Patient-Adapted and Improved Orthopedic Implants, Designs, and Related Tools

• US 20110029091A1
• Filed: 06/23/2010
• Published: 02/03/2011
• Est. Priority Date: 02/25/2009
• Status: Active Grant

• Current Assignee: Conformis Incorporated
• Original Assignee: Conformis Incorporated
• Inventors: Lang, Philipp, Steines, Daniel, Chao, Nam, Slamin, John, Bojarski, Raymond A., Fitz, Wolfgang
• Granted Patent: US 8,771,365 B2
• Time in Patent Office: Days
• US Class Current: 623/20.32
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/3886 for stabilising knees against anterior or lateral dislocations
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30327 differing in diameter
• CPC Class Codes: A61F 2002/30952 using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

Methods and devices are disclosed relating improved articular models, implant components, and related guide tools and procedures. In addition, methods and devices are disclosed relating articular models, implant components, and/or related guide tools and procedures that include one or more features derived from patient-data, for example, images of the patient'"'"'s joint. The data can be used to create a model for analyzing a patient'"'"'s joint and to devise and evaluate a course of corrective action. The data also can be used to create patient-adapted implant components and related tools and procedures.

Claims

1. A tibial implant for a knee arthroplasty, the tibial implant comprising:

(a) a tibial tray sized and shaped generally for placement on a proximal surface of a tibia of a patient and having at least one insert locking mechanism;

(b) a first insert comprising a first reciprocal locking mechanism, a first bottom surface for engaging a surface of the tibial tray, a first articular surface portion generally opposite the first base surface, and a first thickness extending in a generally perpendicular direction between the first bottom surface and the first articular surface; and

(c) a second insert comprising a second reciprocal locking mechanism, a second bottom surface for engaging a surface of the tibial tray, a second articular surface portion generally opposite the second base surface, and a second thickness extending in a generally perpendicular direction between the second bottom surface and the second articular surface;

wherein the first thickness is greater than the second thickness.

2. The tibial tray of claim 1, wherein the first and second thicknesses are measured from geographic centers of the first and second contact areas of the first and second articular surfaces, respectively.

3. The tibial tray of claim 1, wherein the first and second thicknesses are measured from corresponding edges of first and second contact areas of the first and second articular surfaces, respectively.

4. The tibial tray of claim 1, wherein the first and second thicknesses are measured from central points of the first and second articular surfaces, respectively.

5. The tibial tray of claim 1, wherein the first and second thicknesses are measured from the point of the first and second articular surfaces that are closest to the first and second bottom surfaces, respectively.

6. The tibial tray of claim 1, wherein the first and second thicknesses are measured from the point of the first and second articular surfaces that are furthest from the first and second bottom surfaces, respectively.

7. The tibial tray of claim 1, wherein the first and second thicknesses are average thicknesses of the first and second inserts respectively.

8. The tibial tray of claim 1, wherein the first thickness is substantially greater than the second thickness.

9. The tibial tray of claim 1, wherein a difference in the thickness of the first and second thicknesses is a statistically significant difference.

10. The tibial tray of claim 1, wherein a difference in the thickness of the first and second thicknesses is a clinically significant difference.

11. The tibial tray of claim 1, wherein a difference in the thickness of the first and second thicknesses is sufficient to induce a clinical effect.

12. The tibial tray of claim 11, wherein the clinical effect is an alignment of at least a portion of the knee.

13. The tibial tray of claim 11, wherein the clinical effect is a balancing of at least a portion of the knee.

14. The tibial tray of claim 1, wherein the first and second inserts have different curvatures on respective articular surface portions.

15. The tibial tray of claim 1, wherein the first and second inserts have different slopes on respective articular surface portions.

