New double-acting hip prosthesis

Abstract

The present invention discloses a novel double-acting hip joint prosthesis, which includes a housing, a gasket and a snap ring. The housing has a first inner surface, and the first inner surface is recessed to form a first accommodating cavity with an opening. The first inner surface includes a first conical surface, and a first annular groove is provided on the first inner surface. The gasket has a second outer surface, and the second outer surface includes a second conical surface, and a second annular groove is provided on the second outer surface. The snap ring has an inner edge and an outer edge. The first accommodating cavity houses the gasket, the first conical surface is in contact with the second conical surface and has an interference fit, the snap ring is arranged between the housing and the gasket, the outer edge is snap-fitted in the first annular groove, and the inner edge is snap-fitted in the second annular groove. In the novel double-acting hip joint prosthesis disclosed by the present invention, there is an interference connection between the housing and the gasket, and at the same time, a snap connection structure is formed by the snap ring, so that the gasket and the housing can withstand a greater disengagement force.

Description

Technical Field

[0001] The present invention relates to the field of prosthetic joints, and particularly to a novel bipolar hip prosthesis. Background Art

[0002] Existing bipolar hip prostheses include a housing and a liner. The housing is usually made of a metallic material, while the liner is usually made of a wear-resistant material, such as metal. An interference fit is adopted between the housing and the liner. As patients' requirements for the performance of prostheses gradually increase, higher requirements are put forward for the connection strength between the housing and the liner. Summary of the Invention

[0003] According to one aspect of the present invention, there is provided a novel bipolar hip prosthesis to improve the connection strength between the housing and the liner. The prosthesis includes:

[0004] A housing having a first inner surface. The first inner surface is recessed to form a first receiving cavity with an opening. The first inner surface includes a first tapered surface and is provided with a first annular groove;

[0005] A liner having a second outer surface. The second outer surface includes a second tapered surface and is provided with a second annular groove; and

[0006] A snap ring having an inner edge and an outer edge;

[0007] Wherein, the first receiving cavity receives the liner, and the first tapered surface is in contact with and interference-fitted with the second tapered surface;

[0008] The snap ring is disposed between the housing and the liner. The outer edge is snap-fitted in the first annular groove, and the inner edge is snap-fitted in the second annular groove.

[0009] The beneficial effect of this embodiment is that an interference fit is adopted between the housing and the liner, and at the same time, a snap connection structure is formed by the snap ring, so that the liner and the housing can withstand a greater disengagement force, and the connection strength between the liner and the housing is improved.

[0010] In some embodiments, the inner edge has a first surface and a second surface adjacent to the first surface. The diameter of the first surface increases in a direction away from the second surface, and the diameter of the second surface increases in a direction away from the first surface. The beneficial effect is that it is easy for the snap ring to be snapped into the second annular groove, but it is very difficult to be disengaged from the second annular groove.

[0011] In some embodiments, the angle α between the first surface and the central axis CC' of the snap ring is 32 to 45°, and the angle β between the second surface and the central axis CC' is 45 to 60°. The beneficial effect is that it is easy for the snap ring to be snapped into the second annular groove, but it is very difficult to be disengaged from the second annular groove.

[0012] In some embodiments, the outer edge has a third surface, which is a concave surface. The third surface faces the open end of the first accommodating cavity and abuts against the first annular groove. The beneficial effect is that it is relatively easy for the outer edge to deform when being snapped into the first annular groove, but it is very difficult for the outer edge to deform when being disengaged from the first annular groove.

[0013] In some embodiments, the snap ring further includes a fourth surface and a fifth surface. The fourth surface is connected between the second surface and the third surface. The fifth surface is adjacent to the first surface and is an inclined surface. The fifth surface extends from the first surface towards the third surface. The beneficial effect is that the fifth surface is inclined, which is conducive to the outer edge of the snap ring being snapped into the first annular groove.

[0014] In some embodiments, the snap ring further includes a sixth surface, which is connected between the third surface and the fifth surface. The beneficial effect is that the sixth surface appropriately increases the thickness of the outer edge, which is beneficial to improving the clamping strength between the snap ring and the housing.

[0015] In some embodiments, the first annular groove has a first surface, a second surface and a third surface. The second surface forms the bottom surface of the first annular groove. The first surface is opposite to the third surface. The third surface faces the open end of the first accommodating cavity, and the first surface faces the bottom of the first accommodating cavity. The beneficial effect is that the first annular groove receives the outer edge of the snap ring, and the outer edge abuts against the first surface.

