KNEE INSTRUMENTS AND METHODS

• US 20160278938A1
• Filed: 03/25/2016
• Published: 09/29/2016
• Est. Priority Date: 03/25/2015
• Status: Active Grant

• Current Assignee: Goble E. Marlowe
• Original Assignee: Goble E. Marlowe
• Inventors: Goble, E. Marlowe, Creger, Carlyle J., Triplett, Daniel J.
• Granted Patent: US 10,426,565 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61B 2090/067 for measuring angles
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

Knee arthroplasty instrument systems directly reference and align with the anterior distal with the anterior distal femoral cortex, the mechanical axis of the leg, and Whiteside'"'"'s line. The anterior femoral resection is aligned in the same plane as the anterior distal femoral cortex. The center of the femoral head, the medial/lateral center of the distal femur, the medial/lateral center of the proximal tibia, and the second toe, medial/lateral center of the ankle, or anterior tibial spine are all aligned to the mechanical axis of the leg while the leg is in full extension and the knee joint is distracted. Whiteside'"'"'s line is referenced while the distal femur is intact, before any distal femoral resection, and the anterior and posterior femoral resections and chamfer cuts are aligned to this reference using a jig. Methods of using the instrument systems are disclosed.

Claims

1. A system for arthroplasty of a knee joint comprising a femur, a tibia, and a patella, comprising:

a femoral implant;

a tibial implant; and

an instrument system comprising;

a base component comprising a bone contacting surface; and

a femoral extension rod coupled to the base component;

wherein, when the instrument system is operatively attached to the knee joint, the bone contacting surface of the base component is fixed against a distal anterior cortical surface of the femur, the femoral extension rod is centered in a distal medial-lateral width of the femur, and the femoral extension rod extends over a center of a head of the femur.

2. The system of claim 1, wherein the femoral extension rod is coupled to the base component by a first hinge which permits the femoral extension rod to rotate in an anterior-posterior direction when the instrument system is operatively attached to the knee joint.

3. The system of claim 1, wherein the instrument system comprises:

a distal femoral condyle block coupled to the base component;

wherein, when the instrument system is operatively attached to the knee joint, the distal femoral condyle block is above a distal condyle of the femur.

4. The system of claim 1, wherein the instrument system comprises:

a femoral target positioned over the center of the head of the femur;

wherein, when the instrument system is operatively attached to the knee joint, the femoral extension rod is aimed at the femoral target.

5. The system of claim 1, wherein the instrument system comprises:

an angle block assembly coupled to the base component, wherein the angle block assembly comprises a locked state and an adjustable state; and

an angle gage assembly coupled to the angle block assembly, wherein the angle gage assembly comprises a shaft;

wherein, when the instrument system is operatively attached to the knee joint, the shaft extends within an intercondylar notch of the femur;

wherein, when the angle block assembly is in the adjustable state, the shaft is positionable parallel to a Whiteside'"'"'s line of the femur;

wherein, when the angle block assembly is set to the locked state while the shaft is positioned parallel to the Whiteside'"'"'s line, the angle block assembly is locked parallel to the Whiteside'"'"'s line.

6. The system of claim 5, wherein the instrument system comprises:

a cut guide mounting block assembly that couples to the angle block assembly; and

a femoral cut guide coupled to the cut guide mounting block assembly;

wherein, when the instrument system is operatively attached to the knee joint and the cut guide mounting block assembly is coupled to the angle block assembly in the locked state, an anterior femoral cut guide slot of the femoral cut guide is perpendicular to the Whiteside'"'"'s line.

7. The system of claim 1, wherein the instrument system comprises:

a tibial pin guide coupled to the base component; and

a tibial extension rod coupled to the tibial pin guide;

wherein, when the instrument system is operatively attached to the knee joint with the knee joint in full extension, the tibial pin guide is fixed against a proximal anterior cortical surface of the tibia, the tibial extension rod is centered in a proximal medial-lateral width of the tibia, and the tibial extension rod is centered over a distal portion of the tibia.

8. The system of claim 7, wherein the tibial extension rod is coupled to the tibial pin guide by a second hinge which permits the tibial extension rod to rotate in an anterior-posterior direction when the instrument system is operatively attached to the knee joint.

