Bone milling with image guided surgery

1 . A method of resurfacing a bone at a surgical site during a surgical navigation procedure, comprising:

providing a tracking system and a surgical instrument having a tracking array, the tracking array being identified and tracked by the tracking system;

moving the surgical instrument relative to the bone while the tracking system tracks the position of the surgical instrument, the relative movement being projected on an image of the bone;

viewing the projected image as the surgical instrument is moved relative to the bone to determine when the surgical instrument is positioned at the surgical site;

using the surgical instrument to make a hole in the bone at the surgical site; and

inserting a guide pin into the hole.

2 . The method of claim 1 , further comprising:

positioning a surgical tool over the guide pin; and

milling a first portion of the bone with the surgical tool to create a first substantially planar surface on the bone.

3 . The method of claim 2 , further comprising:

using the surgical instrument to make a second hole in the bone at the surgical site;

inserting a second guide pin into the second hole;

positioning the surgical tool over the second guide pin; and

milling a second portion of the bone with the surgical tool to create a second substantially planar surface on the bone, the second surface being substantially coplanar with the first surface.

4 . The method of claim 1 , wherein the moving of the surgical instrument relative to the bone comprises moving a drill guide.

5 . The method of claim 1 , wherein the moving of the surgical instrument relative to the bone comprises moving a drill.

6 . The method of claim 1 , wherein the viewing of the projected image comprises viewing a real-time graphical image of the bone.

7 . The method of claim 2 , wherein the positioning of the surgical tool over the guide pin comprises positioning a reamer over the guide pin.

8 . The method of claim 1 , further comprising:

locating the surgical site by referencing a mechanical axis, the mechanical axis being identified by the tracking system.

9 . The method of claim 8 , wherein the mechanical axis connects the center of a patient's hip with the center of the patient's knee.

10 . The method of claim 1 , wherein the procedure is performed without a referencing guide.

11 . The method of claim 10 , wherein the performance of the procedure without a referencing guide comprises performing the procedure without an intramedullary rod.

12 . The method of claim 1 , wherein the resurfacing of the bone comprises resurfacing a femur.

13 . A method of performing a knee procedure using surgical navigation, comprising:

providing a tracking system and a surgical instrument having a tracking array, the tracking array being identified and tracked by the tracking system;

using the tracking system to guide the surgical instrument to a surgical site on a patient's femur;

using a surgical tool to create a first substantially planar surface on a condyle of the patient's femur at the surgical site; and

installing a surgical implant on the femur;

wherein the procedure is performed without a referencing guide.

14 . The method of claim 13 , further comprising:

determining the location of the surgical site by referencing a mechanical axis identified by the tracking system, the mechanical axis connecting the center of a patient's hip with the center of the patient's knee.

15 . The method of claim 14 , wherein a line representing the mechanical axis is projected on a computer generated image of the femur.

16 . The method of claim 14 , wherein the mechanical axis comprises a femoral mechanical axis.

17 . The method of claim 13 , further comprising:

making a hole in the condyle at the surgical site; and

inserting a guide pin into the hole.

18 . The method of claim 17 , wherein using the surgical tool to create the first substantially planar surface on the condyle comprises positioning the surgical tool over the guide pin and milling a first portion of the condyle with the surgical tool.

19 . The method of claim 18 , further comprising:

making a second hole in the condyle at the surgical site;

inserting a second guide pin into the second hole

positioning the surgical tool over the second guide pin; and

milling a second portion of the condyle with the surgical tool to create a second substantially planar surface on the condyle, the second surface being substantially coplanar with the first surface.

20 . The method of claim 13 , wherein the guiding of the surgical instrument to the surgical site comprises guiding a drill guide.

21 . The method of claim 13 , wherein the guiding of the surgical instrument to the surgical site comprises guiding a drill.

22 . The method of claim 13 , wherein the use of a surgical tool to create a first substantially planar surface on the condyle comprises using a reamer.

23 . The method of claim 13 , wherein the performance of the procedure without a referencing guide comprises performing the procedure without an intramedullary rod.

24 . The method of claim 13 , wherein the knee procedure comprises a knee arthroplasty procedure.

25 . A computer readable storage medium for use with a surgical navigation system, the storage medium storing instructions that, when executed during a bone resurfacing procedure, cause the surgical navigation system to implement the following steps:

tracking a surgical instrument having a tracking array with a tracking system as the surgical instrument moves relative to the bone;

projecting the relative movement of the surgical instrument on an image of the bone;

displaying a mechanical axis on the image, the mechanical axis being positioned relative to the surgical site;

identifying a location on the image having a corresponding location on the bone for inserting a guide pin once the surgical instrument is positioned at the surgical site; and

generating instructions for creating a first substantially planar surface on a first portion of the bone at the location of the first guide pin.

26 . The computer readable storage medium of claim 25 , wherein the stored instructions, when executed, further comprise causing the surgical navigation system to identify a second location on the image having a corresponding location on the bone for inserting a second guide pin to create a second substantially planar surface on a second portion of the bone at the location of the second guide pin.

27 . The computer readable storage medium of claim 26 , wherein the stored instructions, when executed, further cause the surgical navigation system to generate instructions for creating the second substantially planar surface on the second portion of the bone at the location of the second guide pin.

28 . The computer readable storage medium of claim 25 , wherein the stored instructions, when executed, further comprise causing the surgical navigation system to determine the location of the surgical site by referencing the mechanical axis identified by the tracking system, the mechanical axis connecting the center of a patient's hip with the center of a patient's knee.

29 . The computer readable storage medium of claim 25 , wherein the mechanical axis comprises a femoral mechanical axis.

30 . The computer readable storage medium of claim 25 , wherein the bone comprises a femur.