DE2314708A1 - ARTIFICIAL HIP JOINT - Google Patents

Description

Artificial hip joint

The invention relates to an allarthroplastic hip replacement.

In degenerative hip joint diseases with extensive destruction of the joint (coxarthrosis), the femoral head has been replaced by a metal endoprosthesis since 194-6, consisting of the femoral head, femoral neck and a metal stem _a

In 1961 the "total" artificial hip joint was developed. For the metal thigh part, a hemispherical pan made of plastic is inserted into the previously expanded and with Bony socket provided with some hats to better anchor the bone cement. This attachment of the

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Plastic socket is done with bone cement. This "total" artificial hip joint was "modified in the subsequent period.

A number of patients with degenerative hip joint deformities exhibit a primary or secondary protrusion acetabu-ii on. In this special form of coxarthrosis, the bulges The bony base of the pan gradually moves into the pelvis over the years and is also slowly broken down, i.e. at the end of the pathological process there is a place the bony base of the acetabulum shows only soft tissue that can no longer exert an irage function. By stepping down of the femoral head in the small pelvis is also the distance between the small and large rolling hills on the one hand and the On the other hand, the entrance level of the pelvis is smaller, so that there is also a reduced or limited mobility of the hip joint follows.

The cause of the primary, mostly bilateral protrusion acetabuli is unknown. Often the one-sided secondary cases arise recently through the so-called "panning" shivering "after the insertion of an artificial hip joint · Due to causes that are not yet exactly known, but mostly due to creeping infections, it occurs after one has inserted artificial hip joint, especially in the area of the osseous socket, to bone resorption phenomena «, these pathological Gate corridors in turn create a protrusion of the remaining bony socket into the small pelvis «

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By. Surgical findings and later performed radiological and pathological-anatomical studies of the inventors could have provided evidence that in the acetabular protrusion increased bone stability is present at the socket opening due to an annular Sklerosiening the pelvis at this point _o From this finding, the invention proceeds from.

The well-known, for the operative treatment of protrusio aceta- buli used artificial hip joints with hemispherical sockets can cause a central dislocation of the artificial Joint into the pelvis and lead to poor mobility, since the entrance level of the plastic cups is deep in the natural socket and the resection surface of the femoral neck on movement on the natural, bony pelvic inlet. gear.

There was already a fine-meshed wire net for such a trap suggested. The main purpose of this mesh was to prevent bone cement from penetrating the soft tissues of the small pelvis. Before the artificial socket is anchored, three hats are placed in the chisel before the bone cement is introduced bony pelvis driven in behind the socket entrance. This net should above all prevent that about the grooves Bone cement penetrates the small pelvis. However, the biomechanics of the acetabulum should not be improved by this mesh will.

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Such an improved network of body-compatible metal in the form of a grid, according to another proposal, is prevented also the penetration of bone cement into the small one Basin and also improves the anchoring of the socket without, however, having a significant impact on the biomechank of the exercise artificial hip joint.

The invention is based on the object of the disadvantages Avoid the aforementioned surgical procedures and implants. Based on the inventor's knowledge that the stability the pelvic bone at the entrance of the joint socket, at the edge of the socket, is preserved or raised, the invention consists in this Utilize the stability and strength of the existing bone tissue, to support the plastic socket and thus the entire joint. In connection with this, the distance between the hip entrance plane and the section surface of the femoral neck be enlarged «According to the knowledge of the Inventor possible when the artificial socket is fixed in the device that is in a different plane than that in the Plastic pan was previously the case and can be fixed to the basin.

According to the invention, there is an artificial hip joint consisting of the femoral head, femoral neck and the stem to be inserted into the femur on the one hand and in the acetabulum on the On the other hand, the hemispherical pan to be used is marked by a. Support bearing

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for the hemispherical socket in the form of a spherical segment with a surrounding flange. The inside diameter of the spherical section is somewhat larger, preferably 1-2 m larger than the outside diameter of the hemispherical socket. The spherical segment is preferably approximately or equal to a hemisphere. The flange is wide, preferably 8-12 mm wide. The spherical section and / or the flange is provided with openings. The openings in the spherical section can be designed in such a way that, in plan, arrow-shaped claws from the flange are located in the surface of the spherical section, leaving a central opening free. The spherical segment surface between the claws can also be designed in the form of narrow webs which meet in the center _o The spherical segment surface can also consist exclusively of a number of narrow webs which meet in the center. The narrow webs can be provided with waves or hooks on their bands.

The surface of the spherical section and / or the claws and / or the narrow webs are provided with beads which preferably run in the radial direction. According to one embodiment of the invention, eight claws on the flange arranged whose tips preferably 20-25 mm from the flange away end _o According to another, preferred embodiment, are arranged in a star shape on the flange three webs at equal intervals, between which two claws are formed respectively.