9. The system of claim 7, wherein the femoral and tibial extension rods are collinear in an anterior view.

10. The system of claim 7, wherein the instrument system comprises:

a tibial target positioned over a portion of a lower limb associated with the tibia, wherein the portion of the lower limb is selected from the group consisting of a tibial tuberosity, an anterior tibial crest, a medial-lateral width of an ankle, and a second toe;

wherein, when the instrument system is operatively attached to the knee joint with the knee joint in full extension, the tibial extension rod is aimed at the tibial target.

11. The system of claim 10, wherein the tibial target is attached to a foot holder.

12. A method for arthroplasty of a knee joint comprising a femur, a tibia, and a patella, comprising:

placing a bone contacting surface of a base component against a distal anterior cortical surface of the femur;

coupling a femoral extension rod to the base component;

centering the femoral extension rod in a distal medial-lateral width of the femur;

positioning the femoral extension rod over a center of a head of the femur;

rigidly coupling the base component to the distal anterior condylar surface;

making a distal femoral resection perpendicular to a mechanical axis of a leg associated with the femur, wherein the mechanical axis of the leg is indicated by the femoral extension rod; and

coupling a femoral implant to the distal femoral resection.

13. The method of claim 12, wherein centering the femoral extension rod in the distal medial-lateral width of the femur comprises centering the base component relative to a trochlear notch of the femur.

14. The method of claim 12, wherein the femoral extension rod is coupled to the base component by a first hinge which permits the femoral extension rod to rotate in an anterior-posterior direction.

15. The method of claim 12, comprising:

placing the base component between the distal anterior cortical surface of the femur posteriorly and a suprapatellar fat pad associated with the femur anteriorly;

wherein rigidly coupling the base component to the distal anterior cortical surface comprises inserting converging bone pins into a distal metaphyseal equivalent region of the femur and avoiding inserting bone pins into a diaphyseal equivalent region of the femur.

16. The method of claim 12, comprising:

placing the knee joint in full extension;

coupling a tibial pin guide to the base component;

coupling a tibial extension rod to the tibial pin guide, wherein the tibial extension rod is collinear with the femoral extension rod in an anterior view;

centering the tibial extension rod in a proximal medial-lateral width of the tibia;

centering the tibial extension rod over a distal portion of the tibia;

coupling the tibial pin guide to a proximal anterior cortical surface of the tibia;

making a proximal tibial resection relative to a mechanical axis of the leg, wherein the mechanical axis of the leg is indicated by the tibial extension rod and a line extending along the tibial extension rod to the center of the head of the femur; and

coupling a tibial implant to the proximal tibial resection.

17. The method of claim 16, comprising:

maximally distracting the knee joint while centering the tibial extension rod in the proximal medial-lateral width of the tibia and centering the tibial extension rod over the distal portion of the tibia, before coupling the tibial pin guide to the proximal anterior cortical surface of the tibia.

18. The method of claim 16, wherein the tibial extension rod is coupled to the tibial pin guide by a second hinge which permits the tibial extension rod to rotate in an anterior-posterior direction.

19. The method of claim 16, wherein coupling the tibial pin guide to the proximal anterior cortical surface of the tibia comprises driving parallel bone pins through the tibial pin guide into the tibia, the method comprising:

removing the tibial pin guide from the tibia, leaving the parallel bone pins in the tibia;

coupling a distal femoral cut guide to the base component;

coupling a proximal tibial cut guide to the parallel bone pins;

making the distal femoral resection with the knee joint in full extension; and

making the proximal tibial resection with the knee joint in full extension.

20. The method of claim 16, wherein coupling the tibial pin guide to the proximal anterior cortical surface of the tibia comprises driving parallel bone pins through the tibial pin guide into the tibia, the method comprising:

removing the tibial pin guide from the tibia, leaving the parallel bone pins in the tibia;

coupling a distal femoral cut guide to the base component;

coupling a proximal tibial cut guide to the parallel bone pins;

making the distal femoral resection with the knee joint in flexion; and

making the proximal tibial resection with the knee joint in flexion.

21. The method of claim 16, comprising:

centering a tibial target over a portion of a lower limb associated with the tibia, wherein the portion of the lower limb is selected from the group consisting of a tibial tuberosity, an anterior tibial crest, a medial-lateral width of an ankle, and a second toe; and

aiming the tibial extension rod at the tibial target.