[0016] In some embodiments, the second annular groove has a fourth surface, a fifth surface and a sixth surface. The fifth surface forms the bottom surface of the second annular groove. The fourth surface is opposite to the sixth surface. The included angle α between the fourth surface and the central axis BB' is 32 to 45°, and the included angle β between the fifth surface and the central axis BB' is 45 to 60°. The beneficial effect is that the shape of the second annular groove matches the shape of the inner edge of the snap ring and is used to receive the inner edge of the snap ring to form a clamping structure.

[0017] In some embodiments, the second outer surface further includes a second bottom surface. The second conical surface extends away from the second bottom surface, and the diameter of the second conical surface becomes larger. The second bottom surface extends away from the second conical surface, and the diameter of the second bottom surface becomes smaller. The second annular groove is provided at the junction of the second conical surface and the second bottom surface. Or the first inner surface further includes a first bottom surface. The first conical surface extends from the first bottom surface towards the open direction of the first accommodating cavity, and the diameter of the first conical surface becomes larger. The first bottom surface extends from the first conical surface towards the bottom direction of the first accommodating cavity, and the diameter becomes smaller. The first annular groove is provided at the junction of the first conical surface and the first bottom surface. The beneficial effect is that the second annular groove is provided at the junction of the second conical surface and the second bottom surface, enabling the second conical surface and the first conical surface to have a larger interference contact area, improving the connection strength between the gasket and the housing. The first annular groove is provided at the junction of the first conical surface and the first bottom surface, enabling the first conical surface and the second conical surface to have a larger interference contact area, improving the connection strength between the gasket and the housing.

[0018] In some embodiments, the retaining ring is made of polyethylene or a polymer with elastic deformation ability. Its beneficial effect is that it has the ability of elastic deformation and can be snapped into the annular groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is an exploded view of a novel double-acting hip prosthesis according to an embodiment of the present disclosure.

[0020] Figure 2 FIG. is a sectional view of a novel double-acting hip prosthesis according to an embodiment of the present disclosure.

[0021] Figure 3 FIG. is a sectional view of a housing according to an embodiment of the present disclosure.

[0022] Figure 4 FIG. is a sectional view of a gasket according to an embodiment of the present disclosure.

[0023] Figure 5 FIG. is a sectional view of a retaining ring according to an embodiment of the present disclosure.

[0024] Figure 6 FIG. is a partial schematic view of three states of a gasket and a retaining ring before, during, and after snap connection according to an embodiment of the present disclosure.

[0025] Figure 7 FIG. is a partial schematic view of three states of a retaining ring and a housing before, during, and after snap connection according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

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

[0027] Please refer to Figure 1 and Figure 2 , the novel double-acting hip prosthesis includes a housing 100, a gasket 200, and a retaining ring 300. The housing 100 is for mounting on the acetabular surface of the hip joint. The gasket 200 is assembled into the housing 100 and is used to provide a wear-resistant surface for the femoral head of the femur or femoral implant. An interference fit is provided between the housing 100 and the gasket 200, and at the same time, a snap connection structure is formed by the retaining ring 300, so that a greater disengagement force can be borne between the gasket 200 and the housing 100.

[0028] Please refer to Figure 3 , the housing 100 has a first inner surface 101 and a first outer surface 102. The housing 100 can be made of metal, such as cobalt-chromium, titanium, stainless steel, or other biocompatible materials. The first outer surface 102 can be spherical or substantially spherical. The first outer surface 102 can be smooth, or can have a textured, rough, or porous morphology to promote bone ingrowth, for example, a rough or porous morphology can be obtained by thermal spraying treatment or 3D printing.

[0029] In Figure 3 In the illustrated embodiment, the first inner surface 101 is recessed into the housing 100 such that the housing 100 forms a first receiving cavity 103 having a circular opening. The first inner surface 101 includes a first conical surface 104 and a first bottom surface 105. The first conical surface 104 is for interference contact with the gasket 200. The first bottom surface 105 is located at the bottom of the first receiving cavity 103. The first conical surface 104 extends from the first bottom surface 105 towards the opening of the first receiving cavity 103, and the diameter of the first conical surface 104 becomes larger along the extending direction. Preferably, the first conical surface 104 extends from the first bottom surface 105 to the opening of the first receiving cavity 103 to obtain a larger interference contact area. The first bottom surface 105 extends from the first conical surface 104 towards the bottom of the first receiving cavity 103, and the diameter becomes smaller along the extending direction. For example, in Figure 3 the illustrated embodiment, the first bottom surface 105 is spherical. In other embodiments, the first bottom surface 105 may also have other shapes, for example, the first bottom surface 105 may be a plurality of connected conical surfaces.

