Instruments for knee surgery and method of use

• US 20040039395A1
• Filed: 02/03/2003
• Published: 02/26/2004
• Est. Priority Date: 05/24/2002
• Status: Abandoned Application

• Current Assignee: Medicinelodge, Inc (Nelso Antolotti), Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Medicinelodge, Inc (Nelso Antolotti)
• Inventors: Farling, Toby, Justin, Daniel F., Goble, E. Marlowe, Hodorek, Robert A., Van Zile, Richard R., Tria, Alfred J. Jr., Coon, Thomas M., Smucker, Donald M., Gareiss, Warren Scott
• Application Number:
  US10/356,404
• Publication Number:
  US 20040039395A1
• 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

Abstract

The present invention comprises a set of instruments and a method for their use in preparing a knee joint to receive knee implants. The inventive instruments and method are generally suitable for knee joint surgery. Furthermore, they include features that make them suitable for performing minimally invasive knee surgery.

Claims

1. An apparatus for use with a tibia having a tibial axis, an articulating end, and a varus-valgus angle and a posterior slope angle associated with the articulating end, the apparatus comprising:

means for determining a desired position and orientation relative to the tibia; and

means for establishing a position reference on the tibia that records the desired position and orientation, the means for establishing a position reference permitting positive engagement by a bone cutting guide to orient the bone cutting guide to produce a bone cut relative to the position and orientation information.

2. The apparatus of claim 1 further comprising a position reference engaging cut guide having means for positively engaging the position reference to position the cut guide in a desired orientation and means for guiding a cutter to cut the articulating end of the tibia at a known orientation relative to the position reference.

3. The apparatus of claim 2 wherein the means for establishing a position reference comprises a pin guide having at least one bore along which a pin is inserted to record the position and orientation of the pin guide.

4. The apparatus of claim 1 wherein the means for determining a desired position and orientation comprises a body and a rod pivotably mounted to the body in one plane and rigidly mounted to the body in another plane such that the rod is alignable with the tibial axis to rigidly position the body at a desired varus-valgus angle while the body can be freely pivoted to position the body at a desired posterior slope angle independent of the rod position.

5. An apparatus for establishing a position reference on a proximal tibia having a proximal end, a distal end, an anterior side, a posterior side, a tibial axis, and a posterior slope angle and a varus-valgus angle associated with the proximal end, the apparatus comprising:

a tibial template having a body with a front face and an opposite back face, a placement arm extending from the front face and defining a longitudinal axis, the placement arm having an end for engaging the proximal end of the tibia to set the tibial template at a desired posterior slope angle, an alignment rod attached to the body, the alignment rod defining a longitudinal axis generally perpendicular to the placement arm axis, the alignment rod rotatable about an axis parallel to the placement arm axis and fixed relative to an axis perpendicular to the placement arm axis such that positioning the alignment rod parallel to the tibial axis orients the tibial template in a desired varus-valgus angle independent of the posterior slope of the template, the body further including at least one through passageway extending from the front face to the back face to guide the insertion of at least one reference pin into the proximal tibia to fix the reference pin in the tibia relative to the desired posterior slope and varus-valgus angles.

6. The apparatus of claim 5 further comprising a separate tibial cut guide having a body with a front face and an opposite back face, a cut guide for guiding a cutter to cut the proximal tibia, and at least one passageway extending through the body from the front face to the back face to engage the at least one reference pin inserted with the tibial template to orient the cut guide at the desired posterior slope and varus-valgus angles.

7. The apparatus of claim 6 wherein the at least one through passageway through the tibial template is at least two through passageways to guide the insertion of at least two reference pins and wherein the at least one through passageway through the tibial cut guide is at least two through passageways to engage the at least two reference pins.

8. The apparatus of claim 6 wherein the cut guide comprises a bounded slot through the body from the front face to the back face to guide a saw blade.

9. A method comprising the steps of:

positioning a tibial template adjacent a proximal end of a tibia, the tibial template having a position reference guide;

using the position reference guide to create a position reference on the tibia that permits positive engagement by a cut guide;

engaging a tibial cut guide with the position reference; and

guiding a cutter with the cut guide to cut the proximal tibia.

10. The method of claim 9 wherein the step of creating a position reference on the tibia comprises inserting at least two alignment pins through the guide and into the tibia.

11. The method of claim 10 further comprising the step of orienting the template at desired posterior slope and varus-valgus angles before inserting the alignment pins.

12. The method of claim 11 wherein the step of orienting the template includes engaging the proximal tibia with a placement arm to set the posterior slope of the tibial template and positioning an alignment arm parallel to the tibial axis to orient the cut guide in a desired varus-valgus angle independently of the posterior slope of the template.