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An annular web can also be formed in the surface of the spherical section between the flange and the center point bridges the gaps between the radial webs or the tips of the claws.

The support bearing according to the invention is made of a chemically resistant one and body-compatible strong sheet metal, preferably made of the same material as the femoral head. That The support bearing can also consist of a body-compatible plastic and with the acetabulum, which is also made of plastic joined together or consist of one piece.

The invention is explained below on the basis of exemplary embodiments explained in more detail with reference to the drawings. In the drawings show:

1 front view of a hip skeleton, FIG. 2 a perspective view of the individual parts of a

artificial hip joint according to the invention, Fig. 3 perspective view of a hemispherical pan inserted in a support bearing,

Figo 4- one support bearing, partially cut, in side view,

5 shows a top view of a support bearing corresponding to FIG. 4, FIG. 6 shows another embodiment of a support bearing in FIG

Side view,
7 shows a support bearing corresponding to FIG. 6 in plan view,

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"ffig" 8 a further embodiment of a support bearing in side view,

9 is a plan view of a support bearing according to the Pig. 8th

Fig.IQ plan view of a section from a support bearing to show a detail.

Advantages of each embodiment are given along with the description explained in detail.

In Fig. I is the front view of a pelvis with the hip joints shown. An artificial hip joint can be seen on the left side. This consists of a thigh section 1, which is inserted with a pin in the femur 4 after removing the upper part of this bone. In the socket of the pelvis 5 is a support bearing 3 after the invention firmly inserted, and in this is a hemispherical Cup 2 held, which forms the seat for the ball head.

The 4- endoprosthesis used after removal of the upper part of the femur consists of a metal shaft 6, the femoral neck and the femoral head 7 8 _O This coherent part is generally manufactured integrally from a metal körperverträgli- chen. The femoral head 8 has the shape of a ball and is inserted into a hemispherical socket 9, which generally consists of a body-compatible plastic

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and is provided with various indentations on its outer surface so that it is prepared with bone cement in the bony socket of the pelvis 5 can be used. According to the invention, however, in accordance with FIGS. 1 and 2, above a support bearing 3 in this bony socket of the pelvis 5 inserted and fastened with bone cement and only then inserted the hemispherical socket 9 into this support bearing.

The support bearing 3 according to the invention consists essentially of a spherical section 10 which is designed in a special shape and which is surrounded by a flange 11.

The spherical portion 10, which generally has the shape of a hemisphere or approximately the shape of a hemisphere, is with Provided openings, and an embodiment is, as shown in Figs. 2 and 3, designed such that of the annular flange 11 in the surface of the spherical section in plan arrow-shaped claws 13 are inwardly. The breakthrough the spherical segment surface is completely above the tips of the claws 13 and immediately above the flange 11 are the individual ones running between the claws 13 Extension of the opening widened. With an inner diameter of the spherical section of about 50 cm and one Flange width of 8-12 mm, according to a preferred embodiment, the claws 13 are on their foot Flange 11 to the tip 20-25 mm long.

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Each preparation of the bone socket in basin 5 will do that Support bearing 3 with bone cement inserted into the socket in such a way that that the ring-shaped puddle 11 is firmly fixed on all sides against the bone tissue surrounding the socket entrance on the pelvis creates, if necessary with intermediate storage of bone cement · Also at least some parts of the spherical section of the Support bearing 3 lie, with the interim storage of bone cement, against supporting bone tissue in the socket of the Basin. After inserting this support bearing, the Plastic shell 9 of the artificial hip joint in the support bearing used and can be used within the support bearing.

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takes into account the inclination of the so-called antiatorsion, ie _o the axis setting in the sagittal and frontal planes, so that the femoral head 8 inserted into the hemispherical socket 9 occupies almost exactly the same pivot point as the natural femoral head. The hemispherical socket 9 is also fixed by bone cement in the upright position given to it in the support bearing.

In particular from the Pig. 1 it can be seen that with a Support bearing 3 according to the invention prevents the femoral head immediately or in the course of time with the hemispherical Gradually pushing the pan deeper into the pelvic bone, and thus not only displaced the pivot point of the hip joint, but in particular the pressure ratio— se improved in artificial hip joints and at the same time

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an excellent anchoring of the artificial hip joint socket enables _o The support bearing 3 also increases the mobility of artificial hip joints. It is also prevented that the distance between the small and large rolling hills on the one hand and the pelvic entrance plane on the other hand becomes smaller} reduced or restricted mobility of the hip joint can no longer occur. The support bearing according to the invention inevitably increases the distance between the entrance plane of the artificial acetabulum and the resection surface on the femoral neck.

