TOOL FOR PLACING A MALLEOLAR IMPLANT FOR PARTIAL OR TOTAL ANKLE PROSTHESIS

Abstract

A method of implanting in a fibula a malleolar implant including a head and a shank. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and applying a traction force to the malleolar implant so that the shank is pulled into the bore.

Description

BACKGROUND

1. Field of the Invention

The present invention relates to a malleolar implant for a partial or total prosthesis of the ankle and to an ancillary tool for placing such an implant.

2. Description of the Related Art

It is known, for example from EP-A-0 864 304, to fit an ankle prosthesis with a malleolar implant intended to bear against an articular surface at the level of the astragalus, whether it be question of a natural surface or of a surface of a prosthetic component. During an operation on an ankle, access to the internal articular surfaces is limited by the ligamentary system which does not necessarily allow a sufficient dislocation of the joint. In particular, access to the internal surface of the fibular malleolus may be insufficient, which induces difficulties in positioning the implant, particularly by impaction.

With reference to the embodiments of FIGS. 4 and 5, it is envisaged in EP-A-0 864 304 to introduce an implant from the outer face of the fibula. However, this necessarily limits the surface of the head of this implant, which must be less than or equal to the surface of the orifice provided in the bone, so that it is necessarily of relatively small dimensions with the result of substantially fragilizing the malleolus.

For the foregoing reasons, the positioning of the malleolar implants in the known prostheses is not entirely satisfactory.

It is a particular object of the present invention to overcome these drawbacks by proposing a novel malleolar implant which may be positioned precisely, even though access to the internal surface of the fibular malleolus may be limited and whereas its articular head presents dimensions allowing it to perform its function efficiently.

SUMMARY

In one embodiment, the invention is a method of implanting in a fibula a malleolar implant including a head and a shank. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and applying a traction force to the malleolar implant so that the shank is pulled into the bore.

In one embodiment, the invention is a method of implanting in a fibula a malleolar implant including a shank coupled to a head. The method comprises the step of creating a bore in the fibula extending from an inner face to an outer face. The shank and the bore are aligned. A traction force is applied to the shank so that the shank is pulled into the bore.

In another embodiment, the invention is a method of implanting in a fibula a malleolar implant including a shank coupled to a head. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and inserting a traction member through an orifice in the shank. A traction force is applied to the traction member in a direction parallel to a longitudinal axis of the bore so that the shank is pulled into the bore.

In another embodiment, the invention is a method of implanting in a fibula a malleolar implant including a shank coupled to a head. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and inserting a traction member through an orifice in the shank. The traction member is extended through the bore from the inner face to the outer face. A traction force is applied to the traction member from a location external to the outer face of the fibula so that the shank is pulled into the bore.

In another embodiment, the invention is a method of implanting a malleolar implant in a fibula. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and providing a malleolar implant having a shank coupled to a head. A traction force is applied to the implant from a location external to the outer face of the fibula so that the shank is pulled into the bore.

While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood on reading the following description of an embodiment of a malleolar implant and its ancillary tool according to the invention, given solely by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a view in perspective of an implant according to the invention.

FIG. 2 is a view in perspective of the implant of FIG. 1 during positioning in a fibular malleolus, shown with parts torn away.

FIG. 3 schematically shows, with parts torn away, an ancillary tool for placing the implant of FIG. 1, in the course of use.

FIG. 4 is a view in perspective of the tool of FIG. 3, from underneath.

While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Referring now to the drawings, the implant 1 shown in FIGS. 1 and 2 is intended to be introduced in a bore 2 made in the lateral or fibular malleolus 3. The implant 1 comprises a convex head 4, substantially in the form of a spherical cap and of which the radius of curvature is substantially equal to that of the outer cheek of the astragalus of the ankle in question. The shank 5 of the implant 1 is provided with outer radial flanges 6 of which the outer diameter d.sub.6 is substantially equal to the inner diameter d.sub.2 of the bore 2.

According to the invention, two orifices 7 are provided in the shank 5 and are capable of receiving a suture thread 8 or other flexible tie. When such a thread is engaged in one of the orifices 7, it is possible to exert on the thread 8 an effort of traction T which is transmitted by the thread 8 to the shank 5 as represented by arrow T′ in FIG. 2. In this way, by pulling on the thread 8, the surgeon introduces the shank 5 in the bore 2 without having to exert an effort of thrust on the head 4 which may be difficult to access due to the surrounding ligamentary system.

