Arthrogenesis balance and gap gauge

Abstract

A gap gauge for facilitating arthroplasty of a first bone and a second bone of a patient is disclosed. The gap gauge can include a first plate positionable in contact with the first bone and a second plate positionable in contact with the second bone. The second plate can be displaced from the first plate by a displacement. The gap gauge can also include a separator connected to the first plate and the second plate, a separation indicator coupled to the separator and configured to indicate the displacement, and a balance indicator connected to at least one of the first plate and the second plate. The balance indicator can be configured to indicate a balance status between the first plate and the second plate. The separator can be actuated to adjust the displacement.

Description

Technical Field

[0001] The present disclosure relates to surgical devices. More specifically, the present disclosure relates to improved surgical instruments for arthroplasty.

Background Art

[0002] Arthroplasty can be used to relieve joint pain or restore joint function due to conditions such as osteoarthritis, rheumatoid arthritis, or other joint conditions via minimally invasive or invasive surgery. Arthroplasty can be performed on any joint and can include partial or total joint replacement with replacement prostheses or prostheses. During arthroplasty, a surgeon may wish to measure the size of the opening between the two bones of the joint. In addition, the surgeon may also wish to measure the balance of the joint in addition to the size of the opening (referred to as the gap) between the two bones of the joint. For example, during partial or total knee arthroplasty (TKR), a surgeon may wish to measure or gauge the displacement between the two bones of the joint and the balance of the joint. Performing such measurements during minimally invasive or invasive arthroplasty can be challenging considering the forces applied to the joint by the ligaments of the joint and other soft tissues around the joint. Therefore, there is a need for improved systems and methods for measuring the interosseous gap and / or angle during the process of arthroplasty.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The various apparatuses, devices, systems, and / or methods of this disclosure have been developed in response to the current state of the art, and in particular to problems and needs in the art that have not yet been fully addressed by currently available arthroplasty balance gauges or arthroplasty gap gauges. The apparatuses, devices, systems, and / or methods of this disclosure may provide arthroplasty balance, gap gauge, and cutting guide adjustments in a single device that correct the shortcomings of separate arthroplasty balance gauges, arthroplasty gap gauges, and / or cutting guides of the prior art. [Means for solving the problem]

[0004] To achieve the above, and in accordance with the present disclosure embodied and broadly described herein, gap gauges can be provided for facilitating arthroplasty of a patient's first and second bones. One common embodiment of a gap gauge may include a first plate positioned in contact with the first bone and a second plate positioned in contact with the second bone, the second plate being displaced from the first plate by displacement. The gap gauge may also include a separator connected to the first and second plates, the separator being actuated to adjust the displacement; a separation indicator coupled to the separator and configured to show the displacement; and a balance indicator connected to at least one of the first and second plates and configured to show the balance status between the first and second plates.

[0005] In one embodiment, the balance indicator may include a hinge that pivotably connects a second plate to a gap gauge. The hinge may include a pin having a longitudinal axis which is the pivot axis of the second plate. The longitudinal axis may be parallel to the patient's anterior-posterior axis so that the rotation of the second plate about the pivot axis measures one of the following conditions: varus, balanced, and valgus of the first bone relative to the second bone.

[0006] In another embodiment, the gap gauge may include a support plate connected to a hinge and a separator, and the balance indicator may include a lockout mechanism configured to prevent rotation of one of a first plate and a second plate connected to the balance indicator. The lockout mechanism may include a set screw having set and unset configurations, the set screw may include threads configured to engage with threads in an opening. In the set configuration, the set screw may engage with a pin of the hinge so that the pin does not rotate in response to a rotational force applied to at least one of the first plate and the second plate. The engaged pin may also prevent rotation of at least one of the first plate and the second plate connected to the pin. In the unset configuration, the set screw is disengaged from the pin of the hinge so that the pin rotates in response to a rotational force applied to at least one of the first plate and the second plate. In one embodiment, the set screw engages with the pin by biasing a section of the pin having a D-shaped cross-section.

[0007] In one embodiment, the gap gauge may include a first plate molded to engage with the medial and lateral condyles of a first bone, and a second plate molded to engage with the medial and lateral condyles of a second bone.

[0008] In one embodiment, the gap gauge may include a balance gauge connected to a balance indicator. The balance gauge may be configured to measure the balance status. The gap gauge may include a dial having marks positioned on the surface of the dial to indicate a measurement of the balance status of a second plate relative to a first plate, and a needle connected to a balance indicator such that rotation of the second plate about the longitudinal axis of the second plate moves the needle toward the marks on the surface of the dial that reflect the balance status.

[0009] One general embodiment may have an upper plate extending from an upper body, the upper plate being molded to conform to the resection surface of the femur, and may include a lower plate extending from a lower body, the lower plate being molded to conform to the resection surface of the tibia, and the upper plate being displaced from the lower plate by displacement. The gauge may also include a shaft to which at least one of the upper and lower bodies is slidably coupled to allow adjustment of displacement, a separator connected to the upper and lower bodies for adjusting the displacement, and a balance indicator connected to one of the upper and lower plates and configured to indicate the orientation of the upper plate relative to the lower plate.

[0010] In one embodiment, the balance indicator is connected to an upper plate, the upper plate includes a pivot plate and a support plate, and the balance indicator includes a hinge including a pin connected to the pivot plate so that a force applied to the pivot plate can rotate the pivot plate around the pin. The support plate is coupled to the separator so that the operation of the separator moves the support plate perpendicular to the lower plate. The pin may include a cylindrical structure having a longitudinal axis, a proximal end, a distal end, and a center. The proximal end may be connected to a balance gauge, and the distal end includes a pivot for the balance indicator. The pivot may be aligned with the longitudinal axis. In one embodiment, the proximal end may include a first D-shaped cross section, the distal end may include at least one keyed cross section, and the center may include a second D-shaped cross section in which the flat portion of the second D-shaped cross section is offset by 90 degrees from the flat portion of the first D-shaped cross section. The distal end functions as the pivot for the hinge.

[0011] In one embodiment, the gap gauge further includes a handle connected to a lower body, a separation indicator coupled to a separator and configured to indicate displacement, a lockout mechanism connected to an upper body and configured to prevent rotation of an upper plate or a portion of an upper plate connected to a balance indicator, and a spring coupled to a shaft that biases one of the upper body and the lower body in opposition to the movement of the upper plate away from the lower plate. The separator may include a driver, a cam connected to the lower body via the driver, the cam having a contact surface, and a driven part connected to the upper body and configured to be biased to contact the contact surface of the cam so that the rotation of the cam adjusts the displacement. In one embodiment, the driven part slidably contacts the contact surface. The cam may include a radial cam having a central axis, and the contact surface is the circumference of the radial cam about the central axis.

[0012] In one embodiment, the gap gauge may include a balance gauge connected to a balance indicator. The balance gauge may include a dial having marks positioned on its surface to indicate a measure of the orientation of the upper plate relative to the lower plate. The balance gauge may also include a needle connected to the balance indicator such that rotation of one of the upper or lower plates around the patient's anterior-posterior axis moves the needle toward a mark on the surface of the dial that reflects the orientation.

[0013] One general aspect of the present disclosure may include a method for measuring the gap between a patient's femur and tibia. The method may include inserting a first plate and a second plate of a gap gauge between the femur and tibia; activating the first plate and the second plate so that the first plate contacts the resection surface of the femur and the second plate contacts the resection surface of the tibia; reading the separation indicator of the gap gauge to obtain the displacement between the femur and tibia; and reading the balance indicator of the gap gauge to obtain the balance status between the femur and tibia.

[0014] In one embodiment, the method may also include adjusting the tension applied to the femur and tibia by one or more of the medial and lateral collateral ligaments, and reading a balance indicator on a gap gauge to obtain an adjusted balance status between the femur and tibia in response to the adjustment of the tension.

[0015] In another embodiment, adjusting the tension may also involve releasing one or more of the medial collateral ligament and the lateral collateral ligament while the gap gauge remains in place and operating between the femur and tibia.

[0016] In another embodiment, adjusting the tension may also include removing the gap gauge from between the femur and tibia, cutting off one or more of the cut surfaces of the femur and tibia, reinserting the first and second plates of the gap gauge between the femur and tibia, operating the first and second plates apart so that the first plate contacts the cut surface of the femur and the second plate contacts the cut surface of the tibia, reading the separation indicator of the gap gauge to obtain the displacement between the femur and tibia, and reading the balance indicator of the gap gauge to obtain the balance status between the femur and tibia.

[0017] In one embodiment, a gap gauge may be provided to facilitate arthroplasty of a patient's first and second bones. One common embodiment of the gap gauge may include a first plate that is positioned in contact with the first bone. The gap gauge also includes a second plate that is positioned in contact with the second bone, the second plate being displaced from the first plate by displacement. The gap gauge also includes a balance indicator configured to show the balance status between the first and second plates. The gap gauge also includes a pin guide configured to bond to one of the second and first plates, the pin guide may include a first pinhole configured to guide the insertion of a first pin into the second bone.

[0018] In one embodiment, the pin guide may include a mounting function configured to removably connect the pin guide to the second plate so that the pin guide guides the insertion of the first pin into the second bone in accordance with the balance status between the first plate and the second plate. The pin guide may further include a mounting function configured to removably connect the pin guide to the second plate so that the pin guide guides the insertion of the first pin into the first bone in accordance with the balance status between the first plate and the second plate.

