SE1930116A1 - Hip prosthesis - Google Patents

Abstract

Hip prosthesis (1) intended to replace an existing hip joint in a person comprising at least one femoral component (2), comprises at least one ball part (5), at least one neck part (6) and at least one stem part (7), and that at least one joint cup (3) which are connected to each other via at least one cohesive member (4), or the like, with the intention of maintaining the engagement between the femoral component (2) and the articular cup (3). The cohesive member (4) consists of a collar (10) which comprises a through hole (11) which is partially enclosed by material and forms an opening (12) which is wider than the maximum width of the neck part (6) and smaller than the diameter on the spherical part (5) of the femoral component. The collar (10) is connected with connecting means to the joint cup and the person's hip bone.

Description

Technical field The present invention relates to a hip prosthesis, with associated cohesive organs, in accordance with the claims. Technical background and prior art In Sweden, a large number of hip surgeries are currently performed in Sweden, of which 11.9% in 2016 are reoperated / reoperated. In said hip joint surgeries, the existing hip joint is replaced by an artificial hip joint prosthesis. The main reason for replacing a hip joint with a one-hip prosthesis is osteoarthritis or some other type of degenerative joint disease. The replacement of the existing hip joint with a hip prosthesis can also be caused by congenital defects in the hip joint and complications after fractures of the femoral neck.

Referring to Figure 1A, a hip joint 30 is shown in principle prior to surgery. The hip joint 30 consists of a joint head 31, which is articulated arranged in a joint head 32 in the pelvis 33. The joint head 32 forms part of the pelvis 33. The joint head 31 connects via the femoral neck 34 to the femur (femur) 35. The hip joint also comprises a ligament that holds the ball joint together. the joint capsule. The ligament prevents the hip parts from dislocating.

Figure 1B shows in principle an artificial hip joint (hip prosthesis) 1 consisting of a femoral component (joint head) 2 and a joint cup (cup) 3 which is implanted in a human. The femoral component (joint head), which is usually made of metal, is connected with cement, or other for the purpose suitable method for the femur. The guide cup 3 is usually connected to the pelvis by screwing or cementing it.

A problem with implanted hip prostheses is that the joint head can break out (luxate) the urethral cup after it has been implanted. The dislocation causes the patient to be immobilized. Dislocations are usually painful and unpleasant, partly due to the fact that the joint head after the dislocation damages (crushes) muscle tissue, which entails a long rehabilitation time. In order to restore the hip joint after a dislocation, medical care is required and sometimes a reoperation of the hip joint must take place with associated costs. The risk of dislocation significantly increases post-surgery, ie after a new hip surgery has been performed. That the risk of dislocation Increases after a reoperation is particularly problematic considering that the patients where reoperation becomes relevant usually have a high age. The advanced age means that the patient usually recovers more slowly after the operation and that the patient does not unusually have other disease pictures, which impairs the patient's ability to recover after the operation.

A number of methods and devices for preventing dislocation of implanting hip prostheses are already known. It is thus known to retain the joint head in the joint cup (cup) by adding material to the edge of the joint cup (cup) after the ball-bearing part of the joint head has been inserted into the joint cup. The procedure means that the hip joint operation takes time, which in turn increases the risk of infections in connection with the procedure.

A number of patented devices and methods have been developed over time to reduce the problems of dislocation of hip prostheses. For example, U.S. Patent No. 5,560,160 discloses a method and apparatus for reducing the risk of dislocation of a hip prosthesis. The hip prosthesis of the patent comprises an elongate cohesive member which holds the femoral portion and joint capsule together. The construction therefore differs to a significant extent from the construction according to the present patent application.

Patent specification US7780739 describes a variant of a hip joint prosthesis. The construction comprises a guide cup which consists of a first part and a second part which are locked together with a single locking ring. The construction differs significantly from the construction in accordance with the present patent application.

The document FR2765473 describes a variant of a hip joint prosthesis which comprises a femoral component with associated ball part which is intended to be connected to a joint cup. The construction differs to a substantial extent from the construction in accordance with the present patent application. For example, the collar lacks protruding segments with holes extending outside the joint cup. Furthermore, the collar does not comprise the corresponding radially shaped recess at the abutment surface against the ball-shaped part.

