Femur Posterior Reference Dimension Measuring Instrument

Abstract

In an orthopedic instrument (10) for knee arthroplasty: a base (12) having one or more paddles (36) adapted to be seated against one or both of the medial and lateral condyles of the femur and configured to be referenced; a body (14) coupled to the base for rotation relative to the base, the body including an internal recess and slot and a first scale (24) along a first face of the body adjacent the slot; a strut (20) received within the recess and movable relative to the body, the strut (20) having a second scale (28) used with the first scale to determine the posterior size of the femur; and an adjustment mechanism (18) having a third scale (30) for indicating rotation of the femur, the adjustment mechanism (18) being configured to rotate the body relative to the base in a desired direction based on rotation of the femur. The orthopedic instrument (10) for knee arthroplasty includes the above components.

Description

Technical Field

[0001] (Claim of Priority) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 351,619, filed Jun. 13, 2022, the benefit of whose priority is claimed by this specification and which is hereby incorporated by reference in its entirety.

[0002] This disclosure relates to knee arthroplasty. More particularly, this disclosure relates to instruments for use during knee arthroplasty procedures.

Background Art

[0003] In a total knee arthroplasty (TKA) procedure, a patient's distal femur is resected and replaced with a prosthetic femoral implant, and the patient's proximal tibia is resected and replaced with a prosthetic tibial implant. The prosthetic femoral implant articulates with the prosthetic tibial implant to restore joint movement.

[0004] Many factors affect joint movement after a TKA procedure. The size and shape of each prosthetic implant affect joint movement. For this reason, femoral implants are carefully sized, and the anterior-posterior dimension of the distal femur after resection is determined using an anterior-posterior (AP) dimension measuring device. Additionally, the position and orientation of each prosthetic implant, which are determined by the position and orientation of the corresponding bone resection, will affect joint movement.

Summary of the Invention

Problems to be Solved by the Invention

[0005] This patent application provides an exemplary instrument for anterior-posterior (AP) sizing of the femur in TKA. This instrument can also measure the rotation of the femur and set the rotation for the femoral implant to ensure alignment between the femoral implant and the patient's anatomy. The instrument can be used to evaluate the size and alignment of the femur before excising or otherwise operating on the patient's knee joint. This instrument can be used as an aid in planning the TKA procedure, including making perforations for positioning one or more resection guides used in excising the femur.

[0006] In some TKA procedures, it can be difficult to size the femur and set the rotation of the femur. Most TKA procedures utilize different instruments for the left and right knees. Additionally, one instrument may be used for sizing the femur and another for determining the rotation of the femur. Thus, at least two sizing devices, and sometimes additional instruments, are included within one instrument system. Having additional instruments increases the cost and complexity of the procedure.

Means for Solving the Problem

[0007] The inventors of the present application recognized that by providing a single instrument that can measure the anterior-posterior size of the femur and measure and set the rotation, the complexity of the TKA procedure for sizing the femur and measuring and setting the rotation can be reduced. Further, the instrument can be versatile and usable for both the left and right knees. The inventors also recognized that this instrument can be used to guide one or more drills for making an opening in the femur. The instrument can obviate the need for dedicated guides such as a gap reference drill guide. Thus, the instrument can provide one or more drill holes that can be used, for example, to assemble a cut guide. In this way, the number of surgical components can be reduced by the instrument.

[0008] To further illustrate the knee arthroplasty instruments disclosed herein, a non-limiting list of examples is provided herein. The examples are referred to as aspects and techniques.

[0009] In some aspects, the techniques described herein are for an orthopedic instrument for knee arthroplasty and optionally include a base having one or more paddles configured to be positioned in contact with, and for reference to, one or both of the medial and lateral condyles of the femur, a body coupled to the base for rotation relative to the base and including an internal recess and slot and a first scale along a first surface of the body adjacent the slot, a strut received within the recess and movable relative to the body and having a second scale for use with the first scale to determine the posterior size of the femur, and an adjustment mechanism having a third scale for indicating rotation of the femur and configured to rotate the body relative to the base in a desired direction based on rotation of the femur, for an orthopedic instrument for knee arthroplasty.

[0010] In some aspects, the techniques described herein optionally further include a plurality of retention mechanisms each including a ball and spring assembly, the plurality of retention mechanisms being positioned between various components including at least between the base and the body, between the strut and the body, and between the strut and the stylus, for the instrument.

[0011] In some aspects, the techniques described herein optionally relate to an instrument, wherein the adjustment mechanism includes a dial with a handle configured for manual adjustment of the dial by a surgeon.

[0012] In some aspects, the techniques described herein optionally relate to an instrument, wherein the strut includes an assembly including an outer sleeve, an inner shaft, and a cap, the outer sleeve being configured for translational movement but having a fixed rotation relative to the body, while the inner shaft is configured to rotate relative to the outer sleeve and the body.

[0013] In some aspects, the techniques described herein optionally further include a stylus coupled to the support by a cap and movable relative to the support, the cap including an opening for receiving a ball, and the stylus including a plurality of detents configured to be engaged by the ball, for an instrument.

[0014] In some aspects, the techniques described herein optionally relate to an instrument, where the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be received within one of the one or more grooves.

