IMPLANT SENSORS

• US 20090299228A1
• Filed: 06/02/2008
• Published: 12/03/2009
• Est. Priority Date: 06/02/2008
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Parrott, Russell M., Lozier, Antony J., Rich, David B.
• Granted Patent: US 8,029,566 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 17/7275 with expanding cylindrical parts
• CPC Class Codes: A61B 17/8855 inflatable, e.g. kyphoplasty balloons
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00221 with wireless transmission of data, e.g. by infrared radiation or radiowaves
• CPC Class Codes: A61B 2017/00557 inflatable A61B2017/22051 takes precedence
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/48 Operating or control means, e.g. from outside the body, control of sphincters
• CPC Class Codes: A61F 2/488 Means for detecting or monitoring wear
• CPC Class Codes: A61F 2002/30004 the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
• CPC Class Codes: A61F 2002/30581 having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30668 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61F 2002/3067 for data transfer
• CPC Class Codes: A61F 2210/0085 hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2250/0001 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61F 2250/0002 for data transfer
• CPC Class Codes: A61F 2250/0014 having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
• CPC Class Codes: A61F 2310/00353 Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: Y10T 442/3228 : Materials differ

Abstract

Exemplary orthopedic implants are disclosed. The orthopedic implants may include one or more sensors. Exemplary sensors include sensors to monitor bone growth, changes to the implant over time, and proper placement of the implant. The orthopedic implants may include a woven material. Sensor arrangements to detect a state of an item are disclosed. Exemplary states include folded, unfolded, and inflated. Exemplary items include an orthopedic implant and a parachute.

Claims

13. An orthopedic implant for placement in a cavity having a predetermined shape formed in a bone, said orthopedic implant comprising:

a flexible body having an inflated shape generally corresponding to said predetermined shape formed in said bone;

means for sensing said shape of said flexible body; and

a filler, said filler being positioned in said flexible body.

14. The orthopedic implant of claim 13, wherein said filler hardens to form a core of said orthopedic implant.

15. The orthopedic implant of claim 13, wherein said means for sensing said shape of said flexible body is a passive sensing means.

16. The orthopedic implant of claim 13, wherein said means for sensing said shape of said flexible body is an active sensing means.

17. A method of implanting an orthopedic implant in a cavity having a predetermined shape formed in a bone, said method comprising the steps of:

providing a flexible body which is inflatable to a first state having an outer shape generally corresponding to said predetermined shape formed in said bone;

positioning said flexible body in said cavity having said predetermined shape formed in said bone;

inflating said flexible body; and

sensing whether said flexible body is inflated to said first state.

18. The method of claim 17, wherein said step of inflating said flexible body includes said step of filling an interior of said flexible body with a filler which hardens over time.

19. The method of claim 17, wherein said flexible body is a woven body and said step of sensing whether said flexible body is inflated to said first state includes the steps of:

providing at least a first electrically conductive and isolated fiber of said woven body; and

monitoring a conductivity of said first electrically conductive and isolated fiber of said woven body, said conductivity being at a first value when said flexible body is inflated.

20. The method of claim 17, wherein said step of sensing whether said flexible body is inflated to said first state includes the steps of:

providing a plurality of passive sensors supported by said flexible body;

interrogating said plurality of passive sensors to determine whether said flexible body is inflated to said first state.

21. The method of claim 20, wherein said step of interrogating said plurality of sensors to determine whether said flexible body is inflated to said first state includes the steps of:

passing a first plurality of radio frequency frequencies through said bone;

receiving a second plurality of radio frequencies from said plurality of sensors; and

determining whether said flexible body is inflated to said first state based on said received second plurality of radio frequencies.

22. The method of claim 17, wherein said step of sensing whether said flexible body is inflated to said first state includes the steps of:

providing a plurality of optical sensors supported by said flexible body; and

determining a location of each of said plurality of optical sensors.

23. A system for monitoring wear of orthopedic implant for placement proximate a bearing surface when installed in a body, said system comprising:

an orthopedic implant body;

a plurality of sensors supported by said orthopedic implant body and arranged to be positioned proximate said bearing surface, each sensor corresponding to a location on said orthopedic implant; and

an interrogation system to interrogate said plurality of sensors subsequent to installation in said body, each sensor of said plurality of sensors providing a first indication in response to an interrogation signal in an absence of wear of said orthopedic implant at said location corresponding to said sensor and a second indication in response to said interrogation signal in a presence of wear of said orthopedic implant at said location corresponding to said sensor.

1. An orthopedic implant for placement in a cavity formed in a bone, said cavity having a predetermined shape, said orthopedic implant comprising:

a flexible body having an opening, said flexible body having an inflated state wherein said body has an outer shape generally corresponding to said predetermined shape formed in said bone and a non-inflated shape wherein said outer shape has a smaller envelope than said inflated state;

a plurality of sensors supported by said flexible body, said plurality of sensors providing an indication of whether said flexible body is in said inflated state or said non-inflated state; and

a filler, said filler being positioned in said flexible body and causing said flexible body to transition from said non-inflated state to said inflated state.

