Femoral neck intracapsular pressure relief screw without screw withdrawal limitation

Abstract

Provided is a femoral neck intracapsular pressure relief screw (10) without screw withdrawal limitation. A through hole is axially formed in the screw (10). A constant pitch external thread (11) is formed on the outer surface of a front-end screw head (13). The tail is a rod unthreaded on the outer surface. A through hole (12) radially penetrating along the wall thickness of the screw (10) is formed in the middle of the screw (10), which is positioned within the femoral neck capsule. The interior of the screw (10) communicates with the exterior by means of the through hole (12). The foremost end surface of the screw (10) is 1.5-3.5 centimeters from the front end of the through hole (12). After being inserted, the screw (10) is obliquely fixed and supported below the femoral neck and stably assists in fixing and healing a fracture. The opening at the tail of the screw extends out of the joint capsule, and the through hole (12) in the middle of the screw (10) can guide effusions in the joint capsule out of the joint capsule, allowing the effusions to be absorbed by soft tissue, reducing the pressure in the joint capsule, and promoting fast recovery. Since the tail of the screw (10) is an unthreaded rod, when the femoral neck is shortened during healing, the unthreaded rod at the tail will not limit screw withdrawal but enable automatic screw withdrawal, so that the natural healing of the fracture will not be hindered.

Description

Intracapsular decompression screw for the femoral neck with unlimited screw withdrawal Technical Field

[0001] The utility model relates to medical equipment, in particular to orthopedic implants. Background Art

[0002] Surgical treatment of femoral neck fractures is a common clinical option. During treatment, the fracture site needs to be reduced and fixed, typically using three hollow threaded screws for internal fixation. Considering that intracapsular bleeding at the femoral neck fracture site, if not promptly drained, can lead to increased pressure within the hip joint capsule, a major cause of avascular necrosis of the femoral head, a screw has been invented in the prior art to support and divert the femoral neck fracture site. This screw, a fourth screw for fixation of the femoral neck fracture site—a support screw—is hollow inside and has a through hole extending through the screw wall to serve as a drainage hole. The screw is open at both ends, with external threads on both outer surfaces. While these external threads provide exceptionally stable and strong support, the inventors discovered during clinical treatment that the femoral neck of some patients shortens during healing. When the support screw has threads at both ends, this shortening of the femoral neck restricts screw withdrawal and prevents automatic screw removal, potentially delaying the healing process. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to provide a femoral neck intracapsular decompression screw which can support the femoral neck fracture, facilitate intracapsular decompression and is not limited to nail withdrawal.

[0004] In order to solve the above technical problems, the utility model provides a femoral neck intracapsular decompression screw with no limit on screw withdrawal, characterized in that the interior of the screw is an axial through hole, the outer surface of the front end nail head is an equal-thread external thread, and the outer surface of the tail end of the nail is a smooth rod. A through hole radially penetrating the screw wall thickness is opened in the middle part of the screw, which is placed in the femoral neck capsule to connect the inside of the screw with the outside, and the distance between the front end surface of the screw and the front end of the through hole is 1.5-3.5 cm.

[0005] The through hole is a rectangular hole, and its length direction is consistent with the length direction of the screw.

[0006] The rectangular hole has a size of 10×2 mm.

[0007] The through hole is an elliptical hole, and the long axis direction of the through hole is consistent with the length direction of the screw.

[0008] There are two or more through holes, which are staggered or arranged in a row along the length direction of the screw.

[0009] The diameter of each through hole is 1.5-2.5 mm.

[0010] The tail end of the screw is provided with a screw head, and the screw head contains a hexagonal hole for screwing the screw, and the hexagonal countersunk hole is communicated with the through hole inside the screw.

[0011] The external thread at the front end of the screw has a length of 0.5-1.5 cm, is a fine-tooth cortical bone thread, and is a self-tapping thread.

[0012] Compared to existing technologies, the present invention's unrestricted intracapsular decompression screw for the femoral neck, after insertion, is tilted and fixedly supported beneath the femoral neck, stably assisting in the fixation and healing of the fracture site. The open end of the screw protrudes outside the joint capsule, and the through-hole in the front-center portion of the screw drains fluid accumulated within the joint capsule to the outside, where it is absorbed by the soft tissue, reducing pressure within the joint capsule and aiding faster recovery. Because the screw's tail is a smooth rod, if the femoral neck shortens during the healing process, the smooth rod at the tail will not restrict screw withdrawal but will automatically withdraw, thus preventing the natural healing of the fracture site. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0014] FIG1 is a schematic diagram of the femoral neck intracapsular decompression screw in use according to Example 1 of the present invention.

[0015] FIG2 is a cross-sectional view of the femoral neck intracapsular decompression screw according to Example 1 of the present invention.