[0015] In some aspects, the techniques described herein optionally relate to an instrument, where the inner shaft is configured to hold a spring that engages the ball, and the ball is biased by the spring towards the stylus.

[0016] In some aspects, the techniques described herein optionally relate to an instrument, where the outer sleeve is rotationally fixed to the body by a protrusion that defines a second scale, and the protrusion is captured within a slot.

[0017] In some aspects, the techniques described herein optionally relate to an instrument, where the body includes a plurality of guide openings therein, and the base includes a plurality of second guide openings therein.

[0018] In some aspects, the techniques described herein optionally relate to an instrument, where the base includes a recess, a detent, and a slot, and the adjustment mechanism is a dial configured to be rotatably inserted within the recess and selectively engage the ratchet and the detent, and the slot is configured to receive an arm that couples the base to the body.

[0019] In some embodiments, the techniques described herein relate to an instrument, optionally, wherein the arm is engaged by a dial and can travel within an arcuate groove inside the dial.

[0020] In some embodiments, the techniques described herein relate to an instrument, optionally, wherein the body has a rotational capacity of up to 18 degrees (including 18 degrees) relative to the base via an adjustment mechanism.

[0021] In some embodiments, the techniques described herein relate to an orthopedic instrument for knee arthroplasty, optionally, comprising a base having one or more paddles configured to be placed in contact with one or both of the medial and lateral condyles of the femur and configured to reference, a body coupled to the base to rotate relative to the base, the body including an internal recess and slot and a first scale along a first surface of the body adjacent to the slot, a strut assembly received within the recess and movable relative to the body, the strut assembly including an outer sleeve, an inner shaft, and a cap, the outer sleeve being configured to translate but having a fixed rotation relative to the body, while the inner shaft is configured to rotate relative to the outer sleeve and the body, the strut having a second scale used with the first scale to determine the posterior size of the femur, a stylus coupled to the strut by the cap and movable relative to the strut.

[0022] In some embodiments, the techniques described herein relate to an instrument, optionally, wherein the cap includes an opening for receiving a ball, and the stylus includes a plurality of detents configured to be engaged by the ball.

[0023] In some embodiments, the techniques described herein relate to an instrument, optionally, wherein the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be received within one of the one or more grooves.

[0024] In some embodiments, the techniques described herein optionally relate to an instrument in which an inner shaft is configured to hold a spring that engages a ball, and the ball is biased by the spring toward a stylus.

[0025] In some embodiments, the techniques described herein optionally relate to an instrument in which an outer sleeve is rotationally fixed to a body by a protrusion that defines a second scale, and the protrusion is captured within a slot.

[0026] In some embodiments, the techniques described herein further optionally relate to an instrument including an adjustment mechanism having a third scale for indicating rotation of a femur, the adjustment mechanism being configured to rotate a body relative to a base in a desired direction based on rotation of the femur, and a plurality of retention mechanisms including a ball and spring assembly, the plurality of retention mechanisms being positioned between various components including at least between the base and the body and between a strut assembly and the body.

[0027] In some embodiments, the techniques described herein optionally relate to an orthopedic instrument for knee arthroplasty, the orthopedic instrument including a base having one or more paddles optionally mounted in contact with one or both of a medial condyle and a lateral condyle of a femur and configured to be referenced, a body coupled to the base for rotation relative to the base, the body including an internal recess and slot and a first scale along a first face of the body adjacent to the slot, a strut received within the recess and movable relative to the body, the strut having a second scale for use with the first scale to determine a posterior size of the femur, a stylus coupled to the strut and movable relative to the strut, an adjustment mechanism having a third scale for indicating rotation of the femur, the adjustment mechanism being configured to rotate the body relative to the base in a desired direction based on rotation of the femur, and a ball and spring assembly configured to hold the stylus with the strut.

[0028] In some embodiments, the techniques described herein optionally include that the strut includes a cap having an opening for receiving a ball, the stylus includes a plurality of detents configured to be engaged by the ball, the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be received within one of the one or more grooves, relating to an instrument.

[0029] The above aspects can be combined in any one or in any combination, and / or optionally, all the elements or options listed can be configured in a form such that they are available for use or selection.

[0030] These and other embodiments and features of the device are partially specified in the following detailed description. This summary is intended to provide a summary of the subject matter of this patent application. This summary is not intended to provide an exclusive or exhaustive disavowal of the invention. The detailed description is incorporated to provide further information about this patent application.

[0031] In the drawings, like numerals may be used throughout the several views to describe like elements. The drawings generally, but not exclusively by way of example, illustrate various embodiments discussed in this document.

Brief Description of the Drawings

[0032]

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[0033] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. The exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that the exemplary embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies have not been described in detail.

[0034] As used herein, the term "proximal" generally means in the direction toward the patient's head, and the term "distal" means in the opposite direction of proximal, i.e., away from the patient's head. The terms "anterior" and "posterior" as used herein should be given their generally understood anatomical interpretations. Thus, "posterior" means the back side of the patient, e.g., the back side of the knee. Similarly, "anterior" means the front side of the patient, e.g., the front side of the knee. Thus, "posterior" means the opposite direction of "anterior". Similarly, the terms "medial" and "lateral" should be given their generally understood anatomical interpretations. "Medial" means the inner part of the knee prosthesis (when in the direction at the time of implantation), and "lateral" means the outer part. "Medial" means the opposite direction of "lateral". "Varus" is defined as being related to "medial" or being a synonym of "medial", or being disposed relatively more medially compared to the midline or other feature or component. "Valgus" is defined as being related to "lateral" or being a synonym of "lateral", or being disposed relatively more laterally compared to the midline or other feature or component.

