Systems and methods for limb alignment

Abstract

In certain embodiments, the present invention provides devices for determining the tibial mechanical axis and the femoral mechanical axis. The present invention also provides surgical orientation devices, reference devices, and / or modules configured to track the mechanical axes during movement to facilitate limb alignment. The present invention further provides surgical orientation devices, reference devices, and / or modules configured to determine gap measurements.

Description

Technical Field

[0001] Incorporation by reference of priority applications Any application for which a claim of foreign or domestic priority is specified in the application data sheet as filed together with this application, including U.S. Provisional Application No. 62 / 992,537, filed on March 20, 2020, is hereby incorporated by reference in its entirety into this specification under 37 C.F.R. § 1.57.

[0002] This application relates to systems and methods for the evaluation and replacement of joints, particularly systems and methods for the evaluation and replacement of knee and other limb joints that utilize one or more inertial devices to measure limb alignment.

Background Art

[0003] Arthroplasty, including knee arthroplasty, is commonly used to replace a patient's joint with one or more prosthetic joint components. Such procedures often use one or more systems of surgical tools and devices, including, but not limited to, cutting guides (e.g., cutting blocks) and surgical guides, to make surgical incisions along one or more portions of the patient's bone.

[0004] Current systems and methods often require one or more computers, and even more expensive, complex, bulky, and / or large computer navigation systems for three-dimensional imaging, to track the spatial placement and / or movement of surgical instruments or landmarks within the human body. These systems are generally used to assist a user in determining where a tool or landmark is located within a space and often require extensive training, significant expense, and a large room.

[0005] When such complex and expensive systems are not used, simpler methods are employed, such as "estimating" the alignment of anatomical features, including the lower limb bones, with the rods. These simpler methods are not sufficiently accurate in ensuring the proper alignment and placement of prosthetic implant components and the bone to which such components are attached. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Patent Application No. 12 / 509388 [Patent Document 2] U.S. Patent Application No. 13 / 011815 [Patent Document 3] U.S. Patent Application No. 13 / 115065 [Patent Document 4] U.S. Patent Application No. 14 / 399046 [Patent Document 5] U.S. Patent Application No. 14 / 401274 [Patent Document 6] U.S. Patent Application No. 10 / 864085 [Patent Document 7] U.S. Patent Application No. 11 / 182528 [Patent Document 8] U.S. Patent Application No. 12 / 557051 [Patent Document 9] U.S. Patent Application No. 13 / 800620 [Patent Document 10] U.S. Patent Application No. 14 / 643864 [Patent Document 11] U.S. Patent Application No. 15 / 550564 [Patent Document 12] U.S. Patent Application No. 15 / 920216 [Patent Document 13] U.S. Patent Application No. 15 / 920202 [Patent Document 14] International application PCT / US2020 / 063785 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, there is a lack of devices, systems, and methods that can be used to evaluate joint properties such as the relative alignment of the bones and soft tissue condition of the joint in relation to selecting and precisely positioning the components of an artificial joint, without overcomplicating the procedure, overwhelming healthcare workers, and / or imposing the significant costs of complex navigation systems on physicians or healthcare facilities. [Means for solving the problem]

[0008] In some embodiments, a system for limb alignment is provided. The system may include a first orientation device configured to be coupled to the tibia, the first orientation device comprising at least one inertial sensor. The system may also include a second orientation device configured to be coupled to the femur, the second orientation device comprising at least one inertial sensor. In some embodiments, the first or second orientation device comprises a processor configured to receive inertial sensor data, the processor configured to calculate the angle between the femoral mechanical axis and the tibial mechanical axis.

[0009] In some embodiments, the system may include a tibial preparation system comprising a probe member. In some embodiments, the system may include a tibial preparation system comprising a midline reference probe assembly. In some embodiments, the system may include a tibial preparation system comprising a first device interface configured to couple to a first orientation device and a second device interface configured to couple to a second orientation device. In some embodiments, the system may include a femoral preparation system comprising a device interface configured to couple to a second orientation device. In some embodiments, the system may include a femoral preparation system comprising a cutting guide bracket configured to slide relative to the tibial preparation system. In some embodiments, the system may include a femoral preparation system comprising a swivel post configured to pivot relative to the tibial preparation system. In some embodiments, the system may include a femoral preparation system comprising an extension portion configured to position relative to a threaded pin coupled to a portion of the distal femur. In some embodiments, the system may include a femoral preparation system comprising a connector configured to fit onto the lateral portion of the femur. In some embodiments, the system may include a femoral preparation system comprising a connector having a device interface configured to couple to a second orientation device. In some embodiments, the processor is configured to determine the femoral and tibial mechanical axes based at least partially on the placement of anatomical landmarks. In some embodiments, the processor is configured to determine the femoral and tibial mechanical axes based at least partially on the movement of the femur. In some embodiments, the processor is configured to determine the varus / valgus angles of the femoral and tibial mechanical axes.In some embodiments, the processor is configured to determine the flexion / extension angles of the femoral and tibial mechanical axes. In some embodiments, the processor is configured to determine the gap measurement.

[0010] In some embodiments, methods for determining limb alignment are provided. The method may include the step of coupling a first orientation device, which is configured with the tibia, and the first orientation device comprises at least one inertial sensor. The method may include the step of coupling a second orientation device, which is configured with the femur, and the second orientation device comprises at least one inertial sensor. The method may include the step of calculating the femoral mechanical axis and the tibial mechanical axis. The method may include the step of measuring changes in the femoral mechanical axis and the tibial mechanical axis.

[0011] In some embodiments, the method may include the steps of performing a resection and positioning the implant. In some embodiments, the step of measuring changes in the femoral and tibial mechanical axes may further include the step of positioning the leg in an extended position. In some embodiments, the method may include the step of calibrating the first and second orientation devices by mounting the first and second orientation devices onto the tibial preparation system. In some embodiments, the method may include the steps of applying force and measuring the gap distance.

[0012] In some embodiments, a system for limb alignment is provided. The system may include a first sensor configured to be coupled to the tibia, the first sensor comprising at least one inertial sensor. The system may include a second sensor configured to be coupled to the femur, the second sensor comprising at least one inertial sensor. The system may include a processor configured to receive outputs from one or more of the first and second sensors, the processor configured to calculate the position and / or orientation of the femoral and tibial mechanical axes during movement.

[0013] In some embodiments, the system may include a surgical orientation device equipped with a processor. In some embodiments, the surgical orientation device includes a display. In some embodiments, the processor is configured to determine varus / valgus angles. In some embodiments, the processor is configured to determine varus angles at different flexion angles. In some embodiments, the processor is configured to determine axial rotation. In some embodiments, the processor is configured to determine flexion angles. In some embodiments, the processor is configured to determine extension angles. In some embodiments, the processor is configured to provide recommendations for trial implants. In some embodiments, the processor is configured to determine the gap between the tibial plateau and the femoral plateau. In some embodiments, the processor is configured to determine the angle between the tibial plateau and the femoral plateau.

[0014] In some embodiments, a method for determining limb alignment is provided. The method can include coupling a first reference sensor to a first bone of a limb, the first reference sensor including at least one inertial sensor. The method can include coupling a second reference sensor to a second bone of the limb, a joint being formed between the first bone and the second bone, the second reference sensor including at least one inertial sensor. The method can include moving the limb to position the first bone at a plurality of different positions with respect to the second bone where flexion, axial rotation, and / or varus / valgus are different. The method can include outputting a value indicative of limb alignment at one or more of the positions or based on one or more of the positions.

[0015] In some embodiments, the limb is a leg, the first bone is a tibia, and the second bone is a femur. In some embodiments, the method can include positioning a trial implant or an implant on a resection surface of the tibia. In some embodiments, the method can include calibrating the first reference sensor and the second reference sensor. In some embodiments, the step of outputting a value includes outputting a varus / valgus angle. In some embodiments, the step of outputting a value includes outputting a varus angle at different flexion angles. In some embodiments, the step of outputting a value includes outputting an axial rotation. In some embodiments, the step of outputting a value includes outputting a flexion angle. In some embodiments, the step of outputting a value includes outputting a gap measurement between a tibial plateau and a femoral plateau. In some embodiments, the step of outputting a value includes outputting an angle between a tibial plateau and a femoral plateau.

[0016] In some embodiments, a system for limb alignment is provided. The system may include a first orientation device configured to be coupled to the tibia, the first orientation device comprising at least one inertial sensor. The system may also include a second orientation device configured to be coupled to the femur, the second orientation device comprising at least one inertial sensor. In some embodiments, the first and second orientation devices are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is extended.

[0017] In some embodiments, the first and second orientation devices are configured to calculate the relative orientation between the femoral and tibial mechanical axes when the leg is extended before resection. In some embodiments, the first and second orientation devices are configured to calculate the relative orientation between the femoral and tibial mechanical axes when the leg is extended after resection. In some embodiments, the first and second orientation devices are configured to calculate the relative orientation between the femoral and tibial mechanical axes when the leg is extended and the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the relative orientation between the femoral and tibial mechanical axes when the leg is extended and a force is applied. In some embodiments, the amputation block is positioned relative to the femoral mechanical axis. In some embodiments, the amputation block is positioned relative to the tibial mechanical axis. In some embodiments, the second orientation device is configured to connect to the femur at a fixed, known point. In some embodiments, the second orientation device is configured to connect with the femur as the leg moves from a flexed to an extended position. In some embodiments, the femoral mechanical axis and the tibial mechanical axis are two vectors in a three-dimensional coordinate system. In some embodiments, the first and second orientation devices are configured to determine the angles at the joint. In some embodiments, the first and second orientation devices are configured to determine the mechanical axis of the leg. In some embodiments, the first and second orientation devices are configured to determine the angle in the sagittal plane. In some embodiments, the first and second orientation devices are configured to determine the angle in the coronal plane. In some embodiments, the first orientation device is configured to calculate the tibial mechanical axis. In some embodiments, the first orientation device is configured to determine at least two points on the tibial mechanical axis.In some embodiments, the second orientation device is configured to calculate the femoral mechanical axis. In some embodiments, the second orientation device is configured to determine at least two points on the femoral mechanical axis. In some embodiments, the first orientation device and the second orientation device are configured to couple to the tibia for calibration. In some embodiments, the system can include a device interface configured to couple to the outer portion of the femur. In some embodiments, the first orientation device and the second orientation device are configured to determine the varus / valgus angle of the femoral mechanical axis and the tibial mechanical axis. In some embodiments, the first orientation device and the second orientation device are configured to determine the flexion / extension angle of the femoral mechanical axis and the tibial mechanical axis. In some embodiments, the first orientation device and the second orientation device are configured to determine gap measurements.

[0018] In some embodiments, a system for limb alignment is provided. The system can include a first orientation device configured to couple to the tibia, the first orientation device including at least one inertial sensor. The system can include a second orientation device configured to couple to the femur, the second orientation device including at least one inertial sensor. In some embodiments, the first orientation device and the second orientation device are configured to calculate changes in position, orientation, or movement between the femoral mechanical axis and the tibial mechanical axis.

[0019] In some embodiments, the first and second orientation devices perform transection verification. In some embodiments, the first and second orientation devices are configured to calculate the angle with respect to the coronal plane when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the angle with respect to the sagittal plane when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the varus / valgus angle when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the flexion / extension angle when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the soft tissue balancing when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the gap measurement when the implant is positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to validate angular measurements against preoperative measurements. In some embodiments, the first and second orientation devices are configured to validate angular measurements against preoperative measurements from imaging techniques. In some embodiments, the first and second orientation devices are configured to validate deformation correction when the implant is positioned between the tibia and femur.

[0020] In some embodiments, a system for limb alignment is provided. The system may include a first orientation device configured to be coupled to the tibia, the first orientation device comprising at least one inertial sensor. The system may also include a second orientation device configured to be coupled to the femur, the second orientation device comprising at least one inertial sensor. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis.

