Instrumentation for minimally invasive unicompartmental knee replacement

• US 20030100907A1
• Filed: 11/27/2002
• Published: 05/29/2003
• Est. Priority Date: 11/28/2001
• Status: Active Grant

• Current Assignee: MicroPort Orthopedics Holdings, Inc. (MicroPort Scientific Corp.)
• Original Assignee: Wright Medical Technology Incorporated (Stryker Corporation)
• Inventors: Hartdegen, Vernon R., Fencl, Robert M., Rosa, Richard A., Stookey, Eric A., Harris, Brian R. Jr.
• Granted Patent: US 7,060,074 B2
• Time in Patent Office: Days
• US Class Current: 606/86
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1675 for the knee

Abstract

Instrumentation for use in minimally invasive unicompartmental knee replacement includes a tibial cutting guide for establishing a planar surface along a tibial plateau and a tibial stylus having an anatomic contour for controlling the depth of the planar surface along the tibial plateau. The instrumentation further comprises a posterior resection block for preparing a posterior femoral resection, with a forward portion of the posterior resection block having a configuration corresponding to the configuration of a prosthetic femoral component. Instrumentation comprising a resection block and a resurfacing guide are provided for surgically preparing a femoral condyle to receive a prosthetic femoral component. The instrumentation further includes a resurfacing guide and a resurfacing instrument for resurfacing a femoral condyle to a controlled depth. Instrumentation is provided for intramedullary alignment of femoral instruments. Also, instrumentation is provided for preparing the femur and tibia to receive fixation structure of prosthetic femoral and tibial components.

Claims

1. Instrumentation for establishing the location of a tibial resection along a tibial plateau in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

a tibial cutting guide for positioning anteriorly along a tibia and having a planar resection slot extending therethrough from anterior to posterior, said tibial cutting guide being movable along the long axis of the tibia to vary the location of said resection slot along the tibia, said resection slot being adapted to receive a cutting member therethrough to prepare a planar surface along a tibial plateau of the tibia;

and

a tibial stylus for attachment to said tibial cutting guide and comprising a stylus arm positionable to rest on the tibial plateau prior to preparation of the planar surface, said stylus arm being positionable to rest on the tibial plateau via movement of the tibial cutting guide along the long axis of the tibia to establish a location for said resection slot corresponding to a predetermined depth for the planar surface below the level where said stylus arm rests on the tibial plateau, said stylus arm having a curvature from anterior to posterior to accommodate the anatomic curvature of the corresponding femoral condyle.

2. The instrumentation recited in claim 1 wherein said tibial cutting guide includes one or more fixation holes adapted to receive one or more fixation elements for fixating said tibial cutting guide to the tibia.

3. The instrumentation recited in claim 2 wherein said tibial cutting guide includes a plurality of fixation holes and further including at least one fixation element insertable in one of said fixation holes for penetrating the tibia to fixate said tibial cutting guide thereto.

4. The instrumentation recited in claim 3 wherein said tibial cutting guide is removable from said at least one fixation element when said at least one fixation element penetrates the tibia, said tibial cutting guide being repositionable on said at least one fixation element with said at least one fixation element inserted in another one of said plurality of fixation holes to adjust the position of said tibial cutting guide.

5. The instrumentation recited in claim 1 wherein said predetermined depth is in the range of 2 mm to 8 mm.

6. The instrumentation recited in claim 1 wherein said stylus arm is a first stylus arm establishing a first location for said resection slot corresponding to a predetermined first depth for the planar surface and said tibial stylus further includes a second stylus arm alternatively positionable to rest on the tibial plateau prior to preparation of the planar surface, said second stylus arm being positionable to rest on the tibial plateau via movement of said tibial cutting guide along the long axis of the tibia to establish a second location for said resection slot, different from said first location, corresponding to a predetermined second depth for the planar surface, different from said first depth, below the level where said second stylus arm rests on the tibial plateau, said second stylus arm having a curvature from anterior to posterior to accommodate the anatomic curvature of the corresponding femoral condyle.

7. The instrumentation recited in claim 1 wherein said resection slot is positionable perpendicular to the long axis of the tibia.

8. The instrumentation recited in claim 1 wherein said resection slot is positionable to extend posteriorly at a downward angle relative to a plane perpendicular to the long axis of the tibia.

