WO2012113570A1

WO2012113570A1 - Acetabular prosthesis

Info

Publication number: WO2012113570A1
Application number: PCT/EP2012/000810
Authority: WO
Inventors: Peter Copf
Original assignee: Peter Copf
Priority date: 2011-02-25
Filing date: 2012-02-24
Publication date: 2012-08-30
Also published as: EP2677968A1; DE102011012310A1

Abstract

The invention relates to an acetabular prosthesis that has an outer shell (2) which can be implanted into a pelvic bone (4) and in the interior of which an insert (1) is inserted, said insert having an inner recess (1c) that is semi-spherical at least in some regions. A joint ball of a femur implant can be inserted into said recess. The interior and the exterior of said insert (1) are designed in a tapering manner in the direction of a common axis (A), and at least some portions of the insert (1) can be moved into the outer shell (2) in the direction of said axis (A) such that the insert (1) increasingly engages the outer shell (2) in a form-fitting and/or force-fitting manner.

Description

Acetabular cup

The invention relates to an acetabular cup prosthesis. In the prior art it is known to replace hip joints in patients by artificial prostheses.

Here come on the one hand in the prosthesis elements in a

Femur) prostheses are used, which have an upper ball joint, which is then fitted into a correspondingly shaped acetabulum prosthesis, in order to prevent movement about the ball joint center, i. thus essentially allowing the center of the ball of the thigh implant.

It is therefore known in the femurs corresponding

Insert recesses to insert the shaft of a femoral implant, as well as provide a recess in the pelvic bone to place an acetabulum prosthesis in this recess into it. It can then on the one hand acetabular cup prosthesis and on the other hand, the joint ball of a femur implant in their effect together form an artificial hip joint.

It is known to be problematic in this case that forces acting on such an artificial hip joint can cause the individual

Prosthetic elements, be it the hip joint socket prosthesis in the pelvic bone or the femur implant in the thighbone, can be loosened by the forces acting on it, which can lead to considerable problems, which also necessitate reoperation.

CONFIRMATION COPY It is therefore an object of the invention to provide a new acetabular cup prosthesis, which has force or shock absorbing properties to any damage due to excessive force effects between

Avoid joint ball and acetabulum prosthesis.

According to the invention this object is achieved by an acetabular cup prosthesis of the type mentioned above, which has an outer shell which is implanted in a pelvic bone and in the interior of an insert is inserted, which has an at least partially partially spherical inner recess into which a joint ball of a femur implant can be used is, wherein the interior of the outer shell and the exterior of the insert in the direction of a defined common axis are tapered in such a way that the use in the direction of this

the aforementioned axis under increasing form and / or adhesion to the outer shell at least partially in the outer shell is movable into it.

It is thus an essential core idea of the invention

Acetabular cup prosthesis no longer form as in the prior art as a one-piece element, but to make this two-part, between the two, nested parts is given a mobility along a defined common axis, wherein the movement of the arranged in the interior of the outer shell insert relative to the outer shell along this common direction undergoes damping, thus thus acting forces not directly from one

Acetabular cup prosthesis is introduced into the surrounding pelvic bone, but previously experienced a damping, so that such forces cause no damage to the pelvic bone, in particular a recessed therein

Do not loosen the acetabular cup.

The damping is achieved according to the invention in that at a

Movement of the internal mission in the direction of the aforementioned common Axis in the outer shell into a positive and / or frictional connection between the insert and the outer shell increases and therefore counteracts this increasing form and / or adhesion of a further movement in the same direction with increasing extent, in particular by a damping in this aforementioned axial direction is progressively trained.

The aforementioned common axis can in this case be designed so that the center of an inserted into the insert joint ball on this

common axis lies. Furthermore, provision may be made for the outer upper shell edge of the outer shell to lie overall in a plane oriented perpendicular to the abovementioned common axis. This plane can form an equatorial plane with respect to the outer shell. Within this equatorial plane, the outer upper edge of the outer shell reaches its maximum diameter.

