Assessing the condition of a joint and devising treatment

• US 7,881,768 B2
• Filed: 04/24/2007
• Issued: 02/01/2011
• Est. Priority Date: 09/14/1998
• Status: Expired due to Term

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Lang, Philipp, Steines, Daniel
• Primary Examiner(s): Casler; Brian
• Assistant Examiner(s): CWERN, JONATHAN
• Application Number:
  US11/739,326
• Publication Number:
  US 20070276224A1
• Time in Patent Office: 1,379 Days
• Field of Search: 382/128, 345/420, 600/407, 600/416, 600/427
• US Class Current: 600/407
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/4514 Cartilage
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence

Abstract

Methods are disclosed for assessing the condition of a cartilage in a joint, particularly in a human knee. The methods include converting an image such as an MRI to a three dimensional map of the cartilage. The cartilage map can be correlated to a movement pattern of the joint to assess the affect of movement on cartilage wear. Changes in the thickness of cartilage over time can be determined so that therapies can be provided. Information on thickness of cartilage and curvature of cartilage or subchondral bone can be used to plan therapy. Information on movement pattern can be used to plan therapy.

Claims

1. A method of designing a patient-specific implant for treating an articular surface of a joint of a patient, the method comprising:

using a computer to obtain electronic patient-specific image data of dimensions of at least a portion of the articular surface of said joint of said patient;

deriving from said electronic patient-specific image data a patient-specific model of at least a portion of the articular surface of said joint; and

designing a patient-specific implant configured to replace at least a portion of said articular surface of said joint based on said patient-specific model of the at least a portion of the articular surface;

wherein said implant provides the articular surface derived at least in part from the dimensions of the at least a portion of the articular surface of the joint.

2. The method of claim 1, wherein designing the implant includes determining the shape of the implant.

3. The method of claim 1, wherein said image data includes both normal and diseased cartilage tissue.

4. The method of claim 1, wherein said articular surface includes bone.

5. The method of claim 1, wherein said articular surface includes cartilage.

6. The method of claim 1, wherein said patient specific model is derived, at least in part, from bone.

7. The method of claim 1, wherein said patient specific model is derived, at least in part, from cartilage.

8. The method of claim 1, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

9. The method of claim 1, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

10. The method of claim 1, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

11. The method of claim 1, wherein the implant is for one of a tibio-femoral articulation, a hip, and an ankle.

12. The method of claim 11, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

13. The method of claim 11, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

14. The method of claim 11, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

15. The method of claim 1, wherein at least a portion of said implant has a thickness that is similar to normal cartilage.

16. The method of claim 1, wherein substantially each portion of said implant has a thickness that is similar to normal cartilage.

17. The method of claim 1, wherein at least a portion of an undersurface of said implant substantially matches subchondral bone.

18. A method of creating a patient-specific implant, the method comprising:

obtaining electronic cross-sectional or volumetric image data of at least a portion of an articular surface of a joint of a patient;

deriving from the electronic image data a plurality of points of the at least a portion of the articular surface of said joint;

deriving at least one or more patient-specific articular dimensions from the image data of the articular surface of the joint; and

creating the patient-specific implant, for implantation into said joint, based on said patient-specific articular dimensions,

wherein said implant provides the articular surface derived at least in part from the at least one or more patient-specific articular dimensions.

19. The method of claim 18, wherein creating the implant includes determining a shape of the implant.

20. The method of claim 18, wherein said image data includes both normal and diseased cartilage tissue.

21. The method of claim 18, wherein the plurality of points forms a 3-D representation associated with the articular surface.

22. The method of claim 18, wherein said articular surface includes bone.

23. The method of claim 18, wherein said articular surface includes cartilage.

24. The method of claim 18, wherein said points are derived, at least in part, from bone.

25. The method of claim 18, wherein said points are derived, at least in part, from cartilage.

26. The method of claim 18, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

27. The method of claim 18, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

28. The method of claim 18, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

29. The method of claim 18, wherein the implant is for one of a tibio-femoral articulation, a hip, and an ankle.

30. The method of claim 29, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

31. The method of claim 29, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

32. The method of claim 29, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

33. The method of claim 18, wherein at least a portion of said implant has a thickness that is similar to normal cartilage.

34. The method of claim 18, wherein at least a portion of an undersurface of said implant substantially matches subchondral bone.

35. A method of devising a patient-specific implant, the method comprising:

using a computer to generate a three-dimensional representation of at least a portion of an articular surface of a joint of a patient;

deriving at least one or more articular dimensions of said joint; and

devising an implant, for implantation into said joint, based on said three-dimensional representation of the at least a portion of the articular surface of said joint, that is fitted to the one or more articular dimensions of the patient in at least one direction.

36. The method of claim 35, wherein devising the implant includes determining a shape of the implant.

37. The method of claim 35, wherein said articular surface includes bone.

38. The method of claim 35, wherein said articular surface includes cartilage.

39. The method of claim 35, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

40. The method of claim 35, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

41. The method of claim 35, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

42. The method of claim 35, wherein the implant is for one of a tibio-femoral articulation, a hip, and an ankle.

43. The method of claim 42, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

44. The method of claim 42, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

45. The method of claim 42, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

46. The method of claim 35, wherein at least a portion of said implant has a thickness that is similar to normal cartilage.

