Device and method for the in-situ production of articulated spacers

Patent metadata

Field	Value
Publication number	US-9622865-B2
Application number	US-201414278528-A
Country	US
Kind code	B2
Filing date	May 15, 2014
Priority date	May 17, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Devices and methods in-situ produce articular spacers from a bone cement. The devices and methods have a punch surface for forming an articulation surface of a spacer in the bone cement, whereby the bone cement is arranged on a bone surface for fixation of the spacer, whereby the punch surface has a negative image of the articulation surface to be produced, and the surface forming the negative image is open on the side, at least in part, such that the bone cement can be pushed towards the side, away from the articulation surface to be formed. Moreover, the method for producing an articular spacer on a bone may have one or more of the following steps: A) Applying a bone cement to a prepared bone; B) Pressing said device onto the bone cement; and C) Detaching the device from the cured bone cement.

First claim

The invention claimed is:

1. A device for in-situ production of articular spacers from a bone cement, the device comprising a punch surface for forming an articulation surface of a spacer in the bone cement, wherein the bone cement is arrangeable on a bone surface for fixation of the spacer, wherein the punch surface comprises a negative image of the articulation surface to be produced, and the surface forming the negative image is open on a side, at least in part, such that the bone cement is pushable towards a side, away from the articulation surface to be formed, wherein at least one separator for placing on a bone is arranged on the punch surface, wherein a thickness of the bone cement is settable by means of the at least one separator.

2. The device according to claim 1 , wherein the surface representing the negative image is at least partially over the entire circumference open on the side such that the bone cement is pushable laterally in all directions.

3. The device according to claim 1 , wherein at least two separators for placing on a bone are arranged on the punch surface by means of which a thickness of the bone cement is settable.

4. The device according to claim 3 , wherein a height of the at least two separators or the at least one separator above the punch surface can be set variably.

5. The device according to claim 3 , wherein the at least one separator or the at least two separators comprise(s) a bulgable floor for placing on the bone or on the bone surface, wherein the bulgable floor bulges when exposed to a force acting in the direction of the bone, and the punch surface thus becomes detachable from the bone cement formed with the device, wherein the floor is rubber-elastic and the rest of the device is not rubber-elastic.

6. The device according to claim 1 , further comprising at least one ejection facility by means of which the punch surface is mechanically detachable from the bone cement formed with the device through the action of a force, wherein the ejection facility is supported as in a bearing in the separator or ejection facilities are supported as in a bearing in the separators.

7. The device according to claim 6 , wherein the ejection facility is an axially mobile pin or pestle or a screw connected to the device by means of a thread by means of which the punch surface side of the device is pushable away from the bone or from the bone surface, wherein the pins, pestles and/or screws of multiple ejection facilities are connected to each other appropriately such that the pins, pestles and/or screws are pressable onto the bone or onto the bone surface, jointly.

8. The device according to claim 6 , wherein force of the ejection facility is adapted to act on the bone or on the bone surface, perpendicular to the punch surface.

9. The device according to claim 6 , wherein the ejection facility is arranged in an opening perpendicular to the punch surface or in that the ejection facilities are arranged in openings perpendicular to the punch surface.

10. The device according to claim 1 , wherein at least one handle for pressing the device onto the bone is arranged on the side facing away from the punch surface and/or on the lateral surface of the device adjacent to the punch surface.

11. The device according to claim 1 , wherein the device is made of a thermoplastic material comprising polypropylene, polyethylene, polytetrafluoroethylene, polyethyleneterephthalate, polybutyleneterephthalate, Polyamide-6, Polyamide-6.6, Polyamide-10, Polyamide-12 or mixtures thereof, wherein the device consists of the thermoplastic material except for bulgable floor, pins pestles and/or screws.

12. The device according to claim 6 , wherein the device is a tibia punch for forming a tibial plateau and/or a femur punch for forming a condylar surface.

13. The device according to claim 12 , wherein the ejection facilities of the tibia punch are arranged to be asymmetrical to a plane in a knee that is parallel to a sagittal plane of a patient and/or the ejection facility or the ejection facilities of the femur punch are arranged between moulds for condyles to be formed and are oriented such as to be axial to the femur axis.

14. A set comprising at least a pair of the devices according to claim 1 , wherein a first device according to claim 1 is adapted for forming the articulation surface of a first articular spacer and a second device according to claim 1 is adapted for forming the articulation surface of a second articular spacer, wherein the two articulation surfaces touch against each other and form the sliding surfaces of the articular spacer in the patient-inserted state such that the articular spacer assumes a function of the bones of the respective joint.

15. A method for producing an articular spacer on a bone or a bone surface, the method comprising:
A) applying a bone cement to a prepared bone or bone surface;
B) pressing the device according to claim 1 onto the bone cement; and
C) detaching the device from the bone cement after the bone cement at least partially cures.

16. The method according to claim 15 , wherein the bone cement cures after step A) and before step B) to the point at which the bone cement has a doughy consistency.

17. The method according to claim 15 , wherein the device, in step C), is detached from the formed bone cement surface through use of at least one ejection facility, by means of rotating at least one screw as the at least one ejection facility, and/or by pressing onto at least one pin or at least one pestle as the at least one ejection facility and/or through bulging the floor of the at least one separator, by means of the at least one pin or the at least one pestle or the at least one screw as the at least one ejection facility.

18. The method according to claim 17 , wherein the device, in step C), is detached from the formed bone cement surface by means of rotating the at least one screw as the at least one ejection facility and/or by pressing onto the at least one pin or the at least one pestle as the at least one ejection facility and/or through bulging the floor of the at least one separator, by means of the at least one pin or the at least one pestle or the at least one screw as the at least one ejection facility.

19. The method according to claim 15 , wherein the device is pressable onto the bone cement in step B) such that the at least one separator rests on the bone or on the bone surface.

Assignees

• Heraeus Medical Gmbh

Inventors

• Vogt Sebastian

Classifications

• A61F2/38 Primary

  for elbows or knees · CPC title

• A61F2002/30677

  Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body · CPC title

• B29C33/42

  characterised by the shape of the moulding surface, e.g. ribs or grooves · CPC title

• A61F2/30942

  for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques · CPC title

• A61F2002/30957

  using a positive or a negative model, e.g. moulds · CPC title