Active substance applicator for a joint implant, and joint implant having an active substance applicator

Abstract

The present invention provides an active substance application insert (10, 110) for an implant (30), in particular a joint implant. The active substance application insert has a main body (11), an active substance chamber (12) formed in the main body, an application side (13, 113) which forms a front face of the active substance chamber, wherein the application side has a plurality of application openings (14, 114), and a securing means (15) with which the main body can be detachably secured in the implant. In a state in which the main body is inserted into the implant, the application side faces outwards relative to the implant, such that the application openings connect the active substance chamber to the environment of the implant. Furthermore, within the scope of the present invention an implant (30) with a recess (31) for receiving an active substance application insert (10, 110) is provided.

Claims

1. An active substance application insert for an implant, comprising: a main body, an active substance chamber formed in the main body, a peripheral active substance wall that extends around a perimeter of the active substance chamber, an application side which forms a front face of the active substance chamber, wherein the application side faces bone tissue or soft tissue and has a plurality of application openings, and a securing means configured to detachably secure the main body in the implant, wherein in a state in which the main body is inserted into the implant, the application side faces outwards relative to the implant, such that the application openings connect the active substance chamber to the environment outside of the implant when the implant is implanted in a body of a patient, wherein on the side opposite the application side a rear wall is formed, which forms a rear face of the active substance chamber and which faces the implant in the inserted state, wherein at least one section of the rear wall on the rear face of the active substance chamber is formed by a reclosable cover, wherein the main body has a peripheral outer wall between the front face and the rear face, which extends around a perimeter of the active substance application insert, and wherein at least one section of the peripheral active substance wall between the application side and the rear face of the active substance chamber is formed separately from and inside the peripheral outer wall of the main body, such that an annular gap is formed along this section between the peripheral outer wall of the main body and the peripheral active substance wall.

2. The active substance application insert according to claim 1, wherein the securing means is formed by at least one section of the outer side of the peripheral outer wall forming a friction surface.

3. The active substance application insert according to claim 1, wherein the peripheral outer wall forms at least one section of the peripheral active substance chamber wall between the application side and the rear face of the active substance chamber.

4. The active substance application insert according to claim 1, wherein the application side is provided with a tool-engaging means for inserting and/or removing the active substance application insert.

5. The active substance application insert according to claim 1, wherein the application side has at least 4, 6, 8 or 10 and a maximum of 30 application openings.

6. The active substance application insert of claim 5, in which the application openings are distributed evenly over the application side.

7. The active substance application insert according to claim 1, wherein the application openings have a minimum size of 0.5 mm or 1 mm and a maximum size of 2 mm, 3 mm or 4 mm.

8. The active substance application insert according to claim 1, wherein the application openings are circular, oval, rectangular and/or slit-shaped.

9. The active substance application insert according to claim 1, having at least one active substance in the form of a solid, beads, a granulate and/or a gel, which fills the active substance chamber at least in part.

10. The active substance application insert according to claim 9, having an active substance that is an antibiotic.

11. An implant system, the implant system comprising: an implant; and an active substance application insert, wherein the implant comprises a cavity corresponding to a shape of the active substance application insert, the active substance application insert comprising: a main body, an active substance chamber formed in the main body, wherein the active substance chamber is arranged inside a peripheral outer wall, a peripheral active substance wall that extends around a perimeter of the active substance chamber, an application side which forms a front face of the active substance chamber, wherein the application side faces bone tissue or soft tissue and has a plurality of application openings, and a securing means configured to detachably secure the main body in the implant, wherein in a state in which the main body is inserted into the implant, the peripheral outer wall contacts a periphery of the cavity and the front face is coplanar with a surface of the implant, and in the state in which the main body is inserted into the implant, the application side faces outwards relative to the implant, such that the application openings connect the active substance chamber to the environment outside of the implant when the implant is implanted in a body of a patient, wherein the peripheral outer wall is between the front face and a rear face of the active substance chamber, which extends around a perimeter of the active substance application insert, and wherein at least one section of the peripheral active substance wall between the application side and the rear face of the active substance chamber is formed separately from and inside the peripheral outer wall of the main body, such that an annular gap is formed along this section between the peripheral outer wall of the main body and the peripheral active substance wall.