[0021] In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis in the sagittal plane. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis in the coronal plane. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis as an inversion / eversion angle between the tibial and femoral mechanical axes. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis as a flexion / extension angle between the tibial and femoral mechanical axes. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis after resection. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis with the implant positioned between the tibia and femur. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis for comparison with an angle determined preoperatively. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis to measure gap. In some embodiments, the first and second orientation devices are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis to measure soft tissue balancing. In some embodiments, the second orientation device is configured to be coupled to the tibia for calibration.

[0022] In some embodiments, methods for determining limb alignment are provided. The method may include the step of connecting a first orientation device to the tibia, the first orientation device comprising at least one inertial sensor. The method may include the step of connecting a second orientation device to the femur, the second orientation device comprising at least one inertial sensor. The method may include the step of calculating the tibial mechanical axis. The method may include the step of calculating the femoral mechanical axis. The method may include the step of moving the tibia into an extended position and calculating the rotation of the tibial mechanical axis around the femoral mechanical axis.

[0023] In some embodiments, the method may include a step of calculating the tibial mechanical axis before calculating the femoral mechanical axis. In some embodiments, the method may include a step of calibrating the first and second orientation devices before moving the tibia to an extended position. In some embodiments, the method may include a step of calculating the rotation of the tibial mechanical axis around the femoral mechanical axis when a varus force is applied. In some embodiments, the method may include a step of calculating the rotation of the tibial mechanical axis around the femoral mechanical axis when a valgus force is applied. In some embodiments, the method may include a step of calculating the rotation of the tibial mechanical axis around the femoral mechanical axis during soft tissue release. In some embodiments, the method may include a step of calculating the rotation of the tibial mechanical axis around the femoral mechanical axis with respect to one or more planes.

[0024] In some embodiments, a femoral preparation system is provided. The femoral preparation system may include a connector configured to be positioned laterally on the femur. The connector may include a coupling device. The connector may have at least one opening configured to receive a fixation device. The femoral preparation system may include an orientation device configured to be detachably coupled to the connector, the first orientation device comprising at least one inertial sensor.

[0025] In some embodiments, the femoral preparation system may include a device interface configured to connect with a connector and an orientation device. In some embodiments, the femoral preparation system may include a cutting guide bracket configured to connect with a tibial preparation system connected to the tibia. In some embodiments, the femoral preparation system may include a swivel post configured to position the extension portion relative to a fixation device positioned substantially in the center of the intercondylar notch. In some embodiments, the femoral preparation system may include a mounting bracket configured to connect with a connector for the extension portion and the connector. In some embodiments, at least one opening includes a pair of angled openings and an offset opening.

[0026] These and other features, embodiments, and advantages are described below with reference to the drawings, which are intended to illustrate the invention, but are not limiting. In the drawings, similar reference letters consistently indicate the corresponding features throughout similar embodiments. [Brief explanation of the drawing]

[0027] [Figure 1] This is a diagram illustrating an exemplary limb, including the tibia and femur. [Figure 2] This diagram shows the mechanical axes of the tibia and femur. [Figure 3] This diagram illustrates a part of a system for mechanically aligning the femoral axis. [Figure 4] This diagram illustrates a part of a system for mechanically aligning the tibial axis. [Figure 5] This figure illustrates the femoral preparatory system connected to the distal femur and the tibial preparatory system connected to the proximal tibia. [Figure 6] This is an assembly diagram for aligning the mechanical axis of the femur. [Figure 7] This is an assembly diagram for aligning the mechanical axis of the femur. [Figure 8] This is an assembly diagram for calibration. [Figure 9] This is an assembly diagram for calibration. [Figure 10A] This is a diagram illustrating the use of the module. [Figure 10B] This is a diagram illustrating the use of the module. [Figure 11] This is a diagram illustrating gap evaluation. [Figure 12] This is a diagram illustrating one embodiment of the system. [Figure 13] This is a diagram illustrating one embodiment of the system. [Figure 14] This is a diagram illustrating one embodiment of the system. [Figure 15] This is a diagram illustrating one embodiment of the system. [Figure 16] This is a diagram illustrating one embodiment of the system. [Figure 17] This is a diagram illustrating one embodiment of the system. [Figure 18] This is a diagram illustrating one embodiment of the system. [Modes for carrying out the invention]

[0028] Figure 1 illustrates the femur and tibia in a state where the distal portion of the femur and the proximal portion of the tibia form the knee joint. An anatomical coordinate system is included on Figure 1 to present the reader with the proper orientation of the instrument and to help them to more fully understand the structure of the instrument. The anatomical coordinate system shows general directions—anterior, posterior, medial, and lateral—as well as superior and inferior. Other relevant terms include proximal, distal, varus, and valgus. For a given bone, the terms proximal and distal may refer to directions closer to or further away from the body's center, respectively. For a given joint, varus may indicate a joint angle in which the distal portion is closer to the body's midline (e.g., genu varum). For a given joint, valgus may indicate a joint angle in which the distal portion is further away from the body's midline (e.g., genu valgus). These terms relate to the orientation of knee bones such as the femur and tibia and are used in descriptions of various instruments to coincide with their known medical uses. In addition, the terms varus / valgus and posterior / anterior are used herein to describe directional movement. Forces may be applied to bones moving in an anatomical direction or orientation. Varus / valgus is a broad term used herein and includes, without limitation, rotational movement in the medial and / or lateral directions (e.g., right and left in the page) with respect to the knee joint shown in Figure 1. Varus / valgus includes movement or force to temporarily create a varus / valgus condition. Clinically, these forces or movement reveal information about the static and kinematic properties of the joint. Posterior / anterior is a broad term used herein and includes, without limitation, rotational movement in the posterior and / or anterior directions (e.g., in and out of the page) with respect to the knee joint shown in Figure 1.

[0029] Before replacing the femoral and tibial structures of the knee joint with prosthetic components, a surgical cut, commonly called an excision, is typically performed using a saw or one or more other cutting instruments along one or more portions of both the proximal tibia and distal femur. These cuts are made to prepare the tibia and femur for the prosthetic components. After the cuts are made, the prosthetic components can be attached to and / or fixed to the tibia and femur.

[0030] The desired orientation and / or position of these cuts, as well as the desired orientation and / or position of the prosthetic components, may be determined preoperatively, for example, based on one or more mechanical axes passing through the individual patient's leg. After the desired arrangement of these cuts has been determined preoperatively, the surgeon can precisely align the cutting instruments using the systems and methods described herein. Although the systems and methods are described in the context of knee arthroplasty, the systems and / or their components and methods may be similarly used in other types of medical procedures, including, but not limited to, shoulder and hip arthroplasty.

[0031] The systems and methods described herein can also be used for limb alignment and / or joint space measurement. Figure 2 illustrates a mechanical axis penetrating the femur. The systems and methods described herein can determine an axis 10 extending from the center of rotation of the femur within the hip fossa to the central portion of the distal part of the femur. The resection portion 15 of the femur can be a plane perpendicular to the femoral mechanical axis 10. Figure 2 illustrates a mechanical axis penetrating the tibia. The systems and methods described herein can determine an axis 20 extending from the anatomically proximal point on the tibia to the midpoint between the ankles on the patient's ankle. The tibial plateau 25 can be a plane perpendicular to the tibial mechanical axis 20. The systems and methods described herein can determine the angle between the plateaus 15, 25. The plateaus 15, 25 can be estimates of the post-resection planes of the tibia and / or femur. Plateaus 15 and 25 can be planes established through some anatomical reference arrangement.

[0032] The systems and methods described herein can determine the overall limb alignment. For knee surgery, the systems and methods can determine the overall alignment between the femur and tibia, for example, between axes 10 and 20, which can be determined by the systems and methods disclosed herein. The systems and methods described herein can be used in total knee arthroplasty. The systems and methods described herein can be used in unicompartmental knee arthroplasty. The systems and methods described herein can satisfy unmet clinical needs for limb alignment for the knee and other joints.

[0033] In some embodiments, the system and method provide dynamic limb alignment angles. In some embodiments, the system and method provide dynamic limb alignment angles through the range of motion. In some embodiments, the system and method provide dynamic limb alignment angles during flexion / extension. In some embodiments, the system and method provide dynamic limb alignment angles when the user applies varus / valgus forces. In some embodiments, the system and method provide dynamic limb alignment angles before and after tibial resection. In some embodiments, the system and method provide dynamic limb alignment angles before and after femoral resection. In some embodiments, the system and method provide dynamic limb alignment angles before and after any resection. In some embodiments, the system and method provide static limb alignment angles.

[0034] In some methods, the method may include one or more steps of a surgical workflow. The method may include an incision to bring the joint closer. The method may include an initial assessment. The method may include estimating, directing, performing, or otherwise including a proximal tibial resection. The method may include spacer block evaluation for gap balancing. In some methods, spacer block evaluation may only be performed after resections have been made in both the tibia and femur. The method may include estimating, directing, performing, or otherwise including a distal femoral resection. The method may include a trial implant or implant positioning. The method may include a step of cementing the implant. The method may include a step of closing the incision. One or more of these method steps may be facilitated by the use of the systems and methods described herein.

[0035] In some methods, the method may include one or more steps involving limb alignment measurement. The method may include a step of aligning the femoral mechanical axis. The method may include a step of aligning the tibial mechanical axis. The method may include limb alignment measurement during initial evaluation. The method may include limb alignment measurement during femoral amputation. The method may include limb alignment measurement during spacer block evaluation. The method may include limb alignment measurement during trial implant or implant positioning. The method may include limb alignment measurements stored in the patient record before closing the incision and / or completing the procedure, while closing the incision and / or completing the procedure, or after closing the incision and / or completing the procedure, and the patient record is accessible for later review and use.

[0036] The system and method can offer numerous advantages. The system and method can provide reproducible tibial plateau varus / valgus assessment, indication, or other forms of navigation for reproducible tibial plateau varus / valgus evaluation, indication, or resection verification. The system and method can provide reproducible tibial plateau posterior tilt assessment, indication, or other forms of navigation. The system and method can provide a low-destructive fixation method for the instruments or fixtures described herein. The system and method can be easily integrated into current surgical workflows. The system and method can provide reproducible measurement of deep resection of the tibial plateau from the lowest point of the articular articular surface. The system and method can provide tibial plateau resection navigation.

[0037] The system and method can offer many advantages. The system and method can provide measurement of the overall limb alignment of the tibia and femur mechanical axes. The system and method can include instruments for performing minimal resection and re-amputation. The system and method can minimize soft tissue damage using or caused by instruments.

[0038] The system and method can offer many advantages. The system and method can facilitate the control of tibial rotation. The system and method can provide an easy and reproducible measurement of the effect of tibial component rotation on limb alignment. In some methods, tibial rotation includes the dynamic behavior of the tibia. In some methods, tibial rotation includes static, unloaded rotation during extension. In some methods, the effect of tibial component rotation during flexion and extension is measured and displayed. In some methods, dynamic rotation is measured and displayed. The system and method can provide an easy and reproducible measurement of the effect of tibial component rotation on limb alignment, i.e., the space between the femoral condyle and the tibial plateau, when varus / extroverted reactive forces are applied. The system and method can facilitate gap balancing. The system and method can facilitate the assessment, measurement, and adjustment of ligament tension. The system and method can provide meaningful physiological assessments, e.g., measurements for determining overall limb alignment.

