Distal tibia fixator

Abstract

A kind of tibial distal fixator, including retrograde intramedullary nail, multiple guide wires, multiple cannulated locking screws, nail driver and locking screw;Retrograde intramedullary nail is connected with nail driver by locking screw;The tail of retrograde intramedullary nail is provided with intramedullary nail locking thread, the head of nail driver is provided with nail driver locking thread, the tail of retrograde intramedullary nail and the head of nail driver abut, locking screw is inserted into nail driver and retrograde intramedullary nail, and is threadedly connected with nail driver locking thread of nail driver, intramedullary nail locking thread of retrograde intramedullary nail.The tibial distal fixator of the utility model, innovatively carries out optimization adjustment to screw hole shape, on the basis of retaining the basic function of fixed screw hole, it is designed as two modes of one-way adjustable and two-way adjustable, to greatly improve the success rate of installation.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, and in particular to a distal tibial fixator for surgical treatment of distal tibial fractures. Background Technology

[0002] Traditional intramedullary nails were once widely used in the treatment of distal tibial fractures; however, their drawbacks have become increasingly apparent, easily leading to various complications. Due to misalignment of force distribution, prolonged use of traditional intramedullary nails can cause abnormal traction and wear on the soft tissues, ligaments, and articular surfaces around the knee joint, resulting in pain and severely affecting the patient's postoperative activity and rehabilitation.

[0003] Due to the unique anatomical structure of the distal tibia, traditional intramedullary nails present significant challenges in accurately reducing fracture ends, especially when the fracture line and displacement are complex. This undoubtedly poses a risk to fracture healing. Furthermore, traditional intramedullary nails may disrupt blood circulation at the fracture site, leading to insufficient supply of nutrients and growth factors necessary for fracture healing. This can result in delayed fracture healing and, in severe cases, even nonunion, causing immense suffering and a heavy financial burden for patients.

[0004] Retrograde intramedullary nailing, as a novel minimally invasive internal fixation method, has been clinically proven to have good therapeutic effects. It can better adapt to the anatomical characteristics of the distal tibia, has strong stability during fixation, causes less damage to soft tissues and blood vessels, and is conducive to fracture healing.

[0005] However, retrograde intramedullary nailing also has its drawbacks. Its banana-shaped design makes it prone to collision and jamming with the medullary canal wall during placement due to the complex structure of the medullary canal and individual differences, leading to placement failure. This places high demands on the surgeon's skill level. Furthermore, the fixed design of the nail holes in retrograde intramedullary nails makes it difficult to meet the flexible and personalized fixation needs of different patients with varying fracture types, locations, and individual bone differences, thus affecting its clinical application effectiveness and scope.

[0006] Traditional retrograde intramedullary nailing has a fixed placement angle and position. Although the patent application number 201911020975.X provides multiple size specifications to improve applicability, it is still difficult to cope with many unexpected situations in actual clinical applications. After all, there are significant individual differences in human bones, and even if a seemingly suitable size is selected, there may be problems with the screws not being able to stay in place after installation. Once this happens, it is necessary to remove the intramedullary nail and replace it, which undoubtedly increases the complexity of the operation and the patient's suffering.

[0007] The inventors designed a novel retrograde intramedullary nail that enhances placement success rates. The screws can accommodate greater implantation angles, expanding the adjustable range and thus adapting to more fracture types and meeting the needs of special patients. To facilitate angle adjustment, the locking hole angle of the retrograde intramedullary nail has been adjusted, further broadening the adjustment range. Summary of the Invention

[0008] In view of the above-mentioned defects in the prior art, the purpose of this utility model is to provide a distal tibial fixator for surgical treatment of distal tibial fractures.

[0009] The objective of this utility model is achieved through the following technical solution:

[0010] A distal tibial fixator includes a retrograde intramedullary nail, multiple guide wires, multiple cannulated locking screws, a nail inserter, and locking screws. The retrograde intramedullary nail and the nail inserter are connected by the locking screws. The tail of the retrograde intramedullary nail is provided with an intramedullary nail locking thread, and the head of the nail inserter is provided with a nail inserter locking thread. The tail of the retrograde intramedullary nail abuts against the head of the nail inserter. The locking screws are inserted into the nail inserter and the retrograde intramedullary nail, and are threadedly connected to the nail inserter locking thread of the nail inserter and the intramedullary nail locking thread of the retrograde intramedullary nail.