[0035] As used herein, the term "varus-valgus" means either from varus to valgus or from valgus to varus. Similarly, the terms "proximal-distal", "medial-lateral", and "anterior-posterior" mean any of the reference directions possible for each term. Thus, for example, "proximal-distal" or "anterior-posterior" means either "proximal-to-distal" or "distal-to-proximal".

[0036] With reference to FIG. 1, an instrument 10 is shown. The instrument 10 can be configured for anterior-posterior (AP) sizing of the femur, can measure rotation of the femur, and can set rotation for a femoral implant to ensure alignment of the femoral implant with the patient's anatomy.

[0037] The instrument 10 can include a base 12, a body 14, a linkage assembly 16, an adjustment mechanism 18, a strut assembly 20, and a stylus 22.

[0038] The base 12 can be coupled to the body 14 via the linkage assembly 16. The body 14 can be movable relative to the base 12 via the linkage assembly 16. The base 12 can be configured to house the adjustment mechanism 18. The adjustment mechanism 18 can be coupled to the base 12 and can further be coupled to the linkage assembly 16. The adjustment mechanism 18 can be movable relative to the base 12 and can drive movement of the linkage assembly 16, as further described herein.

[0039] The body 14 can be configured to accommodate the linkage assembly 16 and the strut assembly 20. The strut assembly 20 can be coupled to the stylus 22. The stylus 22 can be movable relative to the strut assembly 20 and the body 14. The strut assembly 20 can be movable relative to the body 14, for example, semi - restrictively as further discussed herein.

[0040] The instrument 10 can be configured to be used on either the left or right knee of a patient. Further, the instrument 10 has the ability to measure knee rotation (either to the left or right) up to 9 degrees from a neutral position. This measured rotation (angle) can, for example, indicate the varus / valgus angle of the patient's knee joint and / or the internal / external rotation of the patient's knee joint.

[0041] The adjustment mechanism 18 is adjustable over a range of movement of 18 degrees (9 degrees of varus and 9 degrees of valgus). The adjustment mechanism 18 can include a first scale 24 that indicates the rotation of the femur about axis A in FIG. 1. A second scale 28 can be provided on the body 14 to measure and indicate an appropriate posterior size for a femur implant (not shown). The second scale 28 can be used in combination with a third scale 30 on the strut assembly 20. The stylus 22 can include a fourth scale 32 to measure and indicate an appropriate anterior size for a femur implant (not shown). Using the second scale 28, the third scale 30, and the fourth scale 32, the instrument 10 can measure the anterior - to - posterior distance with reference to the posterior condyle (where the base 12 is in contact) of the femur to the anterior cortex of the femur (see subsequent figures). The anterior cortex can be referenced at the tip of the stylus 22. Using this information (anterior - posterior distance), a stock size of the femur implant can be selected. This stock size can be indicated with one or more of the scales 28, 30, and / or 32 of the instrument 10.

[0042] Figure 1A is an exploded view of the instrument 10 of FIG. 1 with the stylus 22 removed. Thus, FIG. 1A shows the base 12, the body 14, the linkage assembly 16, the adjustment mechanism 18, and the strut assembly 20. The base 12 can include paddles 36 (only one is shown in FIG. 1A), dial recesses 38, and flanges 40. In addition to the second scale 28, the body 14 can include a recess 42 and a drill guide opening 44. The linkage assembly 16 can include fasteners 46, arms 48, and a second fastener 50. In addition to the first scale 24, the adjustment mechanism 18 can include a fastener 52 and a dial 54. The strut assembly 20 can include a third scale 30, an outer sleeve 60, an inner shaft 62, and a cap 64. FIG. 1A shows additional spring and ball assemblies of the instrument 10 that are discussed in more detail below.

[0043] The paddle 36 (only one is shown in FIG. 1A) can include a protrusion from the remainder of the base 12. The paddle 36 can be configured to be adjacent to or otherwise reference the outer and inner condyles of the femur. Opposite the paddle 36, the dial recess 38 can be positioned within the first plane of the base 12. The flange 40 can be adjacent to the paddle 36, but proximal to the paddle 36, on the side of the base 12 facing the femur.

[0044] The body 14 can have an inverted T-shaped configuration with wings that extend laterally from a stem or central portion. The recess 42 can be within the stem and can be configured to receive at least a portion of the strut assembly 20. The recess 42 can include one or more openings, including slots along the first side of the body 14 as further described herein. The drill guide opening 44 can be positioned within the wing of the body 14 and can extend through the body 14 from the first side of the body 14 to the side facing the femur.

