Methods of minimally invasive unicompartmental knee replacement

• US 20030100906A1
• 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 7,141,053 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

A method of minimally invasive unicompartmental knee replacement includes accessing a knee through a minimal incision, forming a planar surface along a tibial plateau of the knee, forming a planar posterior surface along a posterior aspect of the corresponding femoral condyle, resurfacing a distal aspect of the femoral condyle to form a resurfaced area having a curved portion, implanting a prosthetic tibial component on the planar surface along the tibial plateau and implanting a prosthetic femoral component on the prepared surface of the femoral condyle formed by the planar posterior surface and the resurfaced area. The curved portion of the resurfaced area has an anterior-posterior curvature corresponding to a fixation surface of the prosthetic femoral component. Prior to implantation, the femur and tibia are prepared to receive fixation structure of the femoral and tibial components.

Claims

1. A method of establishing the depth for a planar surface to be made along a tibial plateau to receive a prosthetic tibial component in a minimally invasive unicompartmental knee replacement procedure, comprising the steps of

accessing a knee through a minimal incision;

mounting a tibial cutting guide anteriorly along the tibia of the knee for movement along the long axis of the tibia;

mounting a stylus arm on the tibial cutting guide such that a resection slot of the tibial cutting guide is located a predetermined depth below the stylus arm;

positioning the stylus arm upon a tibial plateau of the tibia such that the resection slot is located the predetermined depth below the tibial plateau, said step of positioning including accommodating the corresponding femoral condyle in an anatomic contour of the stylus arm;

inserting a cutting member through the resection slot and into the tibia to effect a planar surface along the tibial plateau at the predetermined depth; and

withdrawing the cutting member from the resection slot.

2. The method recited in claim 1 wherein said step of mounting a tibial cutting guide includes mounting the tibial cutting guide on a tibial alignment guide.

3. The method recited in claim 1 wherein said step of mounting a stylus arm includes mounting the stylus arm on the tibial cutting guide such that the resection slot is located 2 mm to 8 mm below the stylus arm.

4. The method recited in claim 1 wherein said step of inserting includes inserting a planar saw through the resection slot.

5. The method recited in claim 1 wherein said step of mounting a tibial cutting guide includes mounting the tibial cutting guide such that the resection slot is perpendicular to the long axis of the tibia.

6. The method recited in claim 1 wherein said step of mounting a tibial cutting guide includes mounting the tibial cutting guide such that the resection slot extends posteriorly at a downward angle relative to a plane perpendicular to the long axis of the tibia.

7. A method of surgically preparing a femoral condyle to receive a prosthetic femoral component in a minimally invasive unicompartmental knee replacement procedure, comprising the steps of

accessing a knee through a minimal incision;

positioning a femoral resurfacing guide on a femoral condyle of the knee to externally delineate an area of the femoral condyle to be resurfaced to receive a prosthetic femoral component, said step of positioning including externally delineating the area with a rail member of the femoral resurfacing guide; and

removing anatomical tissue from the externally delineated area by moving a tissue removing instrument along the externally delineated area within the confines of the rail member.

8. The method recited in claim 7 wherein said step of removing includes removing anatomical tissue with a rasp.

9. The method recited in claim 7 wherein said step of removing includes removing anatomical tissue with an end mill cutter.

10. The method recited in claim 7 wherein said step of removing includes removing anatomical tissue with a reamer.

11. The method recited in claim 7 wherein said step of removing includes removing anatomical tissue with a burr.

12. The method recited in claim 7 wherein said step of removing includes contacting an engagement wall of the tissue removing instrument with an abutment wall of the femoral resurfacing guide to limit removal of anatomical tissue to a predetermined depth.

13. The method recited in claim 12 wherein said step of contacting includes contacting the engagement wall with a surface of the rail member defining the abutment wall.

14. The method recited in claim 12 wherein said step of removing includes accessing the externally delineated area by introducing the tissue removing instrument through a window of a slide movably carried by the rail member and moving the slide along the rail member as the tissue removing instrument is moved along the externally delineated area, and said step of contacting includes contacting the engagement wall with a surface of the slide defining the abutment wall.