[0019] In another embodiment, the pin guide may include a second pinhole configured to guide the insertion of a second pin into a second bone. In one embodiment, the pin guide is coupled to and extends from the first plate, and as a result, the pin guide guides the insertion of the first and second pins into the second bone, and as a result, the first and second pins are angled relative to the second plate to counteract the balance status between the first and second plates.

[0020] In one embodiment, the first pinhole may include a second pinhole configured to guide the insertion of the first pin into one of the medial and lateral condyles of the second bone, and the pin guide may include a second pinhole configured to guide the insertion of the second pin into the other of the medial and lateral condyles of the second bone.

[0021] In another embodiment, the pin guide may include a second pinhole configured to guide the insertion of a second pin parallel to a first pin into a second bone, and an adjustment function configured to rotate the first and second pinholes together to counteract different angular offsets of the balance status.

[0022] In one aspect, the pin guide may include a base configured to connect to a second plate, an arm that may include a first pin hole, and a mast extending from the base, the mast connecting the arm and the base. The arm may include a second pin hole, and when the gap gauge is in a predetermined position relative to the knee, the first pin hole and the second pin hole are each disposed within the arm on one of the inner and outer sides of the knee.

[0023] In another aspect, the pin guide may include a second pin hole configured to guide the insertion of a second pin into a second bone such that the first pin and the second pin are aligned with each other in a direction based on a second plate where the first pin and the second pin are in a balanced state, and by coupling a cutting guide to the second bone via the first pin and the second pin, the balance status is transmitted to the cutting guide.

[0024] In one aspect, the cutting guide may include a set of multiple holes and may include an alignment mechanism that includes each element (each set) of the set of holes configured to receive one of the first pin and the second pin. The holes of each set may be configured to adjust different angular offsets of the balance status.

[0025] In another aspect, the cutting guide may include a guide mechanism configured to guide the movement of a cutter for excising bone, an alignment mechanism configured to receive the first pin and the second pin and dispose the cutting guide on the bone, and an adjustment mechanism configured to rotate the guide mechanism relative to the alignment mechanism to adjust different angular offsets from the balance status.

[0026] In one aspect, the first plate and the second plate are sized to be inserted between a first bone that may include a tibia and a second bone that may include a femur.

[0027] One general aspect can include a gap measurement and correction assembly for facilitating arthroplasty of a patient's femur and tibia. The gap measurement and correction assembly can also include an upper plate extending from an upper body, a lower plate extending from a lower body, where the upper plate is displaceable from the lower plate by displacement, a separator connected to the upper body and the lower body for adjusting the displacement, a balance indicator connected to one of the upper plate and the lower plate and configured to indicate a non-parallel orientation of the upper plate with respect to the lower plate, and a pin guide configured to guide insertion of a first pin into one of the patient's tibia and femur. The gap measurement and correction assembly can also include a cutting guide attachable to one of the tibia and femur via the first pin, and the cutting guide is configured to guide resection of one of the tibia or femur that resists the non-parallel orientation.

[0028] In one aspect, the assembly can further include an attachment feature configured to removably couple the pin guide to the upper plate such that the pin guide guides insertion of the first pin into the femur according to a non-parallel orientation of the upper plate with respect to the lower plate. The pin guide can further include an attachment feature configured to removably couple the pin guide to the upper plate such that the pin guide guides insertion of the first pin into the tibia according to a non-parallel orientation of the upper plate with respect to the lower plate.

[0029] In another aspect, the pin guide is further configured to guide a second pin into the other of the patient's tibia and femur, and the pin guide can further include an attachment feature configured to removably couple the pin guide to the lower plate such that the pin guide guides insertion of the first pin and the second pin into the femur, such that the first pin and the second pin are aligned at an angle with respect to the upper plate that resists a non-parallel direction of the upper plate with respect to the lower plate.

[0030] In one embodiment, the pin guide may include a base configured to connect to an upper plate, an arm which may include a first pin hole, and a mast extending from the base which connects the arm to the base. The cutting guide may include an alignment mechanism which includes a set of holes, each member of the set of holes configured to receive one of a first pin and a second pin, and each set of holes configured to adjust for different angular offsets for non-parallel orientation.

[0031] In another embodiment, the cutting guide may include a guide mechanism configured to guide the movement of a cutter to cut bone, an alignment mechanism configured to receive a first pin and a second pin and position the cutting guide on the bone, and an adjustment mechanism configured to rotate the guide mechanism relative to the alignment mechanism to adjust for different angular offsets from a non-parallel orientation.

[0032] One general embodiment may include a method for measuring and correcting imbalances for femoral and tibia arthroplasty in a patient. The method includes inserting a first plate and a second plate of a gap gauge between the femur and tibia of the patient's knee joint. The method also includes operating the first and second plates apart so that the first plate contacts the resection surface of the femur and the second plate contacts the resection surface of the tibia. The method also includes reading the balance indicator of the gap gauge to obtain a balance status between the femur and tibia, inserting a first pin through the pin guide of the gap gauge, fixing the first pin to one of the femur and tibia, and using the first pin to attach a cutting guide to one of the femur and tibia. The method also includes using the cutting guide to guide the resection of one of the femur and tibia and counteracting the non-parallel direction of the first plate relative to the second plate.

[0033] These and other features of this disclosure are sufficiently apparent from the following statements and attached claims, or can also be known by performing the disclosures described herein. [Brief explanation of the drawing]

[0034] The exemplary embodiments of this disclosure will become more fully apparent from the following description and the appended claims, together with the accompanying drawings. Understanding that these drawings only illustrate exemplary embodiments and should not be considered to limit the scope of the appended claims, the exemplary embodiments of this disclosure will be described with additional specificities and details through the use of the accompanying drawings:

[0035] [Figure 1A] Figure 1A is a perspective view of a gap gauge according to one embodiment of the present disclosure. [Figure 1B] Figure 1B is a perspective view of the gap gauge shown in Figure 1A. [Figure 1C] Figure 1C is a top view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1D] Figure 1D is a bottom view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1E] Figure 1E is a side view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1F] Figure 1F is a side view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1G] Figure 1G is a side view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1H] Figure 1H is a rear view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1I] Figure 1I is a front view of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a frontal view of the knee joint with the gap gauge from Figure 1A inserted between the two bones. [Figure 3]Figure 3 is a frontal view of the knee joint with the gap gauge from Figure 1A inserted between the two bones. [Figure 4] Figure 4 is a posterior view of the knee joint with the gap gauge from Figure 1A inserted between the two bones. [Figure 5A] Figure 5A is a rear view of the gap gauge shown in Figure 1A, illustrating different balance status states. [Figure 5B] Figure 5B is a rear view of the gap gauge shown in Figure 1A, illustrating different balance status states. [Figure 5C] Figure 5C is a rear view of the gap gauge shown in Figure 1A, illustrating different balance status states. [Figure 6A] Figure 6A is a rear view of the gap gauge shown in Figure 1A, illustrating different displacements. [Figure 6B] Figure 6B is a rear view of the gap gauge shown in Figure 1A, illustrating different displacements. [Figure 6C] Figure 6C is a rear view of the gap gauge shown in Figure 1A, illustrating different displacements. [Figure 7] Figure 7 is a perspective view of the gap gauge shown in Figure 1A. [Figure 8A] Figure 8A is a front view of a gap gauge driver according to one embodiment of the present disclosure. [Figure 8B] Figure 8B is a rear view of a gap gauge driver and cam according to one embodiment of the present disclosure. [Figure 9] Figure 9 shows an exploded view of a gap gauge according to one embodiment of the present disclosure. [Figure 10A] Figure 10A is a perspective view of the pin of the gap gauge shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 10B] Figure 10B is a side view of the pin in Figure 10A according to one embodiment of the present disclosure. [Figure 10C] Figure 10C is a side view of the pin in Figure 10A according to one embodiment of the present disclosure. [Figure 11A] Figure 1A is a perspective view of a lockout mechanism for a gap gauge according to one embodiment of the present disclosure. [Figure 11B] Figure 11B is a perspective view of a lockout mechanism for a gap gauge according to one embodiment of the present disclosure. [Figure 12] Figure 12 shows a flowchart for measuring the gap and / or balance status between a patient's femur and tibia according to one embodiment of the present disclosure. [Figure 13] [Figure 14A] [Figure 14B] [Figure 14C] [Figure 15] [Figure 16A] [Figure 16B] [Figure 17A] [Figure 17B] [Figure 17C] [Figure 17D] [Figure 18A] [Figure 18B] [Figure 18C] [Figure 19] [Figure 20] [Figure 21] [Figure 22]

[0036] Please understand that the drawings are intended to illustrate the concepts of this disclosure and may not be drawn to actual size. Furthermore, the drawings show exemplary embodiments and do not constitute a limitation on the scope of this disclosure. [Modes for carrying out the invention]

[0037] The exemplary embodiments of this application are best understood by reference to the drawings, and throughout the drawings, similar parts are designated by similar numbers. It will be readily apparent that the components of this disclosure, as generally described and illustrated in the drawings of this application, can be arranged and designed in a wide variety of different configurations. That is, the following more detailed description of embodiments of apparatus and methods as shown in the drawings is not intended to limit the scope of this disclosure as claimed in this application or any other application claiming priority to this application, but is merely representative of exemplary embodiments of this disclosure.