22. The method of claim 21, wherein the tibial target is a second fork, wherein aiming the tibial extension rod at the tibial target comprises positioning the tibial extension rod in the second fork.

23. The method of claim 12, comprising:

coupling an angle block assembly to the base component, wherein the angle block assembly comprises a locked state and an adjustable state;

setting the angle block assembly to the adjustable state;

coupling an angle gage assembly to the angle block assembly, wherein the angle gage assembly comprises a shaft;

positioning the shaft parallel to a Whiteside'"'"'s line of the femur before making the distal femoral resection; and

setting the angle block assembly to the locked state.

24. The method of claim 23, comprising:

removing the angle gage assembly from the locked angle block assembly;

coupling a femoral cutting block to the locked angle block assembly;

positioning the femoral cutting block against the femur; and

making a femoral resection selected from the group consisting of an anterior femoral resection, an anterior chamfer cut, a posterior femoral resection, and a posterior chamfer cut.

25. The method of claim 24, wherein the femoral resection is an anterior femoral resection, wherein the anterior femoral resection and the bone contacting surface of the base component lie in a common plane.

26. The method of claim 12, comprising:

positioning a femoral target over the center of the head of the femur; and

aiming the femoral extension rod at the femoral target.

27. The method of claim 26, wherein the femoral target is a fork, wherein aiming the femoral extension rod at the target comprises positioning the femoral extension rod in the fork.

28. An apparatus which references a distal anterior aspect of a femur with the objective of determining a mechanical axis of the femur.

29. The apparatus of claim 28, wherein the apparatus contacts a cortical surface of the distal anterior aspect of the femur in a diaphyseal equivalent region of the femur.

30. The apparatus of claim 29, wherein a bone facing side of the apparatus includes frictional elements that contact the cortical surface.

31. The apparatus of claim 30, wherein the bone facing side of the apparatus is wide at a first end and narrow at a second end, wherein, when the apparatus contacts the cortical surface, the first end is distal and the second end is proximal.

32. The apparatus of claim 31, comprising:

a base component comprising the bone facing side, wherein the first end is at a distal end of the base component, wherein the second end is at a proximal end of the base component, wherein a longitudinal axis of the bone facing side extends between the first end and the second end; and

a handle component adjustably coupled to the distal end of the base component, wherein the handle component extends proximally beside the base component, wherein the handle component is spaced apart anteriorly from the base component, wherein a longitudinal axis of the handle component extends between a distal end of the handle component and a proximal end of the handle component;

wherein the longitudinal axis of the bone facing side forms an angle with the longitudinal axis of the handle component, wherein the angle is adjustable between four degrees and seven degrees.

33. An apparatus for knee arthroplasty, comprising:

a base component that extends between a first distal end and a first proximal end and comprises a first bone facing surface and a first top surface opposite the first bone facing surface; and

a femoral pin guide that extends between a second distal end and a second proximal end and comprises a second bone facing surface and a second top surface opposite the second bone facing surface, wherein the second proximal end is coupled to the first distal end, wherein the second bone facing surface is coupled to the first top surface, parallel to the first bone facing surface, and spaced apart from the first bone facing surface.

34. The apparatus of claim 33, wherein, when the base component is coupled to a distal anterior cortex of a femur, the second bone facing surface is anteriorly elevated relative to anterior aspects of condyles of the femur.

35. The apparatus of claim 33, comprising:

an anterior cut guide comprising a cut slot for an anterior femoral resection, wherein the cut slot defines a cutting path of a saw blade acting through the cut slot;

wherein the femoral pin guide comprises first and second pin holes and first and second mounting holes, wherein the first and second pin holes converge together as they approach the second bone facing surface;

wherein the base component is coupled to a distal anterior cortex of a femur by inserting a first bone pin through the first pin hole and into the femur, and inserting a second bone pin through the second pin hole and into the femur;

wherein, when the base component is coupled to the distal anterior cortex and the anterior cut guide is coupled to the femur, the first pin hole is medial to the first mounting hole, the second mounting hole is lateral to the first mounting hole, the second pin hole is lateral to the second mounting hole, the first bone pin is medial to the cutting path, and the second bone pin is lateral to the cutting path.