[0039] In some embodiments, the system and method may include femoral mechanical alignment. Figure 3 illustrates a system positioned for femoral mechanical alignment. In some embodiments, the system and method may include tibial mechanical alignment. Figure 4 illustrates a system for tibial mechanical alignment. Figure 5 illustrates a femoral preparation system 100 and a tibial preparation system 200. The femoral preparation system 100 comprises a fixture configured to be coupled to the femur. The tibial preparation system 200 comprises a fixture configured to be coupled to the tibia. Figure 6 illustrates a system positioned for femoral mechanical alignment when the leg is in an extended position. Figure 7 illustrates a system positioned for femoral mechanical alignment when the leg is in a flexed position. Figures 8 and 9 illustrate systems positioned for calibration.

[0040] The system and method may include a femoral preparation system 100. In some methods, the femoral preparation system 100 may be used in procedures leading up to resection, including resection. In some methods, the femoral preparation system 100 is used for evaluation and measurement before and / or after resection. In some methods, the femoral preparation system 100 may be used in procedures leading up to resection, without resection. In some methods, the femoral preparation system 100 is used for evaluation and measurement without resection. The system and method may include a tibial preparation system 200. In some methods, the tibial preparation system 200 may be used in procedures leading up to resection, including resection. In some methods, the tibial preparation system 200 is used for evaluation and measurement before and / or after resection. In some methods, the tibial preparation system 200 may be used in procedures leading up to resection, without resection. In some methods, the tibial preparation system 200 is used for evaluation and measurement without resection. The system and method may include a surgical orientation device 300. The system and method may include a reference sensor 400.

[0041] In the femoral axis alignment shown in Figure 3, the femoral preparation system 100 may be coupled to the femur. A reference sensor 400 may be coupled to the femoral preparation system 100. A tibial preparation system 200 may be coupled to the tibia. A surgical orientation device 300 may be coupled to the tibial preparation system 200. The femoral preparation system 100 can determine and / or be attached to the distal point of the femur corresponding to the position of the distal portion of the femoral mechanical axis. In some methods, a pin is inserted at the center of the knee joint on the femur. In some methods, the knee is in a flexed position. In some embodiments, the femoral preparation system 100 may be positioned at the intersection of the whiteside line and the epicondylar axis. In some methods, the anatomical structure of the femur is explored with a probe to determine the position corresponding to the distal point of the femoral mechanical axis. The femoral preparation system 200 can determine the proximal point located on the femoral mechanical axis. In some methods, an outrigger fixture (not shown) is coupled to a pin placed in the center of the knee. The outrigger fixture is used to guide the placement of pins 102 and 104 to the sides of the knee. Pins 102 and 104 are coupled to a fixture portion for mounting a reference sensor 400 for femoral axis alignment. The reference sensor 400 is mounted lateral to the joint to allow the limb to be extended. In some methods, the femur is moved within a range of motion to determine the proximal point of the femoral mechanical axis. In some methods, the surgical orientation device 300 and the reference sensor 400 can determine the mechanical axis of the femur. In some methods, the reference sensor 400 is used to track the movement of the femur and even the amputation block. In some methods, the surgical orientation device 300 is not attached to the femur during or after axis alignment. In some methods, the surgical orientation device 300 may be left attached to assist in the placement of the amputation block. The mechanical axis of the femur can be a line that intersects the distal and proximal points. In some embodiments, the mechanical axis of the femur can be a line that intersects the distal point to which the femoral preparation system 100 is attached.In some embodiments, the mechanical axis of the femur can be a line that intersects with a proximal point established by a reference sensor 400 during the movement of the femur.

[0042] In the tibial axis alignment shown in Figure 4, the tibial preparation system 200 may be coupled to the tibia. The surgical orientation device 300 may be coupled to the tibial preparation system 200. The reference sensor 400 may be coupled to the tibial preparation system 200. In some embodiments, the femoral preparation system 100 is removed, or at least a portion of the femoral preparation system 100 is removed. The tibial preparation system 200 can determine the proximal point of the tibial mechanical axis. In some methods, the anatomical structure of the tibia is probed to determine the proximal point of the tibial mechanical axis. The tibial preparation system 200 can determine the distal point of the tibial mechanical axis. In some methods, the anatomical structure of the tibia is probed as input to determining the distal point of the tibial mechanical axis. In some methods, two parts of the anatomical structure of the tibia are probed to allow the surgical orientation device 300 to determine the distal point corresponding to the tibial mechanical axis. The surgical orientation device 300 and reference sensor 400 can determine the mechanical axis of the tibia. The mechanical axis of the tibia may include the distal and proximal points of the tibia.

[0043] Figure 5 illustrates additional features of the femoral preparation system 100 and the tibial preparation system 200. The femoral preparation system 100 may be used to calculate the femoral mechanical axis penetrating the femur. In some embodiments, the femoral preparation system 100 may be used to modify a natural femur in distal femoral resection, allowing prosthetic components to be securely fitted to the distal end of the femur. The femoral preparation system 100 may support cutting blocks or guides to facilitate one or more resections. As described herein, the femoral preparation system 100 may be designed for total knee arthroplasty or unicompartmental knee arthroplasty. In some embodiments, the femoral preparation system 100 is used to evaluate femoral properties, such as the orientation of the femoral mechanical axis with respect to the tibia or contralateral femur in a controlled manner, in order to assess whether the joint should be modified in a manner that adjusts the orientation of the femur or another bone. Therefore, the femoral preparation system 100 can be used for characterization of femoral joint components without resection or other steps.

[0044] The femoral preparation system 100 may include a femoral fixture assembly 102. The femoral fixture assembly 102 may include a reference sensor device interface 104 which can be used to connect a reference sensor 400 to the femoral fixture assembly 102. In some embodiments, the femoral fixture assembly 102 may include a surgical orientation device interface 106 which can be used to connect a surgical orientation device 300 to the femoral fixture assembly 102.

[0045] The surgical orientation device interface 106 can advantageously allow the surgical orientation device 300 to be quickly coupled to and uncoupled from the femoral fixture assembly 102 during a surgical procedure. This allows the surgical orientation device 300 to be used modularly with various orthopedic fixation devices at one or more stages of the procedure.

[0046] The reference sensor device interface 104 can advantageously allow the reference sensor 400 to be quickly coupled to and uncoupled from the femoral fixation assembly 102 during surgical procedures. This allows the reference sensor 400 to be used modularly with various orthopedic fixation devices at one or more stages of the procedure.

[0047] In several techniques for identifying the distal point of the mechanical axis of the femur, the distal end portion of the femur is exposed using any conventional surgical technique. The tibia and femur can then be flexed to approximately 90 degrees, as shown in Figure 3. It is also possible to flex the leg to other degrees.

[0048] Next, small holes for receiving some of the fixation pins 108 of the femoral fixture assembly 102 can be drilled using any conventional surgical technique in a suitable anatomical position. In some ways, the femoral fixture assembly 102 can be bonded to the distal end portion of the femur. In some ways, the anatomical position can be along the line of the white side. In some ways, the anatomical position can be along the axis of the epicondyle. In some ways, the anatomical position can be at the intersection of the line of the white side and the axis of the epicondyle. The method may include the step of bonding one or more components of the femoral fixture assembly 102 to the femur using one or more fixation pins 108.

[0049] In some methods, the femoral fixture assembly 102 may be offset from the distal end portion of the femur. In some methods, the anatomical placement may be offset from the line of whiteside. In some methods, the anatomical placement may be offset from the epicondylar axis. In some methods, the anatomical placement may be offset from the intersection of the line of whiteside and the epicondylar axis. In some methods, this offset is the input for determining a point along the femoral mechanical axis. In some methods, the anatomical placement can be any preferred anatomical landmark or combination of landmarks within, adjacent to, or offset from the distal end portion of the femur. After the femoral fixture assembly 102 has been attached to the femur, the method may include the step of noting down the distance markings provided by the reference markings to establish the offset, and the placement of the fixing pins 108 relative to the reference markings. In the methods described so far, the distal point corresponding to the femoral mechanical axis can be approximated by using a portion of the femoral fixture assembly 102 to identify the center of the femur.

[0050] This method may further include the step of extending the leg after the surgical orientation device 300 and / or reference sensor 400 have been coupled to the femoral fixture assembly 102. The surgical orientation device 300 and / or reference sensor 400 may be used to determine the relative coordinates of the central pivot point on the femur. By determining the coordinates of the pivot point of the femoral head, the surgical orientation device 300 and / or reference sensor 400 can calculate the arrangement and / or orientation of the mechanical axis penetrating the femur.

[0051] The leg may be moved (for example, rocked) to determine the coordinates of the pivot point of the femoral head, and therefore the pivot point of the mechanical axis. Figures 6 and 7 show the femur at various positions for alignment of the femoral mechanical axis. The femur may be moved in any way to determine its proximal point. In some ways, the reference sensor 400 can determine the mechanical axis of the femur. For example, the leg may be moved in several different directions and / or planes with the surgical orientation device 300 and / or reference sensor 400 coupled to the femoral fixture assembly 102. Readings such as the angular velocity and acceleration of the femur ("surgical orientation device 300 and / or reference sensor 400 data") may be obtained by the surgical orientation device 300 and / or reference sensor 400 until the alignment and / or orientation of the leg and femoral mechanical axis ("femoral mechanical axis") is determined. In one embodiment, when one or more multi-axis (e.g., 3-axis) accelerometers and gyroscopes are used, the data from the surgical orientation device 300 and / or reference sensor 400 for each movement of the femur can be numerically integrated with respect to time to obtain the trajectory of the position and velocity points.

[0052] The acceleration and angular velocity sensed by the surgical orientation device 300 and / or reference sensor 400 during leg movement can be processed while the leg is moved around its pivot point. The surgical orientation device 300 and / or reference sensor 400 can provide an output vector representing the center of rotation with respect to the inertial sensor axis of the surgical orientation device 300 and / or reference sensor 400. The leg may be moved around its pivot point while the inertial data is being processed by the microprocessor. An algorithm implemented on the microprocessor can process the inertial data in real time and determine whether the leg is stationary or moving dynamically. To determine the pivot point, data from one or both states may be used by the algorithm.

[0053] The methods for calculating the arrangement and / or orientation of femoral mechanical axes, and generally for calculating the arrangement and / or orientation of any axis based on pivot points, as described herein, can provide accurate determination of pivot point arrangement and radius of curvature without the burdensome, and sometimes nearly impossible, constraints of external measurements encountered in medical procedures. For example, the methods can enable the calculation of pivot points in blind situations where the end joints are typically hidden or unobservable, such as in the case of the femoral head.

[0054] Figure 5 also illustrates the tibial preparation system 200. The tibial preparation system 200 may be used to calculate the tibial mechanical axis that penetrates the tibia. In some embodiments, the tibial preparation system 200 may be used to modify the natural tibia in a proximal tibial resection, allowing the prosthetic component to be securely fitted to the proximal end of the tibia. The tibial preparation system 200 may support a cutting block or guide to facilitate one or more resections. As described herein, the tibial preparation system 200 may be designed for total knee arthroplasty or unicompartmental knee arthroplasty.

[0055] The tibial preparation system 200 may include a tibial fixture assembly 202. The tibial fixture assembly 202 may include a reference sensor device interface 204 which can be used to connect a reference sensor 400 to the tibial fixture assembly 202. The tibial fixture assembly 202 may include a surgical orientation device interface 206 which can be used to connect a surgical orientation device 300 to the tibial fixture assembly 202.

[0056] The surgical orientation device interface 206 can advantageously allow the surgical orientation device 300 to be quickly coupled to and uncoupled from the tibial fixture assembly 202 during surgical procedures. This allows for modular use, such as the surgical orientation device 300 moving between the femoral fixture assembly 102 and the tibial fixture assembly 202.

[0057] The reference sensor device interface 204 can advantageously allow the reference sensor 400 to be quickly coupled to and uncoupled from the tibial fixture assembly 202 during surgical procedures. This can be used in a modular manner, such as when the reference sensor 400 moves between the femoral fixture assembly 102 and the tibial fixture assembly 202.

