Reconstruction of anterior cruciate ligaments

1. An instrument for locating an attachment position for a reconstructed anterior cruciate ligament (ACL) in a femur comprising:

a handle;

a side piece comprising:

a first surface shaped to fit at least in part against a lateral side wall of an intercondylar notch to locate the instrument relative to the femur, and

a second surface configured to contact a roof of the intercondylar notch at the same time the first surface is at least in part against the lateral side wall of the intercondylar notch to locate the instrument relative to the femur; and

a tip arranged to wrap around a back surface of a condyle of the femur and contact the back surface of the condyle at the same time the first surface is at least in part against the lateral side wall of the intercondylar notch and the second surface is contacting the roof of the intercondylar notch to locate the instrument relative to the femur;

wherein there is a hole in the side piece that defines the attachment position for the reconstructed ACL.

2. The instrument of claim 1 wherein the side piece is coupled to the handle.

3. The instrument of claim 1 wherein the side piece is coupled to the tip.

4. The instrument of claim 1 wherein the tip is coupled to the handle.

5. The instrument of claim 1 wherein the hole is arranged to be located at the centre of the reconstructed ACL attachment position.

6. The instrument of claim 1 wherein there are two holes in the side piece that define one or more attachment positions for the reconstructed ACL.

7. The instrument of claim 6 wherein the two holes are arranged to be respectively located at the centres of two reconstructed ACL attachment positions.

8. The instrument of claim 1 wherein the linear and rotational relationships between the first surface, the second surface, and the tip are defined by accumulation of anatomical measurement data from a statistically significant number of femurs.

9. An instrument for locating an attachment position for a reconstructed anterior cruciate ligament (ACL) in a femur comprising:

a handle;

a side piece comprising:

a first surface shaped to fit at least in part against a lateral side wall of an intercondylar notch to locate the instrument relative to the femur, and

a second surface configured to contact a roof of the intercondylar notch at the same time the first surface is at least in part against the lateral side wall of the intercondylar notch to locate the instrument relative to the femur; and

a tip with a contact surface directed at least in part toward the second surface such that at least part of the contact surface forms an angle of less than 180 degrees with the second surface, wherein the contact surface is configured to contact a part of the femur at the same time the first surface is at least in part against the lateral side wall of the intercondylar notch and the second surface is contacting the roof of the intercondylar notch to locate the instrument relative to the femur;

wherein there is a hole in the side piece that defines the attachment position for the reconstructed ACL.

10. The instrument of claim 9 wherein the side piece is coupled to the handle.

11. The instrument of claim 9 wherein the side piece is coupled to the tip.

12. The instrument of claim 9 wherein the tip is coupled to the handle.

13. The instrument of claim 9 wherein the part of the femur the contact surface is configured to contact is a transverse ridge of the femur.

14. The instrument of claim 9 wherein the part of the femur the contact surface is configured to contact is a back surface of a condyle of the femur.

15. The instrument of claim 9 wherein the hole is arranged to be located at the centre of the reconstructed ACL attachment position.

16. The instrument of claim 9 wherein there are two holes in the side piece that define one or more attachment positions for the reconstructed ACL.

17. The instrument of claim 16 wherein the two holes are arranged to be respectively located at the centres of two reconstructed ACL attachment positions.

18. The instrument of claim 9 wherein the linear and rotational relationships between the first surface, the second surface, and the tip are defined by accumulation of anatomical measurement data from a statistically significant number of femurs.

19. A method of locating an attachment position for a reconstructed anterior cruciate ligament (ACL) in a femur comprising:

passing a tip of a locating instrument around a condyle of the femur by moving the locating instrument distally and laterally;

moving the locating instrument proximally to bring the tip of the locating instrument into contact with a back surface of the condyle;

contacting a first surface of a side piece of the locating instrument against a lateral side wall of an intercondylar notch; and

contacting a second surface of the side piece of the locating instrument against a roof of the intercondylar notch at the same time the first surface is contacting the lateral side wall of the intercondylar notch and the tip of the locating instrument is contacting the back surface of the condyle to locate the instrument relative to the femur.

20. The method of claim 19 , further comprising marking the attachment position for a reconstructed ACL through a hole in the side piece of the locating instrument.

21. The method of claim 19 , further comprising drilling a hole in the femur through a hole in the side piece of the locating instrument.

22. The method of claim 21 wherein the act of drilling a hole in the femur includes drilling a hole with a guidewire.

23. The method of claim 22 wherein the act of drilling a hole with a guidewire includes drilling inside-out by placing a distal end of the guidewire through the hole in the side piece of the locating instrument and drilling.

24. The method of claim 22 wherein the act of drilling a hole with the guidewire includes drilling outside-in by drilling through the femur and into the hole in the side piece of the locating instrument with the aid of a drill guide.