Assessing the condition of a joint and devising treatment

• US 20040167390A1
• Filed: 01/22/2004
• Published: 08/26/2004
• Est. Priority Date: 09/14/1998
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Lang, Philipp, Steines, Daniel, Andriacchi, Thomas P., Alexander, Eugene J.
• Granted Patent: US 8,036,729 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/1122 of movement trajectories
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/4514 Cartilage
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G09B 23/30 Anatomical models G09B23/281 - G09B23/288 take precedence

Abstract

Methods are disclosed for assessing the condition of a cartilage in a joint, particularly 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 treating a human with a joint disease involving cartilage, which method comprises:

obtaining an electronic image of said joint, wherein said image includes both normal and diseased cartilage tissue;

electronically evaluating said image to obtain information comprising volume, area, thickness, curvature, geometry, biochemical contents, signal intensity or relaxation time of said normal or diseased tissue; and

selecting a therapy based on said information.

2. The method of claim 1, wherein said electronically evaluating comprises a method selected from the group consisting of:

(1) a method of estimating the loss of cartilage in a joint, wherein the joint comprises cartilage and accompanying bones on either side of the joint, which method comprises obtaining a three-dimensional map of the cartilage at an initial time and calculating the thickness or regional volume of a region of degenerated cartilage so mapped at the initial time, obtaining a three-dimensional map of the cartilage at a later time, and calculating the thickness or regional volume of a region of degenerated cartilage so mapped at the later time, and determining the loss in thickness or regional volume of the region of degenerated cartilage between the later and initial times;

(2) a method for assessing the condition of cartilage in a joint of a human, which method comprises electronically transferring an electronically generated image of a cartilage of the joint from a transferring device to a receiving device located distant from the transferring device;

receiving the transferred image at the distant location;

converting the transferred image to a degeneration pattern of the cartilage; and

transmitting the degeneration pattern to a site for analysis;

(3) a method for determining the volume of cartilage loss in a region of a cartilage defect of a cartilage in a joint of a mammal which method comprises determining the thickness, D_N, of the normal cartilage near the cartilage defect;

obtaining the thickness of the cartilage defect, D_D, of the region;

subtracting D_D from D_N to give the thickness of the cartilage loss, D_L; and

multiplying the D_L value times the area of the cartilage defect, A_D, to give the volume of cartilage loss;

(4) a method of estimating the change of cartilage in a joint of a mammal over time, which method comprises estimating the thickness or width or area or volume of a region of cartilage at an initial time T₁;

estimating the thickness or width or area or volume of the region of cartilage at a later time T₂; and

determining the change in the thickness or width or area or volume of the region of cartilage between the initial and the later times;

(5) a method for providing a biochemically based map of joint cartilage of a mammal, wherein the joint comprises cartilage and associated bones on either side of the joint, which method comprises measuring a detectable biochemical component throughout the cartilage;

determining the relative amounts of the biochemical component throughout the cartilage;

mapping the amounts of the biochemical component in three dimensions through the cartilage; and

determining the areas of abnormal joint cartilage by identifying the areas having altered amounts of the biochemical component present;

(6) a method of estimating the change of cartilage in a joint, wherein the joint comprises articular cartilage, which method comprises defining a 3D object coordinate system of the joint at an initial time, T₁;

identifying a region of a cartilage defect within the 3D object coordinate system;

defining a volume of interest around the region of the cartilage defect whereby the volume of interest is larger than the region of cartilage defect, but does not encompass the entire articular cartilage;

defining the 3D object coordinate system of the joint at a second timepoint, T₂;

placing the identically-sized volume of interest into the 3D object coordinate system at timepoint T₂ using the object coordinates of the volume of interest at timepoint T₁; and

measuring any differences in cartilage volume within the volume of interest between timepoints T₁ and T₂; and

(7) a method for correlating cartilage image data, bone image data, and opto-electrical image data for the assessment of the condition of a joint, which method comprises (a) obtaining the cartilage image data of the joint with a set of skin reference markers placed externally near the joint;

(b) obtaining the bone image data of the joint with a set of skin reference markers positioned in the same manner as the markers in;

(c) obtaining the opto-electrical image data of the joint with a set of skin reference markers positioned in the same manner as (a) and (b); and

using the skin reference markers to correlate the images obtained in (a), (b) and (c) with each other, wherein each skin reference marker is detectable in the cartilage and bone data and the opto-electrical data;

3. The method of claim 1, wherein said electronic image provides information on the thickness, shape, or curvature of said normal and said disease tissue or the location and size of said diseased tissue.

4. The method of claim 1, wherein said therapy comprises autologous chondrocyte transplantation, osteochondral allografting, osteochondral autografting, tibial corticotomy, femoral or tibial osteotomy.

5. The method of claim 1, wherein said therapy uses cartilage or bone tissue grown ex vivo, stem cells, an artificial non-human material, an agent that stimulates repair of said diseased tissue, or an agent that protects said diseased tissue and that protects adjacent normal tissue.

6. The method of claim 1, wherein said information is used to determine the thickness or other geometrical feature of a tissue transplant, a tissue graft, a tissue implant, a tissue replacement material, a tissue scaffold, or a tissue regenerating material or tissue repair system.

