Clavicular intramedullary nail

Abstract

The utility model relates to a clavicle intramedullary nail, the body is hollow screw, has the hole along its axial penetration, is convenient for active insertion and allocation guide needle, screw tip does not set up cutting edge and does not have self -tapping ability, needs after the fracture proximal end wire attack and implants, the length of second threaded part, first threaded part and non-threaded part is equal, the screw rod of middle part is smooth and does not have thread design, so as to pass through the relatively narrow part of clavicle middle segment and reset narrow part broken bone block, the screw tail sets up internal hexagonal groove, and the screw head threaded pitch is consistent with second threaded part tip, prevents the shortening of clavicle caused by excessive pressure, and the end three layers thread diameter of the threaded part of screw head portion gradually increases, to provide stronger distal holding force.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, specifically, it is a locking intramedullary nail. Background Technology

[0002] Open reduction and internal fixation with plates and screws for clavicle fractures is currently widely used in clinical practice, but its disadvantages cannot be ignored. First, extensive exposure of the clavicle causes extensive soft tissue damage and may also lead to supraclavicular nerve injury, which can cause numbness and decreased sensation in the local chest wall. Extensive soft tissue dissection can also delay fracture healing or even cause nonunion. Second, scarring at the clavicle site severely affects aesthetics, especially since clavicle fractures are more common in younger patients. Third, in patients with a thin physique, the plate may irritate the soft tissues, causing discomfort and requiring secondary removal of the internal fixation. However, refracture after removal of the plate and screws is not uncommon.

[0003] Several patents for locking intramedullary nails are disclosed in the prior art; Chinese patent CN2772458Y discloses a medical hollow bone nail and its installation and removal tool. The inner surface of the rear end of the main nail is hexagonal with threads on the surface, and the front part has a protruding toothed ring. The rear part of the main nail is fitted with a cancellous bone threaded anti-dislodgement cap tube, and then fitted with a hollow cross-shaped nut with internal threads. The installation and removal tool consists of a screwdriver with a hexagonal front and a handle, and a sleeve with a threaded through hole and a bolt. The nut installation and removal tool is a cross-shaped hollow screwdriver; the inner surface of the rear end of the main nail can be hexagonal, and the main nail is fitted with a cancellous bone threaded anti-dislodgement cap tube; the installation and removal tool consists of a metal rod with a hexagonal front end, a toothed ring in the middle, and a handle at the rear end, and a sleeve with a threaded through hole and a bolt.

[0004] Chinese Patent Publication No. CN101455582A discloses a split intramedullary nail device, which modifies the previous solution and includes a first connecting element and a second connecting element connected thereto. The first connecting element is hollow, with a first end with external threads and a stop on the inner side for a hollow bolt-shaped connecting plug to enter. The head of the connecting plug is stopped by the stop. The second connecting element is hollow and long, with a neck at one end for the first connecting element to be inserted, and a second end with external threads at the other end for rotating the second connecting element to allow the second end to enter the medullary cavity and connect to one side of the fractured bone. The neck has internal threads for the connecting plug to extend from the first connecting element and screw into the internal threads to drive the first connecting element to connect to the other side of the fractured bone. At the same time, the relative distance between the first and second connecting elements can be adjusted to ensure that the contact fit of the fractured bones on both sides can be adjusted according to the different bone lengths.

[0005] However, the aforementioned patent documents have some drawbacks: the connecting bolt is an axially penetrating fine screw that needs to be inserted into the lower neck through a threaded connection, which limits the load-bearing capacity of the connecting bolt. Furthermore, the connecting bolt is a hollow round sleeve structure and requires threads to be cut on the outside of the connecting bolt. The matching degree of the thread fit between the connecting bolt and the neck needs to be considered, resulting in greater manufacturing difficulty and cost. Utility Model Content

[0006] The purpose of this invention is to provide a lock-on intramedullary nail, thereby improving the problems existing in the prior art.

[0007] The purpose of this utility model is achieved as follows: a lock-on intramedullary nail includes a screw head, a first threaded part, a non-threaded part, and a second threaded part that are fixedly connected along the axial direction. The screw head, the first threaded part, the non-threaded part, and the second threaded part are all provided with an axially penetrating inner hole. The screw head is provided with an internal hexagonal groove that communicates with its inner hole. The inner hole of the screw head is provided with an axially limiting flange that is coaxial with it.