[0030] In Figure 3 the illustrated embodiment, the first inner surface 101 is provided with a first annular groove 106. Preferably, the first annular groove 106 is a continuous groove extending on the first inner surface 101. Preferably, the first annular groove 106 is provided at the position where the first conical surface 104 is connected to the first bottom surface 105. At this time, the first conical surface 104 is located between the opening of the first receiving cavity 103 and the first annular groove 106. Preferably, the plane where the first annular groove 106 is located is perpendicular to the central axis AA' of the housing 100.

[0031] Please refer to Figure 4 , the gasket 200 has a second inner surface 201 and a second outer surface 202. The gasket 200 can be made of a metal material, such as cobalt-chromium, stainless steel or other biocompatible metal materials, or can also be a ceramic material. In Figure 4 the illustrated embodiment, the second inner surface 201 is recessed to form a second receiving cavity 203 having an opening. The second receiving cavity 203 is for receiving the femoral head of the femur or the femoral implant. The second outer surface 202 includes a second conical surface 204 and a second bottom surface 205. The second conical surface 204 is for interference contact with the housing 100. In Figure 4 the illustrated embodiment, the second conical surface 204 extends from the second bottom surface 205 in a direction away from the second bottom surface 205, and the diameter of the second conical surface 204 becomes larger along the extending direction. Preferably, the second conical surface 204 extends from the second bottom surface 205 to the end of the gasket 200 opposite to the second bottom surface 205 to obtain a larger interference contact area. The second bottom surface 205 extends from the second conical surface 204 in a direction away from the second conical surface 204, and the diameter of the second bottom surface 204 becomes smaller along the extending direction. In Figure 4In the illustrated embodiment, the second bottom surface 205 is spherical, and the spherical radius of the second bottom surface 205 is smaller than Figure 3 the spherical radius of the first bottom surface 105 shown, so that when the gasket 200 is fully inserted into the housing 100, the first bottom surface 105 and the second bottom surface 205 will not interfere with each other.

[0032] In Figure 4 the illustrated embodiment, the second outer surface 202 is provided with a second annular groove 206. Preferably, the second annular groove 206 is a continuous groove extending on the second outer surface 202. Preferably, the second annular groove 206 is provided at the position where the second conical surface 204 is connected to the second bottom surface 205, and at this time, the second conical surface 204 is located between the opening of the second accommodating cavity 203 and the second annular groove 206. Preferably, the plane where the second annular groove 206 is located is perpendicular to the central axis BB' of the gasket 200.

[0033] Please refer to Figure 5 , the snap ring 300 has an inner edge 301 and an outer edge 302. The snap ring 300 is in the shape of a continuous circular ring. The snap ring 300 is made of a polymer having a certain elastic deformation ability, such as polyethylene. By utilizing the characteristic that the snap ring 300 can be elastically deformed, the snap connection between the housing 100 and the gasket 200 can be realized, especially when the material of the gasket 200 is a rigid material that is difficult to deform, such as a metal or ceramic material.

[0034] Please refer to Figure 2 , the first accommodating cavity 103 houses the gasket 200, the first conical surface 104 is in contact with the second conical surface 204 and has an interference fit, the snap ring 300 is arranged between the housing 100 and the gasket 200, the first annular groove 106 receives the outer edge 302, and the second annular groove 206 receives the inner edge 301. The first annular groove 106, the second annular groove 206 and the snap ring 300 form a snap connection structure. Between the housing 100 and the gasket 200 of the present disclosure, there is both an interference connection and a snap connection structure, so that a greater disengagement force can be borne between the gasket 200 and the housing 100.

