CN113208781A

CN113208781A - Acetabular cup prosthesis

Info

Publication number: CN113208781A
Application number: CN202010071018.6A
Authority: CN
Inventors: 胡肖强; 董骧
Original assignee: Beijing Naton Medical Technology Holdings Co Ltd
Current assignee: Beijing Naton Medical Technology Holdings Co Ltd
Priority date: 2020-01-21
Filing date: 2020-01-21
Publication date: 2021-08-06
Anticipated expiration: 2040-01-21
Also published as: CN113208781B

Abstract

The invention discloses an acetabular cup prosthesis, which belongs to the technical field of medical prosthesis and comprises an outer cup and a lining, wherein the inner surface of the outer cup is circumferentially provided with a leaning surface; the outer surface of the lining is provided with a convex snap ring at a bearing part and an elastic locking tongue buckle at a non-bearing part; the raised snap ring and the elastic locking tongue are both abutted against the abutting surface so as to self-lock the inner liner in the outer cup. The acetabular cup prosthesis can ensure the thickness of the lining to the maximum extent, reduces the bone cutting amount of a patient as much as possible, and is easy to mount, difficult to detach and firm to fix.

Description

Acetabular cup prosthesis

Technical Field

The invention relates to the technical field of medical prosthesis, in particular to an acetabular cup prosthesis for hip arthroplasty.

Background

Acetabular cup prostheses are one of the most widely used prostheses in hip arthroplasty and are generally constructed from a metal outer cup with a polyethylene liner. In the operation, the metal outer cup is firstly driven into the acetabulum of a human body, and then the polyethylene lining is installed in the metal outer cup. On one hand, a doctor can easily install the polyethylene lining into the metal outer cup in an operation, and on the other hand, the polyethylene lining is required to be tightly attached and stably fixed in the metal outer cup and cannot loosen or fall off due to the fact that the acetabulum cup prosthesis is required to bear the weight of a human body and the continuous impact of walking load for many years after being installed. Thus, the assembly of the inner liner in the outer cup serves three main functions: easy to be loaded, not easy to be separated and fixed firmly.

Since the cup and liner are in contact with one spherical inner surface and one spherical outer surface, achieving a perfect tight fit requires that the two spherical surfaces be perfectly identical, which is almost impossible due to tolerances during machining. Moreover, the requirements of the locking structures of the outer cup and the inner liner meet the requirements that the inner liner is easy to drive in, and the locking is firm and difficult to remove, which is a pair of contradictions, so that many existing acetabulum products are firm in locking but difficult to drive in; or easy driving and easy loosening.

In addition, in order to ensure sufficient strength and wear resistance, the polyethylene lining is required to have a certain thickness at the main bearing part, generally not less than 5 mm, and the thicker the polyethylene lining, the better. However, in order to minimize the osteotomy of the patient during the operation, the implanted acetabular cup prosthesis cannot be too large, and therefore the polyethylene liner cannot be too thick, and the minimum thickness of the bearing portion is difficult to ensure by redesigning the necessary locking structure on the liner, which is originally limited in thickness.

Disclosure of Invention

The invention aims to solve the technical problem of providing an acetabular cup prosthesis which can ensure the thickness of a lining to the maximum extent, reduce the bone cutting amount of a patient as much as possible, is easy to install, is not easy to fall off and is firmly fixed.

In order to solve the technical problems, the invention provides the following technical scheme:

an acetabular cup prosthesis comprising an outer cup and a liner, wherein:

the inner surface of the outer cup is circumferentially provided with an abutting surface;

the outer surface of the lining is provided with a convex snap ring at a bearing part and an elastic locking tongue buckle at a non-bearing part;

the raised snap ring and the elastic locking tongue are both abutted against the abutting surface so as to self-lock the inner liner in the outer cup.

Furthermore, an annular groove with a triangular longitudinal section is arranged on the inner surface of the outer cup along the circumferential direction, and one side wall of the annular groove close to the opening part of the outer cup is the abutting surface;

or the inner surface of the outer cup is provided with an annular bulge along the circumferential direction, and one side wall of the annular bulge, which is far away from the opening part of the outer cup, is the abutting surface.

Further, the resilient locking tab is formed by digging a tangential groove in the outer surface of the liner, the resilient locking tab facing away from the bottom of the liner.

Further, an extension line of the acting force of the abutting surface facing the elastic locking tongue is positioned below the middle point of the root of the elastic locking tongue.