In one embodiment of the invention, it can be provided that the insert, which serves to receive a joint ball, at least partially contacted with its outer surface in a shell edge of the outer shell region, the inner surface of the interior of the outer shell and in a shell bottom near area to this inner surface of the

Interior system free, in particular spaced.

It is thus possible to move the insert in the direction of the bottom of the outer shell into its interior, as in the direction of the

common axis lying outer region of the insert has no contact with the shell base of the outer shell and thus is movable with increase of the positive and / or frictional connection in the shell edge near area.

For example, the positive connection may increase such that with an axial movement in the direction of the interior of the outer shell between the

Insert and the interior contacted surface increases with progressive axial displacement. It can be provided that the outer shell an elastic

Has compliance and thus due to the elasticity at a decrease in the force acting in the direction of the common aforementioned axis in the shell moved into the insert automatically in the opposite direction to a starting position between the outer shell and use without

Force load is reached, resets.

For this purpose, it may be provided that the shell base of the outer shell in the direction of the aforementioned axis and / or obliquely / radially to the aforementioned axis a relative to the shell edge of the outer shell larger elastic

Having compliance. In particular, for this purpose, the shell edge may have an annular reinforcement.

In order to achieve an increasing in the aforementioned axial direction positive and / or frictional connection between the outer shell and the insert, it may be provided in a possible embodiment that the strength of the taper of the interior of the outer shell and the exterior of the insert in the direction the aforementioned axis is increasing, especially at stages of sudden change is increasing.

This can be done in one possible embodiment e.g. be made such that the interior and / or the exterior of the insert in a cross section in the direction of the aforementioned axis, in particular in a cross-sectional plane which the

includes the aforementioned axis forms a concave traverse.

Accordingly, in the direction of the aforesaid common axis and in the direction of the base of the tray, the angles between a respective straight line element of the traverse and the aforementioned common axis are to be taken. In the sense of this training, therefore, the rejuvenation of

Interior and outer surface of the insert in the aforementioned

Cross-section level stepped. In a development, the shell base of the outer shell may have a stop which limits the displaceability of the insert in the direction of the aforementioned common axis. Such a stop may for example be designed such that the shell base of the outer shell has in its interior a in a plane perpendicular to the aforementioned axis arranged annular and use-facing projection.

This annular projection, which forms the end stop of the axial displaceability, can thereby face a flat surface of the insert, which is oriented in a plane perpendicular to the common axis and thus lies parallel to a plane in which the annular projection is formed.

In one development of the invention, it may be provided that the outer shell has a plurality of openings instead of a closed shell shape. Through these breakthroughs, the rigidity of the outer shell is reduced in favor of a higher elasticity, so that a desired damping along the common axis can be achieved by the number and geometric design of the apertures.

The geometric design of the apertures can in this case be such that webs are formed between the apertures, in particular those webs which are resilient to a force applied by the insert. In this case, the embodiment can be selected such that at least some of the webs formed are arranged at least in regions in a shell circumferential direction which intersects the aforementioned axis.

In a further preferred embodiment, it may be provided that at least some, preferably all, in the shell circumferential direction which intersects the aforementioned axis have webs on the outside of the shell that have outwardly extending projections. These projections, which are preferably located with their outer radial end outside an imaginary spherical shell surface, which is defined by the upper outer shell edge, may therefore be provided in the

To intervene bone material provided in the pelvic bone recess for receiving the outer shell.

For example, the embodiment may be such that in the pelvic bone a teilkugelschalenförmige recess is introduced, which has a radius to the center of the partial sphere, which corresponds to the radius of the outer upper shell edge of the outer shell.

When inserting the outer shell in such a bone recess thus engage the externally arranged on the webs aforementioned projections, which extend in the radial direction outwardly, in the bone material of the pelvic bone and thereby fasten the outer shell of the

acetabular cup prosthesis according to the invention.

