Adjustable cut block

• US 20050149037A1
• Filed: 12/26/2003
• Published: 07/07/2005
• Est. Priority Date: 12/26/2003
• Status: Active Grant

• Current Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Sanford, Adam H., Steffensmeier, Scott J.
• Granted Patent: US 7,282,054 B2
• Time in Patent Office: Days
• US Class Current: 606/87
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 2017/0268 for the knee

Abstract

The present invention provides a cut block for cutting the femur and tibia during knee replacement surgery.

Claims

1. A cut block for cutting the femur and tibia during knee joint replacement surgery, the cut block comprising:

a body having a plurality of cutter guides for guiding a cutter to cut the femur and tibia, the body having an anterior face and a posterior face;

a first reference surface mounted on the body and projecting posteriorly; and

a second reference surface mounted on the body and projecting posteriorly, the spacing of the first and second reference surfaces being adjustable vertically from a first position in which they are generally in the same plane to a second position in which they are spaced apart such that the reference surfaces are able to space the tibia away from the femur.

2. The cut block of claim 1 wherein at least one of the first and second reference surfaces comprises a pin inserted into one of the tibia and femur.

3. The cut block of claim 1 wherein at least one of the first and second reference surfaces comprises a paddle positionable in the knee joint against one of the tibia and femur.

4. The cut block of claim 1 wherein the first reference surface comprises a fixed paddle projecting from the posterior face, the fixed paddle being attached to the body in predetermined fixed relationship and the second reference surface comprises an adjustable paddle.

5. The cut block of claim 4 wherein the cut block includes at least one slot extending from the anterior face to the posterior face and the fixed paddle is removably insertable in the at least one slot to attach the fixed paddle to the body in predetermined fixed relationship.

6. The cut block of claim 5 wherein the cut block includes a plurality of slots able to receive the fixed paddle such that the predetermined fixed relationship of the paddle to the body is selectable.

7. The cut block of claim 4 wherein the fixed paddle further comprises a top surface positionable adjacent the femur, and the adjustable paddle further comprises a bottom surface simultaneously positionable adjacent the tibia, the adjustable paddle being movable downwardly to a position spaced below the fixed paddle such that the bottom surface of the adjustable paddle presses against the tibia to space the tibia away from the femur.

8. The cut block of claim 4 wherein the adjustable paddle further comprises a threaded sleeve attached to the adjustable paddle, the body further comprising a vertical slot for receiving the sleeve for vertical translation within the slot, and an adjustment screw threadably engaging the threaded sleeve, the adjustment screw being fixed to the body to permit rotation of the screw and constrain translation of the screw relative to the body such that rotation of the screw causes the sleeve and adjustable paddle to translate vertically within the slot relative to the fixed paddle.

9. The cut block of claim 1 wherein the body further comprises an anterior face, a top, a bottom, a left side, and a right side, the body being sized to position the cutter guides over one side of the knee for a unicondylar knee replacement procedure, one of the left and right sides being positionable adjacent an outer portion of the knee and the other of the left and right sides being simultaneously positionable adjacent the center of the knee.

10. The cut block of claim 1 wherein the body further comprises an anterior face, a top, a bottom, a left side, and a right side, the body being sized to position the cutter guides over the knee for a total knee replacement procedure, one of the left and right sides being positionable adjacent the medial side of the knee and the other of the left and right sides being simultaneously positionable adjacent the lateral side of the knee.

11. The cut block of claim 1 wherein the cutter guides comprise a femoral cut slot extending from the anterior face to the posterior face to guide a saw blade to cut the femur and a tibial cut slot extending from the anterior face to the posterior face to guide a saw blade to cut the tibia.

12. The cut block of claim 11 wherein the body further comprises an opening from the anterior face to the posterior face between the cut slots to permit viewing of the paddles through the block to verify proper paddle positioning.

13. The cut block of claim 12 wherein the body further comprises a top, a bottom, a first side, and a second side extending between the anterior and posterior faces, the opening also opening toward one of the first and second sides such that the body forms a “

C”

-shape with the top of the “

C”

containing the femoral cut slot and the bottom of the “

C”

containing the tibial cut slot.

14. The cut block of claim 11 wherein the femoral and tibial cut slots are spaced vertically a known, fixed distance such that by cutting the femur and tibia using the cut slots, a known, fixed gap will be created between the femur and tibia that can be filled with an implant having a vertical height equal to the spacing between the cut slots to position the knee the same after implantation of the prosthesis as at the time the cuts were made.

15. A method for cutting the femur and tibia during knee replacement surgery, the method comprising:

exposing a portion of the knee joint;

providing a cut block including a body having cutter guides for guiding a cutter to cut the femur and tibia, the body having a posterior face and first and second reference surfaces, the vertical spacing between the first and second reference surfaces being adjustable;

positioning the knee in a desired knee joint alignment;

contacting one of the tibia and femur with one of the reference surfaces;

contacting the other of the tibia and femur with the other of the reference surfaces;

adjusting the vertical spacing of the reference surfaces to hold the joint in the desired alignment; and

guiding a cutter with the cutter guides of the cut block to cut the femur and tibia.

16. The method of claim 15 further comprising:

providing upper and lower alignment rods;

attaching the alignment rods to the cut block with the upper rod extending upwardly toward the femoral head and the lower rod extending downwardly toward the ankle; and

aligning the knee until the upper alignment rod points to the center of the femoral head and the distal alignment rod is parallel to the tibial mechanical axis.

17. The method of claim 15 wherein the cutter guides for guiding a cutter to cut the femur and tibia include a femoral cut slot for guiding a saw blade to cut the femur and a tibial cut slot for guiding a saw blade to cut the tibia, the femoral and tibial cut slots being spaced a known, fixed distance, the method further comprising:

implanting femoral and tibial joint replacement components to replace the cut portions of the bones, the combined height of the femoral and tibial components being equal to the spacing between the femoral and tibial cut slots such that the joint is aligned the same after implantation of the prostheses as it was at the time the cuts were made.