Distal femoral expandable intramedullary nail

Abstract

The application discloses a distal femur expandable intramedullary nail, which comprises an intramedullary nail rod, a hollow pipeline is arranged through the proximal end and the distal end of the intramedullary nail rod along the axial direction of the intramedullary nail rod, and the hollow pipeline of the intramedullary nail rod is internally provided with an internal thread; the proximal end of the intramedullary nail rod is provided with a locking screw hole, and a proximal locking screw is matched and arranged in the locking screw hole; a rotating positioning rod is arranged in the hollow pipeline of the intramedullary nail rod, the rotating positioning rod is provided with an external thread matched with the internal thread, and the distal end of the rotating positioning rod is connected with an expandable body which is expanded in the femur and is degradable. The application has the advantages of improving the operation accuracy and efficiency, reducing the intraoperative adjustment and radiation exposure, avoiding secondary operation, reducing postoperative complications and medical costs, enhancing the fixing effect, providing stable three-dimensional fixation, promoting fracture healing and the like.

Description

Technical Field

[0001] The present invention relates to an intramedullary nail, in particular to an intramedullary nail capable of expanding the distal end of a femur. Background Art

[0002] Femoral intramedullary nailing is the core internal fixation technology for the treatment of intertrochanteric fractures, femoral shaft fractures and intercondylar fractures. Its core principle is to achieve axial fixation by implanting the intramedullary nail into the femoral medullary cavity, and to achieve three-dimensional stabilization of the fracture end with the help of distal locking screws.

[0003] The existing technology system primarily relies on the following operational process: During surgery, the intramedullary nail and the external aiming frame must be pre-assembled, and precise placement of the distal locking screw is guided by mechanical positioning. Although this technology offers biomechanical advantages such as promoting early weight-bearing, reducing the surgical wound, and achieving dynamic compression, its inherent flaws have severely impacted clinical outcomes. First, there are technical flaws during surgery, including the difficulty of spatial positioning misalignment. Due to the triple influence of differences in the patient's medullary canal curvature, variations in fracture morphology, and deformation after intramedullary nail implantation, the aiming frame's preset positioning significantly deviates from the actual bone canal, necessitating constant adjustment of the external aiming frame's position. This forces the surgeon to repeatedly adjust the instrument's position and rely on multiple X-ray fluoroscopy verifications, resulting in prolonged surgery and a doubling of the risk of radiation exposure for both the doctor and the patient. Second, there are postoperative complications, including the risk of secondary trauma. After the fracture heals, additional surgery is required to remove the distal locking screw, resulting in a secondary surgical incision and an increased risk of infection and nerve damage.

[0004] These technical bottlenecks not only cause serious damage to surgical accuracy and efficiency, but also lead to a series of iatrogenic injury risks. It is urgent to break through the traditional mechanical positioning mode and locking structure design through technological innovation. Summary of the Invention

[0005] In order to solve the deficiencies of the above-mentioned technology, the present invention provides a distal femoral distractible intramedullary nail.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a distal femoral expandable intramedullary nail, comprising an intramedullary nail rod, a hollow tube extending through the distal and proximal ends of the intramedullary nail rod along its axial direction, and an internal thread in the hollow tube of the intramedullary nail rod;

[0007] A locking screw hole is provided at the proximal end of the intramedullary nail rod, and a proximal locking screw is matched and inserted into the locking screw hole;

[0008] A rotation positioning rod is passed through the hollow tube of the intramedullary nail rod. The rotation positioning rod has an external thread matching the internal thread. The distal end of the rotation positioning rod is connected to a degradable expansion body that expands in the femur.

[0009] Furthermore, the hollow tube forms a proximal opening at the proximal end of the intramedullary nail rod, and the hollow tube forms a distal opening at the distal end of the intramedullary nail rod. The rotating positioning rod penetrates the intramedullary nail rod from the proximal opening and connects to the expander.