2. The orthopedic implant of claim 1, wherein said filler is a polymer based material.

3. The orthopedic implant of claim 1, wherein said plurality of sensors are configured to detect a presence of a fold in said flexible body.

4. The orthopedic implant of claim 3, wherein said fold is detected based on said relative position of a first sensor to a second sensor.

5. The orthopedic implant of claim 4, wherein said first sensor and said second sensor are passive sensors interrogated by an external device.

6. The orthopedic implant of claim 5, wherein said first sensor and said second sensor are each resonant circuits which provide said indication based on a separation between said first sensor and said second sensor.

7. The orthopedic implant of claim 6, wherein when said first sensor and said second sensor are spaced a first distance apart said first sensor resonates in response to a first frequency from said external device and said second sensor resonates in response to a second frequency from said external device and when said first sensor and said second sensor are spaced less than said first distance apart said first sensor and said second sensor resonate together in response to a third frequency from said external device.

8. The orthopedic implant of claim 6, wherein said external device interrogates said plurality of sensors through a frequency range including said first frequency, said second frequency, and said third frequency.

9. The orthopedic implant of claim 3, wherein said fold is detected based on said locations of said plurality of sensors.

10. The orthopedic implant of claim 9, wherein said plurality of sensors include a plurality of optical sensors.

11. The orthopedic implant of claim 10, wherein said plurality of optical sensors are in optical communication with an external detector through an optical fiber.

12. The orthopedic implant of claim, 11, wherein said plurality of optical sensors are a plurality of diffraction gratings disposed in said optical fiber, said optical fiber having a first shape indicating said presence of said fold wherein said plurality of diffraction gratings are in a first plurality of locations and a second shape indicating said absence of said fold wherein said plurality of diffraction gratings are in a second plurality of locations.

24. The system of claim 23, wherein said first indication is a response signal and said second indication is the lack of said response signal.

25. The system of claim 24, wherein each sensor includes a controller and said response signal includes a unique identifier.

26. The system of claim 24, wherein each sensor is a resonant circuit and said response signal is at a unique frequency.

27. The system of claim 26, wherein said three-dimensional woven component includes a plurality of materials which form a gradient woven material.

26-1. The system of claim 24, wherein said body includes a three-dimensional woven component.

29. A method of monitoring wear of an orthopedic implant placed proximate a bearing surface when installed in a body, said method comprising the steps of:

providing a body of said orthopedic implant;

providing a plurality of sensors supported by said orthopedic implant body and arranged to be positioned proximate said bearing surface, each sensor corresponding to a location on said orthopedic implant; and

interrogating said plurality of sensors to determine if said orthopedic implant has experienced wear.

30. The method of 29, wherein each sensor of said plurality of sensors provides a first indication in response to an interrogation signal in said absence of wear of said orthopedic implant at said location corresponding to said sensor and a second indication in response to said interrogation signal in said presence of wear of said orthopedic implant at said location corresponding to said sensor.

31. The method of claim 30, wherein said step of interrogating said plurality of sensors to determine if said orthopedic implant has experienced wear includes the steps of:

positioning an external interrogation system proximate to said orthopedic implant; and

for a respective sensor

passing said interrogation signal through said body;

receiving from said respective sensor one of said first indication and said second indication.

32. A woven material for use within the body, the woven material comprising:

a first woven layer having a first plurality of weft fibers and a first plurality of in layer warp fibers, said first layer having a first stiffness;

a second woven layer having a second plurality of weft fibers and a second plurality of in layer warp fibers, said second layer having a second stiffness generally less than said first stiffness;

a third woven layer having a third plurality of weft fibers and a third plurality of in layer warp fibers, said third layer having a third stiffness generally less than said second stiffness;

a first plurality of out of layer warp fibers which couple together said first layer and said second layer; and

a second plurality of out of layer warp fibers which couple together said second layer and said third layer.

33. The woven material of claim 32, further comprising a fourth layer having said first stiffness and coupled to said first layer opposite said second layer.

34. The woven material of claim 32, further comprising a fourth layer having a fourth stiffness and coupled to said third layer opposite said second layer.

35. The woven material of claim 32, further comprising

a fifth layer having a fifth stiffness and coupled to said fourth layer opposite said third layer;

a third plurality of out of layer warp fibers which couple together said third layer and said fourth layer; and

a fourth plurality of out of layer warp fibers which couple together said fourth layer and said fifth layer.

36. The woven material of claim 35, wherein said first plurality of weft fibers and said first plurality of in layer warp fibers are metallic fibers and wherein said second plurality of weft fibers and said second plurality of in layer warp fibers are a blend of metallic fibers are non-metallic fibers.

37. The woven material of claim 36, wherein said third plurality of weft fibers and said third plurality of in layer warp fibers are polymeric fibers and wherein said blend includes metallic fibers and polymeric fibers.

38. The woven material of claim 32, wherein at least one of said first layer, said second layer, and said third layer support a plurality of sensors.

39. The woven material of claim 38, wherein said plurality of sensors are passive radio frequency sensors.

40. The woven material of claim 38, wherein said plurality of sensors are optical sensors.

41. The woven material of claim 32, wherein at least one of said first layer, said second layer, and said third layer includes at least one sensor as a fiber of the layer.