Furthermore, the elastic locking tongue buckle is provided with an inner side surface, an outer side surface parallel to the inner side surface and a top surface vertical to the inner side surface and the outer side surface, and an included angle between the abutting surface and the top surface of the elastic locking tongue buckle is 0-5 degrees.

Furthermore, an included angle between the outer side surface of the elastic locking tongue buckle and the central axis of the lining is 40-50 degrees.

Furthermore, the occupation angle of the convex snap ring in the circumferential direction is 90-180 degrees.

Furthermore, the raised snap ring is a continuous whole section or a plurality of sections arranged at intervals.

Furthermore, the outer edge of the opening of the inner lining is provided with a protruding part, and the inner edge of the opening of the outer cup is provided with a concave part matched with the protruding part.

Furthermore, a connecting line between any point on the abutting surface and the center of the circle of the opening part of the outer cup, and the included angle between the connecting line and the horizontal plane is more than or equal to 45 degrees.

Further, the bottom of the outer cup is provided with a screw hole and/or an instrument operation hole.

The invention has the following beneficial effects:

according to the acetabular cup prosthesis, the lining is an asymmetric locking structure, the locking structure is divided into two parts by the design, and structures such as an elastic locking tongue buckle and the like which need to lose the thickness of the lining are placed at a non-bearing part, so that the condition that the acetabular cup prosthesis is too large due to the excessively thick lining is avoided, and the bone cutting amount of a patient is reduced as much as possible; the bearing part adopts a fixed raised snap ring design to ensure the thickness of the lining to the maximum extent, ensure that the lining has enough strength and wear resistance, and the structures of the bearing part and the non-bearing part of the lining are matched with the abutting surface on the outer cup together to realize the locking of the lining. And when the inner liner is locked in the outer cup, the elastic locking tongue fastener is pressed on the abutting surface of the outer cup by elasticity, and an outer supporting elastic structure is formed on the spherical surface below the inner liner, so that a gap possibly generated due to machining errors is eliminated, and the outer spherical surface of the inner liner is tightly pressed on the inner spherical surface of the outer cup. Therefore, the acetabular cup prosthesis can ensure the thickness of the lining to the maximum extent, reduces the bone cutting amount of a patient as much as possible, and is easy to mount, difficult to detach and firm to fix.

Drawings

FIG. 1 is a schematic structural view of an outer cup of the acetabular cup prosthesis of the invention, wherein (a) is a perspective view, (b) is a top view, and (c) is a cross-sectional view;

FIG. 2 is a schematic structural view of the liner of the acetabular cup prosthesis of the invention, wherein (a) is a perspective view, (b) is a top view, and (c) is a cross-sectional view;

FIG. 3 is a schematic structural view of the acetabular cup prosthesis of the invention in an assembled state, wherein (a) is a perspective view and (b) is a sectional view;

FIG. 4 is a schematic view of the acetabular cup prosthesis of the invention in use;

FIG. 5 is a schematic view of the direction of the force applied by the outer cup to the liner of the acetabular cup prosthesis of the invention;

FIG. 6 is a schematic view of the angle of the contact area between the outer cup and the liner of the acetabular cup prosthesis of the invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides an acetabular cup prosthesis, as shown in fig. 1-3, comprising an outer cup 1 and a liner 2, wherein:

the inner surface of the outer cup 1 is provided with an abutting surface 11 along the circumferential direction, and the abutting surface 11 can be realized in the following ways:

the first method is as follows:

as shown in fig. 1, an annular groove 12 with a triangular longitudinal section is circumferentially arranged on the inner surface of the outer cup 1, and one side wall of the annular groove 12 close to the outer cup opening 13 is the abutting surface 11.

The second method comprises the following steps:

the inner surface of the outer cup is provided with an annular bulge (not shown) along the circumferential direction, and one side wall of the annular bulge, which is far away from the opening part of the outer cup, is the abutting surface.

The third method comprises the following steps:

it will be appreciated by those skilled in the art that the abutment surfaces may also be formed by one and two of the above-described means together.