13. The method of claim 9 further comprising the step of removing the template before mounting the cut guide.

14. A method for establishing a cut guide reference on a distal portion of a femur, the method comprising the steps of:

inserting a guide wire through a first incision formed in the soft tissue surrounding the knee and into the intramedullary canal of the femur so that the soft tissues are in a first position relative to the guide wire, a distal end of the guide wire being in the femur and a proximal end projecting from the femur through the first incision; and

manipulating the knee joint and surrounding soft tissues to a second position in which the proximal end of the guide wire projects from a second incision offset mediolaterally from the first incision.

15. The method of claim 14 further comprising the steps of:

attaching an extension piece to the guide wire to initially drive the rod through the first incision;

removing the extension while the knee is manipulated; and

reattaching the extension to the guide wire once it is positioned in the second incision.

16. The method of claim 14 further comprising the step of attaching a positioning apparatus to the guide wire after the knee is manipulated to place the guide wire in the second position.

17. The method of claim 14 wherein the first incision is in the parapatellar region of the knee joint and the second incision is formed in one of the medial and lateral sides of the femur.

18. A guide for establishing a cut guide orienting reference on a distal portion of a femur having a distal end, a femoral axis, a medial epicondyle, a lateral epicondyle, an epicondylar axis along a line from the medial epicondyle to the lateral epicondyle, a medial side surface, and a lateral side surface, the guide comprising:

a guide body;

means for establishing a desired external rotation angle relative to the femoral axis;

means for establishing a desired varus-valgus angle relative to the femoral axis; and

means for establishing a datum on one of the medial and lateral side surfaces of the femur that records the rotation angle and varus-valgus angle in such a way that the datum can be subsequently referenced by a bone cutting guide to produce a bone cut oriented relative to the angles.

19. The guide of claim 18 wherein the means for establishing a desired external rotation angle relative to the femoral axis comprises at least one probe for aligning with the epicondylar axis.

20. The guide of claim 18 wherein the means for establishing a datum on one of the medial and lateral side surfaces of the femur comprises a pin guide having at least one through bore for guiding the insertion of a reference pin into one of the medial and lateral side surfaces of the femur oriented relative to the desired external rotation and varus-valgus angles.

21. The guide of claim 20 wherein the means for establishing a desired varus-valgus angle relative to the femoral axis comprises mounting the pin guide on the guide body, the pin guide being rotatable relative to the guide body.

22. A femoral positioning guide for establishing a position reference on a femur to guide the cutting of the distal femur, the femur having a proximal end, a distal end, an anatomic axis from the proximal end to the distal end, an intramedullary canal along the anatomic axis, a medial epicondyle, a lateral epicondyle, an anterior surface and a posterior surface, the femoral positioning guide comprising:

a body having a closed end and an opposite open end with opposing sides able to straddle the distal end of the femur;

a pair of probes mounted on the opposing sides in coaxial alignment, the pair of probes being simultaneously alignable with the medial and lateral epicondyles;

an intramedullary rod mounted on the body, the intramedullary rod being engageable with the intramedullary canal; and

means for establishing a position reference on the femur that records a desired position and orientation in a way that permits positive engagement by a bone cutting guide to produce a bone cut relative to the position and orientation information.

23. The femoral positioning guide of claim 22 wherein the means for establishing a position reference on the femur is a pin guide mounted on the body, the pin guide having at least one passageway for guiding the placement of an alignment pin in the femur.

24. The femoral positioning guide of claim 23 wherein the pin guide is rotatably mounted on the body so that the pin guide can be rotated to a desired varus-valgus angle relative to the intramedullary rod.

25. The femoral positioning guide of claim 24 wherein the pin guide is also mounted for translation from a position nearer the body to a position further from the body, the pin guide further including a stylus able to reference the anterior surface of the femur to set the pin guide at a desired translated position relative to the body.

26. The femoral positioning guide of claim 25 wherein the body defines a circular arc, the positioning guide further comprising a plate translatably mounted on the body, the plate able to be translated along a portion of the arc, the pin guide and the intramedullary rod both being mounted on the plate so that they can be angled relative to the probes by translating the plate along the arc of the body while remaining in fixed angular relation to one another.

27. A method comprising the steps of:

positioning a femoral position guide adjacent a distal end of a femur, the femoral position guide having a position reference guide able to be positioned at a desired varus-valgus angle and at a desired external rotation angle;

determining a desired varus-valgus angle and a desired external rotation angle;

creating a position reference on the femur that permits positive engagement by a cut guide to orient the cut guide at the desired varus-valgus and external rotation angles;

engaging a cut guide with the position reference; and

guiding a cutter with the cut guide to cut the femur.

28. The method of claim 27 wherein the step of creating a position reference on the femur comprises inserting two reference pins into the femur with a pin guide.

29. The method of claim 28 further comprising the step of engaging the medial and lateral epicondyles of the femur to orient the pin guide at a desired external rotation angle.