12. The implant system according to claim 11, wherein the securing means is formed by at least one section of the outer side of the peripheral outer wall forming a friction surface.

13. The implant system according to claim 11, wherein the peripheral outer wall forms at least one section of a peripheral active substance chamber wall between the application side and the rear face of the active substance chamber.

14. The implant system according to claim 11, wherein the application side is provided with a tool-engaging means for inserting and/or removing the active substance application insert.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings that supplement this description, exemplary embodiments of the present invention are illustrated and described. Reference is made therein to individual features of these exemplary embodiments by way of reference numbers, wherein throughout the drawings identical reference numbers refer to features having the same design and/or function.

(2) FIG. 1 illustrates a first embodiment of an active substance application insert from the application side, shown together with a removed cover, which is provided for the rear face of the active substance chamber.

(3) FIG. 2 is a side view of the active substance application insert from FIG. 1, also shown together with the removed cover.

(4) FIG. 3 is a view into the active substance chamber of the active substance application insert of FIG. 1, viewed diagonally from the rear face of the active substance application insert.

(5) FIG. 4 illustrates an implant diagonally from the anterior thereof with an inserted active substance application insert as according to a second exemplary embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) On the left-hand side of FIG. 1, an active substance application insert 10 is shown from the application side 13 thereof. The application side 13 is formed as an application front wall. On the right, next to the active substance application insert 10, FIG. 1 shows a rear face 16 designed as a removable cover 20. The removable cover 20 can be pressed into an annular recess 16a of the rear face 16 (cf. FIG. 3) such that it is held in the annular recess 16a by way of a friction fit and in this state it closes the rear face 16 of the active substance chamber 12.

(7) In the embodiment shown, the cover 20 is provided on the rear face of the active substance application insert 10, which faces the bottom of a corresponding recess 31 in an implant 30. This effectively prevents an unintentional opening of the cover 20. As an alternative to the illustrated embodiment of an active substance application insert 10, it is also possible to provide a solid rear wall on the rear face 16, instead of a cover 20. However, a rear face 16 designed as an active substance chamber cover 20 facilitates the filling of the active substance application insert 10 with an active substance, which can be present in one of the forms described above. Alternatively, it is also possible to completely omit a rear wall on the rear face 16. With such an embodiment, the bottom of a recess 31 in an implant 30 closes the rear face 16 of the active substance application insert 10 in the inserted state thereof.

(8) Application openings 14 are formed in the application side 13. Via these application openings 14, the active substance chamber 12 communicates with the outer side of the active substance application insert and therefore in the implanted state of the active substance application insert 10 with the body tissue of a patient. The application side can face bone tissue or soft tissue. Preferably, the active substance application insert 10 is used for a joint implant and more preferably still for a knee joint replacement (cf. FIG. 4).

(9) The application side 13 shown in FIG. 1 has as its application openings 14 six circular through-holes. As already described above, all or some of the application openings 14 may also have a different cross section from a circular cross section. The number and/or size of the application openings can be adapted according to the desired dosage. It is generally the case that a larger number of application openings 14 and/or an enlargement of the application openings 14 allows the dosage of an active substance contained in the active substance chamber 12 to be increased.

(10) Furthermore, it is possible to provide a membrane, a textile material and/or a mesh in at least one section of the application side 14. In the case of a membrane and/or a textile, it is also possible to adjust in a targeted manner the permeability of the active substance from the active substance chamber 12 to the outside and/or the permeability of body fluid into the active substance chamber. The application time for the active substance can also be controlled in this way.

(11) In the exemplary embodiment shown in FIG. 1, the active substance application insert 10 also comprises a tool-engaging means 19. In this embodiment, this is designed as a through-hole and has an internal thread. Moreover, it is clear from FIG. 3 that in this exemplary embodiment the tool-engaging means also provides a connection between the active substance chamber 12 of the active substance application insert 10 and the outer side of the active substance application insert. Thus, in this embodiment the tool-engaging means forms an application opening.

