Modular instrument for positioning acetabular prosthetic socket

• US 20040073225A1
• Filed: 10/15/2002
• Published: 04/15/2004
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Goli V. Subba Rao
• Original Assignee: Goli V. Subba Rao
• Inventors: Subba Rao, Goli V.
• Granted Patent: US 6,743,235 B2
• Time in Patent Office: Days
• US Class Current: 606/91
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4609 of acetabular cups
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/4668 for measuring angles
• CPC Class Codes: A61F 2002/4687 Mechanical guides for implantation instruments
• CPC Class Codes: A61F 2250/0006 for adjusting angular orientation
• CPC Class Codes: A61F 2250/0064 Sets comprising a plurality of prosthetic parts of different sizes

Abstract

A modular implantation instrument for reliably positioning an acetabular prosthetic socket in the acetabulum of a pelvic bone during a total hip joint replacement surgery. The modular instrument has an interchangeable hemispherical ball member to properly engage into an acetabular prosthetic socket. A drive mechanism includes an alignment shaft member, operatively connected through an orientation pillar member to a levelling apparatus and to a laser pen apparatus. The modular instrument includes the hemipherical ball member is threadingly connected into the proximal end of said alignment shaft, the distal end of alignment shaft includes a handle and a knob. The lower end of said orientation pillar member is permanently attached to the shank of the alignment shaft member at angle of 135 degrees to the horizontal axis of said alignment shaft. The orientation pillar member includes a levelling apparatus attached to its upper end, and a laser pen apparatus attached at an intermediate location in the orientation pillar. The levelling apparatus and the laser pen apparatus are independently adjustable parameters. Also disclosed is a detachably implantable level bit member into the levelling apparatus and a detachably implantable laser pen member into the laser pen apparatus, in order to position the acetabular prosthetic socket into correct abduction angle and antiversion angle respectively to prevent complications associated with malpositioning of an acetabular prosthetic socket.

Claims

1. A modular instrument for correct positioning of an acetabular prosthetic socket comprising;

a hemispherical ball member having a threaded pit in the center of its'"'"'s flat surface;

an alignment shaft having a threaded proximal end;

an orientation pillar incorporated with a levelling apparatus fixed at it'"'"'s top end, and a laser pen apparatus coupled at an intermediate location in the orientation pillar

2. A modular instrument as defined in claim 1, wherein the hemispherical ball member comprises an outer convex non-slip surface adapted to cooperate with an acetabular prosthetic socket a means for reliably engaging and releasing the said socket during the implantation into reamed bony acetabulum.

3. A modular instrument as defined in claim 2, wherein said hemispherical ball member comprises of a threaded pit in the central axis of it'"'"'s flat inner surface, and a threaded connector at the proximal end of the alignment shaft member, wherein the said hemispherical ball member and said alignment shaft are threadingly connected.

4. A modular instrument as defined in claim 3, wherein said hemispherical ball member and said alignment shaft are detachably attached, wherein different size hemispherical ball member can be sellected from a plurality of different size hemispherical ball members for custom fitting the prosthetic socket into the reamed bony acetabulum

5. A modular instrument as defined in claim 1, wherein the alignment shaft member includes an intermediate shank for securely attaching an orientation pillar at an angle of 135 degrees.

6. A modular instrument as defined in claim 1, includes an orientation pillar member consisting of a lower end, an intermediate part and an upper end.

7. A modular instrument as defined in claim 6, wherein the lower end of orientation pillar is permanently attached to the shank of alignment shaft at an oblique angle of 135 degrees to the horizontal axis of said alignment shaft.

8. A modular instrument as defined in claim 7, wherein the orientation pillar member further comprises of a levelling apparatus incorporated into its upper end.

9. A modular instrument as defined in claim 8, wherein the upper end of orientation pillar is permanently attached with a semitubular bar member, generally disposed perpendicularly to the vertical axis of the orientation pillar member, and of equal length on either side of the said vertical axis.

10. A modular instrument as defined in claim 8, wherein a level bit member is detachably installed into the semitubular bar member of levelling apparatus to establish the vertical axis of orientation pillar relative to patient'"'"'s horizontal axis, and to establish the abduction angle of alignment shaft member relative to patient'"'"'s horizontal axis.

11. A modular instrument as defined in claim 10, wherein the level bit member is installed into the semitubular member by click-in method;

and

said level bit member further includes an air bubble in a liquid medium, wherein the air bubble migrates to the center of the level bit when the alignment shaft member is abducted to 45 degrees of abduction to the horizontal axis of patient.

12. A modular instrument as defined in claim 11, wherein said air bubble in the level bit member migrates to the proximal end of the said level bit, when the alignment shaft is abducted less than 45 degrees of abduction to the horizontal axis of patient.

13. A modular instrument as defined in claim 10, wherein said air bubble in the level bit member migrates to the distal end of the said level bit, when the alignment shaft is abducted more than 45 degrees of abduction to the horizontal axis of patient.

14. A modular instrument as defined in claim 11, wherein said levelling apparatus, said orientation orientation pillar member, and said alignment shaft member being used in cooperation to correctly position an acetabular prosthetic cup at a predetermined angle of abduction and antiversion or retroversion.

15. A modular instrument as defined in claim 2, wherein the convex surface of the hemispherical ball member is made up of slip resistant surface, made to adapt and cooperate with the concave surface of an acetabular proshetic socket.

16. A modular instrument as defined in claim 1, wherein the implant instrument further includes a laser pen apparatus, wherein a laser pen being installed into a semitubular arm member by a click-in method.

17. A modular instrument as defined in claim 16, wherein the said semitubular arm member is attached to the orientation pillar member at an intermediate location, wherein the distal part of said semitubular member is coupled with a hinge mechanism, wherein the said laser pen angle can be adjusted during the step of implanting an acetabular prosthetic cup for correct angle of antiversion or retroversion.

18. A modular instrument as defined in claim 16, wherein the laser pen member is detachably installed into the semitubular arm member by click-in and click-out method for easy installation, for easy replacement, for sterilisation and for safety purpose.

19. A modular instrument as defined in claim 10, wherein said level bit member is detachably installed into the said semitubular bar member, by means of click-in and click-out method for easy installation, for easy replacement, for sterilisation and for reducing the costs.

20. A modular instrument as defined in claim 1, wherein a hemispherical ball member is threadingly connected to an alignment shaft member, wherein the alignment shaft member is housed with an orientation pillar member, and the orientation pillar member is incorporated with a levelling apparatus and a laser pen apparatus further comprising:

adjustments in hemispherical ball member causes corresponding adjustments in the alignment shaft; and

vice versa;

adjustments in the alignment shaft member causes corresponding adjustments in the orientation pillar member,

adjustments in the orientation pillar member causes corresponding adjustments in the levelling apparatus and laser pen apparatus and vice versa.