[0008] The non-threaded part is integrally connected to a positioning pin, which is inserted into the inner hole of the screw head. The end of the positioning pin is provided with a narrow-diameter threaded part, the diameter of which is smaller than the diameter of the main body of the positioning pin. A shoulder is formed at the connection between the narrow-diameter threaded part and the main body of the positioning pin. The narrow-diameter threaded part moves through the inner hole of the axial limiting flange and partially extends into the internal hexagonal groove. The narrow-diameter threaded part is threadedly connected to a locking nut, which is located in the internal hexagonal groove. A gap is left between the outer end face of the locking nut and the opening face of the internal hexagonal groove to accommodate the insertion of a wrench. The locking nut has a central circular hole that communicates with the inner hole of the positioning pin and accommodates the movable passage of a guide pin. The shoulders of the locking nut and the positioning pin respectively abut against the two axial ends of the axial limiting flange.

[0009] Furthermore, the locking nut has a strip-shaped locking operation hole for engaging with a screwdriver. The locking operation hole intersects with the central circular hole and is integral with it. The length of the locking operation hole is greater than the diameter of the central circular hole.

[0010] Furthermore, the locking nut is designed as a round cap structure, having a cover plate portion and a cylindrical portion. The cylindrical portion of the locking nut has an internal locking thread, which is fitted with a narrow-diameter threaded portion. The intermediate round hole and the locking operation hole are both located on the cover plate portion of the locking nut.

[0011] Furthermore, the central circular hole is coaxial with the inner hole of the positioning pin.

[0012] Furthermore, the diameter of the central circular hole is the same as the inner diameter of the positioning pin.

[0013] Furthermore, the bottom surface of the internal hexagonal slot is provided with a lower groove in the center, the remaining surface of the bottom surface of the internal hexagonal slot is provided as an upper support surface for cooperating with the wrench, the bottom surface of the lower groove is provided as a lower support surface, and the lower support surface supports the locking nut along the axial direction.

[0014] Furthermore, the shoulder of the positioning pin is fitted with the inner end of the axial limiting flange.

[0015] Furthermore, the shoulder of the positioning pin is a conical surface, and the inner end of the axial limiting flange is set as a conical surface that matches the shoulder of the positioning pin.

[0016] The beneficial effects of this utility model are as follows:

[0017] 1. The narrow-diameter threaded part of the locking nut sleeve and the positioning pin is used. Compared with the existing technology, the radial dimension of the threaded fit is larger, and the locking fit of the positioning pin is more stable and reliable.

[0018] 2. The lock nut can be tightened using a common screwdriver. The operating end of the screwdriver is inserted into the locking operating hole of the lock nut to tighten or loosen it. After tightening, the non-threaded part is connected to the first threaded part and the screw head as one unit. The positioning pin is fixedly connected to the screw head as a whole, which facilitates further operations.

[0019] 3. After the positioning pin and the screw head are fixedly connected as a whole, a commonly used hex wrench can be inserted into the internal hex slot of the screw head and rotated to drive the screw head and the entire intramedullary nail to move axially. Attached Figure Description

[0020] Figure 1 This is an external structural diagram of the present invention.

[0021] Figure 2 This is a diagram of the top structure of the screw head.

[0022] Figure 3 yes Figure 2 AA section view in the image.

[0023] Figure 4 This is a schematic diagram of the top structure of the lock nut.

[0024] Figure 5 yes Figure 4 BB section view in the middle.

[0025] Figure 6 This is a diagram illustrating how to tighten a lock nut using a screwdriver.

[0026] Figure 7 This is a diagram illustrating the use of a hex wrench to tighten the entire intramedullary nail. Detailed Implementation

[0027] The following will refer to the appendix in the embodiments of this utility model. Figure 1-7 The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] like Figure 1 As shown, a lock-on intramedullary nail is proposed, comprising a screw head 1, a first threaded portion 2, a non-threaded portion 3, and a second threaded portion 4 that are fixedly connected along the axial direction. The screw head 1, the first threaded portion 2, the non-threaded portion 3, and the second threaded portion 4 are all provided with an axially penetrating inner hole. The screw head 1 and the first threaded portion 2 are integrally formed, and the screw head 1 also has an external thread.

[0029] As a preferred product solution: Overall, the diameter (length) of the intramedullary nail is 5.0 (70-90mm) / 5.5 (70-100mm) / 6.0 (80-110mm); the diameter of the selected guide pin is 1.2mm, and the diameter of the tap is 1mm shorter than the selected diameter.

[0030] like Figure 2 As shown, the screw head 1 is provided with an internal hexagonal groove 1a communicating with its inner hole, and the inner hole of the screw head 1 is provided with an axial limiting flange 1d coaxial with it.

