Total joint arthroplasty system

• US 20090131941A1
• Filed: 12/18/2006
• Published: 05/21/2009
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Otismed Corporation (Stryker Corporation)
• Inventors: Schipper, John, Pearson, Lacerial, Samuel, Stephen M., Park, Ilwhan
• Granted Patent: US 8,801,720 B2
• Time in Patent Office: Days
• US Class Current: 606/87
• CPC Class Codes: A61B 17/154 for preparing bone for knee prosthesis
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/17 Guides or aligning means for drills , mills, pins or wires
• CPC Class Codes: A61B 17/1703 using imaging means, e.g. by X-rays
• CPC Class Codes: A61B 17/171 for external fixation
• CPC Class Codes: A61B 17/1739 specially adapted for particular parts of the body
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: A61B 2017/568 produced with shape and dimensions specific for an individual patient
• CPC Class Codes: A61B 2034/102 Modelling of surgical devices, implants or prosthesis
• CPC Class Codes: A61B 2034/104 Modelling the effect of the tool, e.g. the effect of an implanted prosthesis or for predicting the effect of ablation or burring
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/108 Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 2090/3762 using computed tomography systems [CT]
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61F 2/30 Joints
• CPC Class Codes: B29C 64/386 : Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B29C 64/393 : for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 50/00 : Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 50/02 : for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: G05B 19/4099 : Surface or curve machining, making 3D objects, e.g. desktop manufacturing
• CPC Class Codes: G05B 2219/35134 : 3-D cad-cam
• CPC Class Codes: G06F 30/20 : Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G16H 50/50 : for simulation or modelling of medical disorders
• CPC Class Codes: G16Z 99/00 : Subject matter not provided for in other main groups of this subclass

Abstract

A method and system for performing a total joint arthroplasty procedure on a patient'"'"'s damaged bone region. A CT image or other suitable image is formed of the damaged bone surfaces, and location coordinate values (x_n,y_n,z_n) are determined for a selected sequence of bone surface locations using the CT image data. A mathematical model z=f(x,y) of a surface that accurately matches the bone surface coordinates at the selected bone spice locations, or matches surface normal vector components at selected bone surface locations, is determined. The model provides a production file from which a cutting jig and an implant device (optional), each patient-specific and having controllable alignment, are fabricated for the damaged bone by automated processing. At this point, the patient is cut open (once), the cutting jig and a cutting instrument are used to remove a selected portion of the bone and to provide an exposed planar surface, the implant device is optionally secured to and aligned with the remainder of the bone, and the patient'"'"'s incision is promptly repaired.

Claims

1. A method for performing a total joint arthroplasty procedure on a patient'"'"'s damaged bone, the method comprising:

forming a CT image of a selected region of a damaged bone of a patient;

analyzing the CT image information to provide at least first, second and third location coordinate values for each of a selected sequence of surface point locations on the damaged bone;

providing a model of a selected portion of a surface of the damaged bone, for each of a selected sequence of one or more polygons defined by the sequence of surface point locations, using at least one of a point-to-point mapping and a surface normal vector mapping to provide the model; and

using the bone surface model to generate automated instructions to fabricate, before any incision in the patient'"'"'s body, a cutting jig for cutting and removing the selected portion of the damaged bone, where cutting with the jig provides at least one selected planar surface and at least first and second selected projections to align the jig with a selected axis of the damaged bone.

2. The method of claim 1, further comprising:

providing at least one incision in said patient'"'"'s body to allow access to said damaged bone; and

removing said selected portion of said damaged bone, using said jig and a cutting instrument, to form said bone planar surface on said damaged bone.

3. The method of claim 1, further comprising:

using said bone surface model to generate automated instructions to fabricate an implant device corresponding to said selected portion of said damaged bone, where the implant device includes at least one selected planar surface and at least third and fourth selected projections to align the implant device with said selected axis of said damaged bone.

4. The method of claim 3, further comprising:

fabricating said implant device, using said automated instructions; and

providing at least one incision in said patient'"'"'s body to allow access to said damaged bone, after said implant device has been fabricated.

5. The method of claim 3, further comprising:

providing at least one incision in said patient'"'"'s body to allow access to said damaged bone; and

removing said selected portion of said damaged bone, using said jig, to form said bone planar surface on said damaged bone, and to allow a remainder of said damaged bone, after removal of said selected portion, to mate and align with said implant device.

6. The method of claim 4, further comprising securing said implant device to, and aligning said implant device with, said remainder of said damaged bone.