36. The apparatus of claim 35, comprising:

a drill; and

a block with an inclined plane;

wherein, when the base component is coupled to the distal anterior cortex and the anterior cut guide is coupled to the femur, the drill extends in a proximal-distal direction through the anterior cut guide to a spike protruding from the first bone facing surface of the base component, and the block is seated on a proximal tibial resection with the anterior cut guide resting on the inclined plane, wherein the plane is inclined in a medial-lateral direction and is higher under a lateral femoral condyle.

37. The apparatus of claim 33, comprising:

a distal cut guide comprising a cut slot for a distal femoral resection, wherein the cut slot is adjustable in a proximal-distal direction, wherein the distal cut guide is removably coupled to the second distal end of the femoral pin guide.

38. The apparatus of claim 33, comprising:

a distal cut guide comprising a first cut slot for a first distal femoral resection and a second cut slot for a second distal femoral resection, wherein the second cut slot is proximally spaced apart from the first cut slot, wherein the distal cut guide is removably coupled to the second distal end of the femoral pin guide.

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

mounting an instrument base on the anterior surface of the femur with a posterior surface of the instrument base in contact with the anterior surface of the femur;

mounting anterior and posterior femoral cut guides to the instrument base, the anterior femoral cut guide having a cutter guide aligned coplanar with the posterior surface of the instrument base; and

guiding a cutter with the anterior and posterior cut guides to produce an anterior femoral cut coplanar with the instrument base and a posterior femoral cut offset posteriorly from the anterior cut.

40. The method of claim 39, comprising adjusting the anterior and posterior femoral cut guides to vary the distance between the anterior and posterior cuts to match a femoral implant interior anterior/posterior dimension.

41. The method of claim 39, comprising mounting a tibial cut guide to the posterior femoral cut guide and guiding a cutter with the tibial cut guide to produce a proximal tibial cut offset from the posterior femoral cut.

42. The method of claim 41, wherein the posterior femoral cut is parallel to the proximal tibial cut.

43. The method of claim 41, wherein the tibial cut guide is provided in sizes to match the flexion gap.

44. The method of claim 39, comprising tensioning the knee joint by inserting a wedge between the distal femur and the proximal tibia.

45. The method of claim 39, comprising tensioning the knee joint by adjusting a screw mounted to the base (arm), wherein the screw is vertically adjustable to tension the joint.

46. The method of claim 39, comprising adjusting femoral cut guides along the femoral mechanical axis to abut the distal femur.

47. The method of claim 46, comprising fixing the femoral cut guides to the femur.

48. The method of claim 39, comprising placing the knee in 90 degrees of flexion prior to making cuts.

49. The method of claim 39, comprising adjusting the cut guides on rails.

50. The method of claim 39, wherein a pivot block is mounted on the trunnion of the instrument base and the pivot block angle is adjusted to align with the femoral mechanical axis using an alignment rod.

51. The method of claim 39, comprising performing a trial reduction and adjusting cuts.

52. An instrument system useful in cutting a femur and tibia during knee joint replacement surgery, the instrument comprising:

an instrument base having an instrument mounting portion and a posterior bone mounting surface;

a pivot block mounted to the mounting portion for rotation about an axis;

an arm mounted to the pivot block and extending parallel to the posterior bone mounting surface;

an anterior femoral cut guide mounted to the arm in axial sliding relationship, the anterior femoral cut guide having a cut guide slot parallel to the posterior bone mounting surface of the instrument base;

a posterior femoral cut guide mounted to the anterior femoral cut guide, the posterior femoral cut guide having a cut guide slot parallel to the anterior femoral cut guide cut guide slot, the posterior femoral cut guide being adjustable relative to the anterior cut guide slot to vary the distance between the anterior and posterior cut guide slots; and

a tibial cut guide mounted to the posterior cut guide, the tibial cut guide having a cut guide slot spaced from the posterior cut guide slot.

53. The instrument system of claim 52, comprising a kit of tibial cut guides in sizes to match flexion gap.

54. The instrument system of claim 52, comprising a wedge for tensioning the knee joint.

55. The instrument system of claim 52, comprising a screw mounted to the base arm, wherein the screw is vertically adjustable to tension the knee joint.

56. The instrument system of claim 52, comprising an alignment rod able to align the pivot block with the femoral mechanical axis.