[0031] like Figure 3 As shown, the non-threaded part 3 is integrally connected to a positioning pin 6. The positioning pin 6 is detachably inserted into the inner hole of the screw head 1. The end of the positioning pin 6 is provided with a narrow diameter threaded part 6a. The diameter of the narrow diameter threaded part 6a is smaller than the diameter of the main body of the positioning pin 6. A shoulder is formed at the position where the narrow diameter threaded part 6a is connected to the main body of the positioning pin 6. The narrow diameter threaded part 6a moves through the inner hole of the axial limiting flange 1d and partially extends into the internal hexagonal groove 1a. The narrow diameter threaded part 6a is threadedly connected to a locking nut 5. The locking nut 5 is located in the internal hexagonal groove 1a, and there is a gap between the outer end face of the locking nut 5 and the opening face of the internal hexagonal groove 1a to accommodate the insertion of a wrench. The locking nut 5 has a central circular hole 5b that communicates with the inner hole of the positioning pin 6 and accommodates the movable passage of a guide pin. The shoulders of the locking nut 5 and the positioning pin 6 respectively abut against the two shaft ends of the axial limiting flange 1d.

[0032] like Figure 2 , 4 As shown, the locking nut 5 has a strip-shaped locking operation hole 5c for engaging with a screwdriver. The locking operation hole 5c intersects with the central circular hole 5b and is integrated into one piece. The length of the locking operation hole 5c is greater than the diameter of the central circular hole 5b.

[0033] like Figure 5 As shown, the locking nut 5 is designed as a round cap structure, with a cover plate part and a cylindrical part. The cylindrical part of the locking nut 5 has an internal locking thread 5a, which is fitted with a narrow diameter thread part 6a. The central round hole 5b and the locking operation hole 5c are both opened in the cover plate part of the locking nut 5.

[0034] The operating principle is as follows: Figure 6 As shown, the locking nut 5 can be tightened using a common screwdriver 7. The operating end of the screwdriver 7 is inserted into the locking operating hole 5c of the locking nut 5 to tighten or loosen it. After tightening, the positioning pin 6 and the screw head 1 are fixedly connected as a whole. Figure 7 As shown, by inserting a commonly used hex wrench 8 into the internal hex socket 1a of the screw head 1 and rotating the hex wrench 8, the screw head 1 and the entire intramedullary nail can be driven to move axially; during this process, the hex wrench 8 will move and contact the cover plate of the locking nut 5.

[0035] Because this embodiment uses a locking nut 5 fitted with a narrow-diameter threaded portion 6a of a positioning pin 6, the radial dimension of the threaded engagement is larger than that of the prior art, and the locking engagement of the positioning pin 6 is more stable and reliable.

[0036] like Figure 3 As shown, the central circular hole 5b is coaxial with the inner hole of the positioning pin 6, and the diameter of the central circular hole 5b is the same as that of the inner hole of the positioning pin 6.

[0037] The bottom surface of the aforementioned internal hexagonal groove 1a is provided with a lower groove 1e in the center. The remaining surfaces of the bottom surface of the internal hexagonal groove 1a are provided as an upper support surface 1b that cooperates with the wrench. The bottom surface of the lower groove 1e is provided as a lower support surface 1c. The lower support surface 1c supports the locking nut 5 along the axial direction.

[0038] The shoulder of the positioning pin 6 is fitted with the inner end of the axial limiting flange 1d. The shoulder of the positioning pin 6 is a conical surface, and the inner end of the axial limiting flange 1d is set as a conical surface that matches the shoulder of the positioning pin 6.

[0039] As an improved manufacturing process, the intramedullary nail body is a hollow screw with a through-hole along its axis, facilitating the insertion of a guide pin. The screw tip (the tip of the second threaded portion 4) does not have a cutting edge and lacks self-tapping capability, requiring tapping at the proximal end of the fracture before implantation. The middle screw (the non-threaded portion 3) is smooth and unthreaded, allowing it to pass through the narrower parts of the mid-clavicle and reduce the fracture fragments. The screw tail (the screw head 1) has an internal hexagonal groove 1a, and the thread pitch of the screw head 1 is consistent with that of the tip of the second threaded portion 4 to prevent clavicle shortening caused by excessive pressure. The diameter of the three layers of threads at the end of the threaded portion of the screw head 1 gradually increases to provide stronger distal holding force. The lengths of the second threaded portion 4, the first threaded portion 2, and the non-threaded portion 3 are equal.

[0040] As a preferred usage method, the implantation process is as follows:

[0041] 1. After anesthetizing the patient, position the patient in a beach chair position, that is, adjust the chair to a certain angle so that the patient lies on the chair at a certain angle, thus adjusting the patient's position to the beach chair position.