[0010] Furthermore, a plurality of axial grooves are provided along the circumferential wall of the intramedullary nail rod, and the plurality of axial grooves are equidistantly close to the end where the distal opening of the intramedullary nail rod is located. An internal thread is provided in the hollow tube at the end where the distal opening of the intramedullary nail rod is located.

[0011] Furthermore, the expansion body includes a screw 1 rotatably connected to the distal end of the rotating positioning rod, the distal end of the screw 1 is connected to a plurality of elastic expansion strips matched one to one in the axial groove, the elastic expansion strips are expanded from the axial groove under the extrusion force, and the screw 2 with the elastic expansion strip abuts at the distal end of the elastic expansion strip, and the screw 2 is connected to the distal opening of the intramedullary nail rod.

[0012] Furthermore, the elastic expansion strip is provided with a plurality of bendable grooves with openings facing the central axis of the expansion body along the axial direction, so that the elastic expansion strip is expanded from the axial groove to form the intramedullary nail rod under the extrusion force.

[0013] Furthermore, a tooth row is provided on the outer end surface of the elastic expansion strip to increase the frictional force between the elastic expansion strip and the medullary cavity wall of the distal femur.

[0014] Furthermore, the external thread of the screw 1 matches the internal thread in the hollow pipe.

[0015] Furthermore, the internal thread of the hollow tube is opened inwardly along the proximal opening, and the proximal end of the intramedullary nail rod is provided with an external thread matching the internal thread.

[0016] Furthermore, the expansion body includes a transition piece matched with the rotating positioning rod, and the distal end of the transition piece is connected to a plurality of elastic expansion strips matched one by one in the axial groove. The elastic expansion strips are expanded from the axial groove under the extrusion force, and the intramedullary nail rod is connected to the distal end of the elastic expansion strip. Screw three is connected to the distal end of the intramedullary nail rod.

[0017] Furthermore, the expansion body includes an elastic expansion claw connected to the distal opening, and a conical expansion rod is movably provided in the middle of the elastic expansion claw. The conical expansion rod is connected to the hollow pipe through the external threaded body at its proximal end, and the distal end of the rotating positioning rod is matched with the conical expansion rod.

[0018] The present invention discloses a distal femoral expandable intramedullary nail, which solves the two core problems of traditional intramedullary nails, namely, misaligned positioning during surgery and trauma caused by secondary surgery after surgery, through an innovative expandable structure and degradable materials. It has the significant advantages of improving surgical accuracy and efficiency, reducing intraoperative adjustments and radiation exposure, avoiding secondary surgery, reducing postoperative complications and medical costs, enhancing fixation effects, providing stable three-dimensional fixation, and promoting fracture healing. It has broad prospects in clinical applications and can significantly improve the treatment effect and patient experience of distal femoral fractures. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of embodiment 1 of the present invention.

[0020] Figure 2 for Figure 1 Enlarged schematic diagram of the structure of the part in the middle circle.

[0021] Figure 3 This is a structural diagram of embodiment 2 of the present invention.

[0022] Figure 4 This is a schematic diagram of the internal structure of the intramedullary nail rod of Example 2.

[0023] Figure 5 This is a structural diagram of Example 3.

[0024] Figure 6 This is a schematic diagram of the internal structure of the intramedullary nail rod of Example 3.

[0025] In the figure: 1. Intramedullary nail rod; 2. Proximal locking screw; 3. Rotating positioning rod; 4. Distance expansion body; 5. Axial groove; 6. Screw 1; 7. Elastic distance expansion strip; 8. Screw 2; 9. Bendable groove; 10. Tooth row; 11. Transition piece; 12. Screw 3; 13. Elastic distance expansion claw; 14. Conical expansion rod. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1:

[0028] like Figure 1 and Figure 2 As shown, this embodiment discloses a distal femoral expandable intramedullary nail, comprising an intramedullary nail rod 1 made of titanium alloy or stainless steel. A hollow tube is provided along the axial direction of the intramedullary nail rod 1 and passes through the distal and proximal ends thereof. The hollow tube of the intramedullary nail rod 1 has an internal thread. Note that the position of the internal thread feature within the hollow tube can be adjusted according to the position of the components installed in the intramedullary nail rod 1. A locking screw hole is provided at the proximal end of the intramedullary nail rod 1. A proximal locking screw 2 is matched and inserted into the locking screw hole for fixing the proximal femur.