7. The method of claim 3, further comprising repairing said incision in said patient'"'"'s body, after said implant device is aligned with and secured to said remainder of said damaged bone.

8. The method of claim 1, wherein said process of providing said model of said damaged bone surface comprises:

for at least one polygon in said sequence of said polygons, determining a number V of vertices of the at least one polygon; and

providing a polynomial z=f(x,y) of degree at most V-1 in said first location coordinate x and of degree at most V-1 in said second location coordinate y, defined on the at least one polygon, where the polynomial has a value equal to a selected value of z at each of the V vertices of the at least one polygon.

9. The method of claim 8, further comprising selecting said polynomial f(x,y) to have a minimum polynomial degree in said coordinate x and to have a minimum polynomial degree in said coordinate y.

10. The method of claim 8, further comprising selecting each of said selected values z to correspond to said third location coordinate value for each of said vertices of said at least one polygon.

11. The method of claim 8, further comprising choosing said at least one polygon to be a triangle with non-zero included area.

12. The method of claim 8, further comprising choosing said at least one polygon to be a quadrilateral with non-zero included area.

13. The method of claim 1, wherein said process of providing said model of said damaged bone surface comprises:

providing component values of a surface normal vector at each of at least three vertex locations of a selected surface element on said damaged bone surface;

providing a surface element defined by a selected polynomial of second degree in at least two of three Cartesian location coordinates (x,y,z), the polynomial having at least six initially undetermined parameters; and

determining values for the undetermined parameters so that a surface normal vector of the surface element has the provided surface normal vector component values at each of the at least three vertex locations.

14. The method of claim 13, further comprising selecting said polynomial to represent an ellipsoid in three dimensions.

15. The method of claim 1, further comprising choosing said joint associated with said damaged bone from a group of joints consisting of a hip joint, a knee joint, a foot joint, a toe joint, a shoulder joint, an elbow joint, a wrist joint, a finger joint and a neck joint.

16. A system for performing a total joint arthroplasty procedure on a patient'"'"'s damaged bone, the system comprising:

a CT scanning mechanism to provide a CT image of a selected region of a damaged bone of a patient; and

a computer that is programmed;

to received and analyze the CT image information to provide at least first, second and third location coordinate values for each of a selected sequence of surface point locations on the damaged bone;

to provide a model of a selected portion of a surface of the damaged bone, for each of a selected sequence of one or more polygons defined by the sequence of surface point locations, using at least one of a point-to-point mapping and a surface normal vector mapping to provide the model; and

to use the bone surface model to generate automated instructions to fabricate, before any incision in the patient'"'"'s body, a cutting jig for cutting and removing the selected portion of the damaged bone, where cutting with the jig will provide at least one selected planar surface and at least first and second selected projections to align the jig with a selected axis of the damaged bone.

17. The system of claim 16, further comprising a cutting jig, fabricated according to said automated instructions generated using said bone surface model.

18. The system of claim 17, further comprising a cutting instrument, configured to work cooperatively with said cutting jig to remove said selected portion of said damaged bone to form said bone planar surface.

19. The system of claim 18, wherein said computer is further programmed to use said bone surface model to generate automated instructions to fabricate an implant device corresponding to said selected portion of said damaged bone, where the implant device includes at least one selected planar surface and at least third and fourth selected projections to align the implant device with said selected axis of said damaged bone.

20. The system of claim 19, wherein said implant device is aligned with and secured to a remainder of said bone after removal of said selected portion of said damaged bone.

21. The system of claim 16, wherein said computer is programmed to provide said model of said damaged bone surface by a process comprising:

for at least one polygon in said sequence of said polygons, determining a number V of vertices of the at least one polygon; and

providing a polynomial z=f(x,y) of degree at most V-1 in said first location coordinate x and of degree at most V-1 in said second location coordinate y, defined on the at least one polygon, where the polynomial has a value equal to a selected value of z at each of the V vertices of the at least one polygon.

22. The system of claim 21, wherein said computer is further programmed to select said polynomial f(x,y) to have a minimum polynomial degree in said coordinate x and to have a minimum polynomial degree in said coordinate y.

23. The system of claim 21, wherein said computer is further programmed to select each of said selected values z to correspond to said third location coordinate value for each of said vertices of said at least one polygon.

24. The system of claim 21, wherein said computer is further programmed to choose said at least one polygon to be a triangle with non-zero included area.