[0058] The reference sensor 400 may preferably be coupled to the tibial fixture assembly 202 such that the reference sensor 400 follows the movement of the tibia during knee joint replacement surgery and does not generally move independently with respect to the tibia. The configuration of the reference sensor device interface 204 may allow the reference sensor 400 to be mounted at a low height beneath other components of the tibial fixture assembly 202, thereby allowing the reference sensor 400 to be positioned between at least one movable component of the tibial fixture assembly 202 and the patient's tibia.

[0059] In several techniques for identifying the proximal point of the mechanical axis of the tibia, the proximal end portion of the tibia is exposed using any conventional surgical technique. The tibia and femur can then be flexed to approximately 90 degrees, as shown in Figure 5. It is also possible to flex the leg to other degrees. Small holes for receiving some of the fixation pins of the tibial fixture assembly 202 can then be drilled using any conventional surgical technique in appropriate anatomical placement.

[0060] The tibial fixture assembly 202 may include a midline reference probe assembly 210. The midline reference probe assembly (not shown) may be positioned at a suitable anatomical location on the proximal tibia. In some ways, the anatomical location may be a point immediately behind the insertion site of the anterior cruciate ligament ("ACL"). In some ways, the anatomical location may be a location near the insertion site of the anterior cruciate ligament ("ACL"). In some ways, the anatomical location may be a soft tissue point on the tibia, usually referred to as the A / P point of the mechanical axis. This point is generally located along the intercondylar eminence of the tibia on the tibia and marks the location of the point along the mechanical axis of the tibia. In some ways, the anatomical location may be any suitable anatomical landmark. In some ways, the midline reference probe assembly 210 may be stationary on the anatomical location.

[0061] In several methods, the tibial fixture assembly 202 may be offset from the proximal end portion of the tibia. After the tibial fixture assembly 202 is coupled to the tibia and the midline reference probe assembly is positioned, this method may include the step of noting down the distance markings provided by the reference markings to establish the offset, and the position of the midline reference probe assembly relative to the reference markings. The offset may be input to the surgical orientation device 300. This offset can facilitate the determination of the proximal point of the tibia. In the methods described so far, the proximal point corresponding to the mechanical axis of the tibia can be approximated by using a portion of the tibial fixture assembly 202 to identify the center of the tibia.

[0062] In some ways, the tibial fixture assembly 202 may include a probe assembly 212 comprising an elongated member 214 and a probe member 216. The probe member 216 may be configured to contact an anatomical landmark, such as the ankle joint of a patient. The surgical orientation device 300 may be coupled to the probe assembly 212 such that the movement of the probe assembly 212 causes a corresponding movement of the surgical orientation device 300. Thereafter, the surgical orientation device 300 can track the orientation of the probe assembly 212 as the probe assembly 212 contacts a distal point.

[0063] The method may further include the step of acquiring landmarks to determine the alignment of the mechanical axis passing through the tibia. For example, a landmark may be acquired by engaging the probe member 216 of the probe assembly 212 with the medial malleolus at a first reference position. For example, a landmark may be acquired by engaging the probe member 216 of the probe assembly 212 with the lateral malleolus at a second reference position. Acquisition of the malleolus may be achieved by oscillating one or more parts of the probe assembly 212 and / or tibial fixture assembly 202 so that the probe member 216 contacts the lateral side of the ankle. The surgical orientation device 300 can then determine the alignment of the tibial mechanical axis. In some embodiments, the surgical orientation device 300 can align the sagittal and coronal planes passing through the tibial mechanical axis. In some embodiments, the surgical orientation device 300 can calculate the alignment of the mechanical axis by assuming that the tibial mechanical axis extends from the point of contact between the proximal tibia and the midline probe assembly 210 through a point midway between the two ankle points that contact the probe member 216.

[0064] Each time a landmark is acquired, the user can palpate the ankle. After the ankle position makes contact with the probe member 216, the user can press the user input on the surgical orientation device 300 to cause the surgical orientation device 300 to determine its orientation at a reference position. For example, the surgical orientation device 300 can align and / or calculate its current orientation based on data collected from sensors inside the surgical orientation device 300 at a first reference position and a second reference position. The orientation of the surgical orientation device 300 at the first and second reference positions can be used to identify the orientation of the coronal plane penetrating the tibia, including the mechanical axis of the tibia. The orientation of the surgical orientation device 300 at the first and second reference positions can be used to identify the position and / or orientation of the sagittal plane, including the mechanical axis of the tibia.

[0065] In several ways, the mechanical axis of the tibia is determined. The tibia and femur may be in a flexed position, as shown in Figure 4. The surgical orientation device 300 may be positioned on the tibial preparation system 200. The reference sensor 400 may be positioned on the tibial preparation system 200. During landmark alignment, the surgical orientation device 300 determines the mechanical axis of the flexed tibia. The reference sensor 400 can track the position of the tibia. The surgical orientation device 300 stores the tibial mechanical axis. In some embodiments, the surgical orientation device 300 determines the mechanical axis extending from a contact point of the midline probe assembly 210 and a point midway between two ankle points that contact the probe member 216.

[0066] In several methods, the mechanical axis of the femur is determined. The tibia and femur may be in a flexed position, as shown in Figure 3. The surgical orientation device 300 may be positioned on the tibia preparation system 200. The reference sensor 400 may be positioned on the femur preparation system 100. During landmark alignment, the reference sensor 400 can determine the mechanical axis of the flexed femur. The surgical orientation device 300 stores the femoral mechanical axis. In some embodiments, the surgical orientation device 300 determines the mechanical axis extending from the point of contact between the approximate center of the intercondylar notch and the center of rotation. In some methods, the mechanical axis of the tibia is determined before the mechanical axis of the femur. In other methods, the mechanical axis of the femur is determined before the mechanical axis of the tibia.

[0067] In some methods, the leg is moved into an extended position for limb alignment measurement. The leg is shown in the extended position in Figure 6. The surgical orientation device 300 may be positioned on the tibial preparation system 200. The reference sensor 400 may be positioned on the femoral preparation system 100. In some methods, one of the surgical orientation device 300 and the reference sensor 400 is positioned on the femoral preparation system 100, and the other of the surgical orientation device 300 and the reference sensor 400 is positioned on the tibial preparation system 200.

[0068] The surgical orientation device 300 and reference sensor 400 determined the mechanical axes of the tibia and femur before the leg was moved into an extended position. The surgical orientation device 300 stored the mechanical axes. The mechanical axes of the tibia and femur may be stored as vectors. In some embodiments, the surgical orientation device 300 and reference sensor 400 are configured to sense a change in the orientation of the mechanical axis of the tibia relative to a fixed reference frame when the leg is in an extended position. In some embodiments, the surgical orientation device 300 and reference sensor 400 are configured to sense a change in the orientation of the mechanical axis of the femur relative to a fixed reference frame when the leg is in an extended position. In some embodiments, the surgical orientation device 300 and reference sensor 400 are configured to sense a change in the orientation of the mechanical axes. In some embodiments, the surgical orientation device 300 and reference sensor 400 sense a change in the orientation of the mechanical axes of the tibia and femur when the leg is in an extended position. In some embodiments, the surgical orientation device 300 and reference sensor 400 sense changes in the orientation of the mechanical axes of the tibia and femur when the leg is extended, with respect to the orientation of the mechanical axes of the tibia and femur when the leg is flexed. The leg is shown in the flexed position in Figure 7.

[0069] Changes in the orientation of the mechanical axes of the tibia and femur can determine the varus / valgus angle between the mechanical axes of the tibia and femur. Changes in the orientation of the mechanical axes of the tibia and femur can determine the flexion / contracture angle between the mechanical axes of the tibia and femur. Changes in the orientation of the mechanical axes of the tibia and femur can be measured in the coronal plane. Changes in the orientation of the mechanical axes of the tibia and femur can be measured in the sagittal plane.

[0070] The relative positioning of the surgical orientation device 300 and the reference sensor 400 can determine the angles between the mechanical axes. Varus / valgus includes rotational movement in the medial and / or lateral directions. The surgical orientation device 300 and the reference sensor 400 can be used for limb alignment measurement. The surgical orientation device 300 and the reference sensor 400 can determine the mechanical axis extending from the center of rotation of the femur in the hip fossa to a landmark on the distal portion of the femur. The femoral plateau can be a plane perpendicular to the femoral mechanical axis. The surgical orientation device 300 and the reference sensor 400 can determine the mechanical axis extending from a landmark on the proximal portion of the tibia to the midpoint between the malleoli on the patient's ankle. The tibia plateau can be a plane perpendicular to the tibia mechanical axis. The surgical orientation device 300 and the reference sensor 400 can determine the angles between the plateaus. The surgical orientation device 300 and reference sensor 400 can determine varus / valgus angles between plateaus. The surgical orientation device 300 and reference sensor 400 can determine flexion / contracture angles between plateaus. The surgical orientation device 300 and reference sensor 400 can determine angles with respect to one or more planes. The surgical orientation device 300 and reference sensor 400 can determine angles with respect to one or more anatomical planes. The surgical orientation device 300 and reference sensor 400 can determine angles based on position in a three-dimensional coordinate system.

[0071] In some methods, the mechanical axis is determined before resection. In some methods, the alignment of the tibial and femoral mechanical axes is determined before resection. In some methods, the leg is moved to an extended position for limb alignment measurement before resection. Changes in the orientation of the tibial and femoral mechanical axes between flexion and extension can be memorized. The orientation of the tibial and femoral mechanical axes can be compared with preoperative measurements obtained from imaging techniques such as X-ray. The leg can be moved from an extended position to a flexed position for resection. The leg in a flexed position is shown in Figure 7. The surgeon can then proceed with the resection. The femoral preparation system 100 can be coupled to the cutting guide. The tibial preparation system 200 can be coupled to the cutting guide. The surgical orientation device 300 can be coupled to the cutting guide. The reference sensor 400 can be coupled to the cutting guide. In some embodiments, the resection is performed for total knee replacement. In some embodiments, the resection is performed for partial knee replacement. Further details regarding the addition of cutting guides are disclosed in Patent Document 1 filed July 24, 2009, Patent Document 2 filed January 21, 2011, Patent Document 3 filed May 24, 2011, Patent Document 4 filed November 5, 2014, and Patent Document 5 filed November 14, 2014, the entire content of which is incorporated herein by reference for all purposes.

[0072] In some methods, the alignment of the mechanical axes of the tibia and femur is not determined before resection. The surgeon can proceed with resection after the mechanical axes have been determined. The surgeon can proceed with resection after the mechanical axes have been memorized by the surgical orientation device 300. The leg may remain in a flexed position. The leg may be positioned in a flexed position for mechanical axis alignment and resection.

[0073] In some methods, the alignment of the tibial and femoral mechanical axes is determined after resection. In some methods, the alignment of the tibial and femoral mechanical axes is determined before and after resection. In some methods, the alignment of the tibial and femoral mechanical axes is determined only after resection. In some methods, the leg is moved to an extended position after resection for limb alignment measurement. Changes in the orientation of the tibial and femoral mechanical axes in extension relative to the tibial and femoral mechanical axes in flexion can be determined. Changes in the orientation of the tibial and femoral mechanical axes can be compared with preoperative measurements obtained from imaging techniques such as X-rays. The leg may be moved from an extended position to a flexed position for further resection.