30. The method of claim 29 further comprising the step of inserting an intramedullary rod into the intramedullary canal of the femur and angling the pin guide relative to the intramedullary rod to orient the pin guide at a desired varus-valgus angle.

31. The method of claim 30 further comprising the step of referencing the anterior femoral surface with a probe associated with the pin guide to position the pin guide at a desired anterior-posterior position.

32. An alignment pin for forming a position and orientation reference on a bone, the alignment pin comprising an elongate shaft having a distal segment having a first diameter, a proximal segment having a second diameter, and an intermediate segment between the distal and proximal segments, the intermediate segment having a diameter adjacent the distal segment smaller than the first diameter such that a distal shoulder is formed at the junction of the distal and intermediate segments, the intermediate segment further including a threaded portion proximal to the shoulder.

33. The alignment pin of claim 32 wherein the intermediate segment further includes a frangible portion proximal to the threaded portion that is breakable by bending the intermediate portion to separate the proximal segment from the intermediate segment.

34. The alignment pin of claim 33 wherein the frangible portion has a reduced diameter making it the weakest portion of the alignment pin.

35. The alignment pin of claim 32 wherein the intermediate segment has a diameter adjacent the proximal segment smaller than the second diameter such that a proximal shoulder is formed at the junction of the proximal and intermediate segments.

36. The alignment pin of claim 35 wherein the first diameter is smaller than the second diameter.

37. A method comprising the steps of:

providing at least one alignment pin for a bone, the bone having a proximal end, a distal end, a bone axis running from the proximal end to the distal end, an anterior side, a distal side, a medial side, and a lateral side;

orienting the pin generally transverse to the bone axis in a first plane at a desired first angle relative to the bone and in a second plane at a desired second angle relative to the bone;

inserting the pin into the bone generally transverse to the bone axis to record the desired angles;

engaging the pin with a cut guide to orient the cut guide relative to the desired angles; and

engaging a cutter with the cut guide to cut the bone.

38. The method of claim 37 wherein the step of providing at least one alignment pin comprises providing at least two alignment pins.

39. The method of claim 37 further comprising the steps of:

providing the alignment pin with a distal segment having a first diameter and a segment adjacent the distal segment having a diameter smaller than the first diameter such that a distal shoulder is formed at the junction of the two segments; and

bottoming the cut guide on the shoulder.

40. The method of claim 39 further comprising the step of providing each alignment pin with a threaded segment proximal to the shoulder;

and

threading a nut on the threaded segment to secure the cut guide to the pins.

41. The method of claim 39 further comprising the step of providing the alignment pin with a frangible segment proximal to the shoulder;

and

breaking the pin at the frangible segment after inserting the pin into the bone.

42. The method of claim 39 further comprising the steps of:

providing the alignment pin with a proximal segment having a second diameter and a segment adjacent the proximal segment having a diameter smaller than the second diameter such that a proximal shoulder is formed at the junction of the two segments; and

inserting the pin through a pin guide and into the bone until the proximal shoulder abuts the pin guide.

43. The method of claim 42 further comprising the steps of:

providing the alignment pin with a frangible segment below the proximal shoulder;

breaking the pin at the frangible segment;

removing the proximal portion of the pin; and

removing the pin guide.

44. The method of claim 37 wherein the cut guide comprises a body having a front face and a back face, the body including a slot to engage the alignment pin to orient the template at the desired orientation, the method further comprising the step of sliding the cut guide along the pin with the pin engaging the slot to adjust the position of the cut guide while maintaining its orientation relative to the angles.

45. The method of claim 44 wherein the cut guide includes a perimeter with saw blade guiding surfaces formed on the perimeter and further wherein the step of engaging a cutter with the cut guide comprises engaging the saw blade with the blade guiding surfaces to cut corresponding surfaces in the bone.

46. The method of claim 37 further comprising the step of attaching a modular cutter guiding surface to the cut guide and engaging a cutter with the cutter guiding surface to guide the cut on the bone.

47. The method of claim 46 wherein the cut guide includes a perimeter and a plurality of attachments formed around the perimeter, the modular cutter guiding surface being attachable to each of the plurality of attachments, the method further comprising the steps of sequentially attaching the modular cutter guiding surface to each of the plurality of attachments and making a sequential cuts on the bone corresponding to each attachment.

48. An apparatus for guiding a cutter to cut a femur having a medial side, a lateral side, and a reference on one of the medial and lateral sides establishing a desired orientation for a bone cut, the apparatus comprising:

a template for guiding a cutter to cut the femur; and

means for engaging the reference to orient the template to guide a cutter to cut the femur at the desired orientation.

49. A template for guiding a cutter to cut a femur having a medial side, a lateral side, and an alignment pin inserted into one of the medial and lateral sides to establish a desired orientation for a bone cut, the template comprising:

a body having a front face and a back face, the body including a hole to engage the alignment pin to orient the template at the desired orientation; and

a saw guide for guiding a saw blade to cut the femur.

