Accessory for implanting a hip endoprosthesis, and method for manipulating the same

• US 20050107799A1
• Filed: 01/03/2003
• Published: 05/19/2005
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Smith & Nephew Orthopaedics Ag (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Orthopaedics Ag (Smith & Nephew PLC)
• Inventors: Graf, Reinhard, Brack, Rene, Imhof, Martin
• Granted Patent: US 7,828,806 B2
• Time in Patent Office: Days
• US Class Current: 606/91
• CPC Class Codes: A61B 17/1746 for the acetabulum
• CPC Class Codes: A61B 2090/067 for measuring angles
• CPC Class Codes: A61B 90/11 with guides for needles or instruments, e.g. arcuate slides or ball joints
• CPC Class Codes: A61B 90/50 Supports for surgical instruments, e.g. articulated arms
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/4609 of acetabular cups
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 Necks
• CPC Class Codes: A61F 2002/4668 for measuring angles
• CPC Class Codes: A61F 2002/4681 by applying mechanical shocks, e.g. by hammering

Abstract

The invention relates to an accessory for implanting a hip endoprosthesis, which comprises a manipulation cavity (20), a manipulation head (16) with means (22) for aligning the manipulation cavity (20) in the acetabulum (12), and a device for immobilizing the aligned position of the manipulation cavity (20). The inventive device allows for the corresponding alignment of a bone bur (28) and a drive-in instrument (27) for placing the acetabular cavity.

Claims

1. An accessory for implantation of a hip-joint endoprosthesis, comprising a manipulation cup, a manipulation joint with means for orienting the manipulation cup in an acetabulum and a device to represent the correctly oriented position of the manipulation cup, such that by means of this device a bone-milling cutting head and/or an impact instrument can then be oriented appropriately for placement of a prosthesis cup.

2. The accessory according to claim 1, wherein the manipulation joint head comprises a shoulder that extends radially outward around a spherical part and corresponds to a rim around an opening of the manipulation cup so that the latter can be oriented within the acetabulum.

3. The accessory according to claim 2, wherein the shoulder is defined by shoulder sections distributed approximately uniformly over the circumference.

4. The accessory according to claim 1, wherein the device used to represent the correctly oriented position of the manipulation cup consists of a guide rod that is fixed in a bone and corresponds to a guide device attached to the manipulation cup.

5. The accessory according to claim 4, wherein the guide rod comprises a screw thread on the end section that is anchored in the bone, so that said rod can be screwed into the bone.

6. The accessory according to claim 4, wherein the guide device on the manipulation cup comprises a component connected to the manipulation cup by way of an arm and having a bore to receive and guide the guide rod.

7. The accessory according to claim 4, further comprising a template that is fastened to the guide rod, and that is used to orient the cutting head or a drive axle of a milling cutter in such a way that the orientation of the cutting head matches that of the manipulation cup.

8. The accessory according to claim 7, wherein the orienting template comprises an arm, which can be pushed onto the guide rod and at the free end of which is disposed a direction plate, to assist orientation of the cutter drive axle, such that to orient the drive axle the latter is pivoted parallel to the direction plate while in complete, gap-free contact therewith.

9. The accessory according to claim 8, further comprising a bush within which the drive axle is rotatably seated and against the surface of which the direction plate can be brought into complete, gap-free contact that is maintained during the milling process, wherein said bush is set onto the milling cutter drive axle.

10. The accessory according to claim 9, further comprising a cup impact instrument that is oriented with respect to the direction plate of the orienting template in the same way as can the cutting head and its drive axle.

11. The accessory according to claim 10, wherein the manipulation cup comprises a guide device for two guide rods that is fixed in the bone so as to be parallel to one another.

12. The accessory according to claim 11, wherein the template for orienting the cutting head or its drive axle comprises two through-bores by way of which it is pushed onto the guide rods fixed in the bone.

13. The accessory according to claim 8, wherein the direction plate of the orienting template is bent into a U shape, such that the space between the two limbs of the plate serves to contain the cutter drive axle and/or the cup impact instrument.

14. The accessory according to claim 13, wherein the plate limb nearest a surgeon, comprises on its end face recesses to serve as markings for orienting the cutter drive axle and/or the cup impact instrument parallel to the direction plate or to its limbs.

15. The accessory according to claim 14, wherein the manipulation joint head can be fixed to a neck of a manipulation rasp.

16. The accessory according to claim 1, wherein as a means for orienting the manipulation cup in the acetabulum optical detection means are provided.

17. The accessory according to claim 16, wherein the spherical part of the manipulation joint head comprises a marking, selected from an indentation, a groove or the like, that extends at least partially around the circumference, within a plane that is either perpendicular to a central axis of the joint head or is set at a prespecified angle thereto.

18. The accessory according to claim 1, wherein said means for orienting the manipulation cup in the acetabulum is a circumferential shoulder that extends outward from the joint head in a plane perpendicular to its central axis, in combination with a receptacle that is inclined at an angle to the central axis of the joint head and contains a neck of a manipulation rasp, the long axis of which extends parallel to a femoral neck axis.

19. The accessory according to claim 1, wherein as a device to represent the correctly oriented position of the manipulation cup at least one, of three fixation rods is provided, which extends through a holding device for the manipulation cup.

20. The accessory according to claim 19, wherein at least one of the fixation rods comprises a screw thread on the end section to be anchored in the bone, so that it is screwed into the bone 3.

21. The accessory according to claim 19, wherein to the holding device is connected a guide rod in such a way that the latter extends approximately parallel to a central axis of the manipulation cup.

22. The accessory according to claim 21, further comprising a guide element for a cutter drive axle or a bush enclosing the axle, as well as for a cup impact instrument, such that the guide element is attached to or set onto the guide rod and ensures that the orientation of the drive axle and of the impact instrument corresponds to that of the manipulation cup.

23. The accessory according to claim 22, wherein the guide element is a sleeve or half-sleeve disposed on a connector strap or similar connecting element.

24. The accessory according to claim 23, wherein the length of the connector strap is adjustable.

26. The accessory of claim 7, wherein said template is pushed onto said guide rod.

27. The accessory of claim 8, wherein said arm is an angled strap.

28. The accessory of claim 8, wherein said direction plate has marks (0°

;

±

5°

).

29. The accessory of claim 28, wherein the drive axle is pivoted parallel to the direction plate into a position corresponding to a specified mark (0°

;

±

5°

).

30. The accessory of claim 29, wherein said specified mark is zero position.

31. The accessory of claim 14, wherein said limb is an upper limb.

32. The accessory of claim 15, wherein said manipulation joint head is set into the neck.

25. A method of orienting a bone-milling cutter and an impact instrument for a hip-prosthesis cup in an acetabulum, comprising:

initially positioning a manipulation cup by means of a manipulation joint head,

representing this position of said manipulation cup by at least one guide rod or fixation rod that is fixed in a bone, removing the manipulation cup,

adjusting the position of both the bone-milling cutter and the impact instrument with respect to either the guide rod itself or a guide rod that is attached to a holding device disposed on at least one fixation rod.