[0074] Figures 8 and 9 illustrate the calibration of the surgical orientation device 300 and the reference sensor 400. In some methods, the leg is in an extended position for calibration. In some methods, the leg is in a flexed position for calibration. In some methods, calibration is optional. In some methods, the surgical orientation device 300 and the reference sensor 400 are calibrated after the determination of the mechanical axes of the tibia and femur. In some methods, the surgical orientation device 300 and the reference sensor 400 are calibrated before limb alignment measurement. The surgical orientation device 300 may be positioned on the tibial preparation system 200 for calibration. The reference sensor device 400 may be positioned on the tibial preparation system 200 for calibration. The surgical orientation device 300 and the reference sensor 400 may be assumed to have orientations known relative to each other when mounted on the tibial preparation system 200. The surgical orientation device 300 and the reference sensor 400 may be zero-point adjusted. The surgical orientation device 300 and the reference sensor 400 can reduce errors caused by drift. The surgical orientation device 300 and the reference sensor 400 can be calibrated before the reference sensor 400 is positioned on the femoral preparation system 100 for limb alignment calculation. The reference sensor 400 can be returned to the femoral preparation system 100 after calibration. The femoral preparation system 100 and the tibial preparation system 200 may be equipped with reference sensor device interfaces 104, 204 which can be used to connect the reference sensor 400 to fixture assemblies 102, 202. Figures 7 and 8 illustrate one embodiment of the reference sensor device interfaces 104, 204.

[0075] Figure 10A illustrates the alignment of module 500. The surgical orientation device 300 may be coupled to the tibial fixture assembly 202. The reference sensor 400 may be coupled to the tibial fixture assembly 202. In some embodiments, the reference sensor 400 remains stationary with respect to the tibia. In some embodiments, module 500 is provided. Module 500 may include any of the features of the surgical orientation device 300 and reference sensor 400 described herein. Module 500 may comprise any of the sensors described herein. In some embodiments, the reference sensor 400 and module 500 have the same configuration. In some embodiments, the reference sensor 400 and module 500 have different configurations. In some ways, both the reference sensor 400 and module 500 are utilized. In some ways, the reference sensor 400 is utilized, but module 500 is not. In some embodiments, the reference sensor 400 may be utilized in any way instead of module 500. In some embodiments, module 500 may be used in any way instead of the reference sensor 400.

[0076] The tibial fixture assembly 202 may be partially or completely assembled for the calibration of module 500. The surgical orientation device 300 may be coupled to the movable part of the tibial fixture assembly 202. The reference sensor 400 may be coupled to the fixed or stationary part of the tibial fixture assembly 202. The surgical orientation device 300 and the reference sensor 400 may be coupled to the tibial fixture assembly 202 in the same manner in which these devices were coupled when positioning the tibial mechanical axis. The tibial fixture assembly 202 may include a module interface 250 which can be used to couple module 500 to the tibial fixture assembly 202.

[0077] Module 500 can be coupled to the tibial fixture assembly 202. In some embodiments, module 500 is coupled to a movable part of the tibial fixture assembly 202. In some embodiments, module 500 is coupled to the same movable part of the tibial fixture assembly 202 as the surgical orientation device 300. The angle between the surgical orientation device 300 and module 500 can be fixed during calibration. Module 500 can be calibrated with respect to the surgical orientation device 300.

[0078] In some embodiments, module 500 is coupled to a fixed portion of the tibial fixture assembly 202. In some embodiments, module 500 is coupled to the same fixed portion of the tibial fixture assembly 202 as the reference sensor 400. The angle between the reference sensor 400 and module 500 may be fixed during calibration. Module 500 may be calibrated with respect to the reference sensor 400.

[0079] In some methods, the leg is moved into an extended position as shown in Figure 7A. Module 500 is aligned or calibrated with respect to the reference sensor 400 and / or the surgical orientation device 300. In some methods, module 500 is kept stationary on the tibial fixture assembly 202 during alignment. In some methods, module 500 may be fixed to the tibia. In some methods, module 500 is coupled to the movable part of the tibial fixture assembly 202 during alignment. Module 500 may be moved relative to the reference sensor 400 during alignment. In some methods, the leg is held stationary during alignment. In some methods, the tibia is held stationary during alignment. In some methods, the sensors of module 500 are activated during alignment. In some methods, gyro integration is initiated during alignment.

[0080] As shown in Figure 10B, module 500 can be moved to the femur during limb alignment and gap measurement. In some cases, module 500 is moved from its position on the tibial fixture assembly 202 to its position on the femoral fixture assembly 102. Figure 7B illustrates the positions of the surgical orientation device 300, reference sensor 400, and module 500 during limb alignment and gap measurement. In some embodiments, the surgical orientation device 300 may be coupled to the movable portion of the tibial fixture assembly 202. In some embodiments, the surgical orientation device 300 may be coupled to the fixed portion of the tibial fixture assembly 202. In some embodiments, the reference sensor 400 may be coupled to the fixed portion of the tibial fixture assembly 202. In some embodiments, the reference sensor 400 may be coupled to the fixed portion of the movable fixture assembly 202. In some embodiments, the surgical orientation device 300 tracks the position of the tibia during limb alignment and gap measurement. In some embodiments, the orientation device 300 received information from the reference sensor 400 during limb alignment and gap measurement. In some embodiments, the orientation device 300 received information from the module 500 during limb alignment and gap measurement.

[0081] In some ways, module 500 can be coupled to the femoral fixture assembly 102 during limb alignment and gap measurement. In some embodiments, module 500 is coupled to a fixed portion of the femoral fixture assembly 102. In some embodiments, module 500 is coupled to a movable portion of the femoral fixture assembly 102. In some ways, module 500 tracks the position of the femur during limb alignment and gap measurement.

[0082] In some embodiments, the reference sensor 400 may be moved to the femur during limb alignment and gap measurement. In some methods, the reference sensor 400 is moved from a position on the tibial fixture assembly 202 to a position on the femoral fixture assembly 102. The surgical orientation device 300 may be coupled to the tibial fixture assembly 202. Module 500 may be coupled to the tibial fixture assembly 202. In some embodiments, the surgical orientation device 300 tracks the position of the tibia during limb alignment and gap measurement. In some embodiments, the orientation device 300 receives information from the reference sensor 400 during limb alignment and gap measurement. In some embodiments, the orientation device 300 receives information from module 500 during limb alignment and gap measurement.

[0083] In some cases, the reference sensor 400 can be coupled to the femoral fixture assembly 102 during limb alignment and gap measurement. In some embodiments, the reference sensor 400 is coupled to a fixed portion of the femoral fixture assembly 102. In some cases, the reference sensor 400 tracks the position of the femur during limb alignment and gap measurement.

[0084] The surgical orientation device 300, reference sensor 400, and / or module 500 can track the position of the tibia and femur during limb alignment and gap measurement. In some embodiments, the surgical orientation device 300 tracks the tibia. In some embodiments, the reference sensor 400 tracks the femur. In some embodiments, module 500 tracks the femur. Other configurations are also contemplated. In some embodiments, the reference sensor 400 can track the position and orientation of the tibia. In some embodiments, module 500 can track the position and orientation of the tibia. The user can obtain position and / or orientation signals from the reference sensor 400 and module 500 in real time. The user can obtain limb alignment measurements in real time. In some embodiments, tracking of the tibia and femur is time-limited. In some embodiments, tracking of the tibia and femur is limited in terms of the time until recalibration is required. Recalibration may include any of the steps described herein for aligning or calibrating module 500.

[0085] In some methods, the surgical orientation device 300, reference sensor 400, and / or module 500 receive static measurements based on the position of the tibia and femur. In some methods, the surgical orientation device 300, reference sensor 400, and / or module 500 perform dynamic measurements based on the position of the tibia and femur within the range of motion. In some embodiments, an external reaction force may be applied to the tibia to return it to a neutral position. Any degree of stress may be applied before the tibia is returned to a neutral position. The leg may be abducted. Load may be applied until the clinician feels resistance. Other ranges and degrees of movement may also be possible. In some embodiments, the leg may be swung in one general loop motion returning from home position to home position, the loop motion causing both leg abduction and leg lift. In some embodiments, the tibia and femur may be fixed in a flexion of about 90 degrees. In some embodiments, the tibia and femur may be fixed in a fully extended position. It is also possible to have the leg in other degrees of flexion. Other movements of the leg are also intended.

[0086] In some embodiments, as shown in Figure 10B, the reference sensor 400 can track the tibia and the module 500 can track the femur. Other configurations are also envisioned. In other embodiments, the reference sensor 400 may be coupled to the femoral fixture assembly 102 during limb alignment and gap measurement. The module 500 may be coupled to the tibial fixture assembly 202. In some embodiments, one of the reference sensor 400 and module 500 is coupled to the tibia, and the other of the reference sensor 400 and module 500 is coupled to the femur.

[0087] In other embodiments involving the surgical orientation device 300 and the reference sensor 400, the surgical orientation device 300 may be moved to a fixed portion of the tibial fixture assembly 202, or the portion of the tibial fixture assembly 202 to which the surgical orientation device 300 is attached may be fixed by engaging a clamp or other locking device. The reference sensor 400 may be coupled to a fixed portion of the tibial fixture assembly 202. The surgical orientation device 300 and the reference sensor 400 may be aligned with respect to each other. The surgical orientation device 300 may be moved to a fixed portion of the femoral fixture assembly 102 during limb alignment and gap measurement. In some embodiments, during limb alignment and gap measurement, one of the surgical orientation device 300 and the reference sensor 400 is coupled to the tibia, and the other of the surgical orientation device 300 and the reference sensor 400 is coupled to the femur. In some methods, only the surgical orientation device 300 and the reference sensor 400 are used in limb alignment and gap measurement.

[0088] In some cases, a surgeon can perform a relaxation test to assess ligament gap balancing. The reference sensor 400 and module 500 may be in the same position for the limb alignment and relaxation tests shown in Figure 10B. In some embodiments, module 300 can track the position and / or orientation of the tibia. In some embodiments, the reference sensor 400 can track the position and / or orientation of the femur. In some embodiments, module 500 can track the position and / or orientation of the femur.

[0089] Figure 11 illustrates gap balancing evaluation using at least two of the surgical orientation device 300, reference sensor 400, and module 500. During gap evaluation, one or more of the surgical orientation device 300, reference sensor 400, and module 500 are attached to the tibia. During gap evaluation, one or more of the surgical orientation device 300, reference sensor 400, and module 500 are attached to the femur. In some methods, the surgical orientation device 300 and reference sensor 400 perform gap balancing before limb alignment measurement. In some methods, the surgical orientation device 300 and reference sensor 400 perform gap balancing after limb alignment measurement. In some methods, the surgical orientation device 300 and reference sensor 400 perform gap balancing when the leg is extended for limb alignment measurement. In Figure 11, the surgical orientation device 300, reference sensor 400, and module 500 are shown as icons. In some methods, the surgical orientation device 300 is positioned on the tibia. In some methods, the reference sensor 400 is positioned on the femur. In some methods, the reference sensor 400 may be positioned on the tibia and the module 500 on the femur, or vice versa. In some methods, the reference sensor 400 and the surgical orientation device 300 are used. The reference sensor 400 may be positioned on the tibia and the surgical orientation device 300 on the femur, or vice versa. In some methods, the module 500 and the surgical orientation device 300 are used. The module 500 may be positioned on the femur and the surgical orientation device 300 may be positioned on the tibia, or vice versa. In some methods, the tibial mechanical axis is calculated before the gap balancing evaluation, and the femoral mechanical axis is calculated before the gap balancing evaluation. In some methods, resection is performed before the gap balancing measurement. In some methods, limb alignment measurements are performed before gap balancing measurements.