50. The template of claim 49 wherein the hole comprises a slot through the body from the front face to the back face, the slot permitting the template to be slid along the alignment pin.

51. The template of claim 49 wherein the template comprises a substantially U-shaped, plate-like body having a perimeter, the saw blade guide including saw blade guiding surfaces formed on the perimeter.

52. The template of claim 51 wherein the saw guiding surfaces include anterior, anterior chamfer, distal, posterior chamfer, and posterior saw blade guiding surfaces.

53. The template of claim 51 further including a bounded saw guide slot for guiding a saw blade.

54. The template of claim 54 wherein the saw guide slot is formed in a modular cut guide mounted on the template.

55. The template of claim 54 further including a plurality of pairs of cut guide mounting holes around its perimeter, each pair of mounting holes corresponding to a desired cut plane, and a modular cut guide mountable in each pair of mounting holes.

56. A template for guiding a cutter to cut a femur having at least one alignment pin inserted into it to establish a desired orientation for a bone cut, the template comprising:

a body having a front face and a back face, the body including at least one alignment hole to engage the at least one alignment pin to orient the template at the desired orientation, the body further including a slide engaging surface generally transverse to the alignment hole, the slide engaging surface having a longitudinal axis;

a slide having a first end, a second end, and a longitudinal axis from the first end to the second end, the slide being mounted for translation along the slide engaging surface of the body; and

an implement having a working end being mounted on the slide with the working end in fixed known relationship to the slide.

57. The template of claim 56 further comprising a slide lock mounted on the body and actuable to lock the slide in a desired axial position along the slide engaging surface.

58. The template of claim 56 further comprising a plurality of implements having different working ends and being interchangeably mountable on the slide in fixed known relationship to the slide.

59. The template of claim 58 wherein the plurality of implements includes a distal cut stylus having a reference surface engageable with the femur to set the axial position of the slide and wherein the plurality of implements includes a cut guide interchangeable with the stylus to cut the femur with reference to the axial position of the slide.

60. The template of claim 58 wherein the plurality of implements includes a distal cut guide, an anterior cut guide, and a posterior cut guide.

61. The template of claim 56 wherein the slide engaging surface is an axial through bore and the slide is mounted for translation within the axial through bore.

62. The template of claim 56 wherein the implement includes a mounting shaft and a shoulder adjacent the shaft, the shoulder bottoming on the slide to position the working end in fixed known relationship to the slide.

63. The template of claim 62 wherein the slide has an axial through bore for receiving the mounting shaft.

64. A method comprising the steps of:

positioning a template on an alignment pin inserted into a bone to establish a desired orientation for a bone cut, the template including a body and a slide mounted for translation relative to the body;

mounting a probe in fixed known relationship to the slide;

translating the probe and slide relative to the body until the probe contacts a landmark on the bone;

locking the slide;

removing the probe from the slide and replacing it with a cut guide mounted in fixed known relationship to the slide; and

guiding a cutter with the cut guide to cut the bone.

65. A set guide for inserting at least one alignment pin into a human femur having anterior, distal, and posterior bone surfaces simultaneously viewable fluoroscopically from a sagittal direction, the set guide comprising a body having a profile shape substantially the same as that of a sagittal view of a human distal femur, the body including anterior, distal, and posterior guide surfaces, the guide having at least one through hole for guiding an alignment pin, the set guide being fluoroscopically orientable with the distal femur by aligning the anterior, distal, and posterior guide surfaces with the anterior, distal, and posterior bone surfaces.

66. The set guide of claim 65 wherein the body is made of a radiolucent material.

67. A method comprising the steps of:

positioning a pin guide having a profile shape substantially the same as the profile shape of a bone adjacent the side of a bone;

aligning the pin guide profile with the bone profile;

inserting at least one alignment pin through the pin guide and into the bone to record the aligned position of the pin guide;

removing the pin guide;

engaging the at least one pin with a cut guide to orient the cut guide relative to the aligned position of the pin guide; and

guiding a cutter with the cut guide to cut the bone relative to the aligned position of the pin guide.

68. The method of claim 67 wherein the step of inserting at least one alignment pin comprises inserting at least two alignment pins and the step of engaging the at least one pin with a cut guide comprises engaging the at least two pins.

69. The method of claim 67 wherein the step of aligning the pin guide profile with the bone profile comprises using live fluoroscopy to aid in visualizing the alignment.

70. The method of claim 67 wherein the pin guide comprises at least one elongate pin bore for guiding the insertion of the at least one alignment pin and wherein the step of aligning the pin guide profile with the bone profile comprises viewing down the pin bore to determine when the bore is oriented normal to the viewing angle.