[0011] Furthermore, the proximal segment of the retrograde intramedullary nail is provided with a first threaded hole and a second threaded hole, and the proximal segment of the retrograde intramedullary nail is provided with a third threaded hole, a fourth threaded hole, and a fifth threaded hole; a hollow locking screw is installed in the first threaded hole, the second threaded hole, the third threaded hole, the fourth threaded hole, and the fifth threaded hole, and the guide wire is disposed in the hollow locking screw.

[0012] Furthermore, retrograde intramedullary nails are divided into solid and hollow structures.

[0013] Furthermore, the angles of the retrograde intramedullary nail with solid structure are as follows: with the proximal midline as the reference, the angle of the first threaded hole is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters and angles of the third, fourth, and fifth threaded holes are all equal, and the angle is γ, ranging from [0-60°].

[0014] Furthermore, the angles of the retrograde intramedullary nail with hollow structure are as follows: with the proximal midline as the reference, the angle of the first threaded hole is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters and angles of the third, fourth, and fifth threaded holes are all equal, and the angle is γ, ranging from [0-60°].

[0015] Furthermore, the hollow locking screw is a cortical bone screw or a cancellous bone screw with a diameter of 3.5 mm or 4 mm and a length of 18-40 mm; the retrograde intramedullary nail has a length of 105-145 mm; the locking screw has a length of 30-60 mm; and all are made of titanium alloy. The guide wire and nail inserter are made of stainless steel.

[0016] Furthermore, the first threaded hole is a bidirectional adjustable threaded hole; the second and fifth threaded holes are fixed threaded holes; and the third and fourth threaded holes are unidirectional adjustable threaded holes.

[0017] Furthermore, the tail end of the retrograde intramedullary nail is provided with a groove, and one end of the nail placement device is provided with a protrusion. The groove and the protrusion cooperate to position the retrograde intramedullary nail and the nail placement device to limit each other. The other end of the nail placement device is provided with a protrusion, which is the mounting point for the aiming frame.

[0018] Compared with the prior art, the features and advancements of this invention are as follows:

[0019] This invention relates to a distal tibial fixator, which innovatively optimizes the shape of the screw holes. While retaining the basic functions of the fixation screw holes, it is designed with both unidirectional and bidirectional adjustable modes, significantly improving the success rate of installation. Furthermore, the retrograde intramedullary nail is available in solid and hollow structures. The hollow structure allows for a wider range of angle adjustment, while the solid structure provides stronger support. The stress distribution pattern of the hollow intramedullary nail closely matches the physiological stress state of the human skeleton, enabling more effective stress transfer and dispersion, and significantly reducing stress concentration. Although the tibia bears near-full-body pressure when standing, patients typically use assistive devices to stand during fracture recovery, rather than bearing direct weight. The hollow intramedullary nail of this invention allows for a more uniform stress distribution in the fixation structure, creating a more stable mechanical environment for fracture healing. Moreover, the hollow intramedullary nail also offers significant advantages when the patient needs to remove the nail. It is lighter and conforms better to the body under stress than the solid intramedullary nail, allowing the patient to adapt to the post-removal state more quickly and accelerating recovery. This invention provides a distal tibial fixator that significantly increases the accuracy of screw placement during use. Although the patent application with application number 201911020975.X includes a sighting device, the locking screw still fails to place properly during use. Therefore, this invention uses hollow screws for positioning, eliminating the need for a sighting device. After determining the screw placement position using CT images, the guide wire can be directly installed for positioning, allowing for subsequent operations. Attached Figure Description

[0020] Figure 1 : Structural diagram of the distal tibial fixator;

[0021] Figure 2 : Structural diagram of the distal tibial fixator (without the hollow locking screw inserted);

[0022] Figure 3 : Figure 2 Cross-sectional view along the middle AA;

[0023] Figure 4 : Structural diagram of retrograde intramedullary nail;

[0024] Figure 5 : Structural diagram of the nail inserter;

[0025] Figure 6 (a) is a hollow retrograde intramedullary nail; (b) is a solid retrograde intramedullary nail. Detailed Implementation