[0045] The fastener 46 can couple the arm 48 to the main body 14. However, the fastener 46 can enable the pivotal movement of the arm 48 relative to the main body 14. The arm 48 can extend from a first end (coupled to the fastener 46) to a second end that cooperates with the adjustment mechanism 18 and is movably engaged by the adjustment mechanism. Specifically, the arm 48 can be configured as a follower of the adjustment mechanism 18, as further described and illustrated. The second fastener 50 can be received within an opening in the flange 40 of the base 12 and extend therethrough to be screwed or otherwise fastened to the side of the main body 14 facing the femur. The fastener 50 can be configured to enable the pivotal movement of the main body 14 relative to the base 12, as further exemplified and illustrated herein.

[0046] The fastener 52 of the adjustment mechanism 18 can rotatably hold the dial 54 in a predetermined position relative to the base 12. As discussed previously, the dial 54 can be selectively rotatable up to 9 degrees (including 9 degrees) in the clockwise direction and up to 9 degrees (including 9 degrees) in the counterclockwise direction relative to the base 12 on the fastener 52. Thus, the dial 54 can be rotatable up to 18 degrees (including 18 degrees) on the fastener 52.

[0047] The outer sleeve 60 can have at its distal end or adjacent to its distal end a first opening 66 configured to receive a fastener 67 (such as a pin, screw, etc.) that forms the third scale 30. The outer sleeve 60 can include at its proximal end or adjacent to its proximal end a second opening 68 configured to receive the inner shaft 62. The outer sleeve 60 can be linearly movable proximally-distally relative to the body 14, but need not be rotatable relative to the body 14 since the fastener 67 is captured inside the slot of the body 14. The inner shaft 62 can be rotatable inside the outer sleeve 60. Thus, the inner shaft 62 can be rotatable relative to the outer sleeve 60 and the body 14. The inner shaft 62 can be maintained inside the outer sleeve 60 by a fastener 70 that is at least partially received inside a channel 72 or a narrow region of the inner shaft 62 in addition to the opening of the outer sleeve 60. The cap 64 can be coupled downwardly over and / or across the proximal end of the inner shaft 62. The cap 64 can receive a stylus 22 (not shown in FIG. 1A) and be configured such that the stylus 22 is movable in a non-proximal direction (e.g., movable front-rear).

[0048] Figure 1A shows a spring and ball assembly (also referred to herein as a "retaining mechanism") that can be used with instrument 10. Retaining mechanism 73 can be used to reduce unwanted wobble or play between components. Retaining mechanism 73 can also, in some instances, facilitate a desired amount of engagement between components (e.g., maintain the relative position of components when not being handled / operated on by a surgeon). First ball 74 and first spring 76 can engage external sleeve 60 from a position assembled inside body 14. At least second balls 78A, 78B and second springs 80A and 80B can engage body 14 from a position assembled inside base 12. Third ball 82 and third spring 84 can be assembled within inner shaft 62 and / or cap 64 and third ball 82 can engage stylus 22 (not shown in Figure 1A) through an opening within cap 64.

[0049] Figures 2A through 2C show stylus 22 in further detail. With reference to Figure 2A, stylus 22 can include tip portion 84, curved portion 86, body 88 and front end portion 90. Body 88 can include fourth scale 32, lateral protrusions 92A and 92B, and retaining feature 94 (only in Figure 2C).

[0050] Stylus 22 may or may not be used with the remainder of instrument 10 (Figures 1 and 1A). The use of stylus 22 can be at the discretion of the surgeon. Stylus 22 can have an elongate and relatively thin flat shape. Body 88 can extend along longitudinal axis LA. Curved portion 86 can be connected to body 88, for example, integrally, and can extend along the longitudinal axis, but can also extend in a second direction, such as distally toward tip portion 84. Tip portion 84 can be connected to curved portion 86. Tip portion 84 can be configured to reference an anatomical point on the femur, such as the anterior cortex of the femur, through curved portion 86 and body 88.

[0051] The front end portion 90 can be connected to the main body 88, for example, in an integral form. The front end portion 90 can include a narrow region or a material reduction region to facilitate operation by a surgeon. The lateral protrusions 92A and 92B can extend to the front end portion 90. The lateral protrusions 92A and 92B can extend longitudinally along the length of the main body 88 from the front end portion 90 to the curved portion 86. The lateral protrusions 92A and 92B form regions of reduced thickness compared to the thickness of the rest of the main body 88. The lateral protrusions 92A and 92B are configured to interact with mating features such as grooves and / or protrusions proximal to the cap 64 (FIGS. 1 and 1A). The features of the cap 64, in combination with the lateral protrusions 92A and 92B, can hold the stylus 22 on the cap 64, but can also allow selective movement of the stylus 22 along the longitudinal axis LA. Thus, the stylus 22 may be movable only along the longitudinal axis LA once it is coupled to the cap 64.

[0052] The fourth scale 32 can be positioned on the first surface 96 (e.g., the top surface) of the main body 88. The fourth scale 32 can reference the stock size of the femoral implant based on the distance that the stylus 22 extends from the cap 64 (FIGS. 1 and 1A) to other features on the frontal cortex or femur. The fourth scale 32 can include lines and / or numbers that can be aligned with corresponding lines (scales) on the cap 64.