42. An orthopedic implant for positioning proximate a bone in a body, said orthopedic implant comprising:

a first body portion including a three-dimensional woven material having a plurality of layers; and

a second body portion coupled to said three-dimensional woven material, wherein said three-dimensional woven material includes a first woven layer having a first plurality of weft fibers and a first plurality of in layer warp fibers, said first layer having a first stiffness;

a second woven layer having a second plurality of weft fibers and a second plurality of in layer warp fibers, said second layer having a second stiffness generally less than said first stiffness;

a third woven layer having a third plurality of weft fibers and a third plurality of in layer warp fibers, said third layer having a third stiffness generally less than said second stiffness;

a first plurality of out of layer warp fibers which couple together said first layer and said second layer; and

a second plurality of out of layer warp fibers which couple together said second layer and said third layer.

43. The orthopedic implant of claim 42, further comprising a plurality of sensors supported by said three-dimensional woven material, said plurality of sensors positioned proximate said bone and configured to provide an indication of a presence of bone in-growth into said three-dimensional woven material.

44. The orthopedic implant of claim 42, further comprising a plurality of sensors supported by said three-dimensional woven material, said plurality of sensors positioned proximate said bone and configured to provide an indication of a strain experience by said three-dimensional woven material.

45. An orthopedic implant for positioning proximate a bone in a body, said orthopedic implant comprising:

a body portion including a three-dimensional woven material having a plurality of layers; and

a plurality of sensors supported by said three-dimensional woven material, said plurality of sensors positioned proximate said bone and configured to provide an indication of a presence of bone in-growth into said three-dimensional woven material.

46. The orthopedic implant of claim 45, wherein said plurality of sensors each include a capacitive element having a first dielectric value, said presence of said bone in-growth into said three-dimensional woven material changing said first dielectric value.

47. The orthopedic implant of claim 46, wherein said capacitive element is operatively coupled to an antenna which broadcasts a signal having a frequency based at least in part on said first dielectric value, said antenna broadcasting at a first frequency in said absence of bone in-growth into said three-dimensional woven material and at a second frequency in said presence of bone in-growth into said three-dimensional woven material.

48. An orthopedic implant for positioning proximate a bone in a body, said orthopedic implant comprising:

a body portion including a three-dimensional woven material having a plurality of layers; and

sensing means supported by said three-dimensional woven material, said sensing means being passive.

49. A method of measuring bone in-growth into an orthopedic implant placed proximate a bone when installed in a body, said method comprising the steps of:

providing a body of said orthopedic implant, said body including a woven material;

providing a sensor supported by said woven material and arranged to be positioned proximate said bone; and

interrogating said sensor to determine if said bone has grown into said woven material, said sensor providing a first indication if bone in-growth is present.

50. The method of claim 49, wherein said sensor in response to interrogation provides a signal of a first frequency in said absence of said presence of bone in-growth and a signal of a second, different frequency in said presence of bone in-growth, said second, different frequency being said first indication.

51. A method of measuring strain experienced by an orthopedic implant placed proximate a bone when installed in a body, said method comprising the steps of:

providing a body of said orthopedic implant, said body including a woven material;

providing a sensor supported by said woven material and arranged to be positioned proximate said bone; and

interrogating said sensor to determine an amount of strain experienced by said orthopedic implant.

52. The method of claim 51, wherein said sensor in response to interrogation provides a signal of a first frequency in said absence of strain and a signal of a second, different frequency in said presence of strain, said second, different frequency being said first indication.

53. An assembly, comprising:

a flexible body having a folded state and an unfolded state; and

a plurality of sensors supported by said flexible body, said plurality of sensors providing an indication of whether said flexible body is in said folded state or said unfolded state.

54. The assembly of claim 53, wherein said flexible body is a portion of an orthopedic implant.

55. The assembly of claim 53, wherein said fold is detected based on a relative position of a first sensor to a second sensor.

56. The assembly of claim 55, wherein said first sensor and said second sensor are passive sensors interrogated by an external device.

57. The assembly of claim 56, wherein said first sensor and said second sensor are each resonant circuits which provide said indication based on a separation between said first sensor and said second sensor.

58. The assembly of claim 57, wherein when said first sensor and said second sensor are spaced a first distance apart said first sensor resonates in response to a first frequency from said external device and said second sensor resonates in response to a second frequency from said external device and when said first sensor and said second sensor are spaced less than said first distance apart said first sensor and said second sensor resonate together in response to a third frequency from said external device.

59. The assembly of claim 58, wherein said external device interrogates said plurality of sensors through a frequency range including said first frequency, said second frequency, and said third frequency.

60. An assembly, comprising:

a flexible body having a folded state and an unfolded state; and

means for sensing whether said flexible body is in said folded state or said unfolded state.

61. The assembly of claim 60, wherein said means for sensing said shape of said flexible body is a passive sensing means.

62. The assembly of claim 60, wherein said means for sensing said shape of said flexible body is an active sensing means.