(12) However, as can be seen in a second exemplary embodiment of an application insert 110 shown in FIG. 4, the tool-engaging means 119 can also be designed as a through-hole or blind hole which is introduced in the active substance application insert 110 in such a way that no connection is made to the active substance chamber 112. In the exemplary embodiment in FIG. 4, a central column in the active substance chamber 112 is provided for this. Thus, in this embodiment, the tool-engaging means 119 does not form an application opening 114.

(13) In the exemplary embodiment of an active substance application insert 10 shown in FIGS. 1 and 2, the active substance chamber 12 is formed on the front face by the application side or application front wall 13 and on the rear face 16 by the cover 20. Between the application side 13 and the cover 20, the active substance chamber 12 is also delimited by a peripheral active substance chamber wall 18. Thus, the active substance chamber is defined by the application side 13 formed as the front wall, the rear face 16 designed as the active substance chamber cover 20 and the peripheral active substance chamber wall 18.

(14) The active substance chamber wall 18 is formed in a section 17a/18a of the peripheral outer wall 17 of the main body 11. In an adjacent section 18b towards the rear face, the active substance chamber wall 18 is formed separately from the peripheral outer wall 17, however. Due to this separate formation, the active substance chamber wall 18 is arranged inside the peripheral outer wall 17 of the main body 11. As a result, there is a gap 17c between the corresponding section 17b of the peripheral outer wall 17 and the section 18b of the active substance chamber wall 18.

(15) As can be seen from FIG. 1, for example, in section 17b the peripheral outer wall 17 is formed so as to be continuously annular due to the separation from the active substance chamber wall 18. However, it is also possible to divide in the peripheral direction the peripheral outer wall 17 in this region into outer wall sections which are separated from one another by cuts in the peripheral outer wall 17. These outer wall sections allow the elasticity of the outer wall 17 to be reduced further still. This is particularly advantageous when the securing means 15 is designed as a snap-fit. With such an embodiment, at least one part of the outer wall sections can be designed as snap-fit tabs with a locking function.

(16) As a result of the separation of the peripheral outer wall 17 of the active substance application insert 10 and of the peripheral active substance chamber wall 18 into sections 17b and 18b and the resulting annular gap 17c, the elasticity of section 17b of the peripheral outer wall 17 can be adjusted. It is therefore possible to influence the strength of the fastening of the active substance application insert 10 in an implant 30.

(17) As is illustrated in FIG. 1, this gap 17c of the active substance application insert 10 opens to the front on the side of the application side 13. It is possible to use this gap 17c in addition or alternatively to the tool-engaging means 19 which is formed as a recess. In this case, the recess or through-hole shown in FIG. 1 in the application side 13 can be omitted. In other words, in such an embodiment the tool-engaging means 19 is formed by the gap 17c.

(18) In the embodiments of an active substance application insert 10 shown in the drawings, the peripheral outer wall 17 is provided with a friction surface 15a as the securing means 15. The friction surface 15a may extend over the entire peripheral outer wall 17. It is also possible for the friction surface 15a to extend over a section of the outer wall 17 that is located in sections 17a and/or 17b.

(19) The friction surface 15a may be provided as an enlargement of the cross section on the peripheral outer wall 17 of the main body 11 and/or with a higher surface roughness than the surface of the peripheral outer wall without the friction surface 15a. The friction surface can be provided at least or only on the less elastic section 17a. In this section 17a it is possible to generate a higher friction force in order to secure the active substance application insert 10 in an implant 30 on account of the lower degree of elasticity of the friction surface 15a.

(20) By forming the friction surface 15a in section 17b of the peripheral outer wall 17 of the active substance application insert 10, the elasticity 17b can be selected in a broader area, however, such that when inserted into a corresponding recess 31 of an implant 30 the active substance application insert 10 can be inserted more easily and then fixed in this recess 31. Moreover, the elasticity of section 17a and/or 17b can be selected such that removing the active substance application insert 10 from the recess 31 of an implant 30 is also possible without excessive effort.