[0090] During gap measurement, at least one of the surgical orientation device 300, reference sensor 400, and module 500 can track the position and / or orientation of the tibia. During gap measurement, at least one of the surgical orientation device 300, reference sensor 400, and module 500 can track the position and / or orientation of the femur. During gap measurement, the reference sensor 400 can track the position and / or orientation of the tibia, and module 500 can track the position and / or orientation of the femur in the configuration shown in Figure 11. In some methods, gap balancing is performed using a trial implant or an implant. In some methods, gap balancing is performed using at least one implant positioned between the tibia and femur. The leg may be positioned in an extended state. The angle between the reference sensor 400 and module 500 may be determined with the condyles in contact. This angle may be aligned as 0 degrees. The tibia and femur may pass within the range of motion. In some embodiments, a varus force is applied to the tibia, and the angle between the surgical orientation device 300, reference sensor 400, and / or module 500 on the tibia and the surgical orientation device 300, reference sensor 400, and / or module 500 on the femur can be determined. In some embodiments, a force is applied to the tibia, and the angle between the surgical orientation device 300, reference sensor 400, and / or module 500 on the tibia and the surgical orientation device 300, reference sensor 400, and / or module 500 on the femur can be determined. In some embodiments, a varus force is applied to the tibia, and the angle between the surgical orientation device 300 on the tibia and the reference sensor 400 on the femur can be determined. The intercondylar distance can be known. The intercondylar distance can be determined from images, such as X-ray images. The intercondylar distance can be measured during surgery. This distance can be the input to the surgical orientation device 300. In the example shown, the intercondylar distance is 55 mm. The gap due to the reaction force can be determined based on a geometric relationship between a known applied reaction force and the intercondylar distance.

[0091] During gap evaluation, the tibia and femur can be moved through their range of motion when a valgus force is applied. In some embodiments, a valgus force is applied to the tibia, and the angle between the surgical orientation device 300, reference sensor 400, and / or module 500 on the tibia and the surgical orientation device 300, reference sensor 400, and / or module 500 on the femur can be determined. In some embodiments, a force is applied to the tibia. When the force is applied, the angle between the surgical orientation device 300, reference sensor 400, and / or module 500 on the tibia and the surgical orientation device 300, reference sensor 400, and / or module 500 on the femur is determined. In some embodiments, a valgus force is applied to the tibia, and the angle between the surgical orientation device 300 on the tibia and the reference sensor 400 on the femur can be determined. The intercondylar distance can be determined. The gap due to valgus force can be determined based on geometric relationships in the same manner as the gap due to varus force.

[0092] The gap can be calculated by applying a force and measuring the change in angle between the femoral mechanical axis and the tibial mechanical axis. This angle and the intercondylar distance can yield an estimate of the gap. In some ways, the user applies a varus torque. In some ways, the user applies an valgus torque. In some ways, the user applies a varus torque, then an valgus torque. In some ways, the user applies an valgus torque, then a varus torque. In some ways, the user applies a varus and / or valgus force to the knee in an extended position. In some ways, the user applies a varus and / or valgus force to the knee in a flexed position. In some ways, the user applies a varus force in both flexed and extended positions. In some ways, the user applies a valgus force in both flexed and extended positions.

[0093] One or more of the surgical orientation device 300, reference sensor 400, and module 500 can calculate the gap distance. The gap distance is the product of the measured angles between the surgical orientation device 300, reference sensor 400, and / or module 500 on the tibia and the surgical orientation device 300, reference sensor 400, and / or module 500 on the femur. The gap distance is the product of known intercondylar distances. In some embodiments, dynamic gap height provides insight into medial / lateral ligament tension. Gap height can provide insight into soft tissue balancing. Gap measurement may be evaluated before resection. The gap may be evaluated after resection. The gap may be evaluated both before and after resection. The gap may be evaluated using multiple implants or trial implants.

[0094] The surgical orientation device 300, reference sensor 400, and / or module 500 can be used to measure and record the placement of anatomical landmarks used in knee joint procedures. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used to determine the placement of the proximal or distal point of the mechanical axis of the tibia. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used to determine the placement of the proximal or distal point of the mechanical axis of the femur. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used to perform limb balancing measurements. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used to perform gap balancing measurements. These measurements can improve patient outcomes by quantifying limb alignment, improving implant selection, and / or improving implant placement.

[0095] The surgical orientation device 300, reference sensor 400, and / or module 500 may be equipped with one or more inertial sensors. The inertial sensors can track the orientation and / or position of the tibia and femur during limb alignment and gap measurement. The sensors in the surgical orientation device 300 and the reference sensor 400 can determine the mechanical axis of the femur and the mechanical axis of the tibia. These mechanical axes can guide the cutting block for the desired resection. These mechanical axes can also be used for limb balancing measurement. These mechanical axes can also be used for gap measurement.

[0096] The surgical orientation device 300, reference sensor 400, and / or module 500 may include at least one inertial sensor, such as an accelerometer, a gyroscope, or a combination of these sensors with other sensors. The surgical orientation device 300, reference sensor 400, and / or module 500 may utilize sensors other than optical trackers. The surgical orientation device 300, reference sensor 400, and / or module 500 may measure acceleration. The surgical orientation device 300, reference sensor 400, and / or module 500 may measure velocity. The surgical orientation device 300, reference sensor 400, and / or module 500 may measure the physical properties of the bone to which it is attached. In some embodiments, the surgical orientation device 300, reference sensor 400, and module 500 may comprise a three-axis accelerometer for detecting orientation relative to gravity and multiple gyroscopes for detecting rotation. Other sensors may also be used in various modifications.

[0097] The surgical orientation device 300, the reference sensor 400, and / or module 500 may include one or more sensors that together form an inertial measurement unit (IMU). In some embodiments, the IMU may include a first sensor for determining acceleration and a second sensor for determining gyro positioning. As described herein, the first sensor may be an accelerometer and the second sensor may be a gyroscope sensor. In some embodiments, the sensors may include a three-axis gyroscope sensor and a three-axis accelerometer sensor.

[0098] The surgical orientation device 300, the reference sensor 400, and / or the sensors within the module 500 preferably transfer data between themselves and, optionally, to external devices such as computers, tablets, and / or smartphones, as well as to external displays. The surgical orientation device 300, the reference sensor 400, and the module 500 may be positioned within the surgical field. External devices may be positioned within or outside the surgical field. The surgical orientation device 300, the reference sensor 400, and the module 500 can transfer data wirelessly using Bluetooth®, Wi-Fi®, or other standard wireless telemetry protocols.

[0099] The surgical orientation device 300, the reference sensor 400, and / or the module 500 may include transmitters for transmitting and / or receiving data. In some embodiments, the surgical orientation device 300 may receive data from the reference sensor 400 and the module 500. The surgical orientation device 300, the reference sensor 400, and the module 500 may include transmitters for transmitting data or receiving data from an external output device. In some embodiments, the surgical orientation device 300 may transmit data to the reference sensor 400 and the module 500. In some embodiments, the reference sensor 400 and the module 500 may transmit data between them.

[0100] Information from the reference sensor 400 and module 500 can, for example, correspond to the position and / or orientation of the tibia and femur during limb alignment and / or gap measurement. Information from the reference sensor 400 can, for example, correspond to the position and / or orientation of the tibia and femur during gap measurement. Information from the reference sensor 400 can, for example, correspond to the position and / or orientation of the tibial mechanical axis during range of motion. Information from the reference sensor 400 can, for example, correspond to the position and / or orientation of the tibial mechanical axis while force is applied. Information from module 500 can, for example, correspond to the position and / or orientation of the femoral mechanical axis during range of motion. Information from module 500 can, for example, correspond to the position and / or orientation of the femoral mechanical axis while force is applied.

[0101] The surgical orientation device 300, the reference sensor 400, and / or module 500 may be equipped with indicators. Indicators may be located on the front of each device. Indicators may be located on the outer surface of each device. Indicators may be lights or LEDs indicating that each device is turned on. Indicators may be lights or LEDs indicating that each device is sensing movement. Indicators may be separate components from the outer housing of each device, or they may be on or integrated within the outer housing of each device.

[0102] The surgical orientation device 300, the reference sensor 400, and / or module 500 may include a display. In some embodiments, the surgical orientation device 300 includes a display. The display may be sized so that the user can easily read numbers, lettering, and / or symbols on the display while performing a medical procedure. The display may be sized so that the user can receive instructions. The display may be sized so that the user can view measurement data.

[0103] The surgical orientation device 300, the reference sensor 400, and / or module 500 may include a user input device. The user input device may be located on the front of each device. The user input device may be located on the outer surface of each device. The user input device may include a touchscreen. The user input device may include one or more buttons. The user input device may include one or more switches. The user input device may include one or more scroll wheels. The user input device may be activated, for example, by a finger, hand, and / or instrument, and may select one or more modes of operation for each device. The user input device may be a separate component from the outer housing of each device, or may be integrated on or within the outer housing of each device. In some embodiments, the user input device is a separate component from the housing. For example, the user input device may include a remote input device coupled to each device via a wired or wireless connection. Each device may include means for receiving input from the user.

[0104] The surgical orientation device 300, reference sensor 400, and / or module 500 may comprise one or more functional components configured to sense position, orientation, or movement. The surgical orientation device 300, reference sensor 400, and module 500 may comprise an electronic control unit that communicates with one or more inertial sensors. The surgical orientation device 300, reference sensor 400, and module 500 may comprise a power supply. The surgical orientation device 300, reference sensor 400, and module 500 may comprise internal memory.

[0105] The surgical orientation device 300, the reference sensor 400, and / or module 500 can communicate with external memory. The surgical orientation device 300, the reference sensor 400, and module 500 can communicate with an external output device as described herein. In some embodiments, the external output device may include external memory. The external memory may be a separate component from the external output device, or it may be integrated on or within the external output device. The external output device can enable surgeons, medical professionals, and / or other users to easily, efficiently, and accurately operate the surgical orientation device 300, the reference sensor 400, and module 500.

[0106] In some embodiments, the electronic control unit of the surgical orientation device 300, the reference sensor 400, and / or module 500 receives input from one or more sensors of the surgical orientation device 300, the reference sensor 400, and / or module 500. The electronic control unit can control and / or transmit outputs to an external memory. The electronic control unit can control and / or transmit outputs to an external output device. The electronic control unit may be configured to receive and transmit electronic data. The electronic control unit may be configured to perform calculations based on the received electronic data. The electronic control unit may include a transmitter. The electronic control unit may wirelessly transfer data using Bluetooth®, Bluetooth Low Energy®, Wi-Fi®, or other standard wireless telemetry protocols. The electronic control unit may include a Bluetooth® radio. The electronic control unit may include a Bluetooth Low Energy® radio. In some embodiments, the surgical orientation device 300, the reference sensor 400, and / or module 500 may include a wireless module. In some embodiments, the surgical orientation device 300, the reference sensor 400, and / or module 500 comprises at least one accelerometer, at least one gyroscope, and a wireless module.

[0107] In certain embodiments, the electronic control unit of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be configured to convert electronic data from a machine-readable format to a human-readable format for presentation on an external output device or on the display of the surgical orientation device 300, the reference sensor 400, and / or module 500.

[0108] The electronic control unit of the surgical orientation device 300, the reference sensor 400, and / or module 500 can communicate with internal memory to retrieve and / or store data. The electronic control unit of the surgical orientation device 300, the reference sensor 400, and / or module 500 can communicate with external memory to retrieve and / or store data. The electronic control unit can communicate with internal memory and / or external memory to retrieve program instructions for software and / or hardware. Internal and external memory may include random access memory ("RAM") such as static RAM for temporary storage of information and / or read-only memory ("ROM") such as flash memory for more persistent storage of information. External memory may be integrated with a cloud database. External output devices can retrieve data from the cloud database. The surgical orientation device 300, the reference sensor 400, and / or module 500 can interact with external memory via cloud integration. External memory may be a server.

