible nail, 10-a nail pulling angle, 11 a nail feeding angle, 12-a locking steel plate, 13-a flexible nail and 14-a humeral head.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, technical methods in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any creative effort, shall fall within the scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, back, etc.) are involved in the embodiment of the present invention, the directional indications are only used for explaining the relative positional relationship between the components in a certain posture, the motion situation, etc., and if the certain posture is changed, the directional indications are changed accordingly.
Fig. 1 is a schematic structural view of a flexible nail for proximal humerus fracture according to an embodiment of the present invention, as shown in fig. 1,
the invention provides a flexible nail for proximal humerus fracture, which comprises: the flexible nail body (2) is provided with a flexible nail body,
the flexible nail head part 1 is of a conical structure, is positioned at one end of the flexible nail body 2 and is used for being matched with a conical hole in the locking steel plate;
the flexible nail tail part 4 is of an arc-shaped structure, is arranged at the other end of the flexible nail body 2 and is used for bending the flexible nail in the nail feeding process;
and the antiskid part 3 is arranged on the flexible nail body 2 and is close to the flexible nail tail part 4, and is used for applying pressure to the humerus and preventing nail withdrawal.
Wherein, the bending diameter of the flexible nail tail part 4 is 38mm, is slightly smaller than the diameter of the humerus head, and the length of the bending arc is 6.6 mm. The tail of the flexible nail is arranged to be arc-shaped, so that the flexible nail can be bent in the nail feeding process and is fed in the arc-shaped manner, and the wall attachment fixation is realized. Compared with the straight nail with the same cross section, the flexible nail of the invention increases the pull-out resistance by 65%.
In one embodiment of the invention, a ball-nail model is used for simulating a pulling-out experiment after a nail is driven into a humerus head, numerical simulation is carried out on the nail pulling processes of the ball-straight nail model and the ball-bent nail model respectively, the pulling-out displacements of the two models are equal and are 0.1mm, the displacement distribution is similar, when the same effect is achieved, 100N pulling force needs to be applied to the straight nail, 165N pulling force needs to be applied to a flexible nail driven into the straight nail and the wall, and therefore, the pulling-out resistance of the flexible nail driven into the wall is increased by 65% compared with the straight nail with the same cross section.
As shown in fig. 1, the anti-slip part 3 comprises four sets of anti-slip protrusions 5, 6, 7 and 8 which are arranged on the surface of the flexible nail body 2 at equal intervals, and the projection of every two adjacent sets of anti-slip protrusions on the plane perpendicular to the flexible nail body 2 is in a cross shape. Two sets of anti-skid protrusions that the looks interval set up are in the coplanar, and reduce gradually (namely the projected area of anti-skid protrusion 7 is less than anti-skid protrusion 5, and the projected area of anti-skid protrusion 8 is less than anti-skid protrusion 6) to the staple afterbody direction at the projected area of coplanar, through setting up anti-skid protrusion's size progressively reduced, can reduce anti-skid protrusion in the at utmost and advance the destruction of nail in-process to the sclerotin, make every anti-skid protrusion all have the power of controlling.
Fig. 2 is a schematic structural view of a stud in a flexible nail for proximal humerus fracture according to an embodiment of the present invention, and as shown in fig. 2, a cross-sectional profile of the stud is a curved shape, and a nail feeding angle 11 and a nail pulling angle 10 are provided at a connection portion of the stud and the flexible nail body 2. Wherein, the angle of the nail feeding angle 11 is set to be 23 degrees and is smaller than the friction angle between the bone and the flexible nail piece, thereby realizing the self-locking function; the angle of the nail pulling angle 10 is set to 67 degrees, so that the humerus can be automatically pressed, and the nail is not easy to withdraw. As shown in fig. 3, when λ 1 is 67 °, the pulling force F is the largest, i.e. the bone is most difficult to slide on the anti-skid protrusion, and the pulling force required to pull the bone is:
F＝G sinλ1+Ff
＝G sinλ1+μG cosλ1
＝1.18G sin(λ1+23°)
wherein mu is 0.43, which is the friction coefficient between the bone and the screw. The anti-slip performance is best when the degree of the nail pulling angle is set to 67 deg..
In one embodiment of the invention, the numerical simulation of the nail pulling process is performed on the stud-added flexible nails and the stud-free flexible nails, and the displacement load of 1mm is respectively applied to the two ball-nail models. The counter force of the flexible nail with the anti-skid protrusions is 481N, and the counter force of the flexible nail without the anti-skid protrusions is 142N. The numerical comparison shows that the holding force of the anti-skid protrusions arranged on the flexible nail is 3.3 times that of the flexible nail without the anti-skid protrusions, so that the stability of internal fixation of the humerus is effectively improved.
As shown in fig. 4, the cross section 9 of the flexible nail is a rounded rectangle, the length-width ratio of the rounded rectangle is 5:2, the length of the rounded rectangle is 3.0mm, and the width of the rounded rectangle is 1.2mm, so that the cross section of the flexible nail body is designed to be the rounded rectangle, which can not only effectively prevent the flexible nail from rotating in the humerus, but also bend the flexible nail to the direction with small moment of inertia.