In other words, it suffices for the surgeon to place a thread in one of the orifices 7, to pass the two strands of the thread 8 in the bore 2 via the inner face of the malleolus, then to pull the strands via the outer side of the malleolus. The traction on the thread 8 has the effect of introducing the shank 5 of the implant 1 in the bore 2 and of applying the head 4 on the bone. The effort of traction T exerted on the thread 8 may be intense and directed parallel to the longitudinal axis X.sub.2 of the bore 2, with the result that the shank is efficiently drawn towards the inside of the bore 2. In particular, taking into account the direction and intensity of the effort of traction T, the diameters d.sub.2 and d.sub.6 can be provided to be substantially equal, with the result that the shank 5 is firmly maintained in place after having been positioned.

The shank 5 is provided with two bores 7 distributed along its axis X.sub.5, the bore 7 nearest the end 5a of the shank 5 being used. The fact that the shank 5 comprises a plurality of orifices 7 makes it possible to use an orifice 7 relatively close to the end 5a of the shank 5 and to avail of such an orifice including when the shank 5 is cut in order to adapt its length to the thickness e of the malleolus 3. The number of bores 7 may, of course, be increased if necessary.

The bore 2 is made via the outer face 3a of the malleolus 3 with the aid of the ancillary tool shown in FIGS. 3 and 4. This tool 10 comprises a spacer block 11 provided to be disposed between the tibia T and the astragalus A of an ankle to be fitted with the implant 1. The block 11 comprises a substantially planar upper surface 12 intended to cooperate with a planar surface created by resection of the distal end of the tibia. The lower surface 13 of the block 11 is formed by two planar surfaces 13a and 13b inclined with respect to each other by an angle .alpha., the surfaces 13a and 13b being provided to bear respectively on corresponding surfaces created by resection of the upper face of the astragalus A.

The surface 12 of the block 11 comprises a C-shaped housing 14 intended to receive a shim 15 of which the upper surface 16 is in contact with the lower surface of the tibia T. The thickness E of the shim 15 shown in FIG. 3 is such that its upper surface 16 is flush with the upper surface 12 of the block 11.

However, thicker shims may be used when the distance E′ between the lower surface of the tibia and upper surface of the astragalus is greater than in the configuration shown in FIG. 3.

The block 11 defines a housing 17 for receiving the end 20 of a substantially C-shaped lug 21. The end 20 is provided with a bore (not shown) which, in the configuration of FIGS. 3 and 4, is aligned with a bore 18 made in the block 11 and passing downwardly through this block, i.e. connecting the surfaces 12 and 13. A screw 19 may be introduced in this bore which is at least partially tapped, this making it possible to immobilize the end 20 of the lug 21 inside the housing 17. In practice, the clearance made when the screw 19 is tightened allows a limited pivoting about axis X.sub.18 of the bore 18.

At its end 22 opposite the end 20, the lug 21 supports a clamping system 23 adapted to be maneuvered thanks to a knurl 24 and making it possible to apply the malleolus 3 of the fibula P against a stop 25 formed on an extension 26 of the end 20 of the lug 21. X.sub.23 denotes the longitudinal axis of these clamping means. The clamping means 23 are hollow, with the result that a drill 30 may be introduced up to the level of the outer face 3a of the malleolus 3 in order to make the bore 2 from the outside towards the inside of the malleolus 3. In this way, the surgeon may easily aim at the suitable part of the malleolus 3 thanks to the clamping means 23 which also constitute a bore guide for the drill 30.

As the lug 21 is capable of pivoting about axis X.sub.18, the position of axis X.sub.23 is variable in pivoting about this axis X.sub.18, which makes it possible optimally to adjust the orientation of the bore 2 as a function of the exact geometry of the malleolus 3. .beta. denotes the maximum angle of pivoting of the axis X.sub.23 about axis X.sub.18. In practice, the angle .beta. is of the order of 10.degree.

Thanks to the tool 10, a bore 2 may therefore be formed from the outside, allowing a rapid and efficient implantation of the implant 1.

When shims 15 of thickness greater than those shown in FIG. 2 are used, they can be provided to overlap the bore 18, as the screw 19 is placed in position before positioning of the shim 15 which is effected during operation as a function of the distance E′.

The invention has been shown with a total ankle prosthesis, which corresponds to the geometry of the surfaces 12 and 13 of the block 11. However, it is also applicable to a partial ankle prosthesis, without modification of the implant 1, the ancillary tool in that case being adapted to the geometry of the anatomical articulation surfaces between the tibia and the astragalus.

Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.

Claims

1. A method of implanting in a fibula a malleolar implant including a head and a shank, the method comprising the steps of: creating a bore in the fibula extending from an inner face to an outer face; and applying a traction force to the malleolar implant so that the shank is pulled into the bore.

2. The method of claim 1 comprising applying the traction force to the shank.

3. The method of claim 1 comprising applying the traction force from a location external to the outer face of the fibula.

4. The method of claim 1 comprising applying the traction force so that the head contacts an astragalus or astragalian prosthetic component when the shank is pulled into the bore.

5. The method of claim 1 comprising applying the traction force in a direction parallel to a longitudinal axis of the bore.