9. The instrumentation recited in claim 7 and further comprising a tibial alignment guide forfixation to the corresponding leg and including a shaft extending along the long axis of the tibia when said alignment guide is fixated to the leg, said tibial cutting guide comprising a channel extending therethrough from top to bottom for slidably receiving said shaft, said channel being perpendicular to said resection slot such that said resection slot is perpendicular to the long axis of the tibia when said shaft is received in said channel to establish the planar surface perpendicular to the long axis of the tibia.

10. The instrumentation recited in claim 8 and further comprising a tibial alignment guide for fixation to the corresponding leg and including a shaft extending along the long axis of the tibia when said alignment guide is fixated to the leg, said tibial cutting guide comprising a channel extending therethrough from top to bottom for slidably receiving said shaft, said channel extending posteriorly from top to bottom non-perpendicular to said resection slot such that said resection slot is posteriorly angled downwardly relative to the plane perpendicular to the long axis of the tibia when said shaft is received in said channel to establish the planar surface at a downward posterior angle relative to the plane perpendicular to the long axis of the tibia.

11. The instrumentation recited in claim 10 wherein said downward posterior angle is five degrees.

12. The instrumentation recited in claim 10 wherein said downward posterior angle is seven degrees.

13. The instrumentation recited in claim 1 and further including an alignment module comprising an angled tab having a planar foot insertable in said slot with a close fit and a check rod mounted to said tab, said check rod extending perpendicular to said foot and being alignable with the long axis of the tibia.

14. The instrumentation recited in claim 1 wherein said tibial cutting guide includes a posterior wall for positioning anteriorly adjacent the tibia and said posterior wall has an anatomic configuration to accommodate the anatomic configuration of the tibia.

15. A posterior resection block for preparing a posterior femoral resection in a minimally invasive unicompartmental knee replacement procedure, said posterior resection block comprising

a housing including a forward portion to be disposed adjacent the distal aspect of a femoral condyle with the corresponding knee in flexion, a base plate extending rearwardly from said forward portion for positioning between the posterior aspect of the femoral condyle and a proximal surface of the corresponding tibial plateau, and a planar resection slot extending through said housing from anterior to posterior for receiving a cutting member to effect a planar resected surface along the posterior aspect of the femoral condyle, said forward portion having a configuration and size corresponding to a configuration and size of at least a distal portion of a prosthetic femoral component.

16. The posterior resection block recited in claim 15 wherein said forward portion has a planar surface to be disposed adjacent the distal aspect and said planar surface of said forward portion is perpendicular to said base plate.

17. The posterior resection block recited in claim 15 wherein said configuration of said forward portion corresponds to a medial-lateral and anterior-posterior configuration of at least the distal portion of the prosthetic femoral component.

18. The posterior resection block recited in claim 17 wherein said forward portion is angled in the medial-lateral direction relative to said resection slot.

19. The posterior resection block recited in claim 15 and further including at least one fixation hole in said forward portion for receiving a fixation element to fixate said housing to the femoral condyle.

20. Instrumentation for surgically preparing a femoral condyle to receive a prosthetic femoral component in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

a resection block for fixation to a femur with the knee in flexion, said resection block having a planar resection slot for receiving a cutting member to effect a planar surface along a posterior aspect of a femoral condyle of the femur;

and

a resurfacing guide for fixation to the femur, said resurfacing guide including a rail member externally delineating a distal aspect of the femoral condyle to be resurfaced by a resurfacing instrument.

21. The instrumentation recited in claim 20 wherein said resurfacing guide is attachable to said resection block to form a one-piece assembly prior to fixation of said resection block to the femur.

22. The instrumentation recited in claim 21 wherein said rail member is angled in a medial-lateral direction relative to the plane of said resection slot.

23. The instrumentation recited in claim 20 wherein said resection block comprises a base plate for positioning between the posterior aspect of the femoral condyle and a planar proximal surface of the corresponding tibial plateau with the knee in flexion to effect positioning of said resection slot parallel to the planar proximal surface.

24. The instrumentation recited in claim 20 and further including a handle removably attachable to said resection block.

25. The instrumentation recited in claim 20 wherein said rail member delineates a configuration corresponding to the configuration of the prosthetic femoral component.

26. The instrumentation recited in claim 20 wherein said rail member comprises a protrusion forming a stylus for contacting the femoral condyle to establish the correct position for said resurfacing guide on the femoral condyle.

27. The instrumentation recited in claim 20 wherein said rail member comprises a posterior portion having planar upper and lower surfaces for abutment with the planar surface formed along the posterior aspect of the femoral condyle and with a planar proximal surface of the corresponding tibial plateau, respectively, with the knee in flexion.