[0029] A rotational positioning rod 3 is provided within the hollow conduit of the intramedullary nail rod 1. The rotational positioning rod 3 has an external thread that matches the internal thread. The distal end of the rotational positioning rod 3 is connected to a degradable expansion body 4 that expands within the femur. The hollow conduit forms a proximal opening at the proximal end of the intramedullary nail rod 1, and a distal opening at the distal end of the intramedullary nail rod 1. The rotational positioning rod 3 penetrates the intramedullary nail rod 1 from the proximal opening and connects to the expansion body 4. In this embodiment, the proximal knob of the rotational positioning rod 3 has an external thread that can be screwed in and adjusted in position within the intramedullary nail rod 1 in cooperation with the internal thread, thereby achieving the purpose of transmitting the expansion body 4. For example, in this embodiment, the internal thread of the hollow conduit extends inward along the proximal opening, and the proximal end of the intramedullary nail rod 1 is provided with an external thread that matches the internal thread.

[0030] Two axial grooves 5 are provided along the circumferential wall of the intramedullary nail rod 1. The specific shape of the axial grooves 5 is not limited, but the shapes of the two axial grooves 5 are kept as consistent as possible to ensure the consistency of the opening unit of the expansion body 4. The two axial grooves 5 are equidistant from the end of the distal opening of the intramedullary nail rod 1. In other embodiments, the number of axial grooves 5 can be three or four. An internal thread is provided in the hollow pipe at the end where the distal opening of the intramedullary nail rod 1 is located. Therefore, the distal opening can be connected to a component that closes the hollow pipe through a threaded connection to prevent the expansion body 4 from extending axially.

[0031] The expansion body 4 includes a screw 6 that is rotatably connected to the distal end of the rotation positioning rod 3. The external thread of the screw 6 matches the internal thread in the hollow pipe. The distal end of the screw 6 is connected to a plurality of elastic expansion strips 7 that match one by one in the axial groove 5. The elastic expansion strips are degradable, including but not limited to degradable polylactic acid, pure magnesium, magnesium alloy, zinc alloy and other medical degradable materials. When the rotation positioning rod 3 rotates, the screw 6 is driven to rotate in the hollow pipe to achieve axial displacement, compressing the elastic expansion strip 7. The elastic expansion strip 7 is squeezed out of the axial groove 5 to expand the intramedullary nail rod 1, and the distal end of the elastic expansion strip 7 abuts against an elastic expansion strip. Screw 2 8 of the elastic expansion strip 7 is connected to the distal opening of the intramedullary nail rod 1 and is used to abut the elastic expansion strip 7. It should be understood that the elastic expansion strip 7 connected to screw 1 6 will also deflect with screw 1 6. Under the premise that it adopts the above-mentioned elastic material, the extrusion force generated by screw 1 6 can expand the elastic expansion strip 7 out of the intramedullary nail rod 1. When the elastic expansion strip 7 is mostly expanded out of the intramedullary nail rod 1, the torsional force of the elastic expansion strip 7 limits the screw 1 6 from continuing to rotate, and the adjustment force of the rotating positioning rod 3 reaches the limit, which is sufficient to make the elastic expansion strip 7 contact and fix with the distal femoral medullary cavity wall.

[0032] Preferably, the elastic expansion strip 7 is provided with a plurality of bendable grooves 9 axially extending with their openings facing the central axis of the expansion body 4, so as to facilitate the elastic expansion strip 7 to be squeezed out of the axial groove 5 and out of the intramedullary nail rod 1. A tooth row 10 is provided on the outer end surface of the elastic expansion strip 7 to increase the frictional contact with the distal femoral medullary cavity wall, thereby firmly fixing the elastic expansion strip 7 to the distal femoral medullary cavity wall.