47. The method of claim 35, wherein at least a portion of an undersurface of said implant substantially matches subchondral bone.

48. A method of devising an implant for treating a human joint, the joint including both normal and diseased cartilage, the method comprising:

using a computer to generate a plurality of points of at least a portion of an articular surface of the joint of a patient;

deriving at least one or more articular dimensions of said joint; and

devising an implant, for implantation into said joint, based on said plurality of points, wherein the plurality of points form a 3-D representation of at least a portion of the articular surface of said joint and the implant is fitted to the one or more articular dimensions of the patient in one direction.

49. The method of claim 48, wherein devising the implant includes determining the shape of said implant.

50. The method of claim 48, wherein said articular surface includes cartilage.

51. The method of claim 48, wherein said articular surface includes bone.

52. The method of claim 48, wherein the points are derived, at least in part, from bone.

53. The method of claim 48, wherein the points are derived, at least in part, from cartilage.

54. The method of claim 53, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

55. The method of claim 53, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

56. The method of claim 53, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

57. The method of claim 48, wherein the implant is for one of a tibio-femoral articulation, a hip, and an ankle.

58. The method of claim 57, wherein more than 30% of said implant has a thickness that is similar to normal cartilage.

59. The method of claim 57, wherein more than 50% of said implant has a thickness that is similar to normal cartilage.

60. The method of claim 57, wherein at least more than 70% of said implant has a thickness that is similar to normal cartilage.

61. A method of making a physical model for use in treating a human joint disease involving cartilage, the method comprising:

obtaining electronic cross-sectional or volumetric image data of at least a portion of an articular surface of a joint of a patient, wherein said image data includes both normal and diseased cartilage tissue;

deriving from said electronic image data a three-dimensional representation of at least a portion of the articular surface of said joint; and

making the physical model, for use with said joint, of the three-dimensional representation of the at least a portion of the articular surface.

62. The method of claim 61, wherein said articular surface includes bone.

63. The method of claim 61, wherein said articular surface includes cartilage.

64. The method of claim 61, further including determining a shape of an implant based on said physical model.

65. The method of claim 64, wherein the implant is for one of a tibio-femoral articulation, hip, and ankle.

66. The method of claim 65, wherein more than 30% of said physical model has a thickness that is similar to normal cartilage.

67. The method of claim 65, wherein more than 50% of said physical model has a thickness that is similar to normal cartilage.

68. The method of claim 65, wherein at least more than 70% of said physical model has a thickness that is similar to normal cartilage.

69. The method of claim 61, wherein said three-dimensional representation is derived, at least in part, from bone.

70. The method of claim 61, wherein said three-dimensional representation is derived, at least in part, from cartilage.

71. The method of claim 61, wherein more than 30% of said physical model has a thickness that is similar to normal cartilage.

72. The method of claim 61, wherein more than 50% of said physical model has a thickness that is similar to normal cartilage.

73. The method of claim 61, wherein at least more than 70% of said physical model has a thickness that is similar to normal cartilage.

74. A method of making a physical model for treating a human joint disease involving cartilage, the method comprising:

obtaining electronic cross-sectional or volumetric image data of at least a portion of an articular surface of a joint of a patient, wherein said image data includes both normal and diseased cartilage tissue;

deriving from the said electronic image data a plurality of points that form a 3-D representation of at least a portion of the articular surface of said joint; and

making a physical model based on the 3-D representation of the at least a portion of the articular surface of said joint.

75. The method according to claim 74, further including determining a shape of an implant based on said points.

76. The method of claim 75, wherein at least a portion of said implant has a thickness that is similar to normal cartilage.

77. The method of claim 75, wherein at least a portion of an undersurface of said implant substantially matches subchondral bone.

78. The method of claim 74, wherein the points are derived, at least in part, from bone.

79. The method of claim 74, wherein said points are derived, at least in part, from cartilage.

80. The method of claim 74, wherein said articular surface includes bone.

81. The method of claim 74, wherein said articular surface includes cartilage.

82. The method of claim 74, wherein more than 30% of said physical model has a thickness that is similar to normal cartilage.

83. The method of claim 74, wherein more than 50% of said physical model has a thickness that is similar to normal cartilage.

84. The method of claim 74, wherein at least more than 70% of said physical model has a thickness that is similar to normal cartilage.

85. The method of claim 74, wherein the implant is for one of a tibio-femoral articulation, a hip, and an ankle.

86. The method of claim 85, wherein more than 30% of said physical model has a thickness that is similar to normal cartilage.

87. The method of claim 85, wherein more than 50% of said physical model has a thickness that is similar to normal cartilage.

88. The method of claim 85, wherein at least more than 70% of said physical model has a thickness that is similar to normal cartilage.