16. A tibial implant for knee arthroplasty, the tibial implant comprising:

(a) a medial tibial insert comprising (i) a substantially planar inner surface for engaging a medial tibial tray face and (ii) an articular surface comprising an articular surface plateau and disposed therein a curved portion for opposing an articular surface of a medial femoral condyle; and

(b) a lateral tibial insert comprising (i) a substantially planar inner surface for engaging a lateral tibial tray face and (ii) an articular surface comprising an articular surface plateau and disposed therein a curved portion for opposing an articular surface of a lateral femoral condyle;

wherein the distance from the inner surface to the articular surface of the medial tibial insert is different from the distance from the inner surface to the articular surface of the lateral tibial insert.

17. The tibial implant of claim 16, wherein the minimum distance from the inner surface to the articular surface of the medial tibial insert is different from the minimum distance from the inner surface to the articular surface of the lateral tibial insert.

18. The tibial implant of claim 16, wherein the maximum distance from the inner surface to the articular surface of the medial tibial insert is different from the maximum distance from the inner surface to the articular surface of the lateral tibial insert.

19. The tibial implant of claim 16, wherein the average distance from the inner surface to the articular surface of the medial tibial insert is different from the average distance from the inner surface to the articular surface of the lateral tibial insert.

20. The tibial implant of claim 16, wherein the distance from the inner surface to the articular surface of the medial tibial insert is substantially different from the distance from the inner surface to the articular surface of the lateral tibial insert.

21. The tibial implant of claim 16, wherein the distance from the inner surface to the articular surface of the medial tibial insert is significantly different from the distance from the inner surface to the articular surface of the lateral tibial insert.

22. The tibial implant of claim 16, wherein the distance from the inner surface to a central point of the articular surface of the medial tibial insert is different from the distance from the inner surface to a central point of the articular surface of the lateral tibial insert.

23. The tibial implant of claim 16, wherein the distance from the inner surface to a central point of a contact area of the articular surface of the medial tibial insert is different from the distance from the inner surface to a central point of a contact area of the articular surface of the lateral tibial insert.

24. The tibial implant of claim 16, wherein the distance from the inner surface to an edge of the articular surface of the medial tibial insert is different from the distance from the inner surface to an edge the articular surface of the lateral tibial insert.

25. The tibial implant of claim 16, wherein a first tibial tray comprises the medial tibial tray face and a second tibial tray comprises the lateral tibial tray face.

26. The tibial implant of claim 16, wherein the medial and lateral tibial inserts have different curvatures in the respective curved portions.

27. The tibial implant of claim 16, wherein the medial and lateral tibial inserts have different articular surface plateau slopes.

28. The tibial implant of claim 16, wherein the slope for the articular surface plateau of the medial tibial insert is patient-matched to the patient'"'"'s medial tibial plateau slope.

29. The tibial implant of claim 16, wherein the slope for the articular surface plateau of the medial tibial insert is patient-matched to the patient'"'"'s lateral tibial plateau slope.

30. The tibial implant of claim 16, wherein the slope for the articular surface plateau of the lateral tibial insert is patient-matched to the patient'"'"'s lateral tibial plateau slope.

31. The tibial implant of claim 16, wherein the slope for the articular surface plateau of the lateral tibial insert is patient-matched to the patient'"'"'s medial tibial plateau slope.

32. A method for making a tibial implant for use in repairing or replacing a knee of a patient, comprising:

(a) electronically evaluating at least a portion of the knee based on image data of the of the knee; and

(b) specifying one or more parameters of the tibial implant based at least in part on the evaluation;

wherein the specified parameters define at least in part a tibial implant having a first articular surface higher than a second articular surface relative to a proximal end of a tibia of the knee when the tibial implant is implanted on the proximal end of the tibia.

33. The method of claim 32, further comprising planning a surgical result based on the electronic image data of a patient'"'"'s knee.

34. The method of claim 32, wherein the specified parameters define at least in part a configuration of a tibial implant to substantially achieve a planned surgical result.