28. The instrumentation recited in claim 20 and further comprising an alignment module including an angled tab having a planar foot insertable in said resection slot with a close fit and a check rod mounted to said tab, said check rod extending perpendicular to the plane of said foot and being alignable with the long axis of the corresponding tibia with the knee in flexion.

29. Instrumentation for surgically preparing a femoral condyle to receive a prosthetic femoral component in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

a resection block for fixation to a femur with the knee in flexion, said resection block having a slot for receiving a cutting member to surgically prepare a posterior aspect of a femoral condyle of the femur;

and

a resurfacing guide for fixation to the femur, said resurfacing guide including a rail member extending along at least the medial, lateral and anterior periphery of an area on a distal aspect of the femoral condyle to be surgically prepared with a resurfacing instrument.

30. Instrumentation for surgically resurfacing a femoral condyle to receive a prosthetic femoral component in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

a resurfacing guide for attachment to a femur and comprising a rail member externally delineating an area of a femoral condyle of the femur that is to be surgically resurfaced to receive a prosthetic femoral component, said resurfacing guide having an abutment wall;

and

a resurfacing instrument having a tissue removing surface for removing anatomical tissue from the delineated area of the femoral condyle, said tissue removing surface being movable along the delineated area to remove anatomical tissue therefrom, said resurfacing instrument having an engagement wall for contacting said abutment wall to limit the depth to which anatomical tissue is removed.

31. The instrumentation recited in claim 30 wherein said abutment wall is defined by a front surface of said rail member.

32. The instrumentation recited in claim 30 and further including a slide carried by and movable relative to said rail member along the delineated area, said slide having a window communicating with the delineated area and through which said tissue removing surface is introduced to access the delineated area, said slide moving along said rail member as said tissue removing surface is moved along the delineated area.

33. The instrumentation recited in claim 32 wherein said abutment wall is defined by a surface of said slide.

34. The instrumentation recited in claim 30 wherein said resurfacing instrument includes a ledge spaced from said tissue removing surface and said engagement wall is defined by said ledge.

35. The instrumentation recited in claim 30 wherein said resurfacing instrument comprises a tissue removing member defining said tissue removing surface and having a side wall extending from said tissue removing surface to said ledge, said side wall forming an abutment engageable with an inside surface of said rail member.

36. The instrumentation recited in claim 30 wherein said tissue removing surface is planar.

37. The instrumentation recited in claim 30 wherein said rail member has a surface for positioning adjacent the femoral condyle and said tissue removing surface protrudes beyond said surface of said rail member a predetermined distance when said engagement wall is in contact with said abutment wall.

38. The instrumentation recited in claim 37 wherein said predetermined distance corresponds to a predetermined depth to which the anatomical tissue is removed.

39. The instrumentation recited in claim 30 wherein said resurfacing instrument is adapted to move said tissue removing surface via a powered surgical handpiece.

40. The instrumentation recited in claim 30 wherein said resurfacing instrument is adapted to move said tissue removing surface manually.

41. The instrumentation recited in claim 30 wherein said resurfacing instrument comprises a rasp.

42. The instrumentation recited in claim 30 wherein said resurfacing instrument comprises an end mill cutter.

43. The instrumentation recited in claim 30 wherein said resurfacing instrument comprises a reamer.

44. The instrumentation recited in claim 30 wherein said resurfacing instrument comprises a burr.

45. The instrumentation recited in claim 30 wherein said resurfacing guide comprises a stylus for contacting the femoral condyle to prevent said resurfacing guide from rolling over into hyperextension.

46. The instrumentation recited in claim 45 wherein said stylus maintains a proper depth of resurfacing.

47. The instrumentation recited in claim 45 wherein said stylus provides an indication of where the prosthetic femoral component will transition into the femoral condyle.

48. The instrumentation recited in claim 30 wherein said resurfacing guide is adapted to externally delineate at least an area of a distal aspect of the femoral condyle.

49. Instrumentation for intramedullary alignment of femoral instruments in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

an intramedullary rod for insertion in the intramedullary canal of a femur;

a resection block for fixation to the femur with the knee in flexion, said resection block having a planar slot for receiving a cutting member to establish a planar surface along a posterior aspect of a femoral condyle of the femur and a channel extending through said resection block in a medial-lateral direction parallel to said slot; and

a linking instrument comprising a vertical linking bar and a horizontal linking bar extending from said vertical linking baratan angle, said horizontal linking bar being receivable in said channel to couple said linking instrument to said resection block to form a one-piece construct, said vertical linking bar being mountable to said intramedullary rod in a perpendicular orientation thereto to couple said construct to said intramedullary rod.