U.S. Pat. No. 5,989,293 describes a variant of a joint cup for a joint prosthesis. The articular cup includes a articular cup and a cohesive member that holds together the articular cup and a femoral component connected thereto. The cohesive part includes protruding fl ends which are provided with holes. The holes are located at a radial distance that is greater than the maximum radial extent of the articular cup. The holes are intended to be used for screws with which the joint prosthesis is screwed to the hip bone. The construction in accordance with the specification otherwise differs to a substantial extent from the construction in accordance with the present patent application.

Brief Description of Figures In the following detailed description of the present invention, references and references to the following figures will be made. These figures are briefly described in the following list of figures. The hip prostheses shown in the figures constitute exemplary embodiments of the hip joint prosthesis in accordance with the present patent application. The exemplary embodiment of the hip prosthesis is not limiting of the scope of protection of the present patent application. Note that the figures are schematic and that details can thus be omitted in the figures. Figure 1A schematically shows a hip joint before surgery. Figure 1B schematically shows a hip joint after surgery.

Figure 2 schematically shows a cross section of a hip joint prosthesis in accordance with a first embodiment.

Figures 3A and SB show a first embodiment of the cohesive member. Figure 4A shows the guide gaps in perspective.

Figures 4B and 4C show two additional views of the guide rails.

Figure 5A shows an alternative embodiment of the cohesive member seen from the outside. Figure SB shows an alternative embodiment of cohesive means from the outside. Figure SC shows an alternative embodiment of the cohesive member seen from the inside.

Detailed description of the invention With reference to the figures, a hip joint prosthesis 1 is shown which comprises a femoral component (femoral component) 2 which is connected to a joint shell 3 (cup). The present invention also comprises at least one reading member (cohesive member) 4 which, in use, holds together the femur component 2 and the guide members 3.

The femoral component 2 is preferably of a shape and size (shapes and sizes) that is typical in the field of hip prostheses. The leg component 2 in the embodiment shown comprises a ball part 5, a neck part 6 and a stem part (shaft part) 7. The ball part 5 comprises a hinge surface 8 which preferably has the shape of a partial sphere or a half sphere. In alternative embodiments, the joint surface may be of a different shape suitable for the purpose. The ball part 5 is attached to or formed in one piece with the neck part 6. The neck part 6 is in turn attached to or formed in one piece with a stem part 7 included in the femoral component 2. Preferably the femoral component 2 is made in one piece. In alternative embodiments, the femoral component may be of a different shape than that shown in the figures and / or consist of two or more parts.

The guide cup 3 can also, for its basic construction, consist of some previously known type of guide cup 3 (joint capsule, cup) or the like. The guide cup 3 comprises a cavity 9 (shown in Figure 4A) which is internally spherical (part of a sphere). However, this does not exclude that the guide cup 3 partially has a different shape suitable for the purpose. Specifically with the present is that it comprises at least one locking member 4 with which the ball part 5 is positioned in relation to the hinge cup 3, which means that the ball part 5 of the latch component 2 is prevented from being involuntarily detached from the hinge cup 3.

Referring to Figures 3A and 3B, an exemplary first embodiment of the present cohesive member (locking member) 4. In the exemplary embodiment, the locking member 4 is (or comprises) a collar 10 (tile-shaped structure, alternative term member, body) having a through hole 11, recess bushing or the like. The material of the collar 10 encloses portions of the circumference of the hole 11 in the radial, or substantially radial, direction of the hole. In the preferred embodiment, the collar encloses a part of the hole circumference, the opening 12 being formed in the material around the hole 11. In the exemplary embodiment, the aperture 12 has a width II which is slightly wider than the maximum width of the neck of the femoral component. However, the width of the opening 12 has a width which is smaller than the diameter of the ball part 5 of the femoral component 2.

The collar 10 comprises an inside 13 and an outside 14. By inside 13 is meant the side of the collar 10 which is connected to the hinge cup 3. By outside 14 is meant the opposite side to the inside of the collar 10.

The collar 10 further comprises at least one inner edge 15 located closer to the center in the radial direction than the outer edge 16 which is located further from the center in the radial direction.

In the first embodiment, the outer edge 16 of the collar 10 comprises at least a first segment (part, section) 17 in the radial direction of the locking member 4, which when the locking member and the joint cup are brought together, extends further in radial direction than the radial extent of the joint cup. In the embodiment of the locking member 4 shown in the figures, its outer edge comprises at least a first segment 17, at least a second segment 18 and at least a third segment 19, which when the locking member 4 and the guide cup 3 are connected extend further in radial direction than the radial extent of the guide cup 3 . In alternative embodiments, the locking means 4 may comprise fl one or fewer segments than three.