[0038] This specification employs standard medical orientations, reference planes, and descriptive terminology. For example, anterior means facing the front of the body. Posterior means facing the back of the body. Superior means facing the head. Inferior means facing the feet. Medial means facing the midline of the body. Lateral means moving away from the midline of the body. Axial means facing the central axis of the body. Abaxial means moving away from the central axis of the body. Ipsilateral means the same side with respect to the body. Contralateral means the opposite side with respect to the body. The sagittal plane divides the body into left and right halves. The midsagittal plane divides the body into a symmetrical right and left half. The coronal plane divides the body into anterior and posterior parts. The transverse plane divides the body into upper and lower parts.

[0039] The anterior-posterior axis is the axis perpendicular to the coronal plane. The medial-lateral axis is the axis perpendicular to the midplane. The craniocaudal axis is the axis perpendicular to the transverse plane. These descriptive terms can be applied to living or non-living bodies.

[0040] The terms “connected,” “joined,” and “in contact” refer to any form of interaction between two or more objects, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interactions. Two components can be functionally coupled to one another even if they are not in direct contact with each other. The term “contacting” refers to objects that are in direct physical contact with each other, but the objects are not necessarily mounted together. The term “fluid communication” refers to two mechanisms that are connected in such a way that fluid from one mechanism can flow into the other.

[0041] The term “exemplary” is used herein to mean “serving as an example, illustration, or representation.” No embodiment described herein as “exemplary” is necessarily construed as preferable or advantageous to any other embodiment. Various aspects of the embodiments are shown in the figures, which are not necessarily drawn to exact scale unless otherwise indicated.

[0042] This disclosure discloses a gap gauge for facilitating arthroplasty of the first and second bones of a patient. During arthroplasty, the surgeon may need to confirm that the gap between the two bones of the joint is the desired displacement and that the joint has the desired balance (e.g., balanced, varus, or valgus). Using separate instruments to obtain either displacement or balance status can complicate the procedure and may require more personnel to assist the procedure. When one instrument is replaced with another (e.g., an instrument that measures only balance status and an instrument that measures only displacement), the joint site may shift the displacement and thus alter the displacement that has already been measured, or alter the balance status read using a balance measurement with a single instrument, or an instrument that cannot provide both displacement measurement and balance status. Thus, there is a need for an improved gap gauge. In particular, there is a need for a gap gauge that can provide both displacement measurement and balance status (e.g., balance measurement) using a single instrument. Furthermore, the disclosure provides a gap gauge that allows the user to optionally remove / disable the balance indicator or balance gauge 168 during use, so that the user can use the same instrument to measure only the displacement between two articular bones if necessary.

[0043] Figure 1A is a perspective view showing one exemplary embodiment of a gap gauge 100 for facilitating arthroplasty of a patient's first and second bones. As used herein, “arthroplasty” refers to a surgical procedure to restore and / or improve the function and / or operation of a patient’s joints. Arthroplasty can be performed on the toe joint, ankle joint, knee joint, hip joint, wrist joint, elbow joint, finger joint, etc. In the illustrated embodiment, the first bone may be the femur 102 and the second bone may be the tibia 104. As used herein, “gap gauge” refers to a device, instrument, structure, device, component, system, assembly, hardware, software, firmware, circuit, module, or logic configured, organized, programmed, designed, arranged, or designed to measure the attributes, characteristics, state, or condition of another structure or object, or a set of structures or objects. In one embodiment, the gap gauge is structured, organized, organized, programmed, designed, arranged, or designed to measure the displacement between two structures.

[0044] As part of arthroplasty, a gap gauge 100 can be inserted into an opening 106, also called a gap, between a first bone and a second bone. Using the gap gauge 100, it is possible to determine how much displacement exists between the first bone and the second bone within the opening 106. As used herein, “opening” refers to a gap, hole, opening, void in a structure, etc. In certain embodiments, an opening may refer to a structure specifically configured to receive and / or allow access to something. The amount of displacement may be referred herein to measuring the gap or space between the first bone and the second bone.

[0045] In addition, or alternatively, the gap gauge 100 can be used to determine the balance status of a joint 108, which is part of arthroplasty. The joint 108 may be a toe joint, ankle joint, knee joint, hip joint, arm joint, elbow joint, finger joint, etc. In the illustrated embodiment, the joint 108 is a knee joint, the first bone is the femur 102, and the second bone is the tibia 104. The gap gauge 100 can be used as a single device to determine both the displacement and balance status within the opening 106. Alternatively, a user such as a surgeon can use the gap gauge 100 as a single, convenient device to determine the displacement or balance status with respect to the first and second bones, which are in flexion, extension, or an angle between flexion and extension.

[0046] Figure 1A shows the three-dimensional axis 110. The three-dimensional axis 110 includes the craniocaudal axis 112, the medial-lateral axis 114, and the anterior-posterior axis 116. The three-dimensional axis 110 is used to identify how the gap gauge 100 is positioned and / or oriented relative to the anterior-posterior axis 116 of a patient in a reference anatomical position.

[0047] Figure 1B is a perspective view of the gap gauge of Figure 1A. Figure 1B shows a gap gauge 100 without the first or second bone shown. The gap gauge 100 may generally include a first plate, a second plate, a separator, a separation indicator, and a balance indicator. In the illustrated embodiment, the first plate may be an upper plate 118, and the second plate may be a lower plate 120. The illustrated gap gauge 100 also includes a separator 122, a separation indicator 124, and a balance indicator 126.

[0048] In one embodiment, the upper plate 118 is a plate. As used herein, “plate” refers to a flat structure or a generally flat structure. In certain embodiments, the plate may be configured to support a load. In certain embodiments, the plate may include a generally planar structure. The plate may be a separate structure connected to or integrated with another structure. Alternatively, the plate may be connected to part of another structure. The plate may be two-dimensional or three-dimensional and may have a variety of geometric shapes and / or cross-sectional shapes, including but not limited to rectangles, squares, or other polygons, as well as circles, ellipses, ovals, or other circular or semicircular shapes. The plate may be made from a variety of materials, including metal, plastic, ceramic, wood, fiberglass, and the like. The lower plate 120 may also be a plate.

[0049] The upper plate 118 can be positioned on the opposite side of the lower plate 120. The upper plate 118 can be positioned in contact with a first bone (e.g., femur 102). The lower plate 120 can be positioned in contact with a second bone (e.g., tibia 104). The upper plate 118 and the lower plate 120 are parallel to each other and can cooperate to slide in an opening or gap.

[0050] In one embodiment, the upper plate 118 and the lower plate 120 have structural integrity that allows them to be positioned (e.g., inserted) between the femur 102 and the tibia 104. When initially positioned between the two bones, the upper plate 118 and the lower plate 120 may be in contact with each other, as shown in Figure 1A. Once positioned between the two bones, the user can move the upper plate 118 relative to the lower plate 120, which adjusts the displacement 128 between the upper plate 118 and the lower plate 120. When the upper plate 118 and the lower plate 120 are in contact with each other, the displacement 128 may be zero. In one embodiment, the upper plate 118 and the lower plate 120 may be displaced from each other by the displacement 128 when the gap gauge 100 is first manufactured / assembled.

[0051] As used herein, “displacement” refers to the distance between two objects or the distance between a structure, member, object, component, or part that has moved from a starting position to an ending position, or has had its position changed. Displacement can be measured using a variety of units of measurement, including imperial units, metric units, and angular units. In certain embodiments, displacement is measured in millimeters. In one embodiment, displacement 128 may range from 0 to 25 or more millimeters.

[0052] The user can adjust the displacement 128. The user can separate the upper plate 118 and the lower plate 120 by manually pulling them apart, and / or the user can separate the upper plate 118 and the lower plate 120 using the separator 122. The user may also bring the upper plate 118 and the lower plate 120 together by manually positioning them, and / or the user may bring the upper plate 118 and the lower plate 120 together using the separator 122.

[0053] The separator 122 is connected to the upper plate 118 and the lower plate 120. The separator 122 can adjust the displacement 128. In one embodiment, the operation of the separator 122 adjusts the displacement 128. As used herein, “separator” means a device, apparatus, structure, device, component, system, assembly, or module that is structured, organized, configured, programmed, designed, arranged, or designed to separate a first structure from another structure. In one embodiment, the separator is structured, organized, configured, programmed, designed, arranged, or designed to separate a first plate from a second plate, thereby creating a distance between the first plate and the second plate. The separator 122 can actively adjust the displacement 128 and / or hold the upper plate 118 and the lower plate 120 in a particular state of separation, thereby maintaining a desired displacement 128.

[0054] The separation indicator 124 indicates the displacement 128 between the upper plate 118 and the lower plate 120. The separation indicator 124 can be coupled to the separator 122. As used herein, “separation indicator” means a structured, organized, configured, programmed, designed, arranged, or designed apparatus, device, component, system, assembly, hardware, software, firmware, circuit, module, or logic that indicates to the user the displacement between two or more structures. The separation indicator may include one or more of the following: an audible signal, a tactile signal, a visual signal, or a display. In one embodiment, the visual indicator of the separation indicator may include a number or set of numbers representing units of measurement for the displacement (or distance) between two or more structures. Alternatively or additionally, the separation indicator may include mechanical devices, electromechanical devices, electronic devices (analog or digital), etc.