7. The method of claim 1, wherein said image is obtained using ultrasound, computed tomography, positron emission tomotraphy, a single photon emission computed tomography scan, or MRI.

8. The method of claim 7, wherein said information is used to generate a three-dimensional map of cartilage thickness or a physical model of said normal or said diseased tissue or both.

9. The method of claim 8, wherein said physical model is used to shape a tissue transplant, a tissue graft, a tissue implant, a tissue replacement material, a tissue scaffold or a tissue regenerating material or tissue repair system.

10. A method of treating a human with cartilage degeneration in a joint, which method comprises:

obtaining an electronic image of said joint, wherein said image includes both and diseased cartilage;

electronically evaluating said image to obtain information comprising volume, area, thickness, geometry, biochemical contents or relaxation time of said normal or diseased tissue; and

selecting a therapy to treat or replace said degenerated cartilage, wherein said information is used during selection of treatment or replacement therapy of said degenerated cartilage.

11. The method of claim 10, wherein said information includes thickness, shape, curvature, or location and dimensions of said normal or degenerated cartilage.

12. The method of claim 10, wherein said technique to treat or replace said degenerated cartilage is autologous chondrocyte transplantation, osteochondral allografting, osteochondral autografting, tibial corticotomy, or femoral or tibial osteotomy.

13. The method of claim 10, wherein said treatment or replacement therapy uses cartilage or bone tissue grown ex vivo, stem cells, an artificial non-human material, an agent that stimulates repair of said diseased tissue, or an agent that protects said diseased tissue and that protects adjacent normal tissue.

14. The method of claim 10 wherein said information is used to determine the thickness, shape, curvature, or location and dimensions of a cartilage transplant, a cartilage graft, a cartilage implant, a cartilage replacement material, a scaffold for cartilage cells or acellular cartilage components or a cartilage regenerating material or a cartilage repair system.

15. The method of claim 10, wherein said image is obtained using ultrasound, computed tomography, positron emission tomography, a single photon emission computed tomography scan, or MRI.

16. The method of claim 10, wherein said information is used to generate a three-dimensional map of cartilage thickness or a physical model of said normal or said diseased tissue or both.

17. The method of claim 16, wherein said physical model is used to shape a cartilage transplant, a cartilage graft, a cartilage implant, a cartilage replacement material, a scaffold or a cartilage regenerating material or a cartilage repair system.

18. The method of claim 16, wherein physical model comprises an area of diseased cartilage as well as adjacent normal tissue.

19. The method of claim 18, wherein said adjacent normal tissue is bone, bone marrow, or normal cartilage.

20. The method of claim 16, wherein said physical model is created with use of a 3D Euclidian distance transformation.

21. The method of claim 16, wherein said physical model or a portion of said physical model is implanted into a knee joint.

22. The method of claim 16, wherein said physical model carries cartilage cells or cartilage matrix.

23. A method of treating a human with diseased cartilage in a joint, which method comprises:

utilizing an MRI scan to generate a cross-sectional electronic image of said joint, wherein said image includes both normal and diseased cartilage; and

utilizing information from said image to create a geometric model of an area of diseased cartilage, wherein said geometric model is used in selecting a treatment of said diseased cartilage.

24. The method of claim 23, wherein said area of diseased cartilage includes adjacent normal tissue.

25. The method of claim 23, wherein said geometric model is used to determine the shape of a cartilage transplant, a cartilage graft, a cartilage implant, a cartilage replacement material, a scaffold for cartilage cells or acellular cartilage components or a cartilage regenerating material or a cartilage repair system.

26. A method of assessing cartilage disease in a joint, wherein the joint comprises cartilage and accompanying bones on either side of the joint, which method comprises:

obtaining a three-dimensional map of the cartilage demonstrating the thickness or biochemical contents or relaxation time of normal and diseased cartilage; and

determining the margins of the diseased cartilage in relationship to the normal cartilage in said three-dimensional map.

27. The method of claim 26, wherein said determination of said margins of said diseased cartilage is performed by detecting a difference in said thickness, said biochemical contents or said relaxation time between said normal and said diseased cartilage.

28. The method of claim 26, wherein said determination of said margins of said diseased cartilage is used to determine the area, volume, or thickness of diseased cartilage.

29. The method of claim 26, wherein said determination of said margins of said diseased cartilage is used to determine the percentage of total cartilage surface area in a joint or along an articular surface represented by diseased cartilage or the percentage of weight-bearing surface area in a joint represented by diseased cartilage.

30. The method of claim 26, wherein steps (a) through (b) are carried out at an initial time (T₁) and are carried out again at a later time (T₂).

31. The method of claim 30, wherein the estimation includes an analysis of the degree of degeneration of the cartilage between T₁ and T₂.

32. The method of claim 26, wherein an MRI technique first obtains a series of two-dimensional views of the joint, which are then mathematically integrated to give a three-dimensional image.

33. The method of claim 32, wherein the MRI technique employs a gradient echo, spin echo, fast-spin echo, driven equilibrium Fourier transform, or spoiled gradient echo technique.