As shown in fig. 2, a raised snap ring 21 is arranged on the outer surface of the liner 2 at the bearing position, and an elastic locking tongue 22 is arranged at the non-bearing position, wherein the bearing position is the position which has the main bearing function after the acetabular cup prosthesis is implanted into the human body, and the non-bearing position is the position which has the non-main bearing function after the acetabular cup prosthesis is implanted into the human body, as is well known, the direction of the liner is that the opening 23 inclines downwards, and the liner is internally matched with the femoral head prosthesis 3, as shown in fig. 4, the part of the liner 2 above the horizontal transverse line L1 is the bearing position, the part below the horizontal transverse line L1 is the non-bearing position, and the bearing position usually occupies about 1/3 of the whole area of the liner 2;

at the bearing part, the design of the fixed convex snap ring 21 is adopted, the thickness of the lining is not lost due to the clamping structure, the thickness of the lining 2 can be ensured to the maximum, and at the non-bearing part, the design of the elastic locking tongue buckle 22 is adopted, the elasticity can be obtained to the maximum, the fixing effect of the lining 2 and the outer cup 1 is ensured, and meanwhile, the implantation of the lining 2 is easier. The elastic locking tongues 22 are preferably formed by cutting tangential grooves 24 on the outer surface of the lining 2, which tangential grooves 24 will consume a certain thickness of the lining 2, thus reducing to a certain extent the amount of osteotomy of the patient; the elastic locking tongue 22 faces away from the bottom 25 of the lining 2.

During the use, protruding snap ring 21 and the elastic locking tongue 22 on the inside lining 2 all lean on with outer cup 1 on support to face 11 and lean on in order to lock inside lining 2 in outer cup 1, and is concrete, when inside lining 2 is impressed outer cup 1, the elastic locking tongue 22 of inside lining 2 can inwards compress in order to make things convenient for the assembly, relies on elasticity to outwards pop out after packing into, withstands outer cup 1 support to face 11, tightly dies the interior sphere of the outer sphere of inside lining 2 and outer cup 1 (figure 3), forms the auto-lock. Wherein, the extension/height of the abutting surface 11 in the vertical direction compensates the processing error of the two parts of the outer cup 1 and the inner liner 2, and as long as the processing error of the two parts is within the required tolerance range, the elastic locking tongue 22 of the inner liner 2 can abut against the abutting surface 11 of the outer cup 1, so that the spherical surfaces of the two parts are tightly pressed and fixed without gap.

In the invention, the lining is an asymmetric locking structure, the locking structure is divided into two parts by the design, and structures such as an elastic locking tongue buckle and the like which need to lose the thickness of the lining are placed at a non-bearing part, so that the condition that the acetabular cup prosthesis is too large due to the over-thick lining can be avoided, and the bone cutting amount of a patient is reduced as much as possible; the bearing part adopts a fixed raised snap ring design to ensure the thickness of the lining to the maximum extent, ensure that the lining has enough strength and wear resistance, and the structures of the bearing part and the non-bearing part of the lining are matched with the abutting surface on the outer cup together to realize the locking of the lining. And when the inner liner is locked in the outer cup, the elastic locking tongue fastener is pressed on the abutting surface of the outer cup by elasticity, and an outer supporting elastic structure is formed on the spherical surface below the inner liner, so that a gap possibly generated due to machining errors is eliminated, and the outer spherical surface of the inner liner is tightly pressed on the inner spherical surface of the outer cup. Therefore, the acetabular cup prosthesis can ensure the thickness of the lining to the maximum extent, reduces the bone cutting amount of a patient as much as possible, and is easy to mount, difficult to detach and firm to fix.

As shown in fig. 5-6, when liner 2 of the acetabular cup prosthesis is pushed outward, external force F acting on the top of resilient locking tab 22 may be decomposed into a positive pressure perpendicular to abutting face 11 and a frictional force between resilient locking tab 22 and abutting face 11 parallel to abutting face 11, where θ is the angle of friction between resilient locking tab 22 and abutting face 11, e.g., the angle of friction between polyethylene and titanium alloy θ is about 10-15 degrees. In order to ensure that the lining 2 is not easy to be separated, the extension line of the acting force F of the abutting surface 11 on the elastic locking tongue buckle 22 is preferably positioned below the root midpoint O of the elastic locking tongue buckle 22, so that the elastic locking tongue buckle 22 is always pressed to the bottom of the abutting surface 11 of the outer cup when deformed under the action of external force, and the lining 2 is locked and not easy to be separated. To further achieve this, the resilient locking tongue 22 preferably has an inner side 221, an outer side 222 parallel to the inner side 221, and a top 223 perpendicular to both the inner side 221 and the outer side 222, and the angle α between the abutting surface 11 and the top 223 of the resilient locking tongue 22 is 0-5 degrees, so that the contact point between the two surfaces is kept at the outer sharp point at the top of the resilient locking tongue 22 (i.e. the intersection of the outer side 222 and the top 223), resulting in further downward movement of the extension line of the resultant force of the positive pressure and the friction force, enhancing the locking function. The point O may be a central point of a root connecting line of the elastic locking tongue 22, and the root connecting line is specifically a straight line formed by connecting a connecting point of the inner side 221 and the lining 2 and a connecting point of the outer side 222 and the lining 2.