[0055] The balance indicator 126 indicates the balance status. As used herein, “balance indicator” means a device, component, system, assembly, mechanism, hardware, software, firmware, circuit, module, or logic that is structured, organized, configured, programmed, designed, arranged, or designed to indicate the balance status to a user of a device or apparatus containing a balance indicator. A balance indicator may include one or more of the following: audible signals, tactile signals, visual signals, or displays. Alternatively or additionally, a balance indicator may include mechanical devices, electromechanical devices, electronic devices (analog or digital), etc. As used herein, “balance status” means the state, condition, attribute, value, and / or characteristic of one or more members, components, structures, and / or openings to a desired, correct, and / or equal proportion state between one or more members, components, structures, and / or openings and a reference set of one or more members, components, structures, and / or openings being evaluated, measured, or inspected. In certain embodiments, the balance status may be a binary condition, state, attribute, value, and / or characteristic. For example, the relationship between one or more structures or openings and a reference set of one or more structures or openings may be either balanced or unbalanced (also called imbalanced).

[0056] Alternatively, or additionally, the balance status may be a condition, state, attribute, value, and / or characteristic within a range of possible conditions, states, attributes, values, and / or characteristics. For example, in one embodiment, the balance status may be measured with respect to a scale or range of degrees between a positive maximum value and a negative minimum value, where a balance status of zero on the range represents a balanced state, and a non-zero value along the range represents an unbalanced state. In one embodiment, the range used to measure the balance status may extend from -5 degrees to +5 degrees.

[0057] In certain embodiments, the balance status can represent whether the upper resection of one bone of the joint is parallel to the lower resection of the other bone of the joint. In other embodiments, the balance status can represent to what extent the upper resection of one bone of the joint is parallel to or not parallel to the lower resection of the other bone of the joint. In other embodiments, the balance status can represent how the two bones of the joint and the space / opening between them interact with each other in relation to the medial and lateral collateral ligaments to achieve the desired relationship with the joint.

[0058] In one embodiment, the balance indicator 126 indicates the balance status between the upper plate 118 and the lower plate 120. Alternatively, or additionally, the balance indicator 126 may indicate the balance status of joint 108 and / or the balance status between the medial and lateral collateral ligaments of joint 108. Alternatively, or additionally, the balance indicator 126 may indicate the balance status between the first bone and the second bone. In the context of knee arthroplasty, the balance indicator 126 may indicate whether the arthroplasty is likely to be varus, valgus, or balanced, given that it is completed with implants on the measured bone surface.

[0059] The balance indicator 126 can be connected to one or the other of the upper plate 118 and the lower plate 120, or to both. In one embodiment, the balance indicator 126 is connected to the upper plate 118. In different embodiments, one or more components or elements within the dashed area can function as the balance indicator 126, and therefore the balance indicator 126 is indicated as the dashed area of ​​the gap gauge 100. For example, in one embodiment, the user may observe a non-parallel position of the upper plate 118, or a portion of the upper plate 118, and such observation can function as the balance indicator 126.

[0060] Figures 1C to 1I show a top view (Figure 1C), bottom view (Figure 1D), side view (Figures 1E to G), rear view (Figure 1H), and front view (Figure 1I) of one embodiment of the gap gauge 100. Figure 1C shows an embodiment including a lockout mechanism 130, a pair of grips 132, and a handle 134. As used herein, “handle” refers to a structure used to hold, control, or operate a device, apparatus, component, tool, etc. A “handle” may be designed to be grasped and / or held by one or more hands of a user.

[0061] In certain embodiments, the lockout mechanism 130 may be used by the user to disable, prevent, or turn off the operation of the balance indicator 126 to indicate the balance status. As used herein, “lockout mechanism” refers to any apparatus, fixture, structure, device, component, system, assembly, hardware, software, firmware, circuit, module, or logic configured, configured, programmed, designed, arranged, or designed to prevent, mitigate, or stop the operation of the balance indicator of a gap gauge so that the balance indicator does not report the balance status when the gap gauge is activated. In one embodiment, the lockout mechanism can prevent rotation of a plate connected to the balance indicator of a gap gauge. A pair of grips 132 can be used by the user to position the upper plate 118 relative to the lower plate 120. For example, the user can grasp the pair of grips 132 with one hand and hold the handle 134 with the other hand, and pull up the grips 132 to separate the upper plate 118 from the lower plate 120.

[0062] Figure 1D shows a bottom view of one embodiment of the gap gauge 100. The figure shows the lower plate 120, the lockout mechanism 130, the grip 132, and the handle 134.

[0063] Figure 1E shows a side view of one embodiment of a gap gauge 100. The figure shows an upper plate 118, a lower plate 120, a separator 122, a grip 132, and a handle 134. In addition, the illustrated embodiment includes an upper body 136, a lower body 138, a shaft 140, and a spring 142. As used herein, “body” refers to the main or central part of a structure. In one embodiment, the body may include a housing or frame or framework for a larger system, component, structure, or device. As used herein, “spring” refers to an elastic structure that stores mechanical energy. Springs can be made of various elastic materials such as spring steel and may be cylindrical and / or helical. Various types of springs can be used, such as coil springs and torsion springs. (Searched Wikipedia.com for “spring (device)” on November 28, 2020. Modified. Retrieved January 6, 2020) The upper body 136 provides structural support and integrity to the gap gauge 10 and can accommodate one or more portions of the gap gauge 100. The lower body 138 provides structural support and integrity to the gap gauge 10 and can accommodate one or more portions of the gap gauge 100. In one embodiment, the upper plate 118 extends from the upper body 136 and the lower plate 120 extends from the lower body 138.

[0064] The shaft 140 can connect or link the upper body 136 to the lower body 138. The shaft 140 can be slidably coupled to the upper body 136 and the lower body 138. The slidable coupling between the shaft 140, the upper body 136, and the lower body 138 allows for adjustment of the displacement 128.

[0065] In one embodiment, the shaft 140 can be fitted into an opening in the upper body 136 and pass through the upper body 136 to engage with the lower body 138. In a particular embodiment, the shaft 140 may have threads on the outside of one end of the shaft 140. The threads of the shaft 140 can engage with the threads of an opening in the lower body 138 to connect the shaft 140 to the lower body 138. The shaft 140 may have a head 144 at the end opposite to the end with the threads.

[0066] The opening in the upper body 136 can be sized to accommodate a shaft 140 and a spring 142 wound around the outside of the shaft 140. The spring 142 may be in contact with the upper body 136 and the head 144. The shaft 140 and the spring 142 cooperate to hold the upper body 136 connected to the lower body 138. In one embodiment assembled into the gap gauge 100, the spring 142 can be biased against the head 144 and the upper body 136. The spring 142 can bias the upper body 136 against the movement of the upper plate 118 away from the lower plate 120.

[0067] In certain embodiments, the gap gauge 100 may include a post 146. The post 146 may slidably engage with the upper body 136 and may be connected to the lower body 138. In one embodiment, the post 146 may be screwed into an opening in the upper body 136. The post 146 may cooperate with the shaft 140 to maintain the movement of the upper body 136 along a single axis.

[0068] Figure 1F shows a side view of one embodiment of the gap gauge 100. The side view shows the upper plate 118, lower plate 120, separator 122, lockout mechanism 130, grip 132, handle 134, upper body 136, lower body 138, shaft 140, spring 142, and post 146.

[0069] Figure 1G shows a side view of one embodiment of the gap gauge 100. The side view shows the upper plate 118, lower plate 120, separator 122, lockout mechanism 130, grip 132, handle 134, upper body 136, lower body 138, shaft 140, spring 142, and post 146.

[0070] Figure 1G shows a gap gauge 100 in which a separator 122 operates so that the upper plate 118 and the lower plate 120 are displaced from each other by a displacement 128. In one embodiment, the displacement 128 is a measure between the outer surface of the upper plate 118 and the outer surface of the lower plate 120. Those skilled in the art will recognize that the displacement may also be a measure between the inner surface of the upper plate 118 and the inner surface of the lower plate 120 indicated by the displacement 128'.

[0071] In the illustrated embodiment, the gap gauge 100 may include an upper plate 118 which includes a pivot plate 148 and a support plate 150. The pivot plate 148 may be connected to or coupled to the support plate 150 so that the pivot plate 148 can function as a balance indicator 126. In one embodiment, the pivot plate 148 may pivot about an anterior-posterior axis 116 relative to the support plate 150. As used herein, “support plate” refers to a plate which is structured, organized, configured, programmed, designed, positioned, or engineered to support a load.

[0072] Figure 1H shows a rear view of one embodiment of the gap gauge 100. The rear view shows an upper plate 118, a lower plate 120, a separation indicator 124, a balance indicator 126, a grip 132, a handle 134, a shaft 140, a spring 142, a pivot plate 148, and a support plate 150. In one embodiment, the lower plate 120 may be a first plate, the upper plate 118 may be a second plate, or vice versa. Furthermore, in certain embodiments, the lower plate 120 may be a first plate, the pivot plate 148 may be a second plate, or vice versa. In such embodiments, the gap gauge 100 may not include a support plate 150.