15. A method of surgically preparing a femoral condyle to receive a prosthetic femoral component in a minimally invasive unicompartmental knee replacement procedure, comprising the steps of

accessing a knee through a minimal incision;

establishing a planar surface on a posterior aspect of a femoral condyle of the knee;

positioning a femoral resurfacing guide on the femoral condyle to externally delineate a distal aspect of the femoral condyle;

removing anatomical tissue from the externally delineated distal aspect; and

removing the femoral resurfacing guide from the femoral condyle.

16. The method recited in claim 15 wherein said step of positioning includes externally delineating the distal aspect at least medially, laterally and anteriorly with a rail member of the femoral resurfacing guide.

17. The method recited in claim 16 wherein said step of removing anatomical tissue includes moving a tissue removing instrument along the externally delineated distal aspect.

18. The method recited in claim 17 wherein said step of removing includes accessing the externally delineated distal aspect by introducing the tissue removing instrument through a window of a slide movably carried by the rail member and moving the slide along the rail member in response to moving the tissue removing member along the externally delineated distal aspect.

19. The method recited in claim 15 wherein said step of removing anatomical tissue includes retaining the anatomic geometry of the externally delineated distal aspect.

20. The method recited in claim 15 wherein said step of removing anatomical tissue includes manually moving the tissue removing instrument along the externally delineated distal aspect.

21. The method recited in claim 15 wherein said step of removing anatomical tissue includes mechanically moving the tissue removing instrument along the externally delineated distal aspect.

22. A method of surgically preparing a femoral condyle to receive a prosthetic femoral component in a minimally invasive unicompartmental knee replacement procedure, comprising the steps of

accessing a knee through a minimal incision;

positioning a resection block on the femur of the knee with the knee in flexion such that a planar resection slot through the resection block extends in a plane along a posterior aspect of a femoral condyle of the femur;

positioning a femoral resurfacing guide on the femoral condyle with the knee in flexion such that the femoral resurfacing guide externally delineates a distal aspect of the femoral condyle;

inserting a cutting member through the resection slot to effect a planar surface along the posterior aspect of the femoral condyle; and

moving a tissue removing member within the externally delineated distal aspect to effect a resurfaced area along the distal aspect of the femoral condyle merging with the planar surface.

23. The method recited in claim 22 and further including the step of fixating the resection block and the femoral resurfacing guide to the femur subsequent to said steps of positioning and prior to said steps of inserting and moving.

24. The method recited in claim 22 and further including the step of attaching the resection block to the femoral resurfacing guide prior to said steps of positioning.

25. The method recited in claim 22 wherein said steps of positioning the resection block includes inserting a planar tab of an alignment module in the resection slot, aligning a check rod of the alignment module, which extends perpendicular to the tab, parallel to the long axis of the corresponding tibia to establish a position for the resection slot, and withdrawing the tab from the resection slot after proper positioning of the resection block is established.

26. The method recited in claim 25 wherein said step of positioning the resection block is performed with the femoral resurfacing guide assembled with the resection block to form a one-piece construct.

27. The method recited in claim 22 wherein said steps of positioning include inserting an intramedullary rod in the intramedullary canal of the femur, coupling a linking instrument to the resection block by inserting a horizontal linking bar of the linking instrument in a channel of the resection block that extends parallel to the resection slot, and coupling the intramedullary rod to a vertical linking bar of the linking instrument that extends at an angle to the horizontal linking bar such that the vertical linking bar is perpendicular to the intramedullary rod.

28. The method recited in claim 27 wherein said steps of coupling are performed with the femoral resurfacing guide assembled with the resection block to form a one-piece construct.

29. A method of minimally invasive unicompartmental knee replacement comprising the steps of

accessing a knee through a minimal incision;

forming a planar surface along a tibial plateau of the knee;

forming a planar posterior surface along a posterior aspect of the corresponding femoral condyle;

resurfacing a distal aspect of the femoral condyle to form a resurfaced area including a curved portion having an anterior-posterior curvature extending from the planar posterior surface and a planar portion extending from the curved portion;

implanting a prosthetic tibial component on the planar surface formed along the tibial plateau; and

implanting a prosthetic femoral component on the femoral condyle with a planar rearward section of a fixation surface of the femoral component disposed on the planar posterior surface, a planar forward section of the fixation surface disposed on the planar portion of the resurfaced area and a curved intermediate section of the fixation surface disposed on the curved portion of the resurfaced area.