[0109] The electronic control unit of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be configured to receive real-time data from one or more sensors. The electronic control unit may be configured to use the sensor data to determine, estimate, and / or calculate the mechanical axis of the tibia. The electronic control unit may be configured to use the sensor data to determine, estimate, and / or calculate the mechanical axis of the femur. The electronic control unit may be configured to use the sensor data to determine, estimate, and / or calculate the alignment between the mechanical axis of the tibia and the mechanical axis of the femur. The electronic control unit 20 may be configured to use the sensor data to determine, estimate, and / or calculate the limb alignment. The electronic control unit 20 may be configured to use the sensor data to determine, estimate, and / or calculate the clearance distance under varus / valgus forces.

[0110] In some embodiments, the surgical orientation device 300, the reference sensor 400, and / or one or more sensors of the module 500 may comprise at least one orientation sensor configured to provide an electronic control unit with real-time data relating to the movement, orientation, and / or position of the patient's corresponding anatomical structure. In some embodiments, one or more sensors may include at least one gyro sensor, accelerometer, tilt sensor, magnetometer, and / or other similar one or more devices. One or more sensors may be configured to measure the alignment of the mechanical axis of the leg. In some embodiments, one or more sensors may be configured to provide measurements relative to a reference point, line, plane, and / or zero gravity. Zero gravity as referred herein generally refers to an orientation where the axis of the sensor is perpendicular to the force of gravity, thereby not producing an angular offset with respect to the gravity vector, e.g., tilt, pitch, roll, or yaw. In some embodiments, one or more sensors may be configured to provide measurements for use in dead reckoning or inertial navigation systems.

[0111] In some embodiments, the surgical orientation device 300, reference sensor 400, and / or module 500 can collect data relative to a coordinate system. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a global coordinate system. The surgical orientation device 300, reference sensor 400, and / or module 500 can be synchronized with a global coordinate system. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system including the mechanical axis of the tibia. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system including the mechanical axis of the femur. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system including the origin. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system related to upright lateral film or X-ray images. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system related to anterior / posterior X-rays. The surgical orientation device 300, reference sensor 400, and / or module 500 can be aligned to a coordinate system determined during calibration or alignment.

[0112] In some methods, the surgical orientation device 300 and / or the reference sensor 400 can determine the orientation of the tibia during limb alignment measurement. In some methods, the module 500 can determine the orientation of the femur during limb alignment measurement. The surgical orientation device 300, the reference sensor 400, and / or the module 500 can determine the orientation of the femur relative to the tibia. In some methods, the surgical orientation device 300 and / or the reference sensor 400 can determine the orientation of the tibial mechanical axis. In some methods, the surgical orientation device 300 and / or the reference sensor 400 can determine the orientation of the femoral mechanical axis. The surgical orientation device 300, the reference sensor 400, and / or the module 500 can track these mechanical axes through the range of motion. The system and method can determine various measurements related to limb alignment, including femoral and tibia alignment. The system and method can determine various measurements related to gap, including gap measurement under applied force.

[0113] The system and method can determine the overall varus / valgus limb alignment angle. The system and method can determine the overall varus / valgus limb alignment angle while the leg is in a flexed position. The system and method can determine the overall varus / valgus limb alignment angle while the leg is in an extended position. The system and method can determine the overall varus / valgus limb alignment angle through the range of motion. Varus / valgus relates to the angle within the shaft of a bone or at the joint. Valgus relates to the distal portion of the joint being more laterally positioned, and varus relates to the distal portion of the joint being more medially positioned.

[0114] In normal knee joint alignment, the mechanical axes of the tibia and femur are approximately aligned. In case of misalignment, an angle is created between the mechanical axes of the tibia and femur. In varus, the compressive force on the medial condyle is greater than that on the lateral condyle. In valgus, the compressive force on the lateral condyle is greater than that on the medial condyle.

[0115] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall varus / valgus limb alignment angle by determining the relationship between the mechanical axes of the tibia and femur. In some ways, this is a static determination when the knee is in a flexed position. In some ways, this is a static determination when the knee is in an extended position. In some ways, this is a dynamic determination when the knee is moved through a range of motion, for example, from flexion to extension or from extension to flexion.

[0116] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall varus / valgus limb alignment angle. In some cases, this angle can be determined before any resection. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall varus / valgus limb alignment angle postoperatively. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall varus / valgus limb alignment angle during trial reduction. One or more trial implants can be positioned between the tibia and femur. The knee can be positioned through or through its range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall varus / valgus limb alignment angle for each of the trial implants. A trial implant can be selected to achieve the target varus / valgus limb alignment. An implant corresponding to the trial implant can be implanted.

[0117] The system and method can measure range of motion by measuring the overall change from maximum extension to maximum flexion. The system and method can determine the overall anterior / posterior (flexion / extension) limb alignment angle. The system and method can determine the overall knee flexion angle while the leg is in a flexed position. The system and method can determine the overall knee extension angle while the leg is in an extended position. The system and method can determine the overall anterior / posterior (flexion / extension) limb alignment angle through the range of motion. Knee flexion is bending the knee joint to bring the foot towards the back of the thigh. Knee extension is straightening the knee joint. Flexion and extension are related to the joint movement of the knee. The normal range of motion of the knee is approximately 0° extension and approximately 140° flexion. Some patients may have reduced flexion / extension.

[0118] The surgical orientation device 300, reference sensor 400, and / or module 500 can statically determine limb alignment in a flexed state. The surgical orientation device 300, reference sensor 400, and / or module 500 can statically determine limb alignment in an extended state. The surgical orientation device 300, reference sensor 400, and / or module 500 can dynamically determine limb alignment as the knee moves through its range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine knee extension and knee flexion angles by determining the relationship between the mechanical axes of the tibia and femur.

[0119] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall knee extension and knee flexion angles before any resection. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the knee extension and knee flexion angles after any resection. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall knee extension and knee flexion angles during trial reduction. One or more trial implants can be positioned between the tibia and femur. The knee can be positioned through or through the range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the overall knee extension and knee flexion angles for each of the trial implants. A trial implant may be selected to achieve the target knee extension and knee flexion angles. For example, a trial implant can improve the patient's range of motion toward a normal range of motion. For example, a trial implant can enable full extension. For example, a trial implant can allow for full flexion. A corresponding implant can then be implanted.

[0120] The system and method can calculate the gap space. The system and method can calculate the gap space while the leg is in a flexed position. The system and method can calculate the gap space while the leg is in an extended position. The system and method can calculate the gap space through the range of motion. The gap space is related to the distance between the medial and lateral femoral condyles and the tibial plateau. In some methods, the gap space can be calculated as a gap opening from a single femoral condyle to the tibial plateau, assuming contact between the tibial plateau and the femoral condyles of other compartments. If an implant or trial implant is positioned within the gap space, the gap distance can be related to the distance between the medial and lateral femoral condyles and the implant or trial implant.

[0121] In a healthy knee, there is a layer of cartilage that separates the ends of the tibia and femur. Due to variations in wear between the medial and lateral femoral condyles relative to the tibial condyles in arthritised knees, the gap between the tibial and femoral plateaus may narrow symmetrically or asymmetrically.

[0122] The surgical orientation device 300, reference sensor 400, and / or module 500 can calculate the gap space by determining the relationship between the tibia and femur. In some methods, the gap space is calculated, at least partially, by distance measurement. In some methods, the gap space is calculated, at least partially, by inertial measurement. In some methods, this is a static determination when the knee is in a flexed position. In some methods, this is a static determination when the knee is in an extended position. In some methods, this is a dynamic determination when the knee is moved through a range of motion, for example, from flexion to extension or from extension to flexion.

[0123] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the space before any resection. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the space after any resection. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the space during trial reduction. One or more trial implants can be positioned between the tibia and femur. The knee can be positioned through or through its range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the space for each trial implant. A trial implant that achieves the target space can be selected. An implant corresponding to the trial implant can be implanted.

[0124] The system and method can estimate the limb alignment angle based on the navigated tibial resection angle. The system and method can estimate the limb alignment angle while the leg is in a flexed position. The system and method can estimate the limb alignment angle while the leg is in an extended position. The system and method can estimate the limb alignment angle throughout the range of motion. In some embodiments, the estimated limb alignment angle is varus / valgus. In some embodiments, the estimated limb alignment angle is flexion / extension.

[0125] The navigated tibial resection angle may be a target angle determined preoperatively. The navigated tibial resection angle may be a target angle determined based on preoperative imaging. The navigated tibial resection angle may be a target angle navigated by adjusting the tibial preparation system 200. The tibial resection angle may be determined based on the anatomical structure of the tibia after resection. The tibial resection angle may be determined during surgery. The tibial resection angle may be determined after resection has been performed for resection verification. In some embodiments, the navigated tibial resection angle and the tibial resection angle are the same angle.

[0126] The navigated femoral resection angle may be a target angle determined preoperatively. The navigated femoral resection angle may be a target angle determined based on preoperative imaging. The navigated femoral resection angle may be a target angle navigated by adjusting the femoral preparation system 100. The amputation femoral resection angle may be determined based on the anatomical structure of the femur after resection. The amputation femoral resection angle may be determined during surgery. The amputation femoral resection angle may be determined after resection has been performed for amputation verification. In some embodiments, the navigated femoral resection angle and the amputation femoral resection angle are the same angle.

[0127] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the limb alignment angle based on the tibial resection angle, which is navigated by determining the relationship between the mechanical axes of the tibia and femur. In some ways, this is a static determination when the knee is in a flexed position. In some ways, this is a static determination when the knee is in an extended position. In some ways, this is a dynamic determination when the knee is moved through a range of motion, for example, from flexion to extension or from extension to flexion.

[0128] The surgical orientation device 300, reference sensor 400, and / or module 500 can estimate the limb alignment angle preoperatively. The surgical orientation device 300, reference sensor 400, and / or module 500 can estimate the limb alignment angle postoperatively. The surgical orientation device 300, reference sensor 400, and / or module 500 can estimate the limb alignment angle during trial reduction. One or more trial implants may be positioned between the tibia and femur. The knee may be positioned through its range of motion or through its range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can estimate the limb alignment angle for each of the trial implants. A trial implant that achieves the target limb alignment may be selected. An implant corresponding to the trial implant may be implanted.

[0129] The system and method can perform range of motion calculations. The system and method can calculate the range of motion while the leg is in a flexed position. The system and method can calculate the range of motion while the leg is in an extended position. The system and method can calculate the range of motion throughout the leg's range of motion. In some embodiments, the calculated range of motion is varus / eversion. In some embodiments, the calculated range of motion is flexion / extension. In some embodiments, the calculated range of motion is axial rotation.

[0130] The surgical orientation device 300, reference sensor 400, and / or module 500 can calculate the range of motion by determining the relationship between the mechanical axes of the tibia and femur. In some methods, this is a static determination when the knee is in a flexed position. In some methods, this is a static determination when the knee is in an extended position. In some methods, this is a dynamic determination when the knee is moved through a range of motion, for example, from flexion to extension, or from extension to flexion.

[0131] The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the range of motion preoperatively. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the range of motion postoperatively. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the range of motion during trial reduction. One or more trial implants can be positioned between the tibia and femur. The knee can be positioned through or through the range of motion. The surgical orientation device 300, reference sensor 400, and / or module 500 can determine the range of motion for each of the trial implants. A trial implant that achieves the target range of motion can be selected. An implant corresponding to the trial implant can be implanted.

[0132] The surgical orientation device 300, reference sensor 400, and / or module 500 may be used to determine static limb alignment angles. The surgical orientation device 300, reference sensor 400, and / or module 500 may be used to determine dynamic limb alignment angles. Static measurements include measurements of the leg while it is in a resting position. Dynamic measurements include measurements while the femur is moving, while the tibia is moving, or while both the tibia and femur are moving.

[0133] The surgical orientation device 300, reference sensor 400, and / or module 500 may be used in unicompartmental knee arthroplasty. The surgical orientation device 300, reference sensor 400, and / or module 500 may be used in total knee arthroplasty.