[0073] Figure 1H shows an embodiment of gap gauge 100 including a driver 152 and a fastener 154. The driver 152 functions to actuate the separator 122. The driver 152 may include a circumference having a curved slot to facilitate rotation of the driver 152. In one embodiment, the driver 152 functions to engage with the separator 122 so that a displacement 128 is maintained. As used herein, “driver” means a mechanical piece, component, or structure for causing movement to another piece, component, or structure. (“Driver.” Merriam-Webster.com. Merriam-Webster, 2021. Web amended January 6, 2021.) In certain embodiments, the driver may be a wheel configured or connected to another part such that the rotation or movement of the driver causes movement of other interconnected or interconnected parts of a component, system, apparatus, or device.

[0074] The fastener 154 secures the driver 152 to the gap gauge 100. In one embodiment, the fastener 154 is a bolt that screws into the lower body 138, allowing the driver 152 to rotate freely around the bolt.

[0075] Figure 1I shows a front view of one embodiment of the gap gauge 100. The front view shows an upper plate 118, a lower plate 120, a grip 132, a handle 134, a shaft 140, a spring 142, a pivot plate 148, and a support plate 150. In one embodiment, a balance indicator is connected to a second plate, such as the upper plate 118, and the balance indicator includes a hinge 156 that pivotably connects the upper plate 118 to the gap gauge 100. In one embodiment, the hinge 156 is connected to the support plate 150.

[0076] As used herein, “hinge” means a device, apparatus, structure, component, member, system, assembly, or module that is structured, organized, configured, designed, arranged, or designed to connect two structures such that one structure can rotate relative to the other about a fixed longitudinal axis of the hinge. In one embodiment, a hinge may be considered a mechanical bearing that restricts the relative movement of two structures to a desired type of movement. In certain embodiments, various types of hinges may be used, including barrel hinges, butt hinges, butterfly hinges, case hinges, concealed hinges, continuous / piano hinges, flag hinges, H hinges, HL hinges, pivot hinges, self-closing hinges, spring hinges, living hinges, coach hinges, flush hinges, and the like.

[0077] A hinge may include a pin, one or more knuckles (also called loops, joints, nodes, curls, etc.), and one or more leaves. As used herein, “pin” refers to a cylindrical structure having a cross-sectional diameter small enough to fit within the openings of one or more knuckles of the hinge. In certain embodiments, the pin may include a head at one end, the head may be larger than the diameter of the openings of one or more knuckles, such that the head prevents the pin from passing through the openings of one or more knuckles completely. The pin may be made from a variety of materials, such as metal, plastic, or wood. A leaf is a structure that extends laterally from one or more knuckles and may be integrated with or connected to a structure intended to pivot or rotate around the pin. In certain embodiments, the hinge may include two or more leaves. A leaf may be a planar structure.

[0078] A knuckle is a structure having an opening of a size for receiving a pin. A knuckle connects to at least one leaf. A knuckle can have a circular longitudinal cross-section and can be cylindrical. In certain embodiments, each leaf includes a knuckle that can be aligned along the longitudinal axis of the hinge. When one or more knuckles are aligned along the longitudinal axis of the hinge, a pin can be inserted into the opening of one or more knuckles to secure the leaf(s) connected to each knuckle.

[0079] Figure 1I includes a front view of one embodiment of the balance indicator 126. In such an embodiment, the upper plate 118 may include a pivot plate 148 coupled to the gap gauge 100 by a hinge 156. In certain embodiments, the hinge 156 may function as both a hinge and the balance indicator 126. For example, a user may look at the hinge 156 during arthroplasty and detect that the pivot plate 148 (or upper plate 118) is oriented in a direction not parallel to the lower plate 120. In this way, the user can determine the balance status.

[0080] In one embodiment, the hinge 156 may include a pin 158. The pin 158 can be coupled to or connected to a pivot plate 148. The pin 158 can connect the support plate 150 to the pivot plate 148. In another embodiment, the hinge 156 may not be connected to the support plate 150. The pin 158 has a longitudinal axis 160 which is a pivot axis 162 for the pivot plate 148. A force applied to the pivot plate 148 (e.g., a force in the direction of arrow 164 or arrow 166) can cause the pivot plate 148 to rotate around the pin 158. As used herein, “pivot axis” refers to an axis on which a structure pivots or rotates.

[0081] During arthroplasty, the user can align the longitudinal axis of the pin 158, and therefore the pivot axis of the pivot plate 148, with the patient's anterior-posterior axis 116 in order to determine the balance status. Alternatively, or in addition, during arthroplasty, the user may position the longitudinal axis of the pin 158, and therefore the pivot axis of the pivot plate 148, parallel to the patient's anterior-posterior axis 116 in order to determine or measure varus, balanced, or valgus states.

[0082] If the pivot plate 148 rotates around the pin 158 in the direction of arrow 164, this may indicate an inversion of the first bone relative to the second bone. If the pivot plate 148 rotates around the pin 158 in the direction of arrow 166, this may indicate an eversion of the first bone relative to the second bone. If the pivot plate 148 does not rotate around the pin 158, this may indicate a balanced state of the first bone relative to the second bone.

[0083] Figures 2 and 3 are anterior views of the knee joint with the gap gauge 100 of Figure 1A inserted between two bones, showing the balanced and varus positions, respectively. Although a diagram showing the bones of the joint for the valgus position is not specifically shown, those skilled in the art will understand that the valgus position is simply an angle or orientation of the bones in Figure 3 such that the pivot plate 148 rotates in the direction of arrow 166 rather than arrow 164.

[0084] As used herein, “valgus deformity” refers to a bone or joint condition in which the distal segment of the bone or joint has an undesirable outward angle (an angle away from the midline of the body). For example, in valgus knee, the distal portion of the leg below the knee deviates laterally relative to the femur, resulting in the appearance of a knock knee. The opposite of varus is called valgus. In varus knee, the distal portion of the leg deviates inward relative to the femur, resulting in the appearance of a bowed leg. (Searched Wikipedia.com for “Valgus deformity” on October 20, 2020. Modified. Retrieved January 6, 2020) Valgus deformities can be experienced in a variety of joints, including but not limited to the ankle, elbow, wrist, hip, knee, toe, and wrist joints. As used herein, “varus deformity” refers to a bone or joint condition in which the distal segment of the bone or joint has an undesirable medial angle (i.e., an medial angle toward the midline of the body). The opposite of varus is called eversion. The terms "varus" and "eversion" refer to the direction in which the distal segment of a joint points. For example, varus of the knee results in a bowed leg appearance, where the distal portion of the leg deviates inward relative to the femur. For example, in valgus of the knee, the distal portion of the leg below the knee deviates laterally relative to the femur, resulting in a knocked knee appearance. (Searched Wikipedia.com for "varus deformity" on October 20, 2020. Modified. Retrieved January 6, 2020) Varus deformities can be experienced in a variety of joints, including but not limited to the ankle, elbow, wrist, hip, knee, toe, and wrist joints. As used herein, "balanced state" refers to a state in which a bone or joint has the desired alignment with the central axis of the limb or anatomical structure containing the bone and / or joint. In certain embodiments, a balanced state refers to a state of bone or joint that is neither varus nor eversion.

[0085] Figure 2 shows the balanced state of joint 108. The upper plate 118 and / or pivot plate 148 are in contact with the femur 102. The lower plate 120 is in contact with the tibia 104. The pivot plate 148 is parallel to the lower plate 120. In the illustrated embodiment, a force or tension within joint 108, or movement in the direction of arrow 164, is offset by a force or tension within joint 108, or movement in the direction of arrow 166. As used herein, “tension” refers to a tensile force applied across an elongated structure. For example, ligaments such as the lateral collateral ligament may experience tension due to the way the ligament is attached to the femur and tibia and stretches during knee joint flexion.

[0086] Figure 3 shows the varus position of joint 108. The upper plate 118 and / or pivot plate 148 are in contact with the femur 102. The lower plate 120 is in contact with the tibia 104. The pivot plate 148 is not parallel to the lower plate 120. The inclination of the upper plate 118 and / or pivot plate 148 can be caused by a variety of factors, including, but not limited to, the angle at which the femur 102 and / or tibia 104 are cut, and the forces acting on joint 108 by soft tissues and / or ligaments. In the illustrated embodiment, the force or tension within joint 108, or the movement by the surface of the femur 102 or tibia 104 in the direction of arrow 164, is greater than the force or tension within joint 108, or the movement by the surface of the femur 102 or tibia 104 in the direction of arrow 166.

[0087] Those skilled in the art will recognize that a valgus position may exist in the joint 108 shown in Figure 3 when the upper plate 118 and / or pivot plate 148 rotate about the longitudinal axis 160 in the direction of arrow 166. Such inclination can be caused by a variety of factors, including, but not limited to, the angle at which the femur 102 and / or tibia 104 are cut, and forces acting on the joint 108 by soft tissues and / or ligaments. In such embodiments, the force or tension within the joint 108, or the movement by the surface of the femur 102 or tibia 104 in the direction of arrow 166, is greater than the force or tension within the joint 108, or the movement by the surface of the femur 102 or tibia 104 in the direction of arrow 164.

[0088] Figure 4 is a posterior view of a knee joint with a gap gauge 100 inserted between the femur 102 and the tibia 104. Figure 4 shows a rear view of the gap gauge 100. Figure 4 shows an upper plate 118, a lower plate 120, a separation indicator 124, a balance indicator 126, a grip 132, a handle 134, a shaft 140, a spring 142, a pivot plate 148, a support plate 150, a driver 152, and a fastener 154. The illustrated embodiment includes a balance gauge 168. In one embodiment, the balance gauge 168 may include a dial 170 and a needle 172.