[0033] After maintaining the expanded shape of the elastic expansion strip 7, the rotational positioning rod 3 can be unscrewed and removed from the intramedullary nail rod 1. The unscrewing and removal depends on the matching connection relationship between the thread head and thread groove of the rotational positioning rod 3 and the screw 6. For example, the thread head of the rotational positioning rod 3 can be in the shape of a straight slot, a cross slot, an external hexagonal, or an external plum blossom, and the thread groove of the screw 6 can be in the shape of a straight slot, a cross slot, an internal hexagonal, or a plum blossom. Conversely, the thread groove of the rotational positioning rod 3 can be in the shape of a straight slot, a cross slot, an internal hexagonal, or a plum blossom, and the thread head of the screw 6 can be in the shape of a straight slot, a cross slot, an external hexagonal, or an external plum blossom. Therefore, after the distal end of the femoral intramedullary nail is firmly fixed to the distal femoral bone, after the fracture heals, the elastic expansion strip 7 degrades accordingly, and when removal is required, the intramedullary nail rod 1 can be smoothly removed.

[0034] Example 2:

[0035] like Figure 3 and Figure 4 The embodiment shown discloses a distal expandable intramedullary nail for the femur, comprising an intramedullary nail rod 1, a hollow tube extending through the distal and proximal ends of the intramedullary nail rod 1 along its axial direction, the hollow tube of the intramedullary nail rod 1 having an internal thread; a locking screw hole is provided at the proximal end of the intramedullary nail rod 1, a proximal locking screw 2 is inserted into the locking screw hole; a rotation positioning rod 3 is passed through the hollow tube of the intramedullary nail rod 1, the rotation positioning rod 3 having an external thread matching the internal thread, the distal end of the rotation positioning rod 3 being connected to a expander 4 that expands within the femur and is degradable.

[0036] The hollow conduit forms a proximal opening at the proximal end of the intramedullary nail rod 1 and a distal opening at the distal end of the intramedullary nail rod 1. The rotating positioning rod 3 penetrates the intramedullary nail rod 1 from the proximal opening and connects to the expander 4. Two axial grooves 5 are defined along the circumferential wall of the intramedullary nail rod 1, equidistant from the end where the distal opening of the intramedullary nail rod 1 is located. An internal thread is defined within the hollow conduit at the end where the distal opening of the intramedullary nail rod 1 is located.

[0037] Different from the first embodiment, in this embodiment, the expansion body 4 includes a transition piece 11 matched with the rotation positioning rod 3, and the distal end of the transition piece 11 is connected to two elastic expansion strips 7 matched one to one in the axial groove 5. The elastic expansion strip 7 is expanded from the axial groove 5 under the extrusion force. The principle of the expansion of the elastic expansion strip 7 is consistent. The elastic expansion strip 7 is connected to the distal end of the elastic expansion strip 7 with a screw three 12. The screw three 12 is connected to the distal end opening of the intramedullary nail rod 1 and also plays the role of abutting against the elastic expansion strip 7 at the distal end. In this embodiment, the elastic expansion strip 7 is hinged on the screw three 12.

[0038] After maintaining the expanded shape of the elastic expansion strip 7, the rotation positioning rod 3 can be unscrewed and removed from the intramedullary nail rod 1. The unscrewing and removal depends on the rotation positioning rod 3 and the screw three 12 using the same matching connection relationship of the wire head and the wire groove as in embodiment 1. Therefore, this embodiment also achieves the strong fixation of the distal end of the femoral intramedullary nail and the distal femoral bone. After the fracture heals, the elastic expansion strip 7 degrades accordingly. When it needs to be removed, the intramedullary nail rod 1 can be smoothly removed.