In the embodiments according to Figures 3A and 3B, the protruding segments each comprise a minimum hole which extends in the axial direction of the locking member. In the exemplary embodiment, the locking means comprises at least a first hole, outer hole 20, and a second hole, inner hole 21. The first hole 20 has a greater radial distance from the axial center of the locking means 4 than the second hole 21, the inner hole. The collar 10 comprises at least one recess (milling) 22 of the inner edge 15 in the inside 13 of the collar, in the direction of the ball part 5 when the collar 10 is connected to the hinge cup 3. The recess 22 preferably has a radius shape corresponding to or substantially corresponding radius on the spherical hinge surface. the recess (9) in the joint cup (3).

When the collar 10 is positioned, connected to the joint cup, the surface 23 of the recess 22 is a continuation of the internal spherical joint surface 8 in the joint cup 3. The collar positions the ball part 5 of the joint cup 3 and prevents the femoral component 2 ball part 5 from being involuntarily released from the collar cup 3. recess 24 on the inner edge of the outside of the collar, in the direction of the neck part 6 when the ball-shaped part is connected to the lead bowl and the collar 10 is connected to the joint bowl. The second recess, such as the bevel, 24 in the collar increases the mobility of the shaft relative to the collar and the joint cup. For the user, this entails a higher degree of mobility than without the recess 24.

With the first hole, the hip prosthesis is connected to the pelvis. In the embodiments, this is done by the screws not clogging the guide cup 3. With the inner holes, the locking member 4 is connected to threaded holes in the guide cup 3 with screw connections.

In the exemplary embodiment, the collar 10 is connected to the hinge cup 3 with screw connections or similar connecting means. The positioning of the collar 10, the locking member 4, in relation to the supply bowl 3 can be done by means of a number of different techniques. Preferably, the collar 10 and the joint cup 3 are connected to each other with screw connections which are through the collar 10 and holes are connected in the joint cup 3.

Referring to Figures 4A - 4C, an exemplary embodiment of the guide cup 3 is shown. The guide cup 3 comprises at least a first hole 25 constituting a through hole or alternatively a bottom hole. In the exemplary embodiment, the guide cup comprises at least a first hole 25, constituting a first through hole, and at least a second hole 26, constituting a second bottom hole or a second through hole. In the embodiment shown, the connecting joint cup with the collar 10 to each other with at least one first screw, and at least one second screw.

The collar 10 and the joint cup are held together by the screws which are screwed into the pelvis.

In the exemplary embodiment, the collar 10 comprises holes 27 with the corresponding division and number as the number of holes in the joint bowl 3. The holes 27 in the collar 10 are preferably bevelled in the side which, when joined, is intended to be tormented from the joint bowl 3.

The material in the collar is 10 years thicker where the load on the collar is relatively higher than the split collar when the load is relatively lower and the material is relatively thinner. In a preferred embodiment of the present collar 10, in its upper part 28 it is relatively thicker than in the lower part 29. In preferred embodiments the thickness of the collar 10 decreases successively from the upper part 28 towards the lower part 29 (the part with the opening 12).

In further embodiments, the inner surface of the collar, which constitutes the abutment surface, comprises the articulated cup, at least one protruding segment. Preferably, the embodiments comprise two or three protruding segments.

The protruding segment, not shown in figures, can for instance consist of a spike, a rough structure or the like which is intended to be pressed into the material in the abutment surface of the guide cup. This applies to materials where the protruding segment can be inserted into the material the abutment surface of the guide bowl against the collar. The protruding segment consists, for example, of a conical spike, or the like with limited dimensions in relation to the dimensions of the hinge cup and collar.

In alternative embodiments, the connection of that collar 10 to the hinge cup 3 can take place while the technique is suitable for the purpose. The alternative technique may be fast fasting or the like.

In an alternative embodiment, the material in the hinge cup 3 and the collar 10 consist of material which comprises or consists of ceramic material or a material of glass. For example, the material may consist of a material consisting of (or comprising) nitride glass or the like. Nitride glass is described, for example, in patent specification WO2004063107. By using nitride glass, a more durable joint bowl and a hard-to-break construction are created.

In alternative embodiments, the holes in the hinge cup may be separate channels (holes) relative to the holes for connecting the collar 10 (tray-shaped structure) to the hinge cup 3. The hinge cup can be screwed into the pelvis with screw joints that do not join the collar to the hinge cup. In this case, the guide cup comprises separate bottom holes which after at least some distance are provided with threads (not shown in figures). The collar is screwed after the hinge cup has been connected to the pelvis and fixed with a screw connection in said bottom hole.

