Ancillary tool and method for positioning a prosthetic acetabulum of a hip prosthesis

1. A method for positioning a prosthetic acetabulum with inner and outer surfaces in an anatomical or prosthetic cavity of a patient's hip, comprising the steps of:

providing a tool having a handle for manipulating the acetabulum, the handle, including a rod and a head, the head adapted to cooperatively engage inner faces of an elastically deformable ring including a plurality of petals in an endpiece that is used to grip the inner surface of the acetabulum and which endpiece is removably secured to the distal end of the handle, the petals of the elastically deformable ring including outer surfaces adapted to wedge against the inner surface of the acetabulum and opposite inner surfaces adapted to interact said endpiece with said handle, wherein said endpiece includes a supple part and a rigid part secured to the supple part, wherein the rigid part includes structure for removably securing the rod to the endpiece and wherein said handle further includes elements for applying a first force to urge said head into cooperative engagement with said inner surfaces of said petals of the elastically deformable ring to thereby radially expand said petals of the elastically deformable ring with respect to a longitudinal axis of said endpiece wherein said elements include a threaded portion on the rod, a grip screwed on the threaded section and a movable sleeve fitted between the grip and the head;

placing said endpiece in engagement with said head of said handle and said head within said acetabulum and providing said first force between said head and said endpiece so as to provoke radial elastic deformation of the petals of said elastically deformable ring to thereby grip said acetabulum by said endpiece;

positioning said acetabulum in said cavity of said patient's hip;

applying a second force along said handle to cause said acetabulum to seat within said cavity of said patient's hip;

disengaging said head from said endpiece and releasing said first force to allow the petals of said elastically deformable ring to recover to a non-expanded configuration; and

withdrawing said endpiece from the positioned acetabulum.

2. The method of claim 1 including the additional steps of:

providing a plurality of endpieces having different sizes, different geometric configurations, or both;

selecting an endpiece from said plurality of endpieces that closely matches said inner surface of said acetabulum and securing said selected endpiece to said distal end of said handle.

3. The method of claim 1 , wherein the first force is applied by rotating the grip to move the sleeve toward the endpiece secured to the tool.

4. The method of claim 1 wherein the rigid part of the endpiece includes a tapped section adapted to be secured to a threaded section on a distal end of the rod.

5. The method of claim 4 wherein the endpiece is secured to the rod by screwing the threaded section on the distal end of the rod into the tapped section of the rigid part of the endpiece.

6. The method of claim 1 wherein the tool includes a knob fixed to a proximal end of the tool.

7. The method of claim 6 wherein the second force is an impaction force applied to the knob fixed to the proximal end of the tool.

8. A method of positioning a prosthetic acetabulum with inner and outer surfaces in an anatomical or prosthetic cavity of a patient's hip, comprising the steps of:

(a) contacting the prosthetic acetabulum with a tool having a head movably mounted on a rod adapted to engage an endpiece removably secured to the rod, wherein the endpiece includes a plurality of petals in an elastically deformable ring, wherein the petals have inner surfaces adapted to contact the head and outer surfaces adapted to contact an inner surface of the prosthetic acetabulum wherein said endpiece includes a supple part and a rigid part secured to the supple part, wherein the rigid part includes structure for removably securing the rod to the endpiece;

(b) forcing the head into engagement with the inner surfaces of the petals in deformable ring to radially wedge the outer surfaces of the petals of the deformable ring against the inner surface of the prosthetic acetabulum to secure the prosthetic acetabulum to the tool wherein the step of forcing the head into engagement with the inner surfaces of the petals of the deformable ring includes rotating a grip screwed on a threaded section of the rod in a first direction to urge a movable sleeve fitted between the grip and the head toward a distal position on the rod;

(c) positioning the outer surface of the prosthetic acetabulum in a cavity in a patient's hip;

(d) applying a force to the tool to seat the prosthetic acetabulum in the cavity;

(e) releasing the head from engagement with the petals of the deformable ring to allow the deformable ring to unsecure the prosthetic acetabulum from the tool; and

(f) withdrawing the tool from the positioned prosthetic acetabulum.

9. The method of claim 8 further comprising the step of selecting the endpiece from a plurality of endpieces, wherein the selected endpiece closely matches the size of the inner surfaces of the prosthetic acetabulum.

10. The method of claim 9 further comprising the step of securing the selected endpiece to the rod by screwing a threaded section on the distal end of the rod into a tapped section in a rigid part of the endpiece.

11. The method of claim 8 wherein the step of withdrawing the tool from the positioned prosthetic acetabulum includes rotating a grip screwed on a threaded section of the rod in a second direction to urge a movable sleeve fitted between the grip and the head toward a proximal position on the rod.

12. The method of claim 8 wherein the step of applying a force to the tool to seat the prosthetic acetabulum includes applying an impaction force to a knob fixed to a proximal end of the tool.

13. A method of positioning a prosthetic acetabulum with inner and outer surfaces in an anatomical or prosthetic cavity of a patient's hip, comprising the steps of:

(a) providing a tool having a handle that includes a rod having a threaded medial portion and a threaded distal portion, a movable sleeve adapted to move in distal and proximal directions on the rod, a grip adapted to rotate on the threaded medial portion of the rod to move the sleeve, a movable head adapted to move in distal and proximal direction on the rod and to engage an endpiece, and an endpiece having an elastically deformable ring including a plurality of petals mounted on a rigid part that contains a threaded portion to secure the endpiece to the rod, wherein the petals have outer surfaces adapted to engage the inner surface of a prosthetic acetabulum when the head is forced on inner surfaces of the petals wherein said endpiece includes a supple part and a rigid part secured to the supple part, wherein the rigid part includes structure for removably securing the rod to the endpiece;

(b) placing the endpiece of the tool into the prosthetic acetabulum;

(c) forcing the head into the inner surfaces of the petals by rotating the grip in a first direction to radially expand the petals to an expanded configuration and secure the endpiece in the prosthetic acetabulum by gripping the inner surface of the prosthetic acetabulum with the outer surfaces of the petals;

(d) positioning the prosthetic acetabulum in a cavity of a patient's hip;

(e) applying an impaction force to the tool to seat the prosthetic acetabulum in the cavity;

(f) disengaging the head from the inner surface of the petals by rotating the grip in a second direction to allow the petals to recover to a non-expanded configuration; and

(g) withdrawing the tool from the prosthetic acetabulum.

14. The method of claim 13 further comprising the step of selecting the endpiece from a plurality of endpieces, wherein the selected endpiece closely matches the size of the inner surface of the prosthetic acetabulum.

15. The method of claim 1 wherein the petals are connected to the rigid part of the endpiece by elastically deformable connecting zones.

16. The method of claim 15 wherein the petals move apart radially in a homogenous manner.

17. The method of claim 15 wherein the petals move radially in order to contact the inner surface of the acetabulum.