30. The method recited in claim 29 wherein said step of forming a planar posterior surface includes forming the planar posterior surface parallel to the planar surface formed along the tibial plateau.

31. The method recited in claim 30 wherein said step of forming a planar surface along the tibial plateau includes forming the planar surface along the tibial plateau perpendicular to the long axis of the tibia of the knee.

32. The method recited in claim 30 wherein said step of forming a planar surface along the tibial plateau includes forming the planar surface along the tibial plateau at a downward posterior angle relative to a plane perpendicular to the long axis of the tibia of the knee.

33. A method of minimally invasive unicompartmental knee replacement, comprising the steps of

accessing a knee through a minimal incision;

forming a planar surface along a tibial plateau of the knee;

forming a planar posterior surface along a posterior aspect of the corresponding femoral condyle;

resurfacing a distal aspect of the femoral condyle to form a resurfaced area having a plurality of tangent radii in a sagittal plane matching the fixation surface of a prosthetic femoral component;

implanting a prosthetic tibial component on the planar surface formed along the tibial plateau; and

implanting the prosthetic femoral component on the prepared femoral surface formed by the planar posterior surface and the resurfaced area.

34. A method of minimally invasive unicompartmental knee replacement, comprising the steps of

accessing a knee through a minimal incision;

forming a planar surface along a tibial plateau of the knee;

forming a planar posterior surface along a posterior aspect of the corresponding femoral condyle;

resurfacing a distal aspect of the femoral condyle extending from the planar posterior surface at a medial-lateral angle to obtain a resurfaced area;

implanting a prosthetic tibial component on the planar surface formed along the tibial plateau; and

implanting a prosthetic femoral component on the prepared femoral surface formed by the planar posterior surface and the resurfaced area.

35. A method of preparing a femur to receive a femoral fixation peg and a femoral fixation fin of a prosthetic femoral component to be implanted on a prepared femoral condyle of the femur in a minimally invasive unicompartmental knee replacement, comprising the steps of

accessing the prepared femoral condyle through a minimal incision;

attaching a trial femoral component to the prepared femoral condyle;

inserting a cutting member in a bore hole extending through the trial femoral component at a location corresponding to the location for the femoral fixation peg of the prosthetic femoral component;

advancing the cutting member through the bore hole and into the femur to form a peg hole in the femur for receiving the femoral fixation peg;

withdrawing the cutting member from the bore hole;

aligning a femoral fin punch with the trial femoral component to align a peg element of the femoral fin punch with the bore hole of the trial femoral component and a fin element of the femoral fin punch with a slot extending through the trial femoral component at a location corresponding to the location for the femoral fixation fin of the prosthetic femoral component;

advancing the peg element through the bore hole and into the peg hole;

advancing the fin element through the slot and into the femur to form a slot in the femur for receiving the femoral fixation fin; and

withdrawing the femoral fin punch from the trial femoral component.

36. The method recited in claim 35 wherein said step of advancing the fin element includes engaging anterior and posterior edge surfaces of the fin element with end surfaces of the slot of the trial femoral component to limit penetration of the fin element into the femur.

37. The method recited in claim 35 wherein said step of advancing the cutting member includes engaging a stop on the cutting member with the trial femoral component to limit penetration of the cutting member into the femur.

38. The method recited in claim 35 and further including, prior to said step of aligning, the step of inserting a cutter along the slot of the trial femoral component and into the femur to initially prepare the femur for the fin element of the femoral fin punch.