[0035] Please refer to Figure 5, the inner edge 301 has a first surface 303 and a second surface 304. The first surface 303 is adjacent to the second surface 304. The diameter of the first surface 303 increases in the direction away from the second surface 304, and the diameter of the second surface 304 increases in the direction away from the first surface 303. In some embodiments, the central axis CC' passing through the center of the snap ring 300 and perpendicular to the plane where the snap ring 300 is located is defined. The angle α between the first surface 303 and the central axis CC' is 32 to 45°, and the angle β between the second surface 304 and the central axis CC' is 45 to 60°. The first surface 303 and the second surface 304 form two conical surfaces on the inner side of the snap ring 300. It is easy for the snap ring 300 to be snapped into the second annular groove 206, but it is very difficult to be removed from the second annular groove 206. The outer edge 302 has a third surface 305, and the third surface 305 is a concave surface. In Figure 5 In the illustrated embodiment, the third surface 305 is an arc surface, and its radius is 0.5 to 2 mm. The snap ring 300 further includes a fourth surface 306 and a fifth surface 307. The fourth surface 306 is connected between the second surface 304 and the third surface 305. Preferably, the fourth surface 306 is perpendicular or substantially perpendicular to the central axis CC'. The fifth surface 307 is adjacent to the first surface 303. The fifth surface 307 is an inclined surface that extends from the first surface 303 towards the third surface 305, and the diameter increases along the extending direction. In some embodiments, the snap ring 300 further includes a sixth surface 308, and the sixth surface 308 is connected between the third surface 305 and the fifth surface 307. The sixth surface 308 can increase the thickness of the outer edge 302 and improve the anti-removal ability of the snap ring 300. In Figure 5 In the structure of the snap ring 300 shown, the first surface to the sixth surface are all annular surfaces centered on the central axis CC', and the entity surrounded by these six surfaces forms Figure 5 the snap ring 300 shown.

[0036] Please refer to Figure 3 , the first annular groove 106 has a first surface 107, a second surface 108 and a third surface 109. The second surface 108 forms the bottom surface of the first annular groove 106. The first surface 107 is opposite to the third surface 109. The third surface 109 faces the open end of the first accommodating cavity 103, and the first surface 107 faces the bottom of the first accommodating cavity 103. In Figure 3 In the illustrated embodiment, both the first surface 107 and the third surface 109 are perpendicular to the central axis AA'.

[0037] Please refer to Figure 4, the second annular groove 206 has a fourth surface 207, a fifth surface 208 and a sixth surface 209. The fifth surface 208 forms the bottom surface of the second annular groove 206, and the fourth surface 207 is opposite to the sixth surface 209. The second annular groove 206 is configured such that when the snap ring 300 is snapped into the second annular groove 206, the fourth surface 207 contacts the first surface 303, the fifth surface 208 contacts the second surface 304, and the sixth surface 209 contacts the fourth surface 306. In Figure 4 In the illustrated embodiment, the inclination of the fourth surface 207 is the same as that of the first surface 303, that is, the angle between the fourth surface 207 and the central axis BB' is also α, and the range of α is 32 to 45°. The inclination of the fifth surface 208 is the same as that of the second surface 304, that is, the angle between the fifth surface 208 and the central axis BB' is also β, and the range of β is 45 to 60°.

[0038] Figure 6 Schematically shows Figure 4 the illustrated gasket 200 and Figure 5 the three-state partial schematic diagrams of the illustrated snap ring 300 before, during, and after snap connection. Please refer to Figure 6 , when snap-connecting the snap ring 300 and the gasket 200, first sleeve it on the outer periphery of the gasket 200 from the end of the second bottom surface 205, with the second surface 304 of the snap ring 300 facing the second annular groove 206, and then push the snap ring 300 towards the second annular groove 206. In the advancing direction of the snap ring 300, the diameter of the second outer surface 202 becomes larger, so the second surface 202 will squeeze the inner edge 301. From Figure 6 It can be clearly seen that on the one hand, the deformation amount required for the snap ring 300 to snap into the second annular groove 206 is small, and on the other hand, during the snap connection process, the snap ring 300 generates elastic depression and a certain degree of elastic torsion, resulting in an increase in the inner diameter of the snap ring 300. Therefore, the snap ring 300 of the present disclosure can be easily snapped into the second annular groove 206. After the snap ring 300 is snap-connected to the second annular groove 206, the deformation amount required for the snap ring 300 to be disengaged from the second annular groove 206 is very large, and the inner edge 301 of the snap ring 300 is snap-connected to the second annular groove 206 at all circumferential positions. Therefore, it is very difficult for the snap ring 300 of the present disclosure to be disengaged from the second annular groove 206.