In addition, according to one embodiment of the present invention, the height of the anti-slip part 3 is set to 0.2-0.6 mm, which is specifically divided into three stages: the height of the first-gear antiskid projections is 0.4mm, 0.2mm and 0.2mm from 5 to 8 in sequence; the height of the second-gear antiskid projections is 0.5mm, 0.3mm and 0.3mm from 5 to 8 in sequence; the height of the third-gear antiskid projections is 0.6mm, 0.4mm and 0.4mm from 5 to 8 in sequence. The three sizes of the antiskid lugs respectively correspond to patients with three osteoporosis degrees: the first grade corresponds to patients with osteopenia, the second grade corresponds to patients with osteoporosis, and the third grade corresponds to patients with severe osteoporosis.
Fig. 5 is a schematic structural view of an internal humerus fixation system according to an embodiment of the present invention, and as shown in fig. 4, the internal humerus fixation system is composed of 3 to 4 flexible nails 13, the 3 to 4 flexible nails 13 are arranged in a "claw" shape in a humeral head 14, and the head portion 1 of the flexible nail is butted with a tapered hole of a locking steel plate. In addition, the number of the specific flexible nails 13 can be selected according to the fracture condition of the patient.
The embodiments of the present invention have been described in detail, but the present invention is not limited to the embodiments described above as examples. It will be appreciated by those skilled in the art that various equivalent changes and modifications can be made without departing from the spirit and scope of the invention, and it is intended to cover all such modifications and alterations as fall within the true spirit and scope of the invention.
Claims (5)
1. A flexible nail for internal fixation of a proximal humeral fracture, comprising: flexible nail body, its characterized in that:
the flexible nail head part is of a conical structure and is arranged at one end of the flexible nail body;
the tail part of the flexible nail is of an arc-shaped structure, is arranged at the other end of the flexible nail body and is used for bending the flexible nail in the nail feeding process;
the anti-skid part is arranged on the flexible nail body, is close to the tail part of the flexible nail and is used for applying pressure to the humerus to prevent the nail from moving back;
the anti-skid part comprises four groups of anti-skid protrusions which are arranged on the surface of the flexible nail body at equal intervals, and the projections of every two adjacent groups of anti-skid protrusions on a plane vertical to the flexible nail body are crossed;
the cross-sectional profile of the anti-skid protrusions is curved, nail feeding angles and nail pulling angles are arranged at the joints of the anti-skid protrusions and the flexible nail bodies, the nail feeding angles are 23 degrees, and the nail pulling angles are 67 degrees.
2. The flexible nail according to claim 1, wherein two sets of the anti-slip protrusions arranged at intervals are positioned on the same plane, and the projection area on the plane gradually decreases toward the tail of the flexible nail.
3. The flexible nail of claim 1, wherein the cross-section of the flexible nail body is a rounded rectangle having an aspect ratio of 5: 2.
4. The flexible nail according to claim 1, wherein the curved arc of the tail of the flexible nail has a diameter of 38mm and a length of 6.6 mm.
5. An internal humeral fixation system having the flexible nail of any one of claims 1 to 4, wherein one end of the flexible nail is fixed in the humerus by being connected to the locking steel plate through a tapered structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910159946.5A CN109875667B (en) | 2019-03-04 | 2019-03-04 | Flexible nail and system for internal fixation of proximal humerus fracture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910159946.5A CN109875667B (en) | 2019-03-04 | 2019-03-04 | Flexible nail and system for internal fixation of proximal humerus fracture |
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| Publication Number | Publication Date |
|---|---|
| CN109875667A CN109875667A (en) | 2019-06-14 |
| CN109875667B true CN109875667B (en) | 2021-01-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201910159946.5A Active CN109875667B (en) | 2019-03-04 | 2019-03-04 | Flexible nail and system for internal fixation of proximal humerus fracture |
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Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB695427A (en) * | 1951-10-16 | 1953-08-12 | Leslie Vaughan Rush | Improvements in or relating to fracture fixing devices |
| DE8804455U1 (en) * | 1988-04-02 | 1988-05-26 | Aesculap-Werke Ag Vormals Jetter & Scheerer, 7200 Tuttlingen | Refixation pin |
| US5380334A (en) * | 1993-02-17 | 1995-01-10 | Smith & Nephew Dyonics, Inc. | Soft tissue anchors and systems for implantation |
| CN2640426Y (en) * | 2003-06-24 | 2004-09-15 | 中南大学湘雅医院 | Locking type partial thread cancellous bone screw |
| DE102004009429A1 (en) * | 2004-02-24 | 2005-09-22 | Biedermann Motech Gmbh | Bone anchoring element |
| SE533302C2 (en) * | 2007-07-24 | 2010-08-17 | Henrik Hansson | Device for fixing bone fragments in case of bone fracture |
| CN202843760U (en) * | 2012-06-13 | 2013-04-03 | 富阳市人民医院 | Memory alloy clavicle intramedullary nail |
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2019
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