The locking (fixing) of the collar 10 to the pelvic bone is preferably done with screw connections. However, this does not preclude the use of any other type of fastening device, fixing device or the like. For example, the locking can take place with some type of quick-locking device such as a device which can be inserted into holes in one direction which is caused to expand if it is moved in the other direction.

In the detailed description of the present invention, construction detail may be omitted which will be obvious to a person skilled in the art in the field to which the method and the device relate. Such obvious structural details are included to the extent required for a proper function to be obtained for the present hip prosthesis. Although certain preferred embodiments have been shown in more detail, variations and modifications of the method and apparatus may be apparent to those skilled in the art to which this invention pertains. All such modifications and variations are considered to fall within the scope of the appended claims. Advantages With the present hip prosthesis, a number of advantages are achieved. An advantage is that the hip joint prosthesis with associated cohesive members means that the range of motion is close in relation to a natural hip joint. Another advantage of screwing (the collar and joint cup are screwed directly into the pelvic bone) results in substantially no protrusion of the prosthetic head from the joint cup (no dislocation). An even further advantage of the present construction is that the need to use glue or other foreign substance is substantially reduced. A further advantage of the present construction is that it does not involve any significant temporal change in the surgical procedure. Furthermore, the construction has substantially no sharp edges or the like at the transition between the joint cup and the joint head. The construction also has the advantage that it supplies the body with less foreign material in relation to certain already known constructions.

Claims (10)

1. Hip joint prosthesis (1), intended to replace an existing hip joint in a person, comprising at least one femur component (2) and at least one joint socket (3) which are held together by at least one connecting body (4), which femur component (2) includes at least a ball part (5), at least one neck part (6) and at least one stem part (7), and that the hip joint prosthesis (4) includes which connecting body (4) consists of a collar (10) which includes a through hole (11) which partially enclosed by material and forming an opening (12) which is wider than the maximum diameter of the width of the neck part (6) and less than the diameter of the ball-shaped part (5) of the femur component, which collar is connected by connecting means to the person's hip bone, characterized in that the collar (10) includes at least one first protruding segment (17), at least one second protruding segment (18), with at least one hole (20) each, which protruding segments (17,18) extend in the radial direction of the collar (10) with a radial distance that is far from the collar the center of the joint (10) in relation to the radial extent of the joint cup (3) and the inner edge (15) of the collar (10) on its inner side towards the joint cup (3), includes at least a first recess (22) and that the inner edge of the collar (10) ( 15) in the direction from the joint cup (3) 2. includes a second recess (24). 3. Hip joint prosthesis (1) in accordance with patent claim 1, characterized in that the recess (22) of the collar (10), which forms the contact surface against the ball part (5), is radiused and that 4. the radius corresponding or essentially corresponding to the radius of the recess (9) in the joint cup 5. (3)- 6. Hip joint prosthesis (1) in accordance with patent claim 2, characterized in that the second recess in (24) the inner edge (15) of the collar (10), in the direction from the joint socket (3), consists of a 7. phase. 8. Hip joint prosthesis (1) in accordance with one of claims 1 to 3 characterized by the collar (10) comprising at least one first projecting segment (17), at least one second projecting segment (18), at least one third projecting segment (18), which itself in the radial direction of the collar with a radial distance that is longer from the center of the collar i 9. relation to the radial extension of the joint cup. 10. . Hip joint prosthesis (1) in accordance with at least one of the previous patent claims, characterized in that each segment (17, 19) comprises at least one inner hole (21) and at least one outer hole (20), in relation to the radial direction of the collar (10). Hip joint prosthesis (1) in accordance with one of the previous patent claims, characterized in that the material in the collar (10) is thicker in the upper part of the collar (10) than in its lower open part. Hip joint prosthesis (1) in accordance with at least one of the previous patent claims characterized by the fact that the holes (21) and (20) in the collar (10) consist of countersunk holes. Hip joint prosthesis (1) in accordance with at least one of the previous patent claims, characterized in that the joint cup (3) consists of a glass material alternatively ceramic material. Hip joint prosthesis (1) in accordance with at least one of the previous patent claims, characterized in that the joint cup (3) and the collar (10) are made of a glass material alternatively ceramic material. Hip joint prosthesis (1) in accordance with at least one of the previous patent claims characterized by the inner surface of the collar, which constitutes the contact surface against the joint socket, at least one protruding segment.