50. The instrumentation recited in claim 49 wherein said vertical linking bar has an upper end including a fixture with a passage extending in an anterior-posterior direction for slidably receiving said intramedullary rod.

51. The instrumentation recited in claim 49 wherein said horizontal linking bar includes a socket slidably receiving said vertical linking bar.

52. The instrumentation recited in claim 51 and further including a detent in said socket for securing said vertical linking bar.

53. The instrumentation recited in claim 49 wherein said vertical linking bar is perpendicular to said horizontal linking bar.

54. The instrumentation recited in claim 49 wherein said intramedullary rod has a plurality of fins for seating within the intramedullary canal.

55. Instrumentation for preparing a femur to receive a femoral fixation peg and a femoral fixation fin of a prosthetic femoral component to be implanted on a surgically prepared femoral condyle in knee replacement surgery, said instrumentation comprising

a trial femoral component for fixation on the prepared femoral condyle, said trial femoral component having a bore hole extending therethrough at a location corresponding to the location for the femoral fixation peg, said trial femoral component having a slot extending therethrough at a location corresponding to the location for the femoral fixation fin, said bore hole being adapted to receive a cutting member to form a peg hole in the femur for the femoral fixation peg of the prosthetic femoral component;

and

a femoral fin punch comprising a peg element for insertion in said bore hole to protrude from said trial femoral component into the peg hole formed in the femur and a fin element for insertion in said slot to protrude from said trial femoral component into the femur to form a slot in the femur for receiving the femoral fixation fin.

56. The instrumentation recited in claim 55 wherein said slot in said trial femoral component comprises an anterior slot segment extending anteriorly from said bore hole and a posterior slot segment extending posteriorly from said bore hole, and said fin element comprises an anterior fin element extending anteriorly from said peg element and a posterior fin element extending posteriorly from said peg element.

57. The instrumentation recited in claim 55 and further including a cutting member for insertion in said bore hole to protrude from said trial femoral component into the femur to form the peg hole in the femur and wherein said cutting member includes a stop for engaging said trial femoral component to limit penetration of said cutting member into the femur.

58. The instrumentation recited in claim 55 and further including a handle having a forward end removably engageable with said bore hole to effect positioning of said trial femoral component on the prepared femoral condyle.

59. The instrumentation recited in claim 58 wherein said handle comprises a wedge element movable from a retracted position in which said forward end is disposed forwardly of said wedge element for insertion of said forward end in said bore hole to an extended position in which said wedge element is extended forwardly for insertion into said bore hole alongside said forward end to releasably secure said forward end in said bore hole with a wedging action.

60. The instrumentation recited in claim 59 wherein said wedge element is biased to said extended position.

61. The instrumentation recited in claim 55 wherein said fin element includes anterior and posterior edge surfaces engageable with end surfaces of said slot, respectively, to limit the depth of insertion of said fin element in the femur.

62. Instrumentation for preparing a tibia to receive posterior and anterior tibial fixation pegs of a prosthetic tibial component to be implanted on a surgically prepared tibial plateau in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising

a trial tibial component for placement on the prepared tibial plateau, said trial tibial component having a posterior bore hole therethrough at a location corresponding to the location of the posterior tibial fixation peg and an anterior bore hole therethrough at a location corresponding to the location of the anterior tibial fixation peg;

a guide for being disposed on said trial tibial component with a sleeve of said guide aligned with said posterior bore hole, said sleeve extending at an angle to the prepared tibial plateau; and

a cutting member insertable in said sleeve and through said posterior bore hole for penetration into the tibia to form a posterior peg hole in the tibia for receiving the posterior tibial fixation peg, said cutting member including a stop for engagement with said sleeve to limit penetration of said cutting member into the tibia.

63. The instrumentation recited in claim 62 wherein said sleeve is angled anteriorly relative to the prepared tibial plateau.

64. The instrumentation recited in claim 63 wherein said sleeve is angled about 50 degrees relative to the prepared tibial plateau.

65. The instrumentation recited in claim 62 wherein said cutting member is insertable through said anterior bore hole for penetration into the tibia to form an anterior peg hole in the tibia for receiving the anterior tibial fixation peg, said cutting member including a depth stop to limit insertion of said cutting member through said anterior bore hole to a predetermined depth.

66. The instrumentation recited in claim 65 wherein said depth stop includes indicia on said cutting member.

67. The instrumentation recited in claim 62 wherein said guide is removably attachable to said trial tibial component.