In Figs. 4 and 5 another and particularly preferred one is shown Shown embodiment of a support bearing according to the invention. The flange 11 is shaped with openings 14 provided with drilled or punched holes. The spherical segment surrounded by the flange 11 with openings consists of Erallen 13 in the already related to the First embodiment described form and from three webs 15, which run radially and meet in the center. Two claws 13 are arranged between two webs. The webs are provided with beads 16 in a radial view. These beads serve on the one hand to stiffen the webs and on the other hand to additionally hold the hemispherical Cup 9 “They also provide additional and advantageous anchoring in the surrounding bone cement.

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In general, it should be pointed out that the inside diameter is advantageous of the spherical section 10 of the support bearing 3 is one to two millimeters larger than the outer diameter of the hemispherical pan 9? so that between the surface parts of the Spherical section in the form of claws 13 or webs 15 still has enough space for the pressing in of bone cement is.

According to FIGS. 6 and 7, a further embodiment of a support bearing only has webs 15 which are arranged radially and converge in a star shape in the center. These webs can also be provided with radial beads 16. According to a further development of this embodiment according to FIGS. 8 and 9, the webs 15 are provided at half height by an annular web 17 which has the same center point as the center of the support bearing _o This annular web 17 can also be provided with a bead, and According to a further modification of this exemplary embodiment, the inner parts of the radial webs 15 which lie between the ring 17 and the center point can be omitted. According to FIG. 10, the webs 15 can be provided with corrugations or hooks at their edges, which cause an additional improvement of the anchoring in the bone cement.

According to a further embodiment of the invention, which is particularly preferred and advantageous, there is the support bearing 3 made of a body-compatible plastic

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and is assembled with the hemispherical pan 9 or consisting of one piece, so that, for example, the representation according to the ELg. 3 a single, coherent, represents part made of the same material.

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Claims (1)

Claims Artificial hip joint, consisting of the femoral head, femoral neck and stem to be inserted into the femur on the one hand as well as the hemispherical socket to be inserted into the acetabulum on the pelvis on the other hand, marked by a support bearing (3) for the hemispherical socket (9) in the form of a spherical section (10) with a surrounding Flange (11). 2) Artificial hip joint according to claim 1, characterized in that that the inner diameter of the spherical section (10) is slightly larger, preferably 1-2 mm larger than the outer diameter of the hemispherical pan (9) 3) Artificial hip joint according to claim 1, characterized in that that the spherical section is approximately or equal to a hemisphere. 4.) Artificial hip joint according to claim 1, characterized in that that the flange (11) is wide, preferably 8-12 mm wide. Artificial hip joint according to Claim 1, characterized in that the spherical section (10) and / or 409840 / Ο'U 9 the flange (11) are provided with openings. 6.) Artificial hip joint according to claim 5 »characterized in that that the openings of the spherical section are designed such that arrow-shaped claws in plan (13) from the flange (11) leaving a central one Starting from the opening, lie in the surface of the spherical section (1O), 7.) Artificial hip joint according to claim 5 iukL 6, characterized in that that the spherical segment surface (10) is formed between the claws (I3) in the form of narrow webs (15) is that meet at the center. 80) Artificial hip joint according to claim 5 _}, characterized in that the spherical segment surface (10) consists exclusively of a number of narrow webs (15) which meet in the center. 9) Artificial hip joint according to claim 8, characterized in that that the narrow webs (15) at their edges are provided with shafts or hooks (18). 10.) Artificial hip joint according to one of the preceding claims, characterized in that the surface of the spherical section (10) and / or the claws (13) and / or the narrow webs (15) with preferably radial - 3 ~ 409840 / 0U9 23U708 Directional beads (16) are provided. 11.) Artificial hip joint according to claim 6, characterized in that that eight claws are arranged on the flange (11), the tips of which are preferably 20-25 mm from the flange ends away. 12.) Artificial hip joint according to claim 6 and 7 »characterized in that the flange (11) has three webs (15) in equal distances are arranged in a star shape, between which two claws (13) are formed. 13.) Artificial hip joint according to claim 8, characterized in that that between the flange (11) and the center point an annular web (17) in the surface of the spherical section (10) is formed. 14.) Artificial hip joint according to one of the preceding claims, in particular claim 5? characterized in that the edges of the openings in the spherical section and / or flange are completely or partially bent outwards. 15.) Artificial hip joint according to one of the preceding claims, characterized in that the support bearing (3) consists of a chemically resistant and biocompatible strong sheet metal, preferably made of the same material as the femoral head (1). 16.) Artificial hip joint according to one of the preceding claims, characterized in that the support bearing (3) consists of a body-compatible plastic and with the hemispherical one, which is also made of plastic - 4 409840/0149 Pan (9) is joined together or in one piece "consists. 409840/0149 Blank page