6. The method of claim 1 comprising inserting a traction member through at least one orifice in the shank and applying the traction force to the traction member.

7. The method of claim 1 comprising the steps of: engaging a traction member with the malleolar implant; and applying the traction force through the bore.

8. The method of claim 1 comprising selecting one of a plurality of orifices in the shank and inserting the traction member through the selected orifice.

9. The method of claim 1 comprising applying the traction force to a traction member in a direction away from the head.

10. The method of claim 1 comprising applying the traction force in a direction away from the head and through at least one bore in the shank.

11. The method of claim 1 comprising extending a flexible traction member through a bore in the shank and applying the traction force to the flexible traction member in a direction away from the head.

12. The method of claim 1 comprising aligning the shank with the bore.

13. The method of claim 1 comprising applying a traction force to the implant so that outer radial flanges on the shank frictionally engage with the bore.

14. The method of claim 1 comprising creating a bore in the fibula with a diameter substantially the same as a diameter of the shank.

15. A method of implanting in a fibula a malleolar implant including a shank coupled to a head, the method comprising the steps of: creating a bore in the fibula extending from an inner face to an outer face; aligning the shank and the bore; and applying a traction force to the shank so that the shank is pulled into the bore.

16. The method of claim 15 comprising inserting a traction member through an orifice in the shank and applying the traction force to the traction member.

17. The method of claim 15 comprising inserting a flexible traction member through an orifice in the shank and applying the traction force in a direction away from the head and through the bore.

18. The method of claim 15 applying the traction force in a direction parallel to a longitudinal axis of the bore.

19. The method of claim 15 comprising applying a traction force so that the head contacts an astragalus or astragalian prosthetic component when the shank is pulled into the bore.

20. The method of claim 15 comprising creating a bore with a diameter substantially equal to the diameter of the shank.

21. The method of claim 15 comprising applying the traction force from a location external to the outer face of the fibula.

22. A method of implanting in a fibula a malleolar implant including a shank coupled to a head, the method comprising the steps of: creating a bore in the fibula extending from an inner face to an outer face; inserting a traction member through an orifice in the shank; and applying a traction force to the traction member in a direction parallel to a longitudinal axis of the bore so that the shank is pulled into the bore.

23. The method of claim 22 comprising the steps of: extending the traction member away from the head and through the bore; and applying the traction force to the traction member through the bore.

24. The method of claim 22 comprising selecting one of a plurality of orifices in the shank and inserting the traction member through the selected orifice.

25. The method of claim 22 comprising applying the traction force so that the head contacts an astragalus or astragalian prosthetic component when the shank is pulled into the bore.

26. The method of claim 22 comprising applying the traction force in a direction generally perpendicular to an orifice in the shank.

27. The method of claim 22 comprising creating the bore with a diameter substantially equal to a diameter of the shank.

28. The method of claim 22 comprising engaging a flexible traction member with the shank and applying the traction force.

29. The method of claim 22 comprising applying the traction force from a location external to the outer face of the fibula.

30. A method of implanting in a fibula a malleolar implant including a shank coupled to a head, the method comprising the steps of: creating a bore in the fibula extending from an inner face to an outer face; inserting a traction member through an orifice in the shank; extending the traction member through the bore from the inner face to the outer face; and applying a traction force to the traction member from a location external to the outer face of the fibula so that the shank is pulled into the bore.

31. The method of claim 30 comprising applying the traction force in a direction generally transverse to an elongated axis of the shank.

32. The method of claim 30 comprising selecting an orifice in the shank from a plurality of orifices and inserting the traction member through the selected orifice.

33. The method of claim 30 comprising applying the traction force so that the head contacts an astragalus or astragalian prosthetic component when the shank is pulled into the bore.

34. The method of claim 30 comprising applying the traction force generally parallel to a longitudinal axis of the bore.

35. A method of implanting a malleolar implant in a fibula, the method comprising the steps of: creating a bore in the fibula extending from an inner face to an outer face; providing a malleolar implant having a shank coupled to a head; and applying a traction force to the implant from a location external to the outer face of the fibula so that the shank is pulled into the bore.

36. The method of claim 35 comprising the steps of: inserting a traction member through an orifice in the shank; extending the traction member through the bore from the inner face to the outer face of the fibula; and applying the traction force to the traction member.

37. The method of claim 35 comprising applying the traction force in a direction generally parallel to a longitudinal axis of the bore.

38. The method of claim 35 comprising aligning the shank with the bore.

39. The method of claim 35 comprising frictionally engaging outer radial flanges on the shank with the bore.

40. The method of claim 35 comprising creating the bore with a diameter substantially equal to a diameter of the shank.

41. The method of claim 36 comprising selecting an orifice from a plurality of orifices and inserting the traction member through the selected orifice.