Cutting guide

1. A method of replacing a portion of a patient's joint, the joint including first and second bones, the method comprising:

selecting an implant to replace a portion of a patient's joint, to be positioned onto a cut portion of the first bone;

determining the configuration and dimensions of a cutting guide image by

imaging the first bone prior to making a incision, and

utilizing the image of the first bone, and the dimensions of the selected implant, to determine the configuration and dimension of the cutting guide image;

making an incision proximal to the joint sized smaller than the implant;

exposing at least a portion of the joint through the incision;

projecting a cutting guide image of visible light onto the first bone of the joint, the cutting guide image comprising a plurality of projected guide segments corresponding to the path to be cut, a path corresponding to dimensions of the implant;

aligning a cutting tool with the cutting guide image; and

cutting the first bone of the joint by moving a cutting tool in relation to the cutting guide image.

2. The method of claim 1 , further comprising stretching the incision.

3. The method of claim 1 , further comprising attaching the implant to the cut portion of the first bone.

4. The method of claim 3 , wherein the implant includes a plurality of implant portions and attaching the implant to the cut portion of the first bone includes sequentially inserting the plurality of implant portions through the incision.

5. The method of claim 1 , further comprising measuring the cut portion of the first bone.

6. The method of claim 5 , further comprising:

adjusting the configuration of the cutting guide image; and

cutting the cut portion of the first bone by moving the cutting tool along the adjusted cutting guide image.

7. The method of claim 6 , further comprising selecting a second implant to be positioned on the adjusted cut portion of the first bone and replacing the implant with the second implant.

8. The method of claim 7 , further comprising attaching the second implant to the adjusted cut portion of the first bone.

9. The method of claim 6 , wherein the orientation of the cutting guide image is adjusted.

10. The method of claim 6 , wherein the size of the cutting guide image is adjusted.

11. The method of claim 1 , wherein projecting a cutting guide image comprises projecting a cutting guide image on a side surface of the first bone.

12. The method of claim 1 , wherein projecting a cutting guide image comprises projecting a cutting guide image on an end portion of the first bone.

13. The method of claim 1 , wherein the cutting guide image is a two dimensional image.

14. The method of claim 1 , wherein the cutting guide image is a three-dimensional image.

15. The method of claim 1 , wherein a computer system is used in aligning the cutting tool with the cutting guide image.

16. The method of claim 1 , wherein projecting a cutting guide image onto the first bone of the joint includes sequentially projecting the plurality of guide segments onto the first bone of the joint.

17. The method of claim 1 , wherein the joint is an ankle, elbow, hip, knee, shoulder, spine or wrist joint.

18. The method of claim 1 , wherein the joint is a knee joint including a femur and a tibia.

19. The method of claim 18 , wherein projecting a cutting guide image comprises projecting a cutting guide image onto a side surface of a distal end portion of the femur.

20. The method of claim 19 , wherein the side surface is a medial side of the distal end portion of the femur.

21. The method of claim 19 , wherein the side surface is a lateral side of the distal end portion of the femur.

22. A method of performing surgery on a patient's joint, the joint including first and second bones, the method comprising:

making an incision proximal to the joint;

exposing at least a portion of the joint through the incision;

projecting a cutting guide image of visible light onto the first bone of the joint;

aligning a cutting tool with the cutting guide image; and

cutting the first bone of the joint by moving a cutting tool in relation to the cutting guide image

wherein the joint is a knee joint including a femur and a tibia;

wherein the cutting guide image comprises a plurality of projected guide segments;

wherein projecting a cutting guide image comprises projecting a cutting guide image onto a side surface of a distal end portion of the femur; and

wherein the plurality of projected guide segments comprises:

a distal projected guide segment disposed in a plane which extends perpendicular to a longitudinal central axis of the femur and extends through lateral and medial condyles of the femur;

an anterior chamfer projected guide segment disposed in a plane which extends at an acute angle to a plane containing the distal projected guide segment;

a posterior chamfer projected guide segment disposed in a plane which extends at an acute angle to a plane containing the distal projected guide segment, the plane containing the posterior chamfer projected guide segment extending perpendicular to the plane containing the anterior chamfer projected guide segment;

an anterior projected guide segment disposed in a plane which extends perpendicular to a plane containing the distal projected guide segment and extends generally parallel to a longitudinal central axis of the femur; and

a posterior projected guide segment disposed in a plane which extends parallel to a plane containing the anterior projected guide segment and perpendicular to a plane containing the distal projected guide segment.

23. The method of claim 1 , wherein said visible light is visible through body tissue.

24. The method of claim 1 , further including the steps of:

projecting a signal from the cutting tool responsive to the path being cut;

comparing the location of the signal projected from the cutting tool with the location of the at least one cutting path; and

correcting the path being cut if the path being cut deviates more than a predetermined amount from the at least one cutting path, as indicated by the comparison.

25. The method of claim 24 , wherein said signal in said projecting step is visible light, and wherein in said step of comparing, the surgical practitioner compares the location of the visible light projected from the cutting tool with the dimension and location of the visible light of the at least one cutting path.

26. The method of claim 24 , wherein the step of comparing includes using at least one computer processor operative to alert the surgical practitioner to modify the path being cut if the path being cut deviates more than a predetermined amount from the calculated dimension and location of the at least one cutting path being cut.

27. A method of replacing a portion of a patient's joint, the joint including first and second bones, the method comprising:

selecting an implant to replace a portion of a patient's joint, to be positioned onto a cut portion of the first bone;

determining the configuration and dimensions of a cutting guide image by

imaging the first bone prior to making a incision, and

utilizing the image of the first bone, and the dimensions of the selected implant, to determine the configuration and dimension of the cutting guide image;

making an incision proximal to the joint sized smaller than the implant;

exposing at least a portion of the joint through the incision;

projecting a cutting guide image of visible light onto the first bone of the joint, the cutting guide image comprising a plurality of projected guide line segments of coherent light corresponding to a path to be cut, the path corresponding to dimensions of the implant;

aligning a cutting tool with the cutting guide image; and

cutting the first bone of the joint by moving a cutting tool in relation to the cutting guide image.