[0042] 2. Make a skin incision about 3cm long, cut through the skin and subcutaneous tissue to expose the fracture ends, and use wire tapping to ream the medullary canal at the proximal fracture end;

[0043] 3. Insert the guide needle retrogradely from the cut end toward the distal end, and use a C-arm fluoroscopy machine to confirm the needle insertion point;

[0044] 4. After the guide needle passes through the skin, guide the needle out in the direction of reduction, reduce the fracture, pass the guide needle through the fracture end to the proximal fracture fragment, confirm the guide needle is in the medullary cavity under fluoroscopy, measure the length of the guide needle, and insert a cannulated screw after opening the incision. During this process, reduction forceps should be used to maintain reduction. After confirmation under fluoroscopy, suture the incision.

[0045] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In this utility model, it should also be noted that the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to fixed connection, detachable connection, integral molding connection, mechanical connection, or indirect connection through intermediate connecting parts. The specific meaning of the terms in this utility model can be understood according to the specific circumstances.

[0046] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A locking intramedullary nail, comprising a screw head (1), a first threaded portion (2), a non-threaded portion (3), and a second threaded portion (4) fixedly connected along the axial direction, wherein the screw head (1), the first threaded portion (2), the non-threaded portion (3), and the second threaded portion (4) are each provided with an axially penetrating inner hole, characterized in that: The screw head (1) is provided with an internal hexagonal groove (1a) communicating with its inner hole, and the inner hole of the screw head (1) is provided with an axial limiting flange (1d) coaxial with it. The non-threaded part (3) is integrally connected to a positioning pin (6). The positioning pin (6) is inserted into the inner hole of the screw head (1). The end of the positioning pin (6) is provided with a narrow-diameter threaded part (6a). The diameter of the narrow-diameter threaded part (6a) is smaller than the diameter of the main body of the positioning pin (6). A shoulder is formed at the position where the narrow-diameter threaded part (6a) connects with the main body of the positioning pin (6). The narrow-diameter threaded part (6a) movably passes through the inner hole of the axial limiting flange (1d) and partially extends into the internal hexagonal groove (1a). Inside the narrow-diameter threaded part (6a), a locking nut (5) is threadedly connected. The locking nut (5) is located in the internal hexagonal groove (1a), and there is a gap between the outer end face of the locking nut (5) and the opening face of the internal hexagonal groove (1a) to accommodate the insertion of a wrench. The locking nut (5) has an intermediate circular hole (5b) that communicates with the inner hole of the positioning pin (6) and accommodates the guide pin to move through. The shoulders of the locking nut (5) and the positioning pin (6) respectively abut against the two shaft ends of the axial limiting flange (1d).

2. The intramedullary nail according to claim 1, characterized in that: The locking nut (5) has a strip-shaped locking operation hole (5c) for engaging with a screwdriver. The locking operation hole (5c) intersects with the central circular hole (5b) and is integral. The length of the locking operation hole (5c) is greater than the diameter of the central circular hole (5b).

3. The intramedullary nail according to claim 2, characterized in that: The locking nut (5) is designed as a round cap structure, and has a cover plate part and a cylindrical part. The cylindrical part of the locking nut (5) has an internal locking thread (5a), which is fitted with a narrow diameter thread part (6a). The intermediate round hole (5b) and the locking operation hole (5c) are both opened in the cover plate part of the locking nut (5).

4. The intramedullary nail for locking the bone marrow according to claim 2, characterized in that: The central circular hole (5b) is coaxial with the inner hole of the positioning pin (6).

5. A lock-on intramedullary nail according to claim 4, characterized in that: The diameter of the central circular hole (5b) is the same as the diameter of the inner hole of the positioning pin (6).

6. A lock-type intramedullary nail according to any one of claims 1-5, characterized in that: The bottom surface of the internal hexagonal groove (1a) is provided with a lower groove (1e) in the center. The remaining surface of the bottom surface of the internal hexagonal groove (1a) is set as an upper support surface (1b) to cooperate with the wrench. The bottom surface of the lower groove (1e) is set as a lower support surface (1c). The lower support surface (1c) supports the locking nut (5) axially.

7. A lock-type intramedullary nail according to claim 6, characterized in that: The shoulder of the positioning pin (6) is fitted with the inner end of the axial limiting flange (1d).

8. The intramedullary nail according to claim 7, characterized in that: The shoulder of the positioning pin (6) is a conical surface, and the inner end of the axial limiting flange (1d) is set as a conical surface that matches the shoulder of the positioning pin (6).

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