ANCHOR IMPLANT

Abstract

The present invention relates to a fixation implant with an implant body which is made substantially of a ceramic material and has an external helical thread with more than one thread web and wherein a thread pitch angle of the external helical thread is in the range from 30° to 90°, and to the use thereof as an alloplastic bone implant, as an alloplastic dental implant, in production engineering, medical engineering, surgery, dental technology and/or implant technology.

Claims

1. A fixation implant with an implant body, which is made substantially of ceramic material and has an external helical thread with more than one thread web and wherein a thread pitch angle of the external helical thread is in the range from 30° to 90°.

2. The fixation implant as claimed in claim 1, wherein the fixation implant is an interference screw or an anchor, such as a suture anchor.

3. The fixation implant as claimed in claim 1, wherein the ceramic material is a biocompatible ceramic material, preferably a material based on calcium phosphates, calcium silicates, magnesium silicates, zinc silicates and/or strontium silicates.

4. The fixation implant as claimed in claim 3, wherein the ceramic material based on calcium phosphates is selected from the group consisting of hydroxyapatite, tricalcium phosphate, carbonate apatite, fluorapatite and/or combinations thereof.

5. The fixation implant as claimed in claim 1, wherein the ceramic material is a composite material based on polymer and ceramic material or metal and ceramic material.

6. The fixation implant as claimed in claim 1, wherein the external helical thread has 2, 3, 4, 5 or more thread webs arranged substantially parallel to one another.

7. The fixation implant as claimed in claim 1, wherein the implant body has an axial central channel.

8. The fixation implant as claimed in claim 1, wherein the implant body is configured to be substantially conical or cylindrical.

9. The fixation implant as claimed in claim 1, wherein the external helical thread extends over substantially the entire length of the implant body.

10. Use of a fixation implant as claimed in claim 1 as an alloplastic bone implant, as an alloplastic dental implant, in production engineering, medical engineering, surgery, dental technology and/or implant technology.

Description

[0020] In a preferred embodiment, the external helical thread has 2, 3, 4, 5 or more thread webs arranged substantially parallel to one another.

[0021] The implant body preferably has an axial central channel.

[0022] It is likewise preferable that the implant body is configured to be substantially conical or cylindrical.

[0023] It is particularly preferable that the external helical thread extends over substantially the entire length of the implant body.

[0024] It is particularly preferable that the thread pitch angle of the external helical thread is in the range from at least 45°, preferably 60° to 90°.

[0025] It is particularly preferable to insert the fixation implant by exerting pressure, which can be applied without any rotation tool.

[0026] The invention also relates to a use of a fixation implant in accordance with the invention as an alloplastic bone implant, as an alloplastic dental implant, in production engineering, medical engineering, surgery, dental technology and/or implant technology.

[0027] For the fixation implant of the invention, it has surprisingly been found that first of all, because of the special design of the external helical thread, it can be inserted into a predrilled bone in a self-tapping manner simply by applying axial pressure, and this geometry makes it possible to avoid critical torsional loads. It is not necessary to use a screwdriver, with the torsional loads which that involves. Secondly, this geometry makes it possible to use ceramic materials which were ruled out for the intended medical application because of the torsional moments arising with conventional interference screws. In other words, the shape of the fixation implant enables the use of ceramic material which readily withstands the pressure loads needed for insertion. The fixation implant can be secured to the bone in accordance with the invention in a manner comparable to a wedge, via the contact surface of the external helical thread of the fixation implant. The fixation implant of the invention thus makes it possible to develop a new class of materials for implants of this kind, so that the disadvantageous properties when other classes of materials are used, such as polymers or metals, are avoided. The operative effort in inserting the fixation implant of the invention is minor, and the risk of failure of components as a result of excessive torsional loads (torque) is likewise minimised.

[0028] In principle, there are two types of stress, compressive stresses and tensile stresses. The ceramic material used in accordance with the invention reacts very sensitively to tensile stresses, whereas compressive stresses are tolerated to a considerably greater extent.

[0029] It is a well-known fact that prior art interference screws are inserted into the drilled tunnel with a screwdriver. This gives rise to very high tensile stresses, which bioactive ceramics, for example, such as calcium phosphates or calcium silicates, cannot withstand, so that they break. With the fixation implant of the invention, with its special screw geometry, no screwdriver is needed for insertion any longer, but only an axial compressive force, such as a hammer for example. For this reason, hardly any tensile stresses arise with the fixation implant of the invention, but primarily compressive stresses, which can be tolerated by the ceramic material. In accordance with the invention therefore, only an axial compressive force is required for inserting the fixation implant, in order to insert the implants. The very design means that the fixation implant “screws itself in”.

[0030] Further features and advantages of the fixation implant of the invention will become clear from the following detailed description and the enclosed drawing, in which the Figure shows a fixation implant of the invention, inserted into a bone tunnel together with a ligament, in a section view. FIG. 2 illustrates what is meant by a thread pitch angle with reference to an exemplary screw body.

[0031] As can be seen from the section view shown in FIG. 1, a fixation implant in the form of an interference screw 2 is shown there in a tunnel 5 inside a bone material 1, together with a tendon or ligament 3. The interference screw 2 has a helical thread 4, the helical thread 4 extending over the entire implant body of the interference screw 2.

[0032] In order to insert the interference screw, an orthopaedic surgeon drills a tunnel 5 into the bone material 1, which may, for example, be carried out athroscopically. After the tunnel 5 has been produced, one end of the ligament 3 is positioned as illustrated. The interference screw 2 is then screwed into the tunnel 5 in a self-tapping manner by applying an axial compressive load, in order to secure the ligament 3 in the tunnel. The axial compressive load can be applied in a simple manner by applying a suitable force to the end face of the interference screw 2.

[0033] FIG. 2 shows a screw body which clearly illustrates what is meant by a thread pitch angle. According to the invention, it is necessary for the thread pitch angle to be greater than 30°. This kind of pitch angle of the helical thread makes it possible to insert or introduce a fixation implant of the invention without any need to screw it in actively.

[0034] The features of the invention disclosed in the above description, the claims and the drawing can be essential to implementing the invention in its various embodiments both individually and in any combination.