[0089] Figure 4 shows the medial condyles 174a, 174b and lateral condyles 176a, 176b of the first bone (e.g., tibia 104) and the second bone (e.g., femur 102). As used herein, “medial condyle” refers to one of the two projections at the distal end of the femur, the other being the lateral condyle. The medial condyle is larger than the lateral condyle due to the greater weight bearing caused by the center of mass located medially of the knee. (Searched Wikipedia.com on May 12, 2020 for “medial condyle”. Modified. Retrieved January 6, 2020) As used herein, “lateral condyle” refers to one of the two projections at the distal end of the femur, the other being the medial condyle. The lateral condyle is prominent and wider in both its anterior-posterior and lateral diameters. (Searched Wikipedia.com for "lateral condyle" on April 17, 2020. Updated. Retrieved January 6, 2020.) In the illustrated embodiment, the upper plate 118 can be positioned to engage with or contact the femur 102, and the lower plate 120 can be positioned to engage with or contact the tibia 104. The upper plate 118 can be molded or configured to engage with the medial condyles 174b and lateral condyles 176b of the femur 102. The lower plate 120 can be molded or configured to engage with the medial condyles 174a and lateral condyles 176a of the tibia 104. An example of a suitable shape for the upper plate 118 to engage with the medial condyles 174b and lateral condyles 176b of the femur 102 is shown in Figure 1C. An example of a suitable shape for the lower plate 120 to engage with the medial condyles 174a and lateral condyles 176a of the tibia 104 is shown in Figure 1D. Of course, the size and shape of the upper plate 118 and lower plate 120 can vary depending on the patient's age and size (e.g., smaller for children and larger for adults).

[0090] In one embodiment, the balance gauge 168 can provide a visual indication of the balance status and provide the user of the gap gauge 100 with specific information regarding the magnitude of the imbalance or balance of the joint 108. As used herein, “balance gauge” refers to an apparatus, instrument, structure, device, component, system, assembly, hardware, software, firmware, circuit, module, or logic configured, configured, programmed, designed, or arranged to measure the attributes, characteristics, state, or condition of another structure or object, or a set of structures or objects. In one embodiment, the balance gauge is configured, configured, programmed, designed, arranged, or arranged to measure the balance status between two or more structures. The balance gauge 168 may be connected to the balance indicator 126 such that the movement of the balance indicator 126 is reflected and / or reported by the balance gauge 168. In this way, the balance gauge 168 can measure the balance status.

[0091] Figure 4 shows that a user can determine both displacement using the isolation indicator 124 and balance status using the balance indicator 126 and / or balance gauge 168 in a single viewpoint of the gap gauge 100. This may be useful because other soft tissues or instruments may interfere with the determination of either or both of the displacement and balance status during arthroplasty.

[0092] Figures 5A–5C are rear views of an exemplary gap gauge 100 showing different balance status states. Figures 5A–5C show a dial 170 and a needle 172 coupled to or connected to a balance indicator 126 for measuring the balance status. As used herein, dial refers to a dial on which several measurements are registered by a scale and pointers such as a needle. ("Dial". Merriam-Webster.com. Merriam-Webster, 2021. Web amended January 6, 2021.) As used herein, "needle" refers to a long, thin structure which may include a point at one end and a coupler for connecting the needle to another structure.

[0093] In the illustrated embodiment, the dial 170 includes marks, each mark positioned on the dial face of the dial 170. The marks may represent the pivot angle or movement of the upper plate 118 and / or pivot plate 148 around the pin 158. Each mark on the dial face may represent a different scale of balance status. Alternatively, or in addition, marks positioned on the dial face of the dial may indicate a scale of orientation of the upper plate 118 relative to the lower plate 120.

[0094] In certain embodiments, the dial may include numbers that identify different measurements of the balance status. In one embodiment, the dial 170 includes angle marks ranging from -5 to +5 degrees, where 0 degrees represents a balanced state. As the upper plate 118 and / or pivot plate 148 swivel or rotate around the pin 158, the rotation is measured by the balance indicator 126 and conveyed to the balance indicator 126. The movement of the balance indicator 126 is transferred to the needle 172, which moves the needle 172 to point toward the mark on the dial that reflects the balance status. Rotation of the upper plate 118 or lower plate 120 around the patient's anterior-posterior axis 116 moves the needle 172 to point toward the mark on the dial that reflects the orientation of the plate.

[0095] Figure 5A shows an exemplary balance gauge 168 of the gap gauge 100, which can be positioned to contact the first bone (see Figure 1A) and the second bone (see Figure 1A). When the bone surfaces are parallel and / or the forces within the joint 108 are balanced (e.g., a balanced state), the needle 172 of the balance gauge 168 may point to the center mark of the dial 170 indicating a balanced state, or to a positive or negative degree of rotation around the pivot axis 162.

[0096] Figure 5B shows an exemplary balance gauge 168 of the gap gauge 100, which can be positioned to contact the first bone (see Figure 1A) and the second bone (see Figure 1A). If the bone surfaces are not parallel and / or the forces within the joint 108 are unbalanced (e.g., varus or valgus, depending on which joint is being measured), the needle 172 of the balance gauge 168 may point to the mark to the left of the center mark on the dial 170 (e.g., -5 degrees) to indicate an unbalanced or disproportionate state, a positive or negative degree of rotation around the pivot axis 162.

[0097] Figure 5C shows an exemplary balance gauge 168 of the gap gauge 100, which can be positioned to contact the first bone (see Figure 1A) and the second bone (see Figure 1A). If the bone surfaces are not parallel and / or the forces within the joint 108 are unbalanced (e.g., varus or valgus, depending on which joint is being measured), the needle 172 of the balance gauge 168 may point to the mark to the right of the central mark on the dial 170 (e.g., +5 degrees) to indicate an unbalanced or disproportionate state, a positive or negative degree of rotation around the pivot axis 162.

[0098] Figures 6A–6C are rear views of an exemplary gap gauge 100 showing different displacements. Figures 6A–6C show an upper plate 118, a lower plate 120, and a separation indicator 124. The upper plate 118 may include a pivot plate 148 and a support plate 150. Figures 6A–6C also show a driver 152 and a fastener 154.

[0099] In the illustrated embodiment, the separation indicator 124 may include a dial that may contain a numerical value representing a measure of displacement between the outer surfaces of the upper plate 118 and the lower plate 120. For example, in the illustrated embodiment, the number at the top of the dial when viewed as illustrated may represent the current amount of displacement. For example, "9" may represent a displacement of 9 millimeters. The dial on the driver 152 may include a number of different marks and / or numbers (e.g., readings) each which may represent a different displacement between the upper plate 118 and the lower plate 120. The fastener 154 may allow the driver 152 to rotate about the longitudinal axis of the fastener. The driver 152 may be rotatable to multiple positions, each position which may represent a different displacement corresponding to a number on the dial of the driver 152. The illustrated embodiment may include six different displacements and six numerical values ​​(e.g., 9, 11, 13, 15, 17, and 19) each representing a different displacement.

[0100] Figure 6A shows an exemplary separation indicator 124 of a gap gauge 100 that can be placed in the opening 106 between the first bone (see Figure 1A) and the second bone (see Figure 1A). Once placed and the separator 122 is actuated to the desired displacement, the user can read the displacement by reading the numerical value at the highest position of the separation indicator 124. For example, in Figure 6A, the displacement is 9 millimeters. For example, in Figure 6B, the displacement is 15 millimeters. For example, in Figure 6C, the displacement is 19 millimeters.

[0101] The separator 122 can be operated to bring the upper plate 118 into contact with the resection surface of the femur 102 and the lower plate 120 into contact with the resection surface of the tibia 104. As used herein, “resection surface” refers to the outermost part or layer of a body structure that is exposed after the resection procedure.

[0102] The upper plate 118 can be shaped or configured to facilitate contact with the resection surface of the femur 102. The lower plate 120 can be shaped or configured to facilitate contact with the resection surface of the tibia 104. An example of a suitable shape for the upper plate 118 is shown in Figure 1C. An example of a suitable shape for the tibia 104 is shown in Figure 1D.

[0103] The separator 122 may be actuated by holding the handle 134 with one hand and then rotating the driver 152 to one or more of a plurality of displacement positions. Alternatively, or additionally, the actuated separator 122 may include using the handle 134 to hold the gap gauge 100 in place, rotating the driver 152, and / or pulling the grip 132 to separate the plates 118, 120. With the handle 134 held in place, the driver 152 can be rotated and the grip 132 pulled to assist in the actuated plates 118, 120 simultaneously or nearly simultaneously.

[0104] Figure 7 is a perspective view of an exemplary gap gauge 100. Figure 7 shows a gap gauge 100 including a separator 122 including a cam 702 and a driven part 704. As used herein, “cam” refers to a mechanical device that is structured, organized, configured, programmed, designed, arranged, or engineered to convert one form of motion into another form of motion. For example, a cam can convert rotational motion into linear motion. Similarly, a cam can convert linear motion into rotational motion. A cam can be a rotating or sliding component in a mechanical linkage used in converting rotational motion into linear motion. A cam can be part of a rotating wheel (e.g., an eccentric wheel) or a shaft (e.g., an irregularly shaped cylinder) that strikes or moves a lever at one or more points on the circular path of a rotating wheel. A cam can be a simple tooth or an eccentric disc or other shape that produces a smooth reciprocating motion (back and forth) in a driven part which is a lever configured to contact the cam. (Searched Wikipedia.com for "cam" on December 26, 2020. Modified. Retrieved January 6, 2020) Various types of cams can be used in this disclosure. For example, the cams may be radial cams, disc cams, cylindrical cams, etc.