It may preferably be provided that the outward

extending projections in the outward direction and thus form tips or provided that the projections have an extension in the direction of the webs, arcuate cutting edges, which then cut when inserting the outer shell into a bone recess in the bone substance, so that through the projections or the preferably formed arcuate cutting a rotational inhibition of the outer shell is generated around the aforementioned common axis.

With regard to the choice of material, it may be envisaged to use a very hard, resistant material for use within the outer shell which, in conjunction with a ball joint inserted in the insert, allows its sliding rotation about the joint center without abrasion on the contacting surfaces between joint ball and inner surface of the Use to create. In this case, it may be provided, for example, to design the insert made of sapphire or alternatively also of a ceramic.

The outer shell may be selected from a material that is softer relative to the material of the insert, for example, a titanium alloy. On the one hand, it is possible to produce particularly lightweight outer shells as well as stable ones

Outer shells can be achieved with an elasticity.

The shell edge can be used in different thicknesses in the hip socket prosthesis according to the invention. For example, a set of a plurality of such hip acetabular prostheses according to the invention may be used, from which a doctor selects a suitable hip acetabular prosthesis according to the invention for implantation in accordance with the required thickness of the shell rim. For example, the shell edge may be formed differently thick with respect to its extension perpendicular to the aforementioned axis.

In particular, when the outer shell has the aforementioned breakthroughs can be formed by the presence of the apertures, an annular shell edge, in particular from which can extend in the circumferential direction of the shell, the aforementioned webs. Such an annular shell edge can be available in various ring thicknesses or annular cross sections.

By choosing among such various inventive

Acetabular prostheses, the acetabular prosthesis can be individually adapted to the patient, e.g. in terms of body weight, intended sporting activities or other criteria. In general, the required or desired damping behavior of the invention according to the invention by the selection under different strong shell edges or ring cross sections

Acetabulum prosthesis are chosen because with different

Cup edge strength changes the force with which the insert by the edge

is entwined. An embodiment of the invention is shown in the following figures

described. Show it:

FIG. 1 shows an acetabulum prosthesis according to the invention in one embodiment

Cross section along the common direction

Figure 2 is a view on the inside of the outer shell in the direction of the common axis

Figure 3 is a view on the outside along the common axis

FIG. 1 shows an acetabular cup prosthesis according to the invention with an outer shell 2 into which an insert 1 is inserted, wherein the overall arrangement of this acetabulum prosthesis is introduced into a pelvic bone 4 in a recess 3 adapted to the outside of the outer shell.

The illustration of Figure 1 in a cross section, in the cross-sectional plane of the common, initially mentioned axis A is arranged, shows that both the outside of the insert 1 and the inner surface of the outer shell 2 in the direction of the common axis, here within the considered

Paper level is and is symbolized by the axis A, each tapered, wherein the outer surface of the insert 1 and the inner surface of the outer shell 2 in each case at least partially form a concave traverse in this cross section, so that in an area near the Shell edge 2a of the outer shell 2 one around the

A common axis A extending contact zone 5 results, in which the outer surface of the insert 1 and the inner surface of the outer shell 2 touch. In a region close to the shell base 2b and thus in a region in the direction of the axis A into the interior of the outer shell 2, on the other hand, the outer surface of the insert 1 and the inner surface of the outer shell 2 are free from each other or spaced apart. It is therefore apparent that in the direction of this defined common axis A due to the investment freedom of the insert 1 to the shell base of the outer shell 2 of the insert 1 is hineinbewegbar in the outer shell, wherein due to the tapered formation between the outer surface of the insert 1 and the inner surface of the outer shell 2 in the upper shell edge near region 5 with mutually corresponding surface configurations tapering shape can be seen the positive and / or frictional connection between insert 1 and outer shell 2 in a movement of the insert 1 to the shell base 2b is increasing.