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

[0027] like Figure 1-5 As shown, a distal tibial fixator includes a retrograde intramedullary nail 1, a guide wire 2, a hollow locking screw 3, a nail inserter 4, and a locking screw 5. The retrograde intramedullary nail 1 and the nail inserter 4 are connected by the locking screw 5. The tail of the retrograde intramedullary nail 1 is provided with an intramedullary nail locking thread 6, and the head of the nail inserter 4 is provided with a nail inserter locking thread 7. The tail of the retrograde intramedullary nail 1 abuts against the head of the nail inserter 4. The locking screw 5 is inserted into the nail inserter 4 and the retrograde intramedullary nail 1 and is threadedly connected to the nail inserter locking thread 7 of the nail inserter 4 and the intramedullary nail locking thread 6 of the retrograde intramedullary nail 1. The proximal segment of the retrograde intramedullary nail 1 is provided with a first threaded hole 8 and a second threaded hole 9, and the proximal segment of the retrograde intramedullary nail 1 is provided with a third threaded hole 10, a fourth threaded hole 11, and a fifth threaded hole 15; hollow locking screws 3 are installed in the first threaded hole 8, the second threaded hole 9, the third threaded hole 10, the fourth threaded hole 11, and the fifth threaded hole 15, and guide wires 2 are provided in the hollow locking screws 3.

[0028] The first threaded hole 8 is a bidirectional adjustable threaded hole, and the hollow locking screw 3 can adjust the angle and position of the pin at the first threaded hole 8; the second threaded hole 9 and the fifth threaded hole 15 are fixed threaded holes, and the hollow locking screw 3 cannot adjust the angle and position at the second threaded hole 9 and the fifth threaded hole 15; the third threaded hole 10 and the fourth threaded hole 11 are unidirectional adjustable threaded holes, and the hollow locking screw 3 can adjust the tilt angle when placing the pin at the third threaded hole 10 and the fourth threaded hole 11, but the position cannot be adjusted.

[0029] The retrograde intramedullary nail 1 has a slot 12 at its tail end and a protrusion 13 at one end of the nail inserter 4. The slot 12 and the protrusion 13 cooperate to position the retrograde intramedullary nail 1 and the nail inserter 4 to limit each other. The other end of the nail inserter 4 has a protrusion 14, which is the mounting point for the aiming frame.

[0030] like Figure 6 As shown, the retrograde intramedullary nail 1 comes in solid and hollow structures. The hollow structure allows for a wider angle adjustment range, while the solid structure provides stronger support. Both structures have intramedullary nail locking threads 6 at the tail end. During installation, the tail end of the retrograde intramedullary nail 1 is directly connected to the nail inserter 4 and secured directly by locking screws 5. The two structures of the retrograde intramedullary nail 1 are identical except for the design of the locking screw hole and whether the entire nail is hollow.

[0031] The angles of the solid retrograde intramedullary nail 1 are as follows: with the proximal midline as the reference, the angle of the first threaded hole 8 is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole 9 is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters and angles of the third threaded hole 10, the fourth threaded hole 11, and the fifth threaded hole 15 are all equal, and the angle is γ, ranging from [0-60°].

[0032] The angles of the hollow retrograde intramedullary nail 1 are as follows: with the proximal midline as the reference, the angle of the first threaded hole 8 is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole 9 is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters and angles of the third threaded hole 10, the fourth threaded hole 11, and the fifth threaded hole 15 are all equal, and the angle is γ, ranging from [0-60°].

[0033] During installation, a solid retrograde intramedullary nail 1 can be used for surgical placement, or a hollow locking screw 3 can be used in conjunction with a guide wire 2 for fixation. The hollow locking screw 3 is a cortical bone screw or a cancellous bone screw with a diameter of 3.5mm or 4mm and a length of 18-40mm. The length of the retrograde intramedullary nail 1 is 105-145mm, for example, 110mm, 120mm, or 140mm. The length of the locking screw 5 is 30-60mm, and all are made of titanium alloy. The guide wire 2 and the nail inserter 4 are made of stainless steel. The solid retrograde intramedullary nail 1 has stronger support performance, while the hollow retrograde intramedullary nail 1, through the combination of the guide wire 2 and the hollow locking screw 3, enhances the accuracy of nail placement and reduces the probability of nail placement failure. Furthermore, the aiming frame is relatively expensive; this invention can reduce or replace the use of the aiming frame, thus lowering the operating cost. By combining unidirectional and bidirectional adjustable screw holes with solid or hollow structures, the device can be finely adjusted after implantation into the tibia to find the optimal screw placement angle and reduce patient discomfort.