39. A method of preparing a tibia to receive anterior and posterior tibial fixation pegs of a prosthetic tibial component to be implanted on a prepared tibial plateau in a minimally invasive unicompartmental knee replacement, comprising the steps of

accessing the prepared tibial plateau through a minimal incision;

attaching a trial tibial component on the prepared tibial plateau;

positioning a guide on the trial tibial component with a sleeve of the guide extending at an angle to the prepared tibial plateau and aligned with a posterior bore hole extending through the trial tibial component at a location corresponding to the location of the posterior tibial fixation peg of the prosthetic tibial component;

inserting a cutting member through the sleeve and the posterior bore hole into the tibia to form a posterior peg hole in the tibia for receiving the posterior tibial fixation peg;

withdrawing the cutting member from the sleeve;

inserting the cutting member through an anterior bore hole, extending through the trial tibial component at a location corresponding to the location of the anterior tibial fixation peg of the prosthetic tibial component, and into the tibia to form an anterior peg hole in the tibia for receiving the anterior tibial fixation peg; and

withdrawing the cutting member from the anterior bore hole.

40. The method recited in claim 39 and further including, subsequent to said step of withdrawing the cutting member from the sleeve and prior to said step of inserting the cutting member through the anterior bore hole, the step of removing the guide from the trial tibial component.

41. The method recited in claim 40 wherein said step of inserting the cutting member through the sleeve includes advancing the cutting member until a stop on the cutting member engages the sleeve.

42. The method recited in claim 39 wherein said step of inserting the cutting member through the anterior bore hole includes advancing the cutting member to a depth line on the cutting member.

43. The method recited in claim 39 wherein said step of positioning includes positioning the guide on the trial tibial component via a handle extending from the sleeve.

44. The method recited in claim 39 wherein said step of positioning includes releasably securing the guide to the trial tibial component.

45. The method recited in claim 39 wherein said step of positioning includes positioning the guide on the trial tibial component with the sleeve extending anteriorly at an angle to the prepared tibial plateau.

46. The method recited in claim 39 wherein said step of positioning includes positioning the guide on the trial tibial component with the sleeve extending anteriorly at a 50 degree angle to the prepared tibial plateau.

47. A method of implanting a prosthetic femoral component on a prepared femoral condyle, comprising the steps of

accessing a prepared femoral condyle through a minimal incision;

applying cementitious material to a fixation surface of a prosthetic femoral component, in which the fixation surface has a border surrounding a cavity;

aligning a femoral fixation peg protruding from the fixation surface with a peg hole prepared in the femoral condyle;

aligning a femoral fixation fin protruding from the fixation surface with a slot prepared in the femoral condyle;

inserting the femoral fixation peg and femoral fixation fin in the peg hole and slot, respectively;

placing a planar rearward section of the border on a planar surface prepared along a posterior aspect of the femoral condyle;

placing a curved intermediate section of the border on a curved portion of a resurfaced area prepared along a distal aspect of the femoral condyle extending forwardly from the planar surface;

placing a planar forward section of the border on a planar portion of the resurfaced area extending forwardly from the curved portion; and

securing the prosthetic femoral component on the prepared femoral condyle via the cementitious material.

48. The method recited in claim 47 wherein said step of applying includes applying the cementitious material to the cavity.

49. The method recited in claim 47 wherein said step of inserting includes impacting the prosthetic femoral component to fully seat the femoral fixation peg and femoral fixation fin in the peg hole and slot, respectively.

50. A method of implanting a prosthetic tibial component on a prepared tibial plateau in a minimally invasive unicompartmental knee replacement, comprising the steps of

accessing the prepared tibial plateau through a minimal incision;

applying cementitious material to a fixation surface of a prosthetic tibial component;

aligning anterior and posterior tibial fixation pegs protruding from the fixation surface with anterior and posterior peg holes, respectively, prepared in the tibial plateau;

inserting the anterior and posterior tibial fixation pegs in the anterior and posterior peg holes, respectively;

supporting a continuously planar rim of the fixation surface upon a planar surface prepared along the tibial plateau with the anterior and posterior tibial fixation pegs received in the anterior and posterior peg holes, respectively;

confining the cementitious material to a cavity of the fixation surface, via a dovetail wall surrounding the cavity, as pressure is applied to the prosthetic tibial component; and

securing the prosthetic tibial component on the prepared tibial plateau via the cementitious material.

51. The method recited in claim 50 wherein said step of supporting includes supporting the rim upon the planar surface of the tibial plateau without penetrating the bone.