Acetabular cup universal blocking screw

Abstract

A universal blocking screw for an acetabulum comprises a blocking sleeve for limiting the position of the acetabulum, the upper end surface of the blocking sleeve is provided with a first spherical groove, the lower end is provided with a ball socket, the ball head of a ball head screw can be rotatably fitted in the ball socket of the blocking sleeve, the screw portion extends outward, the bottom of the first spherical groove and the ball socket are connected through an internal threaded hole, a stop ring is threadedly fitted in the internal threaded hole to limit the retreat of the ball head screw, the screw portion of the ball head screw is provided with a prismatic section for applying torque near the ball head, the top of the ball head of the ball head screw is provided with an inner hexagonal countersunk hole, the inner hole of the stop ring makes way for a tool inserted into the inner hexagonal countersunk hole at the top of the ball head, and the lower end surface of the stop ring is provided with a second spherical groove matching the ball head.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an acetabulum cup universal blocking screw. Background Art

[0002] When total hip replacement is used to treat cases with acetabular bone defects, such as congenital hip dislocation, sequelae of infected hip, aseptic loosening of hip joint, etc., the huge bone defect on the acetabular side causes abnormal stress on the hemispherical acetabular cup, which seriously affects the stability of the acetabular cup after implantation. At present, traditional acetabular screws are usually used to fix the acetabular cup to increase the stability of the acetabular cup. However, traditional acetabular screws fix the acetabular cup through the head of the acetabular screw, and traditional acetabular screws rely on the side of the head to contact the surface of the acetabular cup to fix the acetabular cup. The contact area of the side of the screw head and the acetabular cup is small, and the stress at the contact part is too concentrated, which can easily lead to fixation failure and reduce the stability of the acetabular cup. In addition, this side contact positioning can easily form a large shear force, causing the screw to loosen and fail, requiring the acetabular screw to be re-implanted, thereby increasing the patient's pain, reducing the efficiency of the operation, and increasing medical costs. How to avoid the problem of screw loosening due to shear force has long been unresolved. Summary of the Invention

[0003] The purpose of the present invention is to provide an acetabular cup universal blocking screw to address the deficiencies in the prior art, thereby solving the problem that the traditional acetabular screw has a small contact area with the acetabular cup, the stress at the contact part is too concentrated, which easily leads to fixation failure, reduces the stability of the acetabular cup, and forms a large shear force, causing the screw to loosen and fail.

[0004] The object of the present invention is achieved like this:

[0005] A universal blocking screw for an acetabulum comprises a blocking sleeve for limiting the position of the acetabulum, the upper end surface of the blocking sleeve is provided with a first spherical groove, the lower end is provided with a ball socket, the ball head of a ball head screw can be rotatably fitted in the ball socket of the blocking sleeve, the screw portion extends outward, the bottom of the first spherical groove and the ball socket are connected through an internal threaded hole, a stop ring is threadedly fitted in the internal threaded hole to limit the retreat of the ball head screw, the screw portion of the ball head screw is provided with a prismatic section for applying torque near the ball head, the top of the ball head of the ball head screw is provided with an inner hexagonal countersunk hole, the inner hole of the stop ring makes way for a tool inserted into the inner hexagonal countersunk hole at the top of the ball head, and the lower end surface of the stop ring is provided with a second spherical groove matching the ball head.

[0006] The upper end surface of the retaining ring is provided with a third spherical groove with the same radius as the first spherical groove of the blocking sleeve. The first spherical groove and the third spherical groove are both inferior arc grooves and are used to fit with the outer surface of the acetabular cup.

[0007] The maximum rotation angle of the ball screw in the ball socket of the blocking sleeve is 30°.

[0008] A cylindrical section is provided between the ball head and the prism section of the ball head screw.

[0009] The prism section of the ball head screw is a hexagonal prism.

[0010] The inner hole of the retaining ring is a hexagonal through hole.