25. The system of claim 21, wherein said computer is further programmed to choose said at least one polygon to be a quadrilateral with non-zero included area.

26. The system of claim 16, wherein said computer is programmed to provide said model of said damaged bone surface by a process comprising:

providing component values of a surface normal vector at each of at least three vertex locations of a selected surface element on said damaged bone surface;

providing a surface element defined by a selected polynomial of second degree in at least two of three Cartesian location coordinates (x, y, z), the polynomial having at least six initially undetermined parameters; and

determining values for the undetermined parameters so that a surface normal vector of the surface element has the provided surface normal vector component values at each of the at least three vertex locations.

27. The system of claim 26, wherein said computer is further programmed to select said polynomial to represent an ellipsoid in three dimensions.

28. The system of claim 16, wherein said joint associated with said damaged bone is drawn from a group of joints consisting of a hip joint, a knee joint, a foot joint, a toe joint, a shoulder joint, an elbow joint, a wrist joint, a finger joint and a neck joint.

29. A device for assisting in performing arthroplasty on a leg bone having a bone surface and a mechanical axis, the device comprising:

a mating region configured to matingly receive the bone surface; and

a cutting instrument guide including at least one guide surface that is generally perpendicular to the mechanical axis when the bone surface is matingly received by the mating region.

30. The device of claim 29, wherein the leg bone is a femur and the mechanical axis is a femoral mechanical axis.

31. The device of claim 30, wherein the bone surface includes at least a portion of the femur distal end.

32. The device of claim 29, wherein the leg bone is a tibia and the mechanical axis is a tibial mechanical axis.

33. The device of claim 32, wherein the bone surface includes at least a portion of the tibia proximal end.

34. The device of claim 29, wherein at least a portion of the device is manufactured via at least one of CNC and SLA.

35. The device of claim 29, further comprising a body in which the mating region is defined.

36. The device of claim 35, wherein the at least one guide surface is defined on the body.

37. The device of claim 35, further comprising a member separate from and supported off of the body, the at least one guide surface defined on the member.

38. The device of claim 29, wherein the cutting instrument guide includes a saw slot.

39. A method of manufacturing an arthroplasty cutting jig configured to facilitate an arthroplasty procedure on a patient bone, the method comprising using a medical imaging system to capture information regarding at least a portion of the patient bone;

generating a three dimensional image of the at least a portion of the patient bone from the information;

providing a representation of an implant; and

superimposing the representation of the implant over the image of the at least a portion of the patient bone.

40. The method of claim 39, further comprising identifying a mechanical axis associated with the patient bone.

41. The method of claim 40, further comprising orienting a desired cutting plane to be generally perpendicular to the mechanical axis.

42. The method of claim 40, wherein the patient bone is a femur and the mechanical axis is a femoral mechanical axis.

43. The method of claim 40, wherein the patient bone is a tibia and the mechanical axis is a tibial mechanical axis.

44. The method of claim 39, wherein the at least a portion of the patient bone includes at least a portion of the femur distal end.

45. The method of claim 44, wherein the implant is a femoral condyle prosthetic implant.

46. The method of claim 39, wherein the at least a portion of the patient bone includes at least a portion of the tibia proximal end.

47. The method of claim 46, wherein the implant is a tibial plateau prosthetic implant.

48. The method of claim 39, further comprising generating data from the superimposing of the representation of the implant over the image of the at least a portion of the patient bone and causing a manufacturing device to employ the data when the manufacturing device is manufacturing the arthroplasty cutting jig.

49. The method of claim 48, wherein the manufacturing device is at least one of a CNC machine and a SLA machine.

50. The method of claim 39, wherein the medical imaging system is at least one of CT and MRI.

51. A method of performing arthroplasty on a leg bone of a patient, the method comprising:

providing a first arthroplasty cutting jig comprising a mating surface and a first cutting guide surface oriented relative to the mating surface;

causing the mating surface to matingly receive a corresponding surface of the bone;

using the first cutting guide surface to create a first planar bone surface;

removing the first arthroplasty cutting jig from the bone subsequent to the creation of the planar bone surface;

providing a second arthroplasty cutting jig including a planar jig surface and second cutting guide surface oriented relative to the planar jig surface;

abutting the planar jig surface against the planar bone surface; and

using the second cutting guide surface to create a second planar bone surface.

52. The method of claim 51, wherein the first cutting guide surface is oriented relative to the mating surface so the planar bone surface is generally perpendicular to a mechanical axis of the leg bone.