The opposite to the outer shell 2 more stable designed insert 1 thus urges in a movement in the direction of the axis A to the shell base 2b, the outer, contrast elastic shell back, so that it counteracts the axial movement of the insert a damping force. This force increases with increasing axial movement along the axis A.

Evident is on the shell base 2b an annular projection 2c, wherein the ring is arranged in a plane perpendicular to the axis A and a plane parallel to the ring surface 1 b of the insert 1 opposite. This ring 6 thus forms an end stop which limits the maximum axial movement of the insert 1.

In this case, it may also be provided in the movement limitation that the surface areas of insert 1 and outer shell 2 which are initially non-contact in the axial direction and in a direction of movement to the shell base come into contact with one another and thus likewise limit the axial movement distance.

Alternatively, this area can always remain free of investment.

FIG. 1 also shows, in section, further that the insert 1 has a recess 1c formed around the common axis A, which is designed as a partial spherical shape, at least in its deep region facing the base of the shell, so that this recess forms a joint ball of a ball Can accommodate thigh bone implant and together with this ball joint forms an artificial hip joint, which is rotatable about a center of the joint ball, which lies on the common axis A.

The center of the joint ball is therefore in the invention

Hip acetabular prosthesis along the axis A shown displaced and muted movable. It is so with the invention

Acetabular cup prosthesis the ability to dampen forces acting in the joint and thus to gently absorb, without any destructive

Effect on the connection between the prosthetic elements and the surrounding bone mass is to be feared.

FIG. 2 shows a plan view of the interior of the outer shell 2 of FIG

Recognizable in this view, the outer upper edge portion 2a of the outer shell 2, which here is parallel to the paper plane and thus in a plane perpendicular to the common axis A according to the figure 1. The edge 2a can therefore lie in an equatorial plane of an imaginary spherical surface formed by the outer diameter 2a 'of the rim.

The shell edge 2a can - as described in the general part - in

different strengths can be selected. Here, in FIG. 2, the shell edge 2a is substantially annular, so that here e.g. the thickness D of the ring perpendicular to the extension of the axis A, or generally the ring cross-section in a plane parallel to the axis A may vary depending on the requirement.

In the view of the interior of the outer shell, it can be seen that the shell inner or outer surface has openings 7, wherein through the

Variety of breakthroughs 7 and the geometric arrangement of a number of webs 8 and 9 are formed, wherein the webs 8 are oriented in a circumferential direction of the outer shell, in which this circumferential direction axis A cuts. Relative to an imaginary spherical surface around the axis A, the webs therefore lie substantially in the direction of longitudes in a spherical coordinate system.

It can also be seen in FIG. 2 that the inner surface of this outer shell tapers step-like in the direction of the base of the shell, namely here on the steps 10 and 1. By means of these steps, the polygonal line shown in section is generated with reference to FIG.

In a region between the upper edge 2a and the first step 10 according to the invention, a contact area between the outer surface of a

Insert 1 and the inner surface of the outer shell 2 is formed. Due to the taper towards the base of the bowl, which can be rotationally symmetric about the axis A, the positive and non-positive connection between the insert and the outer shell increases in the direction of the base of the bowl.

The figure 2 shows in the plan view of the bowl base formed on the shell base annular projection 2c, which is arranged around the common axis A opening in the bowl base.

FIG. 2 further shows that at least on the webs 8, which extend in a circumferential direction which intersects the axis A, radially outwardly tapering projections 12 are arranged, which are in the same

Can extend circumferential direction and thus arcuate cutting

can train. Accordingly, these cutting edges engage in the bone material of a recess adapted to the outer shape of the shell 2 in one

Pelvic bone and create an inhibition about the axis of rotation A, so that the outer shell 2 can be implanted rotationally fixed in the pelvic bone.

