SYSTEM FOR DETERMINING THE POSITION OF A KNEE PROSTHESIS

• US 20070185498A2
• Filed: 10/22/2003
• Published: 08/09/2007
• Est. Priority Date: 11/06/2000
• Status: Active Grant

• Current Assignee: Omnilife Science, Inc. (OrthoUnited, Inc.)
• Original Assignee: Perception Raisonnement Action en Medecine
• Inventors: Lavallee, Stephane
• Granted Patent: US 8,126,533 B2
• Time in Patent Office: Days
• US Class Current: 606/102
• 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 17/158 Cutting patella
• 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 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/108 Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2068 using pointers, e.g. pointers having reference marks for determining coordinates of body points
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/363 Use of fiducial points
• CPC Class Codes: A61B 2090/3916 Bone tissue
• CPC Class Codes: A61B 2090/3958 emitting a signal
• CPC Class Codes: A61B 2090/3962 palpable
• CPC Class Codes: A61B 2090/3979 infrared
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/062 : using magnetic field
• CPC Class Codes: A61B 6/032 : Transmission computed tomography [CT]
• CPC Class Codes: A61B 90/36 : Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61B 90/39 : Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61F 2/4657 : Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06

Abstract

The invention concerns a system for determining the ideal theoretical position of a knee prosthesis comprising, for determining the position of a tibial prosthesis, means for: determining the shape of the tibia proximal part and its position relative to the centre of the ankle joint; determining a high point of the tibial plateau; calculating the position of the ankle, the orientation and the size relative to the tibia of the tibial prosthesis and the section plane corresponding to the tibial prosthesis taking into account the following parameters: the perpendicular to the section plane passing through the centre of the prosthesis also passes through the centre of the ankle joint; the section plane is at a distance from said high point equal to the height of the prosthesis to be fixed; the large end of the prosthesis is centred on the large end of the tibia cross-section in the section plane; the front edge of the small end of the prosthesis is at a predetermined distance from the small end of the tibia cross-section in the section plane; and determining the orientation in the section plane of the prosthesis such that the large end of the prosthesis should be parallel to the horizontal axis of the knee.

Claims

14. A computer assisted orthopedic surgery system in support of an arthroplasty surgery of a patient'"'"'s knee joint, comprising:

a first locatable element attachable to a first bone on one side of the patient'"'"'s knee joint;

a sensor comprising a second locatable element, the sensor being movable in proximity of the patient'"'"'s knee joint;

a tracking device locating a plurality of positions of the sensor relative to the first locatable element;

a model of a knee joint;

a computer configured to deform the model in response to the plurality of positions of the tracking device and to determine a position for a knee prosthesis on the deformed model; and

a display connected to the computer so as to output the determined position upon the deformed model.

15. The system of claim 14, further comprising a third locatable element attachable to a second bone on another side of the patient'"'"'s knee joint.

16. The system of claim 14, wherein the tracking device comprises at least one of a camera, a magnetic tracker, a mechanical tracker, and an acoustic tracker.

17. The system of claim 14, wherein the tracking device locates the plurality of positions in response to an operator'"'"'s orders.

18. The system of claim 14, wherein the locatable element comprises at least three markers, and wherein the markers comprise at least one of a reflective disk, a reflective sphere, and an infrared diode.

19. The system of claim 14, wherein the sensor comprises at least one of a palpation device, an echographic device, and a radiographic device or combination thereof.

20. The system of claim 19, wherein the palpation device has a ball-shaped end.

21. The system of claim 20, wherein the computer is configured to respond to sliding movement of the ball-shaped end of the sensor on a bone surface to locate the plurality of positions.

22. The system of claim 14, wherein the model of the knee joint comprises at least one of:

a model of a femoral bone;

a model of a tibial bone;

a model of a patella; and

a model of positions of attachments of a medial and lateral ligament on the femoral and tibial bone.

23. The system of claim 14, wherein the model comprises a set of triangular facets connected to one another.

24. The system of claim 14, wherein the computer is further configured to determine section planes on the deformed model.

25. The system of claim 24, wherein the section planes correspond to section planes for implanting a femoral prosthesis.

26. The system of claim 24, wherein the section planes correspond to section planes for implanting a tibial prosthesis.

27. The system of claim 14, wherein the computer is further configured to determine an accuracy of the model based upon a density of the plurality of positions located by the tracking device.

28. The system of claim 27, wherein the accuracy of the model is indicated on the display using at least one of various colors and line thicknesses.

29. The system of claim 14, wherein the locatable elements are geometrically differentiated on the display.

30. The system of claim 29, wherein each locatable element comprises:

a shaped portion; and

at least three markers, wherein the shaped portion supports the at least three markers so as to represent the shaped portion on the display.

31. The system of claim 14, further comprising:

a drilling guide having a third locatable element; and

a section guide assembled into threads formed by the drilling guide.

