Distal femur distractable intramedullary nail

Abstract

The distal femur distractable intramedullary nail comprises an intramedullary nail rod, a hollow pipeline penetrating through the far end and the near end of the intramedullary nail rod is formed in the axial direction of the intramedullary nail rod, and an internal thread is arranged in the hollow pipeline of the intramedullary nail rod; a locking screw hole is formed in the near end of the intramedullary nail rod, and a near-end locking screw is inserted into the locking screw hole in a matched mode. A rotary positioning rod is arranged in the hollow pipeline of the intramedullary nail rod in a penetrating manner, the rotary positioning rod is provided with an external thread matched with the internal thread, and the far end of the rotary positioning rod is connected with a degradable distraction body which is distraction in the femur. The device has the remarkable advantages that the operation precision and efficiency are improved, adjustment and radiation exposure in the operation are reduced, a secondary operation is avoided, postoperative complications and medical cost are reduced, the fixing effect is enhanced, stable three-dimensional fixation is provided, and fracture healing is promoted.

Description

Technical Field

[0001] The invention relates to an intramedullary nail, in particular to an intramedullary nail capable of being expanded at 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 technical system mainly relies on the following operation process: the intramedullary nail and the external aiming frame need to be pre-assembled during the operation, and the precise placement of the distal locking screw is guided by mechanical positioning. Although this technology has biomechanical advantages such as promoting early weight-bearing, reducing surgical wounds, and realizing dynamic pressurization, its inherent defects have seriously affected the clinical effect: first, there are technical defects during the operation, and there is a problem of spatial positioning inaccuracy. Affected by the triple influence of differences in the curvature of the patient's medullary cavity, fracture morphological variations, and deformation after the intramedullary nail is implanted, the preset positioning of the aiming frame and the actual bone channel are significantly offset, and the position of the external aiming frame needs to be adjusted continuously, forcing the surgeon to repeatedly adjust the position of the instrument and rely on multiple X-ray fluoroscopy verifications, resulting in prolonged operation time and doubled risk of radiation exposure for doctors and patients. Secondly, there are defects in postoperative complications, and there is a risk of secondary trauma. After the fracture heals, additional surgery is required to remove the distal locking screw, resulting in a secondary surgical incision, increasing the risk of infection and nerve damage.

[0004] These technical bottlenecks not only cause serious damage to surgical precision 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 channel penetrating the distal and proximal ends of the intramedullary nail rod is provided along the axial direction of the intramedullary nail rod, and the hollow channel of the intramedullary nail rod has an internal thread;

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

[0008] A rotation positioning rod is inserted into the hollow pipe 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 which is expanded 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 positioning rod is rotated to penetrate into the intramedullary nail rod from the proximal opening and connect to the expansion body.

[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, and an internal thread is provided in the hollow pipe 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 by one in the axial groove, the elastic expansion strip is expanded from the axial groove by the extrusion force, and the screw 2 with the elastic expansion strip is abutted 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 distal end of the femoral medullary cavity wall.

[0014] Furthermore, the external thread of screw one 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 by the extrusion force to form an intramedullary nail rod, and screw three is connected to the distal end of the elastic expansion strip, and screw three is connected to the distal end opening of the intramedullary nail rod.

[0017] Furthermore, the expansion body includes an elastic expansion claw connected to the distal opening, 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 and connected to the conical expansion rod.

[0018] The present invention discloses an expandable intramedullary nail for the distal femur, which solves the two core problems of misaligned positioning during surgery and secondary surgical trauma after surgery of traditional intramedullary nails 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 effect, 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 It is a structural diagram of embodiment 1 of the present invention.

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

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

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

[0023] Figure 5 This is a schematic diagram of the structure of the third embodiment.

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

[0025] In the figure: 1. intramedullary nail rod; 2. proximal locking screw; 3. rotation positioning rod; 4. expansion body; 5. axial groove; 6. screw one; 7. elastic expansion strip; 8. screw two; 9. bendable groove; 10. tooth row; 11. transition piece; 12. screw three; 13. elastic expansion claw; 14. conical expansion rod. DETAILED DESCRIPTION

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

[0027] Embodiment 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, which is made of titanium alloy or stainless steel. A hollow pipe is provided along the axial direction of the intramedullary nail rod 1 and passes through the distal and proximal ends thereof. The hollow pipe of the intramedullary nail rod 1 has an internal thread. It should be noted that the position of the internal thread feature in the hollow pipe 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, and a proximal locking screw 2 is matched and inserted in the locking screw hole for fixing the proximal femur;

[0029] A rotation positioning rod 3 is inserted into the hollow pipe of the intramedullary nail rod 1, and the rotation positioning rod 3 has 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. The hollow pipe forms a proximal opening at the proximal end of the intramedullary nail rod 1, and the hollow pipe 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 connects to the expansion body 4. In this embodiment, the proximal knob of the rotation positioning rod 3 has an external thread, and the external thread can be screwed in and adjusted to the position of the rotation positioning rod 3 in the intramedullary nail rod 1 under the cooperation of the internal thread, so as to achieve the purpose of transmitting the expansion body 4. For example, in this embodiment, 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.