[0039] Example 3:

[0040] like Figure 5 and Figure 6 As shown, this embodiment discloses a distal femoral expandable intramedullary nail, comprising an intramedullary nail rod 1, a hollow tube extending axially through the distal and proximal ends of the intramedullary nail rod 1, and an internal thread within the hollow tube of the intramedullary nail rod 1; a locking screw hole is provided at the proximal end of the intramedullary nail rod 1, into which a proximal locking screw 2 is inserted; a rotational positioning rod 3 is passed through the hollow tube of the intramedullary nail rod 1, the rotational positioning rod 3 having an external thread matching the internal thread, and the distal end of the rotational positioning rod 3 is connected to a degradable expander 4 that expands within the femur. The hollow tube forms a proximal opening at the proximal end of the intramedullary nail rod 1 and a distal opening at the distal end of the intramedullary nail rod 1. The rotational positioning rod 3 passes through the proximal opening into the intramedullary nail rod 1 and connects to the expander 4.

[0041] Unlike the two aforementioned embodiments, in this embodiment, the expansion body 4 includes an elastic expansion claw 13 connected to the distal opening. The elastic expansion claw 13 is degradable and may be made of, but is not limited to, biodegradable medical materials such as polylactic acid, pure magnesium, magnesium alloy, and zinc alloy. A tapered expansion rod 14 is movably inserted into the middle portion of the elastic expansion claw 13. The tapered expansion rod 14 is inserted into the hollow conduit through an externally threaded body at its proximal end. The distal end of the rotating positioning rod 3 is mated with the tapered expansion rod 14. Rotating the rotating positioning rod 3 drives the tapered expansion rod 14 to rotate and move axially. As the outer diameter of the tapered expansion rod 14 in contact with the elastic expansion claw 13 gradually expands, the elastic expansion claw 13 gradually opens, achieving a strong fixation between the distal end of the femoral intramedullary nail and the distal femoral bone. After the fracture heals, the elastic expansion claw 13 degrades, allowing the intramedullary nail rod 1 to be removed smoothly when necessary.

[0042] In summary, the present invention solves the problems of spatial positioning misalignment and postoperative secondary surgical trauma in the prior art by designing a distal femoral expandable intramedullary nail. The specific solutions and advantages are as follows: The present invention replaces the traditional distal locking screw with an expandable structure such as an elastic expansion strip or an elastic expansion claw, and does not need to rely on an external aiming frame for precise positioning. The expansion body is driven to expand in the distal femoral medullary cavity by rotating the positioning rod, and is directly fixed in contact with the medullary cavity wall, avoiding the problem of inaccurate positioning of traditional locking screws. Reduce intraoperative adjustments, eliminate the need for repeated adjustment of the external aiming frame, and simplify the surgical process. Reduce radiation exposure, reduce the number of X-ray fluoroscopy times, and reduce the radiation risk for doctors and patients. Improve surgical efficiency, shorten operation time, and enhance surgical accuracy.

[0043] The present invention uses degradable materials such as degradable polylactic acid, pure magnesium, magnesium alloy, zinc alloy, etc. to manufacture the elastic expansion strips or elastic expansion claws of the expansion body. The expansion body gradually degrades after the fracture heals, eliminating the need for secondary surgery to remove it. This avoids secondary surgery, as the expansion body does not need to be removed after degradation, reducing the pain and risk of secondary surgery for the patient. This reduces the risk of infection, avoids secondary surgical incisions, and reduces the risk of postoperative infection and nerve damage. This simplifies postoperative management, reduces postoperative complications, and lowers medical costs.

[0044] In addition, the elastic expansion structure is designed. The expansion body, such as the elastic expansion bar or elastic expansion claw, is designed with axial grooves and bendable grooves, which can expand within the intramedullary nail rod and closely contact the distal femoral medullary cavity wall, providing a stable three-dimensional fixation effect. The outer end surface of the expansion body is equipped with a row of teeth to increase the contact friction with the medullary cavity wall, further enhancing the fixation effect. Modular design: The expansion body and the rotating positioning rod are connected by a wire head and wire groove, which facilitates intraoperative adjustment and postoperative removal, and is simple to operate.