[0105] As used herein, “driven part” refers to a rigid structure that contacts the cam lobe profile. In one embodiment, the driven part can translate the movement of the cam to the driven part and / or a structure connected to the driven part. In certain embodiments, as the cam rotates, the driven part may slide along the contact surface of the cam, thereby converting the rotational motion into linear motion. The driven part may also be called a “cam driven part” or “track driven part.” A cam driven part is a type of structure, roller, or needle bearing designed to follow and / or contact the cam lobe profile of the cam. (Searched Wikipedia.com for “CAM driven part” on November 13, 2020. Modified. Retrieved January 6, 2020)

[0106] Various types of driven parts can be used in this disclosure. The type and shape of the cam driven part may be based on the type of the surface of the driven part that contacts the contact surface of the cam (referred to as the driven surface). In one embodiment, the driven part is a stud that comes at a point to form a knife-edge driven part. Alternatively or additionally, the driven surface can have a variety of other shapes, including but not limited to flat, mushroom, cylindrical, curved, and hemispherical surfaces. Furthermore, the driven part may include rollers at the ends that contact the contact surface of the cam. The rollers at the ends of the driven part can allow the driven part to rotate or slide along the contact surface of the cam.

[0107] In the illustrated embodiment, the cam 702 is connected to or integrated with the driver 152. The driver 152 is connected to the lower body 138 via a fastener 154. In this way, the cam 702 is connected to the lower body 138. The cam 702 includes a contact surface 706. As used herein, “contact surface” refers to the surface of the cam that contacts the driven part. The orientation, arrangement, and position of the contact surface may vary depending on the type of cam used. In embodiments using a radial cam, the radial cam may have a central axis 708, and the contact surface may be the surface of the cam following the circumference of the radial cam around the central axis 708.

[0108] The rotation of the driver 152 also rotates the cam 702. The rotation of the cam 702 moves the upper body 136, which adjusts the displacement of the upper plate 118 relative to the lower plate 120. In one embodiment, the cam 702 is a radial cam and, together with the fastener 154, rotates about a common axis, a central axis 708. As used herein, “radial cam” refers to a type of cam in which the cam has a central axis and the contact surface follows the circumference of the cam about the central axis. In a radial cam, the driven part moves in linear motion in a direction perpendicular to the central axis. The driven part 704 can contact the cam 702 or rest on the cam 702.

[0109] The driven portion 704 is connected to the upper body 136. In one embodiment, the driven portion 704 may be biased against the contact surface 706 by a spring 142 around the shaft 140. The driven portion 704 is sized and shaped such that as the driven portion 704 slides along the contact surface 706 or is positioned along the contact surface 706, it moves the upper body 136 along the shaft 140 relative to the lower body 138. Figure 7 shows an example embodiment in which the support plate 150 is coupled to the separator 122 (e.g., via a cam 702, the driven portion 704, and the upper body 136) such that the operation of the separator 122 moves the support plate 150 perpendicular to the lower plate 120.

[0110] Figure 7 also shows one embodiment of the driver 152, which includes a hole 710 or pocket around the circumference of the driver 152. When the gap gauge 100 is used, the user can insert a rod into the hole 710 to provide leverage for rotating the driver 152.

[0111] Figure 8A is a front view of a driver 152 of a gap gauge 100 according to one embodiment of the present disclosure. Figure 8A shows the separation indicator 124, the driver 152, the central axis 708, and the opening 802. The opening 802 may be the region between the outer surface of the driver 152 and the head of the fastener 154. The opening 802 may have a polygonal cross-sectional shape. In the illustrated embodiment, the opening 802 has a hexagonal cross-sectional shape. The opening 802 may be sized and configured to receive the shaft or drive head of a separate tool, such as a wrench (not shown). A user may use a wrench within the opening 802 to achieve a mechanical advantage when rotating the driver 152 around the central axis 708.

[0112] Figure 8B is a rear view of the driver 152 and cam 702 of a gap gauge 100 according to one embodiment of the present disclosure. Figure 8B shows that the cam 702 may have an irregular radius that varies around a central axis 708. The length of the radius around the central axis 708 may be designed or engineered to achieve or maintain a desired displacement between the upper plate 118 and the lower plate 120 connected to the cam 702 and the driven portion 704.

[0113] Figure 9 shows an exploded view of an exemplary gap gauge 100 according to one embodiment of the present disclosure. Figure 9 provides details of how the hinge 156, pin 158, and needle 172 can work together to provide a balance indicator 126. In a particular embodiment, the balance indicator 126 includes a lockout mechanism 130 that can prevent rotation of the pivot plate 148 relative to the lower plate 120 and / or support plate 150 when the lockout mechanism 130 is in a configured state.

[0114] Figure 9 shows a support plate 150 including a knuckle 902 and openings 904a, 904b for at least one corresponding knuckle of the pivot plate 148. The knuckle 902 can connect the support plate 150 to the hinge 156 and the pivot plate 148. In such an embodiment, the support plate 150 and the pivot plate 148 can each function as leaves of the hinge 156. When assembled, one or more knuckles of the pivot plate 148 align with one or more knuckles 902 of the support plate 150 and accept the pin 158. In this way, the pivot plate 148, the pin 158, and the support plate 150 function as a hinge for implementing one embodiment of the balance indicator 126.

[0115] In certain embodiments, the pivot plate 148 may rotate freely around the pin 158. In such embodiments, the pin 158 may include one or more pins 906. The pins 906 engage with the pin 158 and the pivot plate 148 such that rotation of the pivot plate 148 causes rotation of the pin 158. Furthermore, if the pin 158 is fixed or prevented from rotating around the pivot axis 162, the pins 906 may also hold the rotation of the pivot plate 148.

[0116] The pin 158 extends into the upper body 136 and can be coupled to the needle 172. In this way, rotation of the pin 158 moves the needle 172 and directs it in a different direction. In certain embodiments, the pin 158 may pass through a slot in the post 146 to allow both rotation of the pin 158 and movement of the pin 158 away from the lower body 138 when the gap gauge 100 is used.

[0117] Figure 9 shows a lockout mechanism 130 which may include a set screw 908. The set screw 908 has threads that engage with the threads of an opening 910 in the upper body 136. Moving the set screw 908 into the opening 910 activates the lockout mechanism 130, preventing the rotation of the pin 158 and the connected pivot plate 148. Moving the set screw 908 out of the opening 910 stops the lockout mechanism 130, allowing the pin 158 and the connected pivot plate 148 to rotate.

[0118] As used herein, “set screw” typically refers to a type of screw commonly used to fasten a first object into or against a second object, without the use of a nut. A set screw can be headless, meaning the screw is fully threaded and the head does not protrude beyond the main diameter of the screw. If a set screw has a head, the threads may extend to the head. A set screw can be driven by an internal wrench, such as a hex socket (Allen), star (Torx), square socket (Robertson), or slot. In one embodiment, the set screw passes through a threaded hole in the second object (outer object) and is tightened against the first object (inner object), preventing the inner object from moving relative to the outer object. A set screw can exert compressive and / or clamping forces through the end of the set screw protruding through the threaded hole. (Searched Wikipedia.com for “set screw” on August 17, 2020. Modified. Retrieved January 6, 2020)

[0119] Figure 10A is a perspective view of a pin 158 of the gap gauge 100 of Figure 1A according to one embodiment of the present disclosure. The pin 158 may be a cylindrical structure having a longitudinal axis 160. The pin 158 may include a proximal end 1002, a distal end 1004, and a center 1006. In one embodiment, the proximal end 1002 is connected to a balance gauge 168. For example, the proximal end 1002 may include a D-shaped cross section including a flat portion 1008. In one embodiment, the D-shaped cross section of the proximal end 1002 may be sized to receive a D-shaped opening in a needle 172 which can slide on the proximal end 1002 and be positioned for a balance indicator 126 and / or balance gauge 168.

[0120] The distal end 1004 may function as the pivot for the hinge 156 of the gap gauge 100. Alternatively, or additionally, the distal end 1004 may function as the pivot for the balance indicator 126. The pivot may be aligned with the longitudinal axis 160. Furthermore, the distal end 1004 and / or the center 1006 may include one or more keyed sections 1010. In one embodiment, the keyed section 1010 may be used by pin 906 to connect pin 158 to the pivot plate 148.

[0121] In one embodiment, the central section 1006 may include a section 1012 containing a plane 1014. The plane 1014 of section 1012 may function as part of a lockout mechanism 130. For example, in one embodiment, a set screw 908 can bias the pin 158 against the plane 1014 to prevent rotation of the pin 158. In the illustrated embodiment, section 1012 has a D-shaped cross section. In one embodiment, the D-shaped cross section of section 1012 may be offset by 90 degrees from the D-shaped cross section of the proximal end 1002 containing the flat portion 1008. In one exemplary embodiment, the 90-degree offset allows the needle 172 not to register / measure an imbalance when the lockout mechanism 130 is activated to prevent rotation of the pin 158.