[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 the 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 rotatably connected to the distal end of the rotating positioning rod 3, the external thread of the screw 6 matches the internal thread in the hollow pipe, and the distal end of the screw 6 is connected with a plurality of elastic expansion strips 7 matched one by one in the axial groove 5, and 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 rotating 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, and the elastic expansion strip 7 is expanded from the axial groove 5 by the extrusion force to the intramedullary nail rod 1, and the elastic expansion strip 7 is abutted against the distal end of the elastic expansion strip 7. Screw 2 8 of the elastic expansion strip 7, screw 2 8 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 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 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 medullary cavity wall of the femur.

[0032] Preferably, the elastic expansion strip 7 is provided with a plurality of bendable grooves 9 with openings facing the central axis of the expansion body 4 along the axial direction, so as to facilitate the elastic expansion strip 7 to be squeezed out of the intramedullary nail rod 1 from the axial groove 5. The outer end surface of the elastic expansion strip 7 is provided with a tooth row 10 for increasing the contact friction with the distal femoral medullary cavity wall, so that the elastic expansion strip 7 is firmly fixed to the distal femoral medullary cavity wall.

[0033] After maintaining the expanded shape of the elastic expansion strip 7, the rotation positioning rod 3 can be screwed out and removed from the intramedullary nail rod 1. The screwing out and removal depends on the matching connection relationship between the rotation positioning rod 3 and the screw 6 using the thread head and thread groove. For example, the thread head of the rotation positioning rod 3 adopts a straight groove, a cross, an external hexagonal, and an external plum blossom shape, and the thread groove of the screw 6 correspondingly adopts a straight groove, a cross groove, an internal hexagonal, and a plum blossom shape; conversely, the thread groove of the rotation positioning rod 3 can also adopt a straight groove, a cross groove, an internal hexagonal, and a plum blossom shape, and the thread head of the screw 6 adopts a straight groove, a cross, an external hexagonal, and an external plum blossom shape. 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 it needs to be removed, the intramedullary nail rod 1 can be smoothly removed.

[0034] Embodiment 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 penetrating the distal and proximal ends of the intramedullary nail rod 1 being provided along the axial direction thereof, the hollow tube of the intramedullary nail rod 1 having an internal thread; a locking screw hole being provided at the proximal end of the intramedullary nail rod 1, a proximal locking screw 2 being inserted in the locking screw hole; a rotation positioning rod 3 being 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 degradable expansion body 4 which is expanded in the femur.

[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 into the intramedullary nail rod 1 from the proximal opening and connects to the expansion body 4. Two axial grooves 5 are provided along the circumferential wall of the intramedullary nail rod 1. The two axial grooves 5 are equidistantly close to the end 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 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 and connected to the rotation positioning rod 3, and the distal end of the transition piece 11 is connected to two 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 under the extrusion force. The principle of the expansion of the elastic expansion strip 7 is the same. A screw three 12 of the elastic expansion strip 7 is connected to the distal end of the elastic expansion strip 7. The screw three 12 is connected to the distal 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 between the wire head and the wire groove as in embodiment 1. Therefore, this embodiment also achieves that 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. When it needs to be removed, the intramedullary nail rod 1 can be smoothly removed.

[0039] Embodiment three:

[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 penetrating the distal and proximal ends of the intramedullary nail rod 1 is provided along the axial direction 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 in the locking screw hole; a rotation positioning rod 3 is passed through the hollow tube of the intramedullary nail rod 1, and the rotation positioning rod 3 has an external thread matching the internal thread, and the distal end of the rotation positioning rod 3 is connected to a degradable expander 4 that expands in the femur. 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, and the rotation positioning rod 3 penetrates into the intramedullary nail rod 1 from the proximal opening and connects to the expander 4.