[0016] FIG3 is a three-dimensional external view of the intracapsular decompression screw of the femoral neck according to Example 1 of the present invention. DETAILED DESCRIPTION

[0017] As shown in Figures 1-3, the utility model shows a femoral neck intracapsular decompression screw 10 with unlimited screw withdrawal. The cylindrical screw has an axial through-hole inside, an equal-thread external thread 11 on the front end, and a smooth rod on the rear end. A through-hole 12 is provided in the front-center portion of the screw, extending radially through the screw wall, connecting the interior and exterior of the screw. The front end of the through-hole 12 is 1.5-3.5 cm away from the front end of the screw. After the screw is inserted, the through-hole 12 is located within the femoral neck joint capsule, allowing the accumulated fluid to flow through the through-hole into the screw's through-hole and drain from the rear end of the screw into the soft tissue outside the capsule, where it is then absorbed.

[0018] The external thread 11 on the outer surface of the screw head at the front end is a self-tapping thread, preferably a fine-pitch cortical bone thread. The rear end of the screw has a hexagonal countersunk hole for convenient screw insertion, which facilitates screw insertion. The length of the external thread 11 is preferably about 1 cm, preferably within the range of 0.5-1.5 cm. Different sizes can be selected according to the patient's body shape during treatment.

[0019] The through hole 12 is preferably a long rectangular hole with a width of approximately 2 mm. The long rectangular through hole has a larger area, facilitating the flow of accumulated fluid into the screw. Alternatively, an elliptical hole or two or more circular holes arranged in an array may be used, with a small hole diameter of 1.5-2.5 mm. The length of the through hole 12 is axially aligned with the screw, which reduces the impact of the hole on the screw's strength.

[0020] As shown in Figure 1, using the screw of the utility model, the nailing process is as follows:

[0021] 1) Mark the surgical position of the screw on the outside of the greater trochanter 21 of the femur, and insert a guide needle at this position. Insert the guide needle from the outside of the greater trochanter 21 to the bottom of the femoral neck 22. The guide needle enters the joint capsule 23 through the lateral cortex of the femur, then exits from the lesser trochanter 24 and enters the bottom of the femoral head 25.

[0022] 2) Use a cannulated drill to drill along the guide pin;

[0023] 3) Insert the screw 10 of the present invention into the drilled hole. The main body of the screw 10 is positioned outside the cortex of the femoral neck and within the hip joint capsule. The screw head 13 is fixed below the femoral head 25 along the neck-shaft angle 26 toward the femoral head. The through hole 12 is located within the joint capsule 23, and the screw tail 14 is located below the greater trochanter 21 of the femur to facilitate drainage.

Claims

1. A femoral neck intracapsular decompression screw (10) with no limit on screw withdrawal, characterized in that: The interior of the screw is an axially through hole, the outer surface of the front end of the nail head is an equal-thread external thread (11), and the outer surface of the tail end of the nail is a smooth rod. A through hole (12) that radially penetrates the wall thickness of the screw is opened in the middle part of the screw and is placed in the femoral neck capsule to connect the inside of the screw with the outside, and the distance between the front end surface of the screw and the front end of the through hole (12) is 1.5-3.5 cm.

2. The unlimited screw withdrawal intracapsular decompression screw (10) for the femoral neck according to claim 1, characterized in that: The through hole (12) is a rectangular hole, and its length direction is consistent with the length direction of the screw.

3. The femoral neck intracapsular decompression screw (10) according to claim 2, characterized in that: The rectangular hole has a size of 10×2 mm.

4. The intracapsular decompression screw (10) for the femoral neck with unlimited screw withdrawal according to claim 1, characterized in that: The through hole (12) is an elliptical hole, and the direction of its long axis is consistent with the length direction of the screw.

5. The unlimited screw withdrawal intracapsular decompression screw (10) for the femoral neck according to claim 1, characterized in that: The through holes (12) are two or more and are staggered or arranged in a row along the length direction of the screw.

6. The unlimited screw withdrawal intracapsular decompression screw (10) for the femoral neck according to claim 5, characterized in that: The diameter of each through hole is 1.5-2.5 mm.

7. The unlimited screw withdrawal intracapsular decompression screw (10) for the femoral neck according to any one of claims 1 to 6, characterized in that: The tail end of the screw is provided with a screw head, and inside the screw head is a hexagonal hole (14) for screwing the screw, and the hexagonal countersunk hole is communicated with the through hole inside the screw.

8. The unlimited screw withdrawal intracapsular decompression screw (10) for the femoral neck according to any one of claims 1 to 6, characterized in that: The external thread (11) at the front end of the screw has a length of 0.5-1.5 cm, is a fine-pitch cortical bone thread, and is a self-tapping thread.

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