(21) The elasticity is preferably selected such that a manual insertion and/or removal is possible. At least in the case of a removal it is preferable for a tool to be used which engages with a tool-engaging means 19 of the active substance application insert.

(22) Furthermore, as a result of the separation of the active substance chamber wall 18 and the outer wall 17 of the main body 11, the influence of compressive forces created by the insertion of the active substance application insert 10 into an implant 30 is minimised on the side of the active substance chamber 12. For a start, this prevents possible damage to the active substance chamber 12. In addition, distortion of the application openings 14 cannot occur on the application side 13 and therefore an intended dosage cannot be influenced in an undesired way. This is particularly advantageous in the case of application openings 14 of a size in the lower part of the range indicated above.

(23) Even if the elastic section 17b of the peripheral outer wall 17 in the exemplary embodiment of an active substance application insert 10 shown in FIGS. 1 to 3 is arranged on the side of the application side 13, it is also possible to provide this elastic section 17b on the side of the rear face. With such an embodiment, in the inserted state of the active substance application insert 10 the annular gap 17c therefore faces the bottom of a recess 31 in an implant 30.

(24) As illustrated in FIGS. 1 to 4, the peripheral outer wall 17 of the active substance application insert 10, 110 is cylindrical. In addition to the circular-cylindrical shape shown, other cylindrical shapes are also conceivable, as already stated above. However, the cylindrical shape shown simplifies the insertion of the active substance application insert 10 since the orientation thereof about its longitudinal axis, which extends from the front face to the rear face of the active substance application insert 10, does not have to be taken into consideration.

(25) As can also be seen from the side view of the active substance application insert 10 in FIG. 2, the rear face 16 or the active substance chamber cover 20 is arranged perpendicularly to the longitudinal axis of the active substance application insert 10. The application side 13, however, has an angle to the longitudinal axis. As a result of this arrangement, which is inclined with respect to the longitudinal axis, the application side 13 is adapted to the outer contour of the implant 30 into which the active substance application insert 10 is to be inserted. Depending on the outer contour of the implant 30, the application side 13 may also have a more complex shape, such as a curved shape, for example. As a result of adapting the shape and/or orientation of the application side 13 to the outer contour of an implant 30 in this way, injury to surrounding tissue can in particular be prevented.

(26) In FIG. 4, a very limited adaptation of the application side 13 of a second embodiment of the active substance application insert 110 to the outer contour of the illustrated knee joint implant 30 has been carried out. Furthermore, in contrast to the embodiment of the active substance application insert 10 shown in FIGS. 1 to 3, the application side 113 of the active substance application insert 110 is designed with its application openings 114 as a removable cover 120. As a consequence, the active substance chamber can be replaced or refilled without the active substance application insert 110 having to be removed for this.

(27) The active substance application inserts 10, 110 are preferably inserted in permanent implants 30. Yet it is also possible to use an active substance application insert 10, 110 as according to the invention with an interim prosthesis. However, particularly in the case of permanently or definitively inserted implants there is the advantage that an explantation of the implant is generally avoided, even in the event of an infection.

(28) If the present invention is used with a knee joint implant, it is preferable for an active substance application insert as according to the invention to be provided on the medial and/or lateral side of the femur components of such an implant. With this positioning, the application side faces soft tissue, as a consequence of which the active substance disperses quickly and reliably into the surroundings of the implant.

LIST OF REFERENCE NUMBERS

(29) 10, 110 Active substance application insert 11 Main body 12 Active substance chamber 13, 113 Application side 14, 114 Application openings 15 Securing means 15a Friction surface 16 Rear face 16a Annular recess 17 Peripheral outer wall 17a Outer wall section as chamber wall 17b Outer wall section separated from the active substance chamber wall 17c Gap 18 Peripheral active substance chamber wall 18b Separated section of the active substance chamber wall 19, 119 Tool-engaging means 20, 120 Active substance chamber cover 30 Implant 31 Recess for receiving an active substance application insert