As shown in fig. 6, in order to minimize the resistance when the lining 2 is installed, the included angle δ of the elastic locking tongue 22 with the vertical direction (i.e. the included angle between the outer side surface 222 (or the extension line thereof) of the elastic locking tongue 22 and the central axis of the lining 2 (shown as the vertical line L2) should be minimized to reduce the resistance, but too small an included angle δ may reduce the outward springing range of the elastic locking tongue 22 and affect the locking of the lining 2, and preferably 40-50 degrees.

In the embodiment of the invention, as shown in fig. 2, the angle of the raised snap ring 21 in the circumferential direction is preferably 90-180 degrees, and the liner 2 is locked by the cooperation of the opposite elastic locking tongue 22, the angle is too small to cover the bearing part/range of the acetabular cup prosthesis, and the angle exceeding 180 degrees causes interference due to the lack of elasticity of the raised snap ring 21, and the reliability of the liner 2 fixation is lost. The raised snap ring 21 may be a continuous whole section or may be a plurality of sections arranged at intervals. The height of raised snap ring 21 above the outer surface of liner 2 may be different from the height of resilient locking tab 22 above the outer surface of liner 2. Preferably, the height of the raised snap ring 21 is lower than the height of the resilient locking tongue 22, which facilitates easier loading of the liner 2 into the outer cup 1.

In the embodiment of the invention, the acetabular cup prosthesis can also be provided with an anti-rotation structure, namely, as shown in fig. 1-2, the outer edge of the opening of the inner liner 2 is provided with a protruding part 26, and the inner edge of the opening of the outer cup 1 is provided with a concave part 14 matched with the protruding part 26, so that the two parts are matched to prevent the rotation between the outer cup 1 and the inner liner 2. The number of the protruding portions 26 may be one or more, and the number of the recessed portions 14 may be one or more. The bottom of the outer cup 1 can be provided with screw holes 15 so as to fix the outer cup 1 in the acetabulum of a human body through screws; and/or, the bottom of the outer cup 1 can be provided with an instrument operation hole 16 so as to facilitate the clamping of the outer cup 1 by an instrument. As shown in fig. 1 (c), a connecting line L3 between any point on the abutting surface 11 and the center of the opening 13 of the outer cup, the angle β between the connecting line L3 and the horizontal plane is greater than or equal to 45 degrees, preferably 45 degrees, so that the position of the abutting surface 11 in the outer cup 1 is far away from the cup mouth, thereby being suitable for more types of liners 2 and being compatible with polyethylene liners and ceramic liners. In addition, the outer cup 1 is preferably made of metal such as titanium alloy, and the liner 2 is preferably made of polyethylene.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An acetabular cup prosthesis, comprising an outer cup and an inner liner, characterized in that,

2. The acetabular cup prosthesis according to claim 1, wherein the inner surface of the outer cup is circumferentially provided with an annular groove with a triangular longitudinal section, and a side wall of the annular groove close to the opening of the outer cup is the abutting surface;

3. The acetabular cup prosthesis of claim 1, wherein the resilient locking tab is formed by digging a tangential groove on an outer surface of the liner, the resilient locking tab facing away from a bottom of the liner.

4. An acetabular cup prosthesis according to any one of claims 1 to 3 wherein an extension of the force of abutment against the resilient locking tongue lies below a root midpoint of the resilient locking tongue.

5. The acetabular cup prosthesis of claim 4, wherein the resilient locking tab has an inner side, an outer side parallel to the inner side, and a top side perpendicular to the inner and outer sides, and the abutment surface is at an angle of 0-5 degrees to the top side of the resilient locking tab.

6. The acetabular cup prosthesis of claim 5, wherein an angle between an outer side surface of the resilient locking tab and a central axis of the liner is 40-50 degrees.

7. The acetabular cup prosthesis of any of claims 1-3, wherein the raised snap ring has a circumferential footprint of 90-180 degrees.

8. The acetabular cup prosthesis of claim 7, wherein the raised snap ring is a continuous, one-piece segment or a plurality of spaced-apart segments.

9. The acetabular cup prosthesis of any of claims 1-3, wherein the outer open rim of the inner liner is provided with a protrusion and the inner open rim of the outer cup is provided with a recess that mates with the protrusion.

10. An acetabular cup prosthesis according to any one of claims 1 to 3 wherein a line drawn between any point on the abutment surface and the centre of the open portion of the outer cup is at an angle of 45 degrees or greater to the horizontal.