35. The method of claim 34, wherein the surgical result is knee balancing during a surgical procedure.

36. The method of claim 35, wherein the knee balancing comprises knee balancing during extension.

37. The method of claim 35, wherein the knee balancing comprises knee balancing during flexion.

38. The method of claim 34, wherein the surgical result is knee alignment.

39. The method of claim 38, wherein the knee alignment comprises knee alignment of anatomical axes.

40. The method of claim 38, wherein the knee alignment comprises knee alignment of biomechanical axes.

41. The method of claim 38, wherein the knee alignment comprises knee alignment of femur and tibia.

42. The method of claim 41, wherein the alignment of femur and tibia comprises linear alignment of femur and tibia.

43. The method of claim 41, wherein the alignment of femur and tibia comprises rotational alignment of femur and tibia.

44. The method of claim 34, wherein the surgical result comprises establishment of a joint line of a medial compartment of the knee relative to a lateral compartment of the knee.

45. The method of claim 32, wherein the electronically evaluating at least a portion of the knee comprises determining a difference in the relative position of at least a portion of first and second articular surfaces of the knee.

46. The method of claim 32, wherein the electronically evaluating at least a portion of the knee comprises determining a joint line of the knee.

47. The method of claim 46, wherein determining a joint line of the knee comprises pre-surgically determining a joint line of the knee.

48. The method of claim 46, wherein determining a joint line of the knee comprises post-surgically determining a joint line of the knee.

49. A method for making a tibial implant having at least one of a medial tibial insert and a lateral tibial insert that substantially matches a patient'"'"'s biological feature in one or more measurements, or as a predetermined percentage thereof, the method comprising:

(a) preoperatively identifying a feature measurement of the patient'"'"'s joint; and

(b) designing at least one of the medial tibial insert and the lateral tibial insert to include substantially the same feature measurement or a predetermined percentage of the feature measurement identified in step (a).

50. The method of claim 49, wherein designing the at least one of the medial tibial insert and lateral tibial insert comprises computer-aided design (CAD) and computer-aided manufacturing (CAM).

51. The method of claim 49, wherein designing the at least one of the medial tibial insert and lateral tibial insert comprises cutting the feature measurement from a blank.

52. The method of claim 49, wherein the substantially matching feature measurement is selected from the group consisting of:

an insert mediolateral dimension substantially matching a corresponding patient mediolateral dimension or a predetermined percentage thereof, an insert thickness substantially matching a corresponding thickness of resected patient tissue or a predetermined percentage thereof, an insert perimeter shape substantially matching a corresponding patient perimeter shape or a predetermined percentage thereof, an insert surface slope substantially matching a corresponding patient slope or a predetermined percentage thereof, and an insert surface curvature substantially matching a corresponding patient curvature or a predetermined percentage thereof.

53. The method of claim 49, wherein substantially matching includes smoothing a line or curve of the patient'"'"'s biological feature.

54. A method for implanting a knee implant in a patient'"'"'s knee, the method comprising the steps of:

(a) preparing a proximal end of a tibia to receive an implant; and

(b) inserting at least one tibial implant onto the prepared proximal end of the tibia such that a first articular surface of the at least one implant engages a first articular surface of a femur or femoral implant and a second articular surface of the at least one implant engages a second articular surface of the femur or femoral implant;

wherein the first articular surface is higher than the second articular surface relative to an anatomical axis of the tibia.

55. The method of claim 54, wherein the at least one tibial implant comprises a single tibial implant tray.

56. The method of claim 55, further comprising a single tibial insert.

57. The method of claim 55, further comprising dual tibial inserts.

58. The method of claim 54, wherein the at least one tibial implant comprises two tibial implant trays.

59. The method of claim 58, further comprising a single tibial insert for each of the two tibial implant trays.

60. The method of claim 54, further comprising adjusting height of first articular surface relative to second articular surface.

