Orthopaedic prosthesis having a superparamagnetic material and associated method

• US 20060282168A1
• Filed: 06/13/2005
• Published: 12/14/2006
• Est. Priority Date: 06/13/2005
• Status: Abandoned Application

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: DiSilvestro, Mark R., Sherman, Jason T.
• Application Number:
  US11/151,146
• Publication Number:
  US 20060282168A1
• Time in Patent Office: Days
• US Class Current: 623/18.120
• CPC Class Codes: A61B 17/1707 using electromagnetic effects, e.g. with magnet and external sensors
• CPC Class Codes: A61B 17/1725 for applying transverse screws or pins through intramedullary nails or pins
• CPC Class Codes: A61B 17/72 Intramedullary pins, nails or other devices A61B17/744 takes precedence
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61F 2/30 Joints
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/3676 Distal or diaphyseal parts of shafts
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/40 for shoulders
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/488 Means for detecting or monitoring wear
• CPC Class Codes: A61F 2002/30052 differing in electric or magnetic properties
• CPC Class Codes: A61F 2002/30079 magnetic
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30617 Visible markings for adjusting, locating or measuring
• CPC Class Codes: A61F 2002/3071 : Identification means; Administration of patients
• CPC Class Codes: A61F 2210/009 : magnetic
• CPC Class Codes: A61F 2250/0045 : differing in electromagnetical properties
• CPC Class Codes: A61F 2250/0085 : Identification means; Administration of patients
• CPC Class Codes: A61F 2250/0086 : with bar code
• CPC Class Codes: A61F 2250/0097 : Visible markings, e.g. indicia
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers

Abstract

An implantable orthopaedic prosthesis includes a superparamagnetic material. Features and/or location of the prosthesis may be determined in vivo by use of the superparamagnetic material. Methods of using such a prosthesis are also disclosed.

Claims

1. An orthopaedic implant comprising a superparamagnetic material.

2. The orthopaedic implant of claim 1, further comprising an elongated nail having a hole defined therein.

3. The orthopaedic implant of claim 2, wherein a wall which defines the hole is coated with a composition comprising the superparamagnetic material.

4. The orthopaedic implant of claim 2, wherein the hole is at least partially filled with a composition comprising the superparamagnetic material.

5. The orthopaedic implant of claim 2, wherein the superparamagnetic material is positioned on an outer surface of the elongated nail at a location proximate to the hole.

6. The orthopaedic implant of claim 2, wherein the hole comprises a screw hole adapted to receive a bone screw.

7. The orthopaedic implant of claim 1, further comprising a polymer component, wherein the superparamagnetic material is secured to the polymer component.

8. The orthopaedic implant of claim 7, wherein:

the polymer component comprises a polyethylene bearing, and

the superparamagnetic material is embedded in the polyethylene bearing.

9. The orthopaedic implant of claim 1, further comprising a first component and a second component, wherein:

at least one of the first component and the second component is movable relative to the other, and

the superparamagnetic material is secured to both the first component and the second component.

10. The orthopaedic implant of claim 9, wherein:

the first component comprises a tibial tray, and

the second component comprises a tibial bearing.

11. The orthopaedic implant of claim 9, wherein:

the first component comprises a tibial tray, and

the second component comprises a femoral knee component.

12. The orthopaedic implant of claim 1, wherein the superparamagentic material is arranged in a pattern which defines a machine-readable indicia.

13. The orthopaedic implant of claim 12, wherein the machine-readable indicia comprises a barcode.

14. The orthopaedic implant of claim 1, wherein:

the implant defines a thickness, and

the superparamagnetic material is arranged in a pattern which changes as a result of changes in the thickness of the implant.

15. A method of determining the position of a first implanted orthopaedic component relative to a second implanted orthopaedic component, the method comprising the steps of:

exposing the first implanted orthopaedic component and the second implanted orthopaedic component to a magnetic field,

determining the position of a superparamagnetic material secured to the first implanted orthopaedic component relative to a superparamagnetic material secured to the second implanted orthopaedic component, and

correlating the position of the first implanted orthopaedic component relative to the second implanted orthopaedic component based on the determining step.

16. The method of claim 15, wherein:

the first component comprises a tibial tray,

the second component comprises a femoral knee component, and

the correlating step comprises correlating the position of the tibial tray relative to the femoral knee component to determine the thickness of a tibial bearing positioned between the tibial tray and the femoral knee component.

17. The method of claim 15, wherein:

the first component comprises a tibial tray,

the second component comprises a tibial bearing, and

the correlating step comprises correlating the rotational position of the tibial tray relative to the tibial bearing.

18. A method of determining the position of an implanted orthopaedic component relative to a bone, the method comprising the steps of:

exposing the implanted orthopaedic component and the bone to a magnetic field,

determining the position of a superparamagnetic material secured to the implanted orthopaedic component relative to a superparamagnetic material secured to the bone, and

correlating the position of the implanted orthopaedic component relative to the bone based on the determining step.

19. The method of claim 18, further comprising the step of determining a degree of subsidence of the implanted orthopaedic component based on the correlating step.

20. The method of claim 18, further comprising the step of determining a degree of migration of the implanted orthopaedic component based on the correlating step.

21. A method of visualizing a polyethylene orthopaedic component subsequent to implantation thereof, the method comprising the step of detecting presence of a superparamagentic material secured to the implanted polyethylene orthopaedic component.

22. The method of claim 21, wherein the detecting step comprises detecting presence of the superparamagnetic material with an X-ray.

23. A method of monitoring wear of a polyethylene orthopaedic component subsequent to implantation thereof, the method comprising the steps of:

exposing the implanted polyethylene orthopaedic component to a magnetic field,

detecting a superparamagnetic material secured to the implanted polyethylene orthopaedic component, and

determining wear of the implanted polyethylene orthopaedic component based on the detecting step.