[0053] The stylus 22 can have a second surface 98. The second surface 98 can be on the side opposite the first surface 96. The retention feature 94 can be formed within the body 88 and can extend into the second surface 98 having an opening at the second surface 98. The retention feature 94 can include a detent or other feature configured to receive a portion of the third ball 82 (FIG. 1A) extending from the cap 64. The retention feature 94 can have a position along a longitudinal axis LA corresponding to, for example, the fourth scale 32. Thus, each of the retention features 94 can have a longitudinal position corresponding to one of the fourth scales 32.

[0054] A retaining force by the third spring 84 (FIG. 1A) via the third ball 82 can be applied to the stylus 22. Simultaneously with the application of this force, the stylus 22 can be captured and held by the lateral protrusions 92A and 92B by the generally opposing forces of the grooves and protrusions.

[0055] Figures 3 through 3E show various views of the instrument 10. FIG. 3 shows the first side 100 (front side when the instrument 10 is assembled to the femur). The components of the instrument 10 were discussed previously in relation to FIGS. 1 and 1A.

[0056] FIG. 3A shows the second side 102 (rear side when the instrument 10 is assembled to the femur). FIG. 3A shows the structure of the cap 64 in more detail. Specifically, the third ball 82 is captured within the recess 104 of the cap 64. The recess 104 can extend into the first surface 106 within the cap 64. The third ball 82 can extend from the first surface 106 and engage the stylus 22 as discussed previously.

[0057] The cap 64 can include arms 108A and 108B. The arms 108A and 108B can extend from the first surface 106. The arms 108A and 108B can include grooves 110A and 110B, protrusions 112A and 112B, and fifth scales 114A and 114B.

[0058] The grooves 110A and 110B can be sized to accommodate the side protrusions 92A and 92B (FIGS. 2A through 2C). The protrusions 112A and 112B can extend in a direction returning toward each other to form a restraint or capture structure proximal to the cap 64. The protrusions 112A and 112B can be engaged by a portion of the stylus 22, such as a component of the body 88 (FIGS. 2A through 2C). The protrusions 112A and 112B can be engaged by the stylus 22 and capture the stylus 22 as described above. This engagement can be facilitated by the third ball 82 that is forced against the stylus 22 as described above. The fifth graduations 114A and 114B (e.g., lines) can be positioned proximal to the protrusions 112A and 112B, respectively. The fifth graduations 114A and 114B can interact with the fourth graduation 32 of the stylus 22 as described above.

[0059] FIG. 3A further shows a recess 116 within the body 14. The recess 116 is configured to accommodate the flange 40 therein. The recess 116 and the flange 40 can be shaped to allow pivotal movement of the body 14 relative to the base 12 on the second fastener 50.

[0060] FIG. 3B shows a side view of the instrument 10. FIG. 3C shows a cross-sectional view taken along line C-C of FIG. 3. FIG. 3C shows the base 12, the body 14, the linkage assembly 16, the adjustment mechanism 18, and the support assembly 20. As discussed above, the base 12 can include the paddle 36 (only one is shown in FIG. 3C), the dial recess 38, and the flange 40. The body 14 can include the recess 42. The linkage assembly 16 can include the second fastener 50. The adjustment mechanism 18 can include the fastener 52 and the dial 54. The support assembly 20 can include the third graduation 32 (which can be a simple mark, line, etc., a part of the fastener 67), the outer sleeve 60, the inner shaft 62, and the cap 64. FIG. 3C also shows the first ball 74 and the first spring 76, and the third ball 82 and the third spring 84.

[0061] Figure 3D shows a second cross-section along the D-D line of FIG. 3. The view of FIG. 3D shows a portion of the main body 14 and the base 12, and further shows a second ball 78A and a second spring 80A. The second ball 78A can be pushed toward the base 12 (e.g., toward the flange 40) by the second spring 80A. The engagement by the second ball 78A (and a second ball 78B not shown) can reduce unwanted play and wobbling between the base 12 and the main body 14.

[0062] Figure 3E shows a third cross-section along the E-E line of FIG. 3. FIG. 3E shows a portion of the main body 14 together with a fastener 46 and a part of the arm 48 of the linkage assembly 16.

[0063] FIGS. 4 and 4A show the main body 14 and the support assembly 20 in a state where the position of the support assembly 20 is shifted compared to FIG. 3C. Based on FIG. 4, in addition to the second scale 28, the recess 42, and the drill guide opening 44, the main body 14 can include wings 118A and 118B, second drill guide openings 120A and 120B, a stem 122, and a slot 124.

[0064] The wing 118A can define one of the drill guide opening 44 and the second drill guide opening 120A. The second drill guide opening 120A can be offset by a desired amount (e.g., 2 mm) from the drill guide opening 44. The wing 118A can extend laterally from the stem 122. Similarly, the wing 118B can define one of the drill guide opening 44 and the second drill guide opening 120B. The second drill guide opening 120B can be offset by a desired amount (e.g., 2 mm) from the corresponding drill guide opening 44. The wing 118B can extend laterally from the stem 122.

[0065] The stem 122 can have a proximal-distal elongated shape and can have a second scale 28 on its first surface. The stem 122 can define a recess 42 internally. The slot 124 can extend from the first surface and communicate with the recess 42.