FIG. 3 shows a view of the same shell 2 from the outside, the cutting edges 12 running in the circumferential direction being recognizable here as well. The outer upper edge 2a defines here with respect to the outer shell a maximum outer ball diameter, which limits the entire outer dimension of the shell 2 except for the projections 12 on the webs eighth

The openings 7 are in the embodiment of the invention

Acetabular cup prosthesis also advantageous insofar as that in this

Breakthroughs can grow into bone mass and can surround the webs.

Especially the shell bottom near distance range between the outer surface of the insert 1 and the inner surface of the outer shell 2 allows such ingrowth of bone mass, thus also to secure the acetabular cup according to the invention after a corresponding Einwachszeit in the direction of the common axis A and firmly with the Connect bone.

To make this possible, it may be provided that in the direction of the axis A of the annular projection has such a large elevation relative to the tray base 2b and the axial travel of the insert 1 so limited that even in a stop position between the insert and the surface of the ring Distance region between the insert 1 and the shell base 2b remains so that this distance range for the ingrowth of bone material is available, without this ingrowth limits the axial travel of the insert.

Claims

claims

1. acetabulum prosthesis, characterized in that it has a

outer shell (2), which is implanted in a pelvic bone (4) and in the interior of an insert (1) is inserted, the one

at least partially part-spherical inner recess (1c), in which a joint ball of a femur implant is used, wherein the interior and the exterior of the insert (1) in the direction of a common axis (A) are tapered and the insert (1) in the direction this axis (A) under increasing form and / or adhesion to the outer shell (2) at least partially in the outer shell (2) is movable into it.

2. A prosthesis according to claim 1, characterized in that the insert (1) with its outer surface in a shell edge (2a) near the region of the outer shell (2) at least partially contacted the inner surface of the interior and in a shell base (2b ) near area to the inner surface of the interior system-free,

in particular spaced.

3. Denture according to one of the preceding claims, characterized

characterized in that the shell base (2b) of the outer shell (2) in the direction of the aforementioned axis (A) and / or obliquely / radially to the aforementioned axis (A) over the shell edge (2a) has greater elastic compliance.

4. A prosthesis according to one of the preceding claims, characterized

in that the strength of the taper of the interior and exterior of the insert (1) in the direction of said axis (A)

is increasingly, in particular such that the interior and / or the Outer of the insert (1) in a cross section in the direction of the aforementioned axis (A) forms a concave traverse.

5. A prosthesis according to one of the preceding claims, characterized

characterized in that the shell base (2b) of the outer shell (2) has an annular insert-facing projection (2c) arranged in a plane perpendicular to the aforementioned axis (A),

in particular, limits the extent of the axial displaceability of the insert (1).

6. Denture according to one of the preceding claims, characterized

characterized in that the outer shell (2) has a plurality of

Breakthroughs (7).

7. A prosthesis according to claim 6, characterized in that between the apertures webs (8,9) are formed, in particular, which are resilient to a force applied by the insert.

8. A prosthesis according to claim 6 or 7, characterized in that

at least some webs (8) of the formed webs (8,9) at least partially in a said axis (A) intersecting

Cup circumferential direction are arranged.

A prosthesis according to claim 8, characterized in that at least some, preferably all, webs (8) arranged in the shell circumferential direction intersecting the aforesaid axis (A)

Shell outside have outwardly extending projections (12), in particular, the tapering outward.

Prosthesis according to claim 9, characterized in that

Protrusions (12), in particular by the projections (12) formed arcuate cutting edges (12), cut when inserting the outer shell (2) in a bone recess in the bone substance and a Rotary locking of the outer shell (2) to produce the aforementioned axis (A).

1 1.Prothese according to any one of the preceding claims, characterized

in that the insert (1) is made of sapphire and the outer shell (2) is made of a titanium alloy.

12. Set comprising a plurality of acetabulum prostheses according to one of the preceding claims, characterized in that the plurality of acetabulum prosthesis of different strength

Have shell edges (2a), in particular the respective shell edges (2a) are annular with different ring cross sections perpendicular to the ring plane.