[0011] The longitudinal section of the ball socket of the blocking sleeve is in the shape of a major arc.

[0012] The opening diameter of the lower end of the ball socket of the blocking sleeve is smaller than the diameter of the ball head of the ball screw.

[0013] The present invention provides a universal blocking screw for an acetabular cup, comprising a blocking sleeve for limiting the position of the acetabular cup. The blocking sleeve has a first spherical groove on its upper end surface, which abuts against the outer surface of the acetabular cup, thereby achieving surface contact with the acetabular cup, increasing the contact area and ensuring the stability of the acetabular cup. A ball socket is provided at its lower end, and the ball head of a ball screw rotatably fits within the blocking sleeve's socket. The screw portion extends outward, thereby enabling the blocking sleeve to universally rotate about the ball head through the engagement of the socket and the ball head of the ball screw. After the ball screw is implanted, the blocking sleeve can be adjusted according to the position of the acetabular cup to ensure that the first spherical groove of the blocking sleeve abuts against the outer surface of the acetabular cup, achieving surface contact. The bottom of the first spherical groove is connected to the ball socket via an internal threaded hole. A retaining ring is threadedly engaged within the internal threaded hole to limit the retraction of the ball screw. The screw shaft of the ball screw is provided with a prismatic section near the ball head for applying torque. This facilitates the retraction of the ball screw by turning the prismatic section with a wrench after implantation, allowing the retaining sleeve to fit tightly against the outer surface of the acetabular cup. The ball head of the ball screw is provided with a hexagonal countersunk hole at the top of the ball head. The inner hole of the retaining ring makes way for a tool inserted into the hexagonal countersunk hole at the top of the ball head, ensuring that the retaining ring will not be affected when a hexagonal wrench inserted into the hexagonal countersunk hole of the ball screw passes through the inner hole to tighten the ball screw. The lower end surface of the retaining ring is provided with a second spherical groove that matches the ball head. This ensures that the retaining ring does not affect the relative rotation of the ball head and socket. By tightening the retaining ring to tighten the ball head against the socket, the contact area between the retaining ring and the ball head is increased, making the fixing structure of the ball head screw and the blocking sleeve more stable, thereby ensuring the stability of the acetabular cup. The acetabular cup universal blocking screw contacts the acetabular cup surface through the upper end surface of the blocking sleeve, so that the acetabular cup universal blocking screw exerts an axial force on the acetabular cup surface, thereby avoiding the formation of shear force, ensuring that the acetabular cup universal blocking screw is firmly locked and prevents failure.

[0014] The acetabular cup universal blocking screw of the present invention is cleverly designed and easy to implement; the contact area between the acetabular cup universal blocking screw and the acetabular cup is increased, the contact parts are evenly stressed, the implantation process is simple and easy to operate; at the same time, the formation of shear force is effectively avoided, the stability of the acetabular cup is increased, and the surgical effect is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the acetabular cup universal blocking screw;

[0016] Figure 2 A top view of the universal blocking screw of the acetabulum;

[0017] Figure 3 Schematic diagram of the structure of the blocking sleeve;

[0018] Figure 4 Schematic diagram of the structure of a ball head screw;

[0019] Figure 5 This is a structural diagram of the anti-retraction ring;

[0020] Figure 6 It is a side view of the universal blocking screw of the acetabular cup;

[0021] Figure 7 This is the matching diagram of the blocking sleeve and the ball screw;

[0022] Figure 8 This is a diagram showing the coordination between the acetabular cup universal blocking screw and the acetabular cup. DETAILED DESCRIPTION