61. The method of claim 54, further comprising aligning the patient'"'"'s joint.

62. The method of claim 61, further comprising assessing the alignment of the patient'"'"'s joint.

63. The method of claim 61, further comprising adjusting alignment of the patient'"'"'s joint.

64. The method of claim 54, further comprising adjusting rotational alignment of the patient'"'"'s joint.

65. The method of claim 54, further comprising adjusting linear alignment of the patient'"'"'s joint.

66. The method of claim 54, further comprising adjusting alignment of the patient'"'"'s femur and tibia.

67. The method of claim 54, further comprising adjusting a biomechanical axis of the patient'"'"'s joint.

68. The method of claim 54, further comprising adjusting an anatomical axis of the patient'"'"'s joint.

69. The method of claim 54, further comprising balancing a patient'"'"'s joint.

70. The method of claim 69, further comprising assessing the balance of the patient'"'"'s joint.

71. The method of claim 69, further comprising adjusting the balance of the patient'"'"'s joint.

72. The method of claim 69, wherein balancing of the patient'"'"'s joint comprises balancing of the patient'"'"'s joint in extension.

73. The method of claim 69, wherein balancing of the patient'"'"'s joint comprises balancing of the patient'"'"'s joint in flexion.

74. The method of claim 54, further comprising planning a surgical procedure based on electronic image data of the patient'"'"'s knee.

75. The method of claim 74, further comprising performing the surgical procedure.

76. The method of claim 74, further comprising planning the surgical procedure based on electronic image data of the patient'"'"'s knee in order to achieve a predetermined surgical result.

77. The method of claim 76, wherein step (b) substantially achieves the predetermined surgical result.

78. The method of claim 76, wherein the surgical result includes joint balancing.

79. The method of claim 76, wherein the surgical result includes joint alignment.

80. The method of claim 54, wherein step (b) comprises inserting a first insert.

81. The method of claim 80, further comprising adjusting balance with a second insert.

82. The method of claim 80, further comprising adjusting alignment with a second insert.

83. The method of claim 80, further comprising inserting a second insert.

84. The method of claim 83, further comprising replacing the second insert with a third insert.

85. The method of claim 84, further comprising adjusting balance with the third insert.

86. The method of claim 84, further comprising adjusting alignment with the third insert.

87. A method for balancing or optimizing ligament tension during implantation of a knee implant in a patient, the method comprising the steps of:

(a) assessing the patient'"'"'s medial joint gap distance and tension;

(b) assessing the patient'"'"'s lateral joint gap distance and tension; and

(c) selecting independent medial and lateral tibial inserts to provide proper gap distance and tension.

88. The method of claim 87, wherein the selected medial and lateral tibial inserts have different thicknesses.

89. The method of claim 87, wherein in step (c) the selected medial tibial insert is selected from among two or more medial tibial inserts having different thicknesses.

90. The method of claim 87, wherein in step (c) the selected lateral tibial insert is selected from among two or more lateral tibial inserts having different thicknesses.

91. The method of claim 87, wherein the selection of one or both medial and lateral tibial inserts substantially restores the patient'"'"'s natural medial and lateral joint gaps.

92. The method of claim 87, wherein the selection of one or both medial and lateral tibial inserts substantially restores the patient'"'"'s natural kinematics.

93. A kit for implanting a tibial implant in a patient in need of knee replacement, the kit comprising:

(a) a tibial tray comprising a first surface for affixing the tray to the patient'"'"'s tibia and an opposing second surface for engaging a medial tibial insert; and

(b) two or more medial tibial inserts having different thicknesses from which to select one medial tibial insert for engaging with the tibial tray.

94. A kit for implanting a tibial implant in a patient in need of knee replacement, the kit comprising:

(a) a tibial tray comprising a first surface for affixing the tray to the patient'"'"'s tibia and an opposing second surface for engaging a lateral tibial insert; and

(b) two or more lateral tibial inserts having different thicknesses from which to select one lateral tibial insert for engaging with the tibial tray.