[0039] Figure 7 Schematically shows Figure 5 the illustrated snap ring 300 and Figure 3 the three-state partial schematic diagrams of the illustrated housing 100 before, during, and after snap connection. Please refer to Figure 7, when assembling the housing 100, the assembly of the snap ring 300 and the gasket 200 is inserted into the first accommodating cavity 103 of the housing 100, and the assembly is pushed into the first accommodating cavity 103. For example, the assembly can be tapped to move the gasket 200 into the first accommodating cavity 103. During this process, the outer edge 302 of the snap ring 300 slides along the first conical surface 104 towards the first annular groove 106. In the advancing direction of the snap ring 300, the diameter of the first conical surface 104 becomes smaller. Therefore, the outer edge 302 is elastically deformed under the extrusion of the first conical surface 104. As the gasket 200 penetrates deeper into the first accommodating cavity 103, an interference is generated between the first conical surface 104 and the second conical surface 204, and the amount of interference increases as the gasket 200 is pushed forward. Continue to push the gasket 200 until the outer edge 302 snaps into the first annular groove 106, and at this time, the sound of snapping can be heard. After the outer edge 302 snaps in, the third surface 305 faces the open end of the first accommodating cavity 103 and abuts against the first surface 107. When the outer edge 302 snaps into the first annular groove 106, the deformation is relatively easy, but it is very difficult for the outer edge 302 to be deformed when it is disengaged from the first annular groove 106. The conical surface design of the present disclosure can also play a guiding role. When the snap ring 300 snaps into the first annular groove 106, the central axis of the gasket 200 coincides exactly with the central axis of the housing 100.

[0040] For the gasket 200 made of a rigid and difficult-to-deform material, the traditional connection method can only adopt interference connection. However, the novel double-moving hip joint prosthesis of the present disclosure is further clamped by the snap ring 300 on the basis of the interference connection, which further improves the connection strength between the housing 100 and the gasket 200. In the performance study of the novel double-moving hip joint prosthesis in an embodiment of the present disclosure, the housing 100 is fixed, and a thrust is applied to the gasket 200. When the gasket 200 is disengaged from the housing 100, the required thrust is as high as 2900N.

[0041] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A novel double-acting hip joint prosthesis, characterized in that, Comprising: A housing having a first inner surface which is recessed to form a first accommodating cavity with an opening. The first inner surface includes a first conical surface and is provided with a first annular groove; A gasket having a second outer surface which includes a second conical surface and is provided with a second annular groove; and A snap ring having an inner edge and an outer edge; Wherein, the first accommodating cavity houses the gasket, and the first conical surface is in contact with and interference-fitted with the second conical surface; The snap ring is disposed between the housing and the gasket. The outer edge is snap-fitted in the first annular groove, and the inner edge is snap-fitted in the second annular groove; The inner edge has a first surface and a second surface adjacent to the first surface. The diameter of the first surface becomes larger in the direction away from the second surface, and the diameter of the second surface becomes larger in the direction away from the first surface; the first surface and the second surface form two conical surfaces on the inner side of the snap ring; The snap ring is in the shape of a continuous circular ring; the material of the snap ring is polyethylene or a polymer with elastic deformation ability; The outer edge has a third surface which is a concave surface. The third surface faces the open end of the first accommodating cavity and abuts against the first annular groove; The snap ring further includes a fourth surface and a fifth surface. The fourth surface is connected between the second surface and the third surface. The fifth surface is adjacent to the first surface. The fifth surface is an inclined surface which extends from the first surface towards the third surface and the diameter becomes larger along this extending direction; The snap ring further includes a sixth surface which connects the third surface and the fifth surface.

2. The novel double-acting hip joint prosthesis according to claim 1, characterized in that, The angle α between the first surface and the central axis CC' of the snap ring is 32 - 45°, and the angle β between the second surface and the central axis CC' is 45 - 60°.

3. The novel double-acting hip joint prosthesis according to claim 1, characterized in that, The first annular groove has a first surface, a second surface and a third surface. The second surface forms the bottom surface of the first annular groove. The first surface is opposite to the third surface. The third surface faces the open end of the first accommodating cavity, and the first surface faces the bottom of the first accommodating cavity.

4. The novel double-acting hip joint prosthesis according to claim 1, characterized in that, The second annular groove has a fourth surface, a fifth surface and a sixth surface. The fifth surface forms the bottom surface of the second annular groove. The fourth surface is opposite to the sixth surface. The angle α between the fourth surface and the central axis BB' is 32 - 45°, and the angle β between the fifth surface and the central axis BB' is 45 - 60°.

5. The novel double-acting hip joint prosthesis according to claim 1, wherein, The second outer surface further includes a second bottom surface. The second conical surface extends away from the second bottom surface, and the diameter of the second conical surface increases. The second bottom surface extends away from the second conical surface, and the diameter of the second bottom surface decreases. The second annular groove is disposed at the junction of the second conical surface and the second bottom surface. Or the first inner surface further includes a first bottom surface. The first conical surface extends from the first bottom surface towards the opening of the first accommodating cavity, and the diameter of the first conical surface increases. The first bottom surface extends from the first conical surface towards the bottom of the first accommodating cavity, and the diameter decreases. The first annular groove is disposed at the junction of the first conical surface and the first bottom surface.

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