32. The system of claim 31, wherein the computer is further configured to determine a location of the drilling guide on the deformed model.

33. The system of claim 15, wherein the first bone is a femur and the second bone is a tibia, the tibia and femur are connected by a medial and a lateral ligament, and wherein the computer is further configured to determine an elongation of the medial and lateral ligaments in response to displacement of the medial and lateral ligaments as the tibia is displaced.

34. The system of claim 33, wherein the computer is further configured to determine when the elongation limit of the medial and lateral ligaments has been exceeded.

35. The system of claim 14, further comprising a fourth locatable element attachable to a patella, wherein the first bone is a femur and the second bone is a tibia, and wherein the patella, tibia, and femur are connected, and wherein the computer is further configured to determine a trajectory of the patella as the knee is moved from extension to flexion.

36. The system of claim 35, wherein the computer is further configured to determine a point on an internal patella surface, wherein the point on the internal patella surface better coincides with a center of a groove of a femoral prosthesis.

37. The system of claim 14, wherein the first bone is a tibia and the computer is further configured to determine the position, orientation, and size of a tibial prosthesis for implantation into the tibial bone.

38. The system of claim 14, wherein the first bone is a tibia and the computer is further configured for performing the steps of:

determining a reference point on a superior surface of the tibia;

calculating a position of a section plane for implanting a tibial prosthesis, wherein the position is a distance from the reference point equal to a thickness of the superior surface of a tibial prosthesis and wherein the section plane is perpendicular to a plane crossing a center of the tibial prosthesis and a center of an ankle joint; and

calculating an orientation of the tibial prosthesis such that an anterior edge of the tibial prosthesis is at a predetermined distance from an anterior edge of the section plane;

whereby the calculated position and orientation coincides with the position determined for the knee prosthesis.

39. The system of claim 14, wherein the first bone is a femur and the computer is further configured to determine the position, orientation, and size of a femoral prosthesis.

40. The system of claim 14, wherein the first bone is a femur and the computer is further configured for performing the steps of:

determining a most distal point on the femur, a most posterior point on the femur, and a trajectory of a center of a patella during knee flexion;

calculating a position of a distal section plane wherein the position is a distance from the most distal point equal to a thickness of a distal portion of a femoral prosthesis;

calculating a position of a posterior section plane wherein the position is a distance from the most posterior point equal to a thickness of a posterior condyle of the femoral prosthesis;

calculating a maximum size of the femoral prosthesis to be implanted; and

calculating a position of implantation of the femoral prosthesis such that a trochlea of the femoral prosthesis is in alignment with the trajectory of the center of the patella;

whereby the calculated position and size coincides with the position determined for the knee prosthesis.

41. A computer assisted orthopedic surgery system in support of an arthroplasty surgery of a patient'"'"'s knee joint, comprising:

a first locatable element attachable to a first bone on one side of the patient'"'"'s knee joint;

a sensor comprising a second locatable element, the sensor being movable in proximity to the patient'"'"'s knee joint;

a means for locating a plurality of positions of the sensor relative to the first locatable element;

a model of the knee joint;

a means for deforming the model in response to the plurality of positions provided by the locating means;

a means for determining a position, orientation, and size of a knee prosthesis on the deformed model; and

a means for outputting the deformed model and indicating the determined position for the knee prosthesis on the deformed model.

42. The system of claim 41, further comprising a means for determining section planes on the deformed model.

43. The system of claim 41, further comprising a means for determining an accuracy of the deformed model.

44. The system of claim 43, further comprising a means for indicating the accuracy of the deformed model.

45. The system of claim 41, further comprising:

a drilling guide having a third locatable element; and

a section guide assembled into threads formed by the drilling guide

46. The system of claim 45, further comprising a means for determining a location of the drilling guide on the deformed model.

47. The system of claim 41, further comprising a means for geometrically differentiating the locatable elements.

48. The system of claim 41, further comprising a third locatable element attachable to a second bone on another side of the patient'"'"'s knee joint.

49. The system of claim 47, wherein the first bone is a femur and the second bone is a tibia, and wherein the tibia and femur are connected by a medial and a lateral ligament, further comprising a means for determining an elongation of the medial and lateral ligaments in response to displacement of the medial and lateral ligaments as the tibia is displaced.

50. The system of claim 48, wherein the computer is further configured to determine when the elongation limit of the medial and lateral ligaments has been exceeded.

51. The system of claim 48 further comprising:

a means for determining motion limits of a patient'"'"'s knee joint; and

a means for outputting a simulated image of the motion limits.

52. The system of claim 47, further comprising:

a fourth locatable element attachable to a patella;

a means for determining a trajectory of the patella as the knee is moved from extension to flexion; and

a means for outputting the trajectory of the patella.

53. The system of claim 51 further comprising a means for determining a point on an internal patella surface, wherein the point on the internal patella surface better coincides with a center of a groove of a femoral prosthesis.