WO2011103851A1

WO2011103851A1 - Connecting element for modular components

Info

Publication number: WO2011103851A1
Application number: PCT/DE2011/000096
Authority: WO
Inventors: Hans-Joachim Fischer; Nikola Bukvic
Original assignee: Aap Implantate Ag
Priority date: 2010-02-26
Filing date: 2011-01-31
Publication date: 2011-09-01
Also published as: DE102010010073B4; DE102010010073A1; EP2538887A1

Abstract

The invention relates to a connecting element for modular components of implants, in which the implant modules, such as the proximal and distal components, are interconnected by means of a mounting screw. The front surfaces of the connecting element and the contact surfaces of the implant module facing towards said front surfaces are embodied as conical surfaces which change the axial stress applied by the mounting screw in the conical contact surfaces into corresponding radial or annular stress for connecting the components. The conical surfaces are annular and embodied as double conical surfaces having an outer and an inner cone.

Description

Connector for modular components

The invention relates to a connecting element for modular components according to the preamble of patent claim 1.

Such a connection element is known from DE 295 06 036 UT.

In addition to the connection on the one hand, for the modular and flexible coordination of the implant dimensions on the other hand also corresponding components can be used, which allows the individual adaptation of the implant to the biomechanical and anatomical conditions.

When using modular implant components z. B. for hip or shoulder joints, often a component is first introduced and / or cemented. Subsequently, the other modules u. U. using appropriate

Spacers first loosely assembled by means of the fastening screw.

The usual spacers have at their corresponding planar contact surfaces radially extending grid grooves, which serve as anti-rotation.

Since the connection is still loose, an alignment of the

Implant components are made by twisting and only then the components are firmly connected by means of the fastening screw.

The disadvantage of such connection / spacers is that by

incorrect positioning of the locking grooves on each other, or by contamination (bone and tissue residues) on the locking grooves a permanent clamping force between the individual components can not be maintained. This results in the loosening between the components and thereby over-stressing the connecting screw, which can lead to failure of the implant.

It should be mentioned that it is known from EP 2 133 041 A1 to separate parts of the prosthesis from one another in that between them a separating gap bridging annular groove is formed, which enables the intermediate sliding of a separating tool. The object of the invention is to provide a connecting element for the secure and reproducible connection of modular components of implants.

This object is achieved according to the invention in a connection element for modular components of implants, in which the implant modules, such as the proximal and distal components are connected to each other by means of a fastening screw, characterized in that the end faces of the connecting element and the contact surfaces of the implant modules facing this formed as conical surfaces are,

which convert the axial tension in the conical contact surfaces applied by the fastening screw into a corresponding radial or annular stress for connection of the components, the conical surfaces being designed annularly as double-cone surfaces with an outer cone and an inner cone.

The connecting element designed according to the invention permits any stepless rotation relative to one another, so that no angle-dependent raster positions have to be set.

In addition, the modules center themselves when merging.

After assembly, the rotation is ensured by self-locking by the surface pressure, due to the introduced axial force and the resulting radial ring tension, but which is reversible at any time, as by means of an external cutting tool, the conical contact surfaces are releasable.

The connection between the individual implant modules, z. As proximal components and distal modules (shaft module) with the possible involvement of appropriate fasteners and spacers, thus carried out via a preferably central mounting screw.

The connection is in this case rotationally symmetrical with conical, positive

Connection structures executed. The dimensioning of this compound is designed so that by the force applied to the connection axial stress in the conical

Contact surfaces a corresponding radial or ring tension for safe and

permanent connection is established.

The elastic deformation (spring element) enables optimum surface contact. Further advantages can be seen in the fact that the hoop stress generated by the applied axial tension in the conical contact surfaces of the individual components leads to an improved force introduction and an optimized force flow within the

connected components, which can be detected by the voltage curve with a FEM analysis.

According to a preferred embodiment, the annular conical surfaces are as

Double cone surfaces formed with an outer and an inner cone.

The angle range β for the configuration of the conical contact surfaces amounts to between 3 ° and 30 °, preferably about 10 °.

An angle of about 10 ° represents the optimal compromise between form-fitting and adhesion on the one hand and the solubility on the other.

In this case, the corresponding conical surfaces are matched to one another such that preferably the outer conical surface represents the loaded, self-locking contact surface.

According to a further embodiment of the invention, the outer conical surface is opposite the outer periphery of the connecting element or the implant modules or a

Spacer arranged radially offset inwardly, so that in each case a cross-gap separating the annular gap is formed at interlocking cones on the outer circumference between the mutually facing abutment surfaces, which allows the intermediate sliding of a cutting tool.

The invention will be explained in more detail with reference to the drawings. Showing:

Fig. 1 shows schematically the implant modules with the connecting element and a

spacer

2 corresponding contact surfaces of the elements,

3 shows the release of the modular components by means of an external parting tool, 4 shows the representation of the preferred angular range for the cone connection,

Fig. 5 is a schematic representation of the connecting element with the

corresponding cones on average and

Fig. 6 shows the representation of the active principle of the cone connection.

The modular implant system z. B. for hip or shoulder joints is composed of a proximal 2 and a distal module 1 (head component and shaft module) and the connecting element 4, wherein the individual parts are held together via a preferably central fastening screw 3.

It can be seen from the illustration in FIGS. 2 and 4-6 that the connecting element 4 (as well as the corresponding contact surfaces for the connecting element on the proximal and distal implant modules 1 and 2) corresponds to a ring-shaped one

Have conical surfaces.

Corresponding means here that at one end face of the contacting surfaces in each case a conical, with respect to the surface axially projecting conical ring is provided, while on the opposite surface a corresponding, the cone ring receiving annular groove is present.

These conical surfaces have an outer and an inner conical surface 5 and 6.

The outer conical surface is offset radially inwards relative to the outer circumference of the connecting element or the implant modules or a spacer, so that, when the cones are inserted into one another, an annular groove 7 results, which bridges the separating gap.

As FIG. 3 shows, an external separating tool 8 can be introduced into this groove 7, with which the corresponding cones can be detached from one another.

In the illustrations in Figures 5 and 6 is by arrows on the one hand, the axial

Strain indicated by the central fastening screw 3 (Figure 5), as well as the radial tension of the cones (Figure 6).

Claims

claims

A modular component connector of implants in which the implant modules, such as the proximal and distal components (2, 1), are connected together by a fastening screw (3),

characterized,

in that the end faces of the connecting element (4) and the contact surfaces of the implant modules (1, 2) facing them are in the form of conical surfaces (5, 6) which rotate the axial tension in the conical contact surfaces, which is applied by the fastening screw (3), into a corresponding radial surface. or react ring strain to connect the components

the conical surfaces (5, 6) are designed annularly as double conical surfaces with an outer and an inner cone.

2. Connecting element according to claim 1,

characterized,

that the angular range β for the configuration of the conical contact surfaces is between 3 ° and 30 °.

3. Connecting element according to claim 2,

characterized,

that the angular range ß for the configuration of the conical contact surfaces is 10 °.

4. Connecting element according to one of the preceding claims,

characterized,

in that the corresponding conical surfaces are coordinated with one another such that the outer or inner conical surface is a loaded, self-locking supporting surface.

5. Connecting element according to one of the preceding claims,

characterized, in that the outer conical surface (5) is offset radially inwards relative to the outer circumference of the connecting element (4) or the implant modules (1, 2) or a spacer (9) so that, when the cones engage in one another, on the outer circumference between the mutually facing abutment surfaces each one the separating gap bridging annular groove is formed, which allows the intermediate sliding of a separating tool (7).