[0023] refer to Figures 1 to 8A universal blocking screw for an acetabular cup includes a blocking sleeve 1 for limiting the position of the acetabular cup, wherein the upper end surface of the blocking sleeve 1 is provided with a first spherical groove 4, and the lower end is provided with a ball socket 6, and the longitudinal section of the ball socket 6 of the blocking sleeve 1 is in the shape of a major arc. The ball head 7 of a ball head screw 3 is rotatably fitted in the ball socket 6 of the blocking sleeve 1, and the screw portion 9 extends out of the blocking sleeve 1 to cooperate with the bone. The opening diameter of the lower end of the ball socket 6 of the blocking sleeve 1 is smaller than the diameter of the ball head 7 of the ball head screw 3, and the opening diameter of the upper end of the ball socket 6 is smaller than the diameter of the ball head 7 of the ball head screw 3. The maximum rotation angle of the ball head screw 3 in the ball socket 6 of the blocking sleeve 1 is 30°. The bottom of the first spherical groove 4 is connected to the ball socket 6 via an internal threaded hole 5. A retaining ring 2 is threadedly engaged within the internal threaded hole 5 to limit the retraction of the ball screw 3. The screw portion 9 of the ball screw 3 is provided with a prismatic section 8 near the ball head 7 for applying torque. A cylindrical section 10 is provided between the ball head 7 and the prismatic section 8 of the ball screw 3. The prismatic section 8 of the ball screw 3 is hexagonal. This facilitates the retraction of the ball screw 3 by turning the prismatic section 8 with a wrench after implantation, allowing the ball screw 3 to be retracted and the blocking sleeve 1 to fit tightly against the outer surface of the acetabular cup. A hexagonal countersunk hole 11 is provided at the top of the ball head of the ball screw 3. The inner hole of the retaining ring 2 provides space for a tool to be inserted into the hexagonal countersunk hole 11 at the top of the ball head. The inner hole 14 of the retaining ring 2 is a hexagonal through hole. Tightening the retaining ring 2 with a hexagonal wrench that matches the inner hole 14 secures the ball screw 3 to the blocking sleeve 1. The diameter of the inner hole 14 is larger than that of the hexagonal countersunk hole 11, ensuring that when a hexagonal wrench inserted into the hexagonal countersunk hole 11 of the ball screw 3 passes through the inner hole 14 to tighten the ball screw 3, the stop ring 2 will not be affected and will not rotate. The lower end surface of the stop ring 2 is provided with a second spherical groove 12 that matches the ball head 7. This ensures that the stop ring does not affect the rotation of the ball head and the socket when the ball head and the socket rotate relative to each other. By tightening the stop ring to tighten the ball head against the socket, the contact area between the stop ring and the ball head is increased, making the fixed structure of the ball screw and the blocking sleeve more stable, thereby ensuring the stability of the acetabular cup. The upper end surface of the stop ring 2 is provided with a third spherical groove 13 with the same radius as the first spherical groove 4 of the blocking sleeve 1. The first spherical groove 4 and the third spherical groove 13 are both inferior arc grooves, both of which are used to fit the outer surface of the acetabular cup. This further increases the contact area between the acetabular cup universal blocking screw and the acetabular cup, thereby ensuring the stability of the acetabular cup. At the same time, the formation of shear force is avoided to ensure that the universal blocking screw of the acetabular cup is firmly locked to avoid failure.

[0024] The outer peripheral wall of the blocking sleeve 1 of this embodiment is cylindrical, and the diameter of the cylindrical cross-section is 10 mm; the hole depth of the inner hole of the retaining ring 2 is 3 mm; the length of the cylindrical section 10 of the ball screw 3 is 3 mm, the length of the prismatic section 8 is 10 mm, and the maximum rotation angle of the ball screw 3 in the ball socket 6 of the blocking sleeve 1 is 30 °.