[0066] As shown in FIGS. 4 and 4A, a third scale 30 (part of the fastener 67) can be held within the slot 124. The third scale 30 can include a protrusion 126 (such as the head or other feature of the fastener 67) captured by the slot 124. This arrangement of the captured protrusion 126 can prevent the outer sleeve 60 (FIG. 4A) from rotating, but can allow limited translational movement of the outer sleeve 60 relative to the body 14 (determined by the length of the slot 124).

[0067] FIGS. 5 through 5D show further features of the base 12. These features can include, as previously discussed, the paddle 36 (only mentioned in FIG. 5), the dial recess 38, and the flange 40. Referring now to FIG. 5A, the base 12 can further include one or more drill guide openings 128A and 128B, a slot 130, and a first opening 132 and a second opening 134.

[0068] The first drill guide opening 128A can be positioned adjacent to the first paddle 36, and the second drill guide opening 128B can be positioned adjacent to the second paddle 36. The drill guide openings 128A and 128B are optional, and some surgeons may not utilize them to fix the base 12 to the femur. The slot 130 can extend from its proximal side into the dial recess 38. The slot 130 can be configured to accommodate at least a portion of the arm 48 (FIG. 1A). The first opening 132 can be positioned inside the dial recess 38, for example, at its center. The first opening 132 can be configured to threadedly receive or otherwise accommodate the distal portion of the fastener 52 (FIG. 1A). The second opening 134 can be positioned within the flange 40 and can be configured to accommodate the second fastener 50 (FIG. 1A) therein.

[0069] FIG. 5B shows a cross-section along line B-B of FIG. 5A. FIG. 5C shows a cross-section through a portion of the dial recess 38. FIG. 5D is an enlarged view of a portion of the dial recess 38 of FIG. 5C.

[0070] FIG. 5B shows the dial recess 38, the flange 40, the first opening 132, and the second opening 134. As shown from FIG. 5B to FIG. 5D, a protrusion or detent 136 projecting from the side portion 138 of the base 12 forming the dial recess 38 can be positioned inside the dial recess 38. Although a single detent 136 is shown from FIG. 5B to FIG. 5D, it is contemplated that multiple detents or other engagement features can be utilized in other embodiments. As best shown in FIG. 5D, the detent 136 can be an arm having a tapered or angled ramp surface 140 and a peak 142 adjacent to the ramp surface 140.

[0071] Figures 6A and 6B show an embodiment of the arm 48. As shown in Figure 6A, the arm 48 can have an elongated length with a body 144, a first end 146, and a second end 148. The first end 146 can be opposite the second end 148. The first end 146 can include an opening 150. The second end 148 can include a pin 152. The opening 150 can be configured to receive the fastener 46 (Figure 1A). The pin 152 can be configured to be received within a channel or groove 154 (Figure 7A) inside the dial 54. The groove 154 can have an arcuate or curved shape and can include, for example, a cam groove.

[0072] Figures 7A and 7B show the dial 54. As shown in Figure 7A, the dial 54 includes a first scale 24 along a surface 155. The dial 54 can include a handle portion 156 (Figure 7A) with an opening 158 (Figure 7A) configured to receive a fastener 52 (Figure 1A) therein. The dial 54 can further include a ratchet 160 with a detent 161 along its second side 162.

[0073] The detent 161 can be shaped to interact with the ramp surface 140 and the peak 142 (Figure 5D) of the tooth stop 136 (Figure 5D). The engagement of the tooth stop 136 and the detent 161 can hold the dial 54 relative to the base 12 (Figure 1A) unless selectively rotated by the surgeon. The interaction and engagement of the arm 48 (Figures 6A and 6B), specifically the pin 152 and the channel or groove 154, can cause pivotal rotation of the body 14 (Figure 1A) along with the pivotal movement of the dial 54. The pin 152 and the channel or groove 154 can also limit the rotation of the dial 54 when the pin 152 (Figures 6A and 6B) reaches one of the ends of the channel or groove 154. This limitation to the rotation of the dial 54 can be, for example, a substantial 9 degrees including 9 degrees in the clockwise direction from a neutral position and a substantial 9 degrees including 9 degrees in the counterclockwise direction.

[0074] Figure 8 shows an instrument 10 assembled to the distal portion 200 of the femur 202. The instrument 10 is in the process of measuring the proximal-distal size of the femur 202 using the strut assembly 20 and the stylus 22 as described previously. Briefly, the base 12 can be positioned to contact the posterior and anterior condyles 206 (only one condyle is shown in Figure 8) via the paddle 36 of the base 12 (only one is shown in Figure 8). The strut assembly 20 may be movable to an appropriate posterior reference height relative to the body 14. The stylus 22 may be movable relative to the body 14 and the strut assembly 20 to reference a second portion of the femur 202, such as by referencing an anatomical feature (e.g., the anterior cortex). Using the graduations (second, third, fourth, fifth, etc.) discussed previously, the anterior-posterior size can be measured and an appropriate stock size of the femoral implant can be selected.