[0034] The installation process of the distal tibial fixator is as follows: The screw inserter 4 is installed externally at the tail of the retrograde intramedullary nail 1, and then the two are fixed together using locking screws 5. The screw inserter 4 is then mounted on a sighting device (a universal medical device) via its aiming bracket mounting point. Under the action of the sighting device, the retrograde intramedullary nail 1 is placed inside the tibia. After confirming the installation of the retrograde intramedullary nail 1, the locking screw 5 is inserted. The screw placement process involves determining the screw placement angle and position based on CT results, then using guide wire 2 for positioning, determining the installation angle, position, and depth to prevent joint perforation. Next, hollow locking screws 3 are first inserted into the second threaded hole 9 and the fifth threaded hole 15 to fix the retrograde intramedullary nail 1. Then, based on the fixation, hollow locking screws 3 are installed in the third threaded hole 10 and the fourth threaded hole 11, following the same process as before. Finally, the position and angle of the hollow locking screw 3 in the first threaded hole 8 are determined and installed based on the actual installation status.

[0035] However, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Any changes or modifications to the above embodiments that are within the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A distal tibial fixator, characterized in that: The device includes a retrograde intramedullary nail (1), multiple guide wires (2), multiple hollow locking screws (3), a nail placement device (4), and a locking screw (5); the retrograde intramedullary nail (1) and the nail placement device (4) are connected by the locking screw (5); the tail of the retrograde intramedullary nail (1) is provided with an intramedullary nail locking thread (6), the head of the nail placement device (4) is provided with a nail placement device locking thread (7), the tail of the retrograde intramedullary nail (1) abuts against the head of the nail placement device (4), and the locking screw (5) is inserted into the nail placement device (4) and the retrograde intramedullary nail (1), and is threadedly connected to the nail placement device locking thread (7) of the nail placement device (4) and the intramedullary nail locking thread (6) of the retrograde intramedullary nail (1).

2. The distal tibial fixator according to claim 1, characterized in that: The proximal segment of the retrograde intramedullary nail (1) is provided with a first threaded hole (8) and a second threaded hole (9), and the proximal segment of the retrograde intramedullary nail (1) is provided with a third threaded hole (10), a fourth threaded hole (11), and a fifth threaded hole (15); a hollow locking screw (3) is installed in the first threaded hole (8), the second threaded hole (9), the third threaded hole (10), the fourth threaded hole (11), and the fifth threaded hole (15), and the guide wire (2) is provided in the hollow locking screw (3).

3. The distal tibial fixator according to claim 1 or 2, characterized in that: The retrograde intramedullary nail (1) is divided into solid and hollow structures.

4. The distal tibial fixator according to claim 3, characterized in that: The angles of the solid retrograde intramedullary nail (1): with the proximal midline as the reference, the angle of the first threaded hole (8) is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole (9) is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters of the third threaded hole (10), the fourth threaded hole (11), and the fifth threaded hole (15) are all equal, and the angle is γ, ranging from [0-60°].

5. The distal tibial fixator according to claim 3, characterized in that: The angles of the hollow retrograde intramedullary nail (1): with the proximal midline as the reference, the angle of the first threaded hole (8) is α, ranging from [0-70°], and the inner diameter is 3.5-5.5 mm; the angle of the second threaded hole (9) is β, ranging from [0-65°], and the inner diameter is 3.5-5 mm; the diameters of the third threaded hole (10), the fourth threaded hole (11), and the fifth threaded hole (15) are all equal, and the angle is γ, ranging from [0-60°].

6. The distal tibial fixator according to claim 4 or 5, characterized in that: The hollow locking screw (3) is a cortical bone screw or a cancellous bone screw with a diameter of 3.5 mm or 4 mm and a length of 18-40 mm. The retrograde intramedullary nail (1) has a length of 105-145 mm. The locking screw (5) has a length of 30-60 mm. All of them are made of titanium alloy. The guide wire (2) and the nail inserter (4) are made of stainless steel.

7. The distal tibial fixator according to claim 4 or 5, characterized in that: The first threaded hole (8) is a bidirectional adjustable threaded hole; the second threaded hole (9) and the fifth threaded hole (15) are fixed threaded holes; the third threaded hole (10) and the fourth threaded hole (11) are unidirectional adjustable threaded holes.

8. The distal tibial fixator according to claim 4 or 5, characterized in that: The retrograde intramedullary nail (1) has a slot (12) at its tail end, and a protrusion (13) is provided at one end of the nail inserter (4). The slot (12) and the protrusion (13) cooperate to position the retrograde intramedullary nail (1) and the nail inserter (4) to limit each other. The other end of the nail inserter (4) has a protrusion (14), which is the mounting point for the aiming frame.

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