[0025] The acetabulum cup universal blocking screw of the present invention is operated in total hip replacement surgery according to the following steps: using an acetabulum grinding rasp to process the acetabulum fossa to a suitable size, selecting a suitable screw insertion position and direction on the bone bed of the bone defect position, so that the first spherical groove of the blocking sleeve and the acetabulum cup surface can be brought into contact after the acetabulum cup universal blocking screw is implanted. After drilling with an electric drill, the acetabulum cup universal blocking screw is manually screwed in to a suitable depth, and an acetabulum cup trial mold is implanted to determine whether the acetabulum cup placement angle is suitable, and whether the positional relationship between the upper end of the blocking sleeve of the acetabulum cup universal blocking screw and the acetabulum cup is suitable. The distance between the upper end of the blocking sleeve of the acetabulum cup universal blocking screw and the acetabulum cup trial mold is preferably 2mm to avoid direct contact. After removing the acetabular cup trial mold, adjust the implantation depth of the acetabular cup universal blocking screw to the appropriate position, adjust the first spherical groove of the blocking sleeve to face the outer surface of the acetabular cup, tighten the retaining ring so that the blocking sleeve and the ball screw are tightly fixed, and at the same time, the upper end face of the retaining ring will not be exposed from the internal threaded hole of the blocking sleeve, and the third spherical groove of the retaining ring is connected to the first spherical groove of the blocking sleeve to form a spherical groove that fits the outer surface of the acetabular cup. Tap and implant the acetabular cup, and use the conventional acetabular screw to fix the acetabular cup. Use a wrench to clamp the prismatic segment of the acetabular cup universal blocking screw and retract the ball screw so that the spherical groove on the upper end face of the acetabular cup universal blocking screw is in surface contact and tightly fitted with the outer surface of the acetabular cup, and lock the acetabular cup universal blocking screw. Implant bone mud at the bone defect site to complete the operation.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A universal blocking screw for an acetabular cup, characterized in that: The invention comprises a blocking sleeve (1) for limiting the position of the acetabulum, wherein the upper end surface of the blocking sleeve (1) is provided with a first spherical groove (4), the lower end is provided with a ball socket (6), the ball head (7) of a ball screw (3) is rotatably fitted in the ball socket (6) of the blocking sleeve (1), the screw portion (9) extends outward, the bottom of the first spherical groove (4) and the ball socket (6) are connected through an internal threaded hole (5), and a retaining ring (2) is threadedly fitted in the internal threaded hole (5) , used to limit the ball screw (3) from retreating, the screw portion (9) of the ball screw (3) is provided with a prism section (8) for applying torque near the ball head (7), the top of the ball head of the ball screw (3) is provided with a hexagonal countersunk hole (11), the inner hole of the retaining ring (2) is provided with a tool for inserting into the hexagonal countersunk hole (11) at the top of the ball head, and the lower end surface of the retaining ring (2) is provided with a second spherical groove (12) matching the ball head (7).

2. The acetabular cup universal blocking screw according to claim 1, characterized in that: The upper end surface of the retaining ring (2) is provided with a third spherical groove (13) having the same radius as the first spherical groove (4) of the blocking sleeve (1); the first spherical groove (4) and the third spherical groove (13) are both inferior arc grooves and are used to fit with the outer surface of the acetabular cup.

3. The acetabular cup universal blocking screw according to claim 1, characterized in that: The maximum rotation angle of the ball screw (3) in the ball socket (6) of the blocking sleeve (1) is 30°.

4. The acetabular cup universal blocking screw according to claim 1, characterized in that: A cylindrical section (10) is provided between the ball head (7) and the prism section (8) of the ball head screw (3).

5. The acetabular cup universal blocking screw according to claim 1, characterized in that: The prism section (8) of the ball head screw (3) is in the shape of a hexagonal prism.

6. The acetabular cup universal blocking screw according to claim 1, characterized in that: The inner hole (14) of the retaining ring (2) is a hexagonal through hole.

7. The acetabular cup universal blocking screw according to claim 1, characterized in that: The longitudinal section of the ball socket (6) of the blocking sleeve (1) is in the shape of a superior arc.

8. The acetabular cup universal blocking screw according to claim 1, characterized in that: The diameter of the lower opening of the ball socket (6) of the blocking sleeve (1) is smaller than the diameter of the ball head (7) of the ball head screw (3).

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