[0075] Figure 9 shows an instrument 10 assembled to the distal portion 200 of the femur 202 and in the process of measuring the rotation of the femur 202. Specifically, the adjustment mechanism 18 can be rotated clockwise relative to the base 12 to rotate the body 14 relative to the base 12 and the femur 202 via the linkage assembly 16. The rotation of the femur 202 and the body 14 is indicated by the first graduation 24 on the dial 54. The rotation up to 9 degrees shown in Figure 9 is purely exemplary and is shown to illustrate the rotational ability of the instrument 10 for measuring the rotation of the femur 202 for the purpose of assembling an implant, guide, etc. The rotation of the femur is determined by visual alignment with the Whiteside line running from the center of the intercondylar notch to the deepest point of the trochlear groove.

[0076] Figure 10 shows an instrument 10 that is assembled to the distal portion 200 of the femur 202 and is in a process of using one of the drill guide openings 128B and the drill guide opening 44. The use of one of the drill guide openings 128B and the drill guide opening 44 can occur once the proximal-distal size and rotation of the femur 202 are determined. Specifically, the drill guide opening 128B can be used to guide a first tool 208 (such as a drill, pin, fastener, etc.) into the femur 202. Once installed, a drill, pin, fastener, etc. can be removed or used to assist in the assembly of the base 12 to the femur 202. A similar process can also be repeated with the drill guide opening 128A.

[0077] To create a recess within the femur 202, a second tool 210 (such as a drill) can be guided by one of the drill guide openings 44 of the body 14. This recess can be used for a cut guide (such as via a peg, pin, fastener, etc.) for performing resection or other surgical techniques on the femur 202 or for the assembly of other instruments. It is possible to repeat the use process of the second tool 210 by using a second one of the drill guide openings 44 to guide a perforation on the second lateral side of the body 14.

[0078] Optionally, the instrument 10 can include a modular accessory set not specifically shown. The instrument 10 and the accessories can be provided together as one system. In this way, a surgeon or another user can select a first accessory from the system and attach it to or use it with the instrument 10. Depending on the progress of the surgical procedure, the surgeon can select a second accessory from the system and attach it to or use it with the instrument 10 or the first accessory. Thus, in some embodiments, the first accessory can remain in place when the second accessory is attached. To selectively house and hold the desired modular accessories on the instrument 10, various coupling mechanisms (e.g., threaded joints) and locking mechanisms (e.g., wedges, detent balls, etc.) can be used. Additional information regarding modular accessories for the instrument 10 can be found in U.S. Patent No. 10,166,034 to Claypool et al. entitled "Knee Arthroplasty Instrument," the entire disclosure of which is incorporated herein by reference.

[0079] Unless otherwise indicated, the components described herein can be monolithic (i.e., single-component structures) or can be joined together using known methods (e.g., using mechanical mechanisms known in the art such as interference fits, joining features such as threads, mating elements, etc.).

[0080] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings, by way of example, illustrate specific examples in which the present invention can be practiced. These examples are also referred to herein as "embodiments". Such embodiments can include elements in addition to those illustrated or described. However, the inventors of the present application also contemplate embodiments in which only the illustrated or described elements are provided. Further, the inventors of the present application also contemplate embodiments (or one or more aspects thereof) that use any combination or substitution of these illustrated or described elements, either with respect to a particular embodiment (or one or more aspects thereof) or with respect to other embodiments (or one or more aspects thereof) illustrated or described herein.

[0081] In the event of any conflict in usage between this document and any document so incorporated by reference, the usage in this document shall govern.

[0082] As used herein, the term "a" or "an" is used to include one or more than one, regardless of any other instance or use of "at least one" or "one or more", as is common in patent documents.

[0083] In this book, unless otherwise indicated, the term "or" means non-exclusive or, or "A or B" is used to include "A but not B", "B but not A", and "A and B". In this book, the terms "including" and "in which" are used as plain English equivalents of the respective terms "comprising" and "wherein". Similarly, in the following claims, the terms "including" and "comprising" are open-ended, i.e., a system, device, article, composition, formulation, or process that includes elements in addition to those recited after such terms in the claim is still considered to be within the scope of that claim. Moreover, in the following claims, the terms "first", "second", and "third" are used only as labels and are not intended to impose numerical requirements on their objects.

[0084] The above description is intended to be illustrative rather than restrictive. For example, the above-described embodiments (or one or more aspects thereof) may be used in combination with each other. For example, those skilled in the art may be able to use other embodiments after examining the above description. The abstract is provided in compliance with 37 C.F.R. § 1.72(l) to enable the reader to quickly confirm the technical disclosure. The abstract is submitted with the understanding that it is not to be used to interpret or limit the scope or meaning of the claims. Similarly, in the above detailed description, various features may be grouped together to simplify the disclosure. This should not be construed as intending that features of the disclosed subject matter not claimed are essential to any of the claims. Rather, the inventive subject matter may lie in less than all the features of a particular disclosed embodiment. Accordingly, the following claims are hereby incorporated into the detailed description by way of example, or as separate embodiments each standing on its own, and such embodiments are intended to be combinable with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the appended claims, along with the full scope of equivalents to which those claims are entitled.