[0041] Different from the above two embodiments, in this embodiment, the expansion body 4 includes an elastic expansion claw 13 connected to the distal opening, and the elastic expansion claw 13 is degradable, including but not limited to degradable polylactic acid, pure magnesium, magnesium alloy, zinc alloy and other medical degradable materials. The middle part of the elastic expansion claw 13 is movably penetrated with a conical expansion rod 14, and the conical expansion rod 14 is connected to the hollow pipe through the external threaded body at its proximal end. The distal end of the rotating positioning rod 3 is matched and connected to the conical expansion rod 14, and the rotating positioning rod 3 rotates to drive the conical expansion rod 14 to rotate and move axially. As the outer diameter of the conical expansion rod 14 in contact with the elastic expansion claw 13 gradually expands, the elastic expansion claw 13 gradually opens, and the distal end of the femoral intramedullary nail is firmly fixed to the distal femoral bone. After the fracture heals, the elastic expansion claw 13 degrades accordingly, and when it needs to be removed, the intramedullary nail rod 1 can be removed smoothly.

[0042] In summary, the present invention solves the problems of spatial positioning misalignment and postoperative secondary surgical trauma existing 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 contacted and fixed with the medullary cavity wall, avoiding the problem of inaccurate positioning of traditional locking screws. Reduce intraoperative adjustments, no need to repeatedly adjust the external aiming frame, and simplify the surgical process. Reduce radiation exposure, reduce the number of X-ray fluoroscopy, 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 make elastic expansion strips or elastic expansion claws of the expansion body. The expansion body gradually degrades after the fracture heals, and no secondary surgery is required to remove it. Avoid secondary surgery, the expansion body does not need to be removed after degradation, and reduces the pain and risk of secondary surgery for patients. Reduce the risk of infection, avoid secondary surgical incisions, and reduce the risk of postoperative infection and nerve damage. Simplify postoperative management, reduce postoperative complications, and reduce medical costs.

[0044] In addition, the elastic expansion structure design is adopted. The expansion body, such as the elastic expansion strip or the elastic expansion claw, can expand in the intramedullary nail rod through the axial groove and the bendable groove design, and closely contact the distal femoral medullary cavity wall to provide a stable three-dimensional fixation effect. The outer end surface of the expansion body is provided with a row of teeth to increase the contact friction with the medullary cavity wall and further enhance the fixation effect. Modular design: The expansion body and the rotating positioning rod adopt a matching connection relationship of a wire head and a wire groove, which is convenient for intraoperative adjustment and postoperative removal, and is easy to operate.

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

Claims

1. A distal femoral expandable intramedullary nail, characterized in that: It comprises an intramedullary nail rod (1), a hollow pipeline is provided along the axial direction of the intramedullary nail rod (1) and passes through the distal and proximal ends thereof, and the hollow pipeline 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 inserted into 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.

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 rotating positioning rod (3) penetrates into the intramedullary nail rod (1) from the proximal opening and connects to the expansion body (4).

3. The distal femoral expandable intramedullary nail according to claim 2, characterized in that: A plurality of axial grooves (5) are provided along the circumferential wall of the intramedullary nail rod (1), and the plurality of axial grooves (5) are 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 pipe at the end portion where the distal opening of the intramedullary nail rod (1) is located.

4. The distal femoral expandable intramedullary nail according to claim 3, characterized in that: The expansion body (4) includes a screw (6) rotatably connected to the distal end of the rotating 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 out of the axial groove (5) by the extrusion force to form an intramedullary nail rod (1); the distal end of the elastic expansion strip (7) is abutted against a screw (8) of the elastic expansion strip (7); the screw (8) is connected to the distal end opening of the intramedullary nail rod (1).

5. The distal femoral expandable intramedullary nail according to claim 4, 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 subjected to the extrusion force to expand the intramedullary nail rod (1) from the axial groove (5).

6. The distal femoral expandable intramedullary nail according to claim 4 or 5, 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 wall of the distal femoral medullary cavity.

7. The distal femoral expandable intramedullary nail according to claim 6, characterized in that: The external thread of the screw 1 (6) matches the internal thread in the hollow pipe.

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

9. The distal femoral expandable 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 strip (7) is expanded from the axial groove (5) by the extrusion force to form an intramedullary nail rod (1). A screw three (12) is connected to the distal end of the elastic expansion strip (7), and the screw three (12) is connected to the distal opening of the intramedullary nail rod (1).

10. The distal femoral expandable 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 inserted into the middle of the elastic expansion claw (13). The conical expansion rod (14) is connected to the hollow pipeline through the external threaded body at its proximal end, and the distal end of the rotating positioning rod (3) is matched and connected to the conical expansion rod (14).

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