[0045] The above embodiments are not limitations of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A distal femoral expandable intramedullary nail, characterized in that: It comprises an intramedullary nail rod (1), a hollow tube is provided along the axial direction of the intramedullary nail rod (1) and passes through the distal and proximal ends thereof, and the hollow tube of the intramedullary nail rod (1) has an internal thread; A locking screw hole is provided at the proximal end of the intramedullary nail rod (1), and a proximal locking screw (2) is inserted into the locking screw hole; A rotation positioning rod (3) is provided in the hollow tube of the intramedullary nail rod (1), the rotation positioning rod (3) having an external thread matching the internal thread, and the distal end of the rotation positioning rod (3) is connected to a degradable expansion body (4) that expands in the femur; A plurality of axial grooves (5) are provided along the circumferential wall of the intramedullary nail rod (1), the plurality of axial grooves (5) being equidistantly close to the end portion where the distal opening of the intramedullary nail rod (1) is located, and an internal thread is provided in the hollow conduit at the end portion where the distal opening of the intramedullary nail rod (1) is located; The expansion body (4) includes a screw (6) rotatably connected to the distal end of the rotation positioning rod (3), the distal end of the screw (6) is connected to a plurality of elastic expansion strips (7) matched one by one in the axial groove (5), the elastic expansion strip (7) is expanded from the axial groove (5) by the extrusion force, and the screw (8) with the elastic expansion strip (7) abuts the distal end of the elastic expansion strip (7), and the screw (8) is connected to the distal end opening of the intramedullary nail rod (1); The external thread of the screw 1 (6) matches the internal thread in the hollow pipe.

2. The distal femoral expandable intramedullary nail according to claim 1, characterized in that: The hollow tube forms a proximal opening at the proximal end of the intramedullary nail rod (1), and the hollow tube forms a distal opening at the distal end of the intramedullary nail rod (1). The rotation positioning rod (3) penetrates into the intramedullary nail rod (1) from the proximal opening and is connected to the expansion body (4).

3. The distal femoral expandable intramedullary nail according to claim 2, characterized in that: The elastic expansion strip (7) is provided with a plurality of bendable grooves (9) along the axial direction, with the openings facing the central axis of the expansion body (4), so that the elastic expansion strip (7) is squeezed to expand the intramedullary nail rod (1) from the axial groove (5).

4. The distal femoral expandable intramedullary nail according to claim 3, characterized in that: The outer end surface of the elastic expansion strip (7) is provided with a tooth row (10) that increases the frictional force of contact with the medullary cavity wall of the distal femur.

5. The distal femoral distractible intramedullary nail according to claim 4, characterized in that: The internal thread of the hollow pipe is opened inward along the proximal opening, and the proximal end of the intramedullary nail rod (1) is provided with an external thread matching the internal thread.

6. The distal femoral distractible intramedullary nail according to claim 3, characterized in that: The expansion body (4) includes a transition piece (11) matched with the rotation positioning rod (3), and the distal end of the transition piece (11) is connected to a plurality of elastic expansion strips (7) matched one by one in the axial groove (5). The elastic expansion strips (7) are expanded from the axial groove (5) by the extrusion force to form the intramedullary nail rod (1). The distal end of the elastic expansion strip (7) is provided with a screw three (12), and the screw three (12) is connected to the distal end opening of the intramedullary nail rod (1).

7. The distal femoral distractible intramedullary nail according to claim 2, characterized in that: The expansion body (4) includes an elastic expansion claw (13) connected to the distal opening, and a conical expansion rod (14) is movably provided in the middle of the elastic expansion claw (13). The conical expansion rod (14) is connected to the hollow pipe through the external threaded body at the proximal end, and the distal end of the rotating positioning rod (3) is matched with the conical expansion rod (14).

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