Claims

1. An orthopedic instrument for knee arthroplasty, comprising: a base having one or more paddles configured to be placed in contact with one or both of the medial and lateral condyles of the femur and configured to be referenced; a body coupled to the base so as to rotate relative to the base, the body including a recess and a slot therein and a first scale along a first surface of the body adjacent to the slot; a strut housed within the recess and movable relative to the body, the strut having a second scale used in conjunction with the first scale to determine the posterior size of the femur; an adjustment mechanism having a third scale for indicating rotation of the femur, the adjustment mechanism being configured to rotate the body relative to the base in a desired direction based on rotation of the femur; An orthopedic instrument for knee arthroplasty, comprising the above components.

2. The instrument according to claim 1, further comprising a plurality of retaining mechanisms including ball and spring assemblies, the plurality of retaining mechanisms being positioned between various components including at least between the base and the body, between the strut and the body, and between the strut and the stylus.

3. The instrument according to any one of claims 1 to 2, wherein the adjustment mechanism includes a dial with a handle configured for manual adjustment by a surgeon.

4. The instrument according to any one of claims 1 to 3, wherein the strut comprises an assembly including an outer sleeve, an inner shaft, and a cap, the outer sleeve being configured to translate but having a fixed rotation relative to the body, while the inner shaft is configured to rotate relative to the outer sleeve and the body.

5. The instrument according to claim 4, further comprising a stylus coupled to the strut by the cap and movable relative to the strut, the cap including an opening for housing a ball, the stylus including a plurality of detents configured to be engaged by the ball.

6. The instrument according to claim 5, wherein the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be housed within one of the one or more grooves.

7. The inner shaft is configured to hold a spring that engages with the ball, and the ball is biased by the spring toward the stylus, the instrument according to any one of claims 5 to 6.

8. The outer sleeve is fixed against rotation relative to the body by a protrusion that defines the second scale, and the protrusion is captured within the slot, the instrument according to any one of claims 4 to 7.

9. The body includes a plurality of guide openings therein, and the base includes a plurality of second guide openings therein, the instrument according to any one of claims 1 to 8.

10. The base includes the recess, the detent, and the slot, and the adjustment mechanism is a dial configured to be rotatably inserted within the recess and selectively engage the ratchet and the detent, and the slot is configured to receive an arm that couples the base to the body, the instrument according to any one of claims 1 to 9.

11. The arm is engaged by the dial and is capable of traveling within an arcuate groove within the dial, the instrument according to claim 10.

12. Via the adjustment mechanism, the body has a rotational capacity of up to 18 degrees (including 18 degrees) relative to the base, the instrument according to any one of claims 1 to 11.

13. An orthopedic instrument for knee arthroplasty, A base having one or more paddles configured to be placed in contact with one or both of the medial and lateral condyles of the femur and configured to be referenced, A body coupled to the base so as to rotate relative to the base, the body including a recess and a slot therein and a first scale along a first face of the body adjacent to the slot, A strut assembly housed within the recess and movable relative to the body, the strut assembly including an outer sleeve, an inner shaft, and a cap, the outer sleeve being translational but fixed against rotation relative to the body, while the inner shaft is configured to rotate relative to the outer sleeve and the body, and the strut having a second scale used with the first scale to determine the posterior size of the femur, the strut assembly A stylus coupled to the strut by the cap and movable relative to the strut, An orthopedic instrument for knee arthroplasty, including **Claim 14** The instrument according to claim 13, wherein the cap includes an opening for receiving a ball, and the stylus includes a plurality of detents configured to be engaged by the ball. **Claim 15** The instrument according to claim 14, wherein the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be received within one of the one or more grooves. **Claim 16** The instrument according to any one of claims 14 to 15, wherein the inner shaft is configured to hold a spring that engages the ball, and the ball is biased by the spring toward the stylus. **Claim 17** The instrument according to any one of claims 13 to 16, wherein the outer sleeve is fixed against rotation relative to the body by a protrusion that defines the second scale, and the protrusion is captured within the slot. **Claim 18** An adjustment mechanism having a third scale for indicating rotation of the femur, the adjustment mechanism configured to rotate the body relative to the base in a desired direction based on rotation of the femur, A plurality of retaining mechanisms including a ball and spring assembly, the plurality of retaining mechanisms positioned between various components including at least between the base and the body and between the strut assembly and the body, The instrument according to any one of claims 13 to 17, further comprising **Claim 19** An orthopedic instrument for knee arthroplasty, A base having one or more paddles configured to be placed in contact with one or both of the medial and lateral condyles of the femur and configured to be referenced, A body coupled to the base for rotation relative to the base, the body including an internal recess and slot and a first scale along a first surface of the body adjacent to the slot, A strut received within the recess and movable relative to the body, the strut having a second scale used with the first scale to determine a posterior size of the femur, A stylus coupled to the strut and movable relative to the strut, An adjustment mechanism having a third scale for indicating rotation of the femur, the adjustment mechanism configured to rotate the body relative to the base in a desired direction based on rotation of the femur; A ball and spring assembly configured to hold the stylus together with the strut; An orthopedic instrument for knee arthroplasty, comprising: **Claim 20** The instrument according to claim 19, wherein the strut includes a cap having an opening for receiving the ball, the stylus includes a plurality of detents configured to be engaged by the ball, the cap includes one or more grooves and one or more protrusions, and the stylus includes one or more lateral protrusions configured to be received within one of the one or more grooves.

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