[0122] Figures 10B and 10C are side views of the pin 158 of Figure 10A according to one embodiment of the present disclosure. Figure 10B shows an embodiment of the pin 158 that includes a first section 1016 having a larger diameter than the second section 1018.

[0123] Figures 11A and 11B are perspective views of a lockout mechanism 130 of a gap gauge 100 according to one embodiment of the present disclosure. Figure 11A shows the lockout mechanism 130 when the set screw 908 is in a set configuration. Figure 11B shows the lockout mechanism 130 when the set screw 908 is in an unset configuration. As used herein, “set configuration” refers to the arrangement and / or relationship between a set screw and a pin such that the set screw prevents the pin from rotating about the longitudinal axis of the pin. In the set configuration, the set screw 908 advances within the opening 910 and engages with the plane 1014 of section 1012.

[0124] As used herein, “unset configuration” refers to the arrangement and / or relationship between a set screw and a pin such that the set screw allows the pin to rotate about the longitudinal axis of the pin. In a set configuration, the set screw 908 is housed within the opening 910 to disengage the plane 1014 of section 1012.

[0125] Figure 12 shows a flowchart for a method 1200 for measuring the gap and / or balance status between a patient's femur and tibia, according to one embodiment of the present disclosure. Generally, method 1200 may include the use of a gap gauge including both a separation indicator and a balance indicator 126. In certain embodiments, the gap gauge may also include a balance gauge.

[0126] Method 1200 may begin with step 1210, in which a first plate (e.g., lower plate 120) and a second plate (e.g., upper plate 118) of a gap gauge can be inserted between the femur and the tibia. In certain embodiments, the gap gauge may be positioned so that the pivot axis of the hinge can be aligned with the patient's anterior-posterior axis.

[0127] Once the gap gauge is in place, method 1200 may proceed to step 1220, in which the first plate and the second plate are moved apart such that the first plate contacts the resection surface of the femur and the second plate contacts the resection surface of the tibia.

[0128] Once the first and second plates are released and actuated, method 1200 may proceed to step 1230, in which the separation indicator of the gap gauge may be read to obtain the displacement between the femur and the tibia. Once the displacement is read, method 1200 may proceed to step 1240, in which the balance indicator of the gap gauge may be read to obtain the balance status between the femur and the tibia.

[0129] Using an exemplary gap gauge 100, a surgeon may select from a set of prostheses available for arthroplasty, based on the displacement and / or balance status. In one example, the surgeon may select a different prosthesis than the one preoperatively selected, based on the balance status reported / measured by the balance indicator 126 and / or exemplary balance gauge 168. The different prosthesis may be selected to compensate for the balance status reported / measured by the balance indicator 126 and / or exemplary balance gauge 168. If a compensatory prosthesis is selected, the surgeon may not need to make any modifications to the joint 108 to achieve the desired balance state.

[0130] In another example, if the balance status indicates a varus state, the first prosthesis may be selected during the procedure. If the balance status indicates a valgus state, the second prosthesis may be selected during the procedure. Alternatively, or in addition, the displacement and / or balance status may be used by the surgeon to determine whether to perform further resection of the femur 102 and / or tibia 104, whether to release one or more of the medial and lateral collateral ligaments, or whether to take other steps of the arthroplasty to achieve the desired outcome for the arthroplasty.

[0131] Once the displacement and balance status are read, method 1200 may proceed to step 1250, in which the tension applied to the femur and / or tibia by the medial collateral ligament and / or lateral collateral ligament is adjusted. Once the tension applied to the femur and / or tibia is adjusted, method 1200 may proceed to step 1260, in which the balance indicator of the gap gauge is read and the adjusted balance status between the femur and tibia is obtained in response to the tension adjustment. After reading the adjusted balance, method 1200 may terminate with the joint balance having a desired balance status.

[0132] Alternatively, or in addition thereto, method 1200 may proceed to a step in which the tension applied to the femur and tibia by one or more of the medial and lateral collateral ligaments is adjusted, and a balance indicator on a gap gauge is read to obtain an adjusted balance status between the femur and tibia in response to the tension adjustment.

[0133] Alternatively, or in addition to the above, if the tension applied to the femur and tibia by one or more of the medial and lateral collateral ligaments is adjusted, method 1200 may proceed to a step in which one or more of the medial and lateral collateral ligaments are released and the gap gauge remains in place between the femur and tibia and remains activated.

[0134] Alternatively, or in addition to the above, if the tension applied to the femur and tibia by one or more of the medial and lateral collateral ligaments is adjusted, method 1200 may proceed to the step of removing the gap gauge from between the femur and tibia. Once the gap gauge is removed from between the femur and tibia, method 1200 may proceed to the step of removing one or more of the resection surfaces of the femur and tibia. Once one or more of the resection surfaces of the femur and tibia are removed, method 1200 may proceed to the step of reinserting the first and second plates of the gap gauge between the femur and tibia. Once the first and second plates of the gap gauge are reinserted between the femur and tibia, method 1200 may proceed to a step in which the first and second plates act apart so that the first plate contacts the excised surface of the femur or a further excised surface, and the second plate contacts the excised surface of the tibia or a further excised surface. Once the first and second plates act apart, method 1200 may proceed to a step in which the separation indicator of the gap gauge is read to obtain the displacement between the femur and tibia. Once the displacement is obtained, method 1200 may proceed to a step in which the balance indicator of the gap gauge is read to obtain the balance status between the femur and tibia.

[0135] Any method disclosed herein includes one or more steps or actions for carrying out the described method. The steps and / or actions of a method may be interchangeable with one another. In other words, the order and / or use of any particular steps and / or actions may be changed unless a particular order of steps or actions is required for the proper operation of the embodiment.

[0136] Throughout this specification, any reference to “an embodiment” or “the embodiment” means that the specific features, structure, or characteristics described in relation to that embodiment are included in at least one embodiment. Therefore, not all quotations or variations thereof listed throughout this specification necessarily refer to the same embodiment.

[0137] Similarly, in the above description of embodiments, it should be understood that for the purpose of streamlining the disclosure, various features may be grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be interpreted as reflecting an intention that any claim requires more features than those explicitly enumerated in that claim. Rather, as the following claims demonstrate, embodiments of the invention consist of combinations of fewer features than all of the single disclosed features described above. Thus, the claims following the detailed description are thus explicitly incorporated into this detailed description, and each claim is based on its own as a separate embodiment. This disclosure includes all permutations of the independent claims and their dependent claims.

[0138] The term “first” in the claims relating to a feature or element does not necessarily imply the presence of a second or additional such feature or element. Elements described in means-plus-function form are intended to be interpreted in accordance with Section 112 of the United States Patent Act. 6. It will be apparent to those skilled in the art that modifications can be made to the details of the embodiments described herein without departing from the basic principles described herein.

[0139] While specific embodiments and uses of this disclosure have been illustrated and described, it should be understood that the scope of the disclosure is not limited to the detailed configurations and components disclosed herein. Various modifications, changes, and variations that would be apparent to those skilled in the art can be made in the arrangement, operation, and details of the methods and systems of this disclosure described herein without departing from the spirit and scope of the art.

Claims

1. A gap gauge for facilitating arthroplasty of the first and second bones of a patient, A first plate that can be positioned in contact with the first bone, A second plate that can be positioned in contact with a second bone, the second plate being displaced from the first plate by displacement, A separator connected to the first plate and the second plate, wherein the separator can be operated to adjust the displacement, A separation indicator, coupled to the separator and configured to indicate displacement, Includes a balance indicator connected to at least one of the first plate and the second plate, configured to indicate the balance status between the first plate and the second plate, The balance indicator is connected to the second plate, and the balance indicator includes a hinge that pivotably connects the second plate to the gap gauge. The hinge includes a pin having a longitudinal axis which is the pivot axis of the second plate, the longitudinal axis being parallel to the patient's anterior-posterior axis such that the rotation of the second plate about the pivot axis measures one of the following: varus, balanced, and valgus of the first bone relative to the second bone. The balance indicator further includes a support plate connected to the hinge and the separator, and the balance indicator includes a lockout mechanism configured to prevent rotation of one of the first plate and the second plate connected to the balance indicator. The lockout mechanism further includes a set screw having set configurations and non-set configurations, the set screw having threads configured to engage with threads in an opening, wherein in the set configuration, the set screw engages with the pin of the hinge such that the pin does not rotate in response to a rotational force applied to at least one of the first plate and the second plate. In the non-set configuration, the set screw is disengaged from the pin of the hinge so that the pin rotates in response to a rotational force applied to at least one of the first plate and the second plate, providing a gap gauge.

2. The gap gauge according to claim 1, wherein the set screw engages with the pin by biasing the planar surface of the section of the pin, and the section of the pin has a D-shaped cross-section.

3. The first plate is shaped to engage with the medial and lateral condyles of the first bone, The gap gauge according to claim 1, wherein the second plate is shaped to engage with the medial and lateral condyles of the second bone.

4. The gap gauge according to claim 1, further comprising a balance gauge connected to the balance indicator, wherein the balance gauge is configured to measure the balance status.

5. The aforementioned gap gauge is A dial having marks positioned on the surface of the dial to indicate the measured value of the balance status of the second plate relative to the first plate, and The gap gauge according to claim 4, further comprising a needle connected to a balance indicator such that rotation of the second plate about the longitudinal axis of the second plate moves the needle toward the mark on the surface of the dial that reflects the balance status.

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