[0134] The surgical orientation device 300, reference sensor 400, and / or module 500 can be used for intraoperative measurements. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used for preoperative measurements. The surgical orientation device 300, reference sensor 400, and / or module 500 can be used for postoperative measurements.

[0135] One or more of the surgical orientation device 300, the reference sensor 400, and / or the module 500 can provide the user with a visual representation. In some embodiments, the surgical orientation device 500 may include a display. The visual representation may include angles, distances, or any other measurements. The visual representation may include limb alignment angles, including varus / valgus, medial / lateral, anterior / posterior, and / or flexion / extension. The visual representation may include graphic representations of the tibia, femur, and / or leg.

[0136] One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be reusable. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be sterilized. In some embodiments, the surgical orientation device 300, the reference sensor 400, and module 500 may be re-sterilizable. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be sterilized in an autoclave. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be disposable. In some embodiments, the surgical orientation device 300, the reference sensor 400, and module 500 may be discarded after a single use.

[0137] One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include one or more inertial sensors. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include an accelerometer. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include a gyroscope. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include a wireless module. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include at least one inertial sensor and a wireless module. In some embodiments, each of the surgical orientation device 300, the reference sensor 400, and / or module 500 may include at least one inertial sensor and a wireless module.

[0138] One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 may be configured to communicate with an external device. One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 may be configured to communicate with a cloud. The surgical orientation device 300, the reference sensor 400, and / or modules 500 are configured to communicate with each other. One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 can receive signals related to position and / or orientation. One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 can transmit signals related to position and / or orientation.

[0139] One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may have any features of the surgical orientation device and reference device described in Patent Document 3, which is incorporated herein by reference. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may comprise any navigation unit including one or more of an accelerometer, gyroscope, display, touchscreen, button, and wireless module.

[0140] In some embodiments, the inertial sensor communicates with a central processor. In some embodiments, the reference sensor 400 communicates with the central processor of the surgical orientation device 300. In some embodiments, the reference sensor 400 communicates with the central processor of an external device, such as external memory or the cloud. In some embodiments, the module 500 communicates with the central processor of the surgical orientation device 300. In some embodiments, the module 500 communicates with the central processor of an external device, such as external memory or the cloud. In some embodiments, the surgical orientation device 300 communicates with the central processor of an external device, such as external memory or the cloud. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 communicate with the surgical orientation device 300. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 communicate with an external device, such as a computer, tablet, or smartphone. One or more of the surgical orientation device 300, the reference sensor 400, and / or the module 500 comprises any device having a wireless module.

[0141] One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be attached to one or more of the tibia and femur. The surgical orientation device 300 and / or reference sensor 400 may be directly attached to the tibia during tibia preparation. The surgical orientation device 300 and / or reference sensor 400 may be directly attached to the femur during femoral preparation. The surgical orientation device 300 and / or reference sensor 400 may be directly attached to the femur and / or tibia in an open wound.

[0142] The femoral preparation system 100 and / or tibial preparation system 200 may include pin fixtures configured to bond to their respective bones. The femoral preparation system 100 and / or tibial preparation system 200 may include reference sensor device interfaces 104, 204 which can be used to bond a reference sensor 400 to fixture assemblies 102, 202. The femoral preparation system 100 and / or tibial preparation system 200 may include surgical orientation device interfaces 106, 206 which can be used to bond a reference sensor 400 to fixture assemblies 102, 202. The surgical orientation device 300 and / or reference sensor 400 may be percutaneously attached to assemblies 102, 202 having interfaces 104, 106, 204, 206.

[0143] Module 500 can be coupled to one or more of the tibia and femur. Module 500 can be directly attached to the tibia during limb alignment and space measurement. Module 500 can be directly attached to the femur during limb alignment and space measurement. Module 500 can be coupled to the femoral fixture assembly 102. Module 500 can be coupled to the tibial fixture assembly 202. Module 500 can be coupled to the femoral fixture assembly 102 during calibration. Module 500 can be coupled to the tibial fixture assembly 202 during calibration. Module 500 can be coupled to any interface of assemblies 102 and 202. Module 500 can be percutaneously coupled to assembly 202.

[0144] One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be attached to the femur. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be attached to the tibia. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be attached to the patient's skin. One or more of the surgical orientation device 300, the reference sensor 400, and / or module 500 may be attached to the patient's soft tissue.

[0145] One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 may include an adhesive configured to adhere to the patient's skin. One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 may include a wrap or strap configured to surround a portion of the patient's anatomical structure. One or more of the surgical orientation device 300, the reference sensor 400, and / or modules 500 may include an inertial sensor embedded in a fabric.

[0146] The selection and placement of tibial implants are performed after the completion of tibial resection. The selection and placement of femoral implants are performed after the completion of femoral resection. Tibial implants can be rotated in any direction on the resected tibia surface. Tibial implants can be selected from a range of implants with different gap heights. Tibial implants can be selected from a range of implants with different varus angles. Tibial implants can be selected from a range of implants with different valgus angles. Tibial implants can be selected from a range of implants with different ranges of motion. Tibial implants can be selected from a range of implants with different flexion. Tibial implants can be selected from a range of implants with different extension.

[0147] More accurate and / or quantifiable alignment methods are likely to improve implant performance and patient satisfaction. The system and method provides, in some embodiments, such more accurate and / or quantifiable alignment methods for improving implant performance and patient satisfaction. The system and method provides a method for quantifying the alignment of the mechanical axes of the tibia and femur. The system and method provides a method for quantifying limb alignment angles. The system and method provides a method for quantifying gap height.

[0148] The system and method can provide recommendations regarding trial implants or implants. The system and method can provide estimated gap distances. The system and method provides means for quantifying varus force as a function of angle measurements. This angle can determine the gap, which is a function of the applied angle and the intercondylar distance. The system and method provides means for quantifying valgus force as a function of angle measurements. The system and method provides means for quantifying the overall knee extension angle. The system and method provides means for quantifying the overall knee flexion angle. The system and method provides means for quantifying axial rotation. The system and method provides means for quantifying range of motion.

[0149] The system and method, in some embodiments, provides a method for selecting one or more tibial and femoral implants by limb alignment and / or gap measurement based on the mechanical axes of the femur and tibia. In some patients, the femur contacts the tibia at two points, one medial and one lateral. As the knee flexes throughout its range of motion, the arrangement of these contacts on the tibia may change. There may be medial and lateral contacts throughout the entire range of motion. Tibial and femoral implants may be selected based on the shape of the contacts. As an example, tibial and femoral implants may be selected to alter the gap. Tibial and femoral implants may be selected to increase or decrease the overall flexion angle.

[0150] In some methods, one of the reference sensor 400 and module 500 is securely attached to the femur and tibia, respectively. In some methods, the reference sensor 400 attached to the tibia may be approximately aligned with the tibial mechanical axis. In some methods, the module 500 attached to the femur may be approximately aligned with the femoral mechanical axis. The reference sensor 400 and module 500 are preferably mounted in such a way that the patella functions normally and reproduces normal knee kinematics. In some embodiments, internalized mounting to both the tibia and femur is preferred to accommodate typical surgical exposures. The surgical orientation device 300 may also be located within the surgical field. In some methods, the surgical orientation device 300 is coupled to the tibial fixture assembly 202.

[0151] In several ways, the orientation of the tibia and femur mechanical axes is calculated. The mechanical axes can be calculated relative to a surgical orientation device 300, a reference sensor 400, and / or module 500. The mechanical axes can be calculated relative to a reference frame including gravity. The mechanical axes can be calculated relative to a global coordinate system. The mechanical axes can be calculated relative to an external reference coordinate system. The mechanical axes can be calculated using an offset based on one or more configurations of the tibial fixture assembly 202 or the femoral fixture assembly 102. The offset can be applied to the calculated mechanical axes to improve accuracy.

[0152] To establish the characteristics of the knee joint, the surgeon can fully extend the knee. The surgeon can also fully flex the knee. The surgeon can move the leg within a short range of motion. The surgeon can rotate around the femoral head in all directions. The surgeon can rotate around the long axis of the leg. The surgeon can apply varus torque to the knee. The surgeon can apply valgus torque to the knee. The surgeon can perform one or more of these actions sequentially. The surgeon can perform one or more of these actions simultaneously. These actions may be performed before resection to establish the characteristics of the knee joint. These actions may be performed after resection to determine the characteristics of the knee joint using a trial implant or implant. These actions may be performed postoperatively to establish the characteristics of the knee joint.

[0153] In some cases, the reference sensor 400 and module 500 may be stationary relative to each other during calibration. The reference sensor 400 and module 500 may be attached to the tibial fixture assembly 202. The reference sensor 400 and module 500 may be fixed relative to each other. While stationary, the reference sensor 400 and module 500 can perform a transfer alignment to calculate the relative misalignment between the reference sensor 400 and module 500. In some embodiments, the orientation of module 500 may be established within the reference frame of the reference sensor 400. In some embodiments, the orientation of the reference sensor 400 and module 500 may be established within the reference frame of the surgical orientation device 300.

[0154] Next, during limb alignment and / or gap balancing, the knee is moved through its range of motion. The relative rotation between the tibia and femur is measured by comparing the angular changes recorded by the respective reference sensors 400 and module 500 throughout the range of motion. Inertial measurements can be transmitted to the surgical orientation device 300. These rotations can be attributed to three directions corresponding to flexion / extension, axial rotation, and varus / valgus. The processor of the surgical orientation device 300 can provide user-readable outputs relating to one or more of these rotations. The user-readable output may be the flexion angle. The user-readable output may be the extension angle. The user-readable output may be the varus angle. The user-readable output may be the valgus angle. The user-readable output may be the axial rotation of the tibia relative to the femur. The user-readable output may be the axial rotation measurement. The user-readable output may be a graphic display. The user-readable output may be a graph. The user-readable output may be varus / valgus angles at different degrees of flexion. The surgical orientation device 300 can display numerical values. The surgical orientation device 300 can display numerical values ​​for varus / valgus angles at various flexion angles, such as 90 degrees or 120 degrees. The surgical orientation device 300 can display numerical values ​​for rotation angles at various flexion angles, such as 90 degrees or 120 degrees.

[0155] During trial reduction, the surgeon repeats the transfer alignment. In some methods, the surgeon implants a surgical orientation device 300 in the tibia and a reference sensor 400 in the femur. The leg is moved through its range of motion. The surgical orientation device 300 then displays limb alignment and / or gap balancing measurements related to the trial implant. In some embodiments, the surgical orientation device 300 can compare the inertial sensor output to targets. These targets may be based on published mean values ​​for a healthy knee. These targets may be based on kinematic measurements obtained from the patient before resection. These targets may be based on kinematic measurements obtained from the opposite knee.

[0156] In some embodiments, the surgical orientation device 300 can provide recommendations related to the trial implant. In some embodiments, the surgical orientation device 300 can provide recommendations for changing the varus / valgus angle of the trial implant. In some embodiments, the surgical orientation device 300 can provide recommendations for changing the gap height. In some embodiments, the surgical orientation device 300 can provide recommendations for rotating the trial implant. In some embodiments, the surgical orientation device 300 can provide recommendations based on inertial sensor measurements from the reference sensor 400 and module 500.

[0157] In some methods, the surgeon applies alternating varus and valgus torques to the knee to measure the allowable opening in each compartment. This varus or valgus angle can be displayed on a surgical orientation device 300. This measurement can complement conventional visual estimations of knee laxity in the varus / valgus direction. This angle provides a means for quantitatively comparing medial and lateral laxity. In some embodiments, the surgeon can use inertial data from a reference sensor 400 and / or module 500 to balance medial / lateral laxity. In some embodiments, the surgeon can use inertial data from a reference sensor 400 and / or module 500 to release soft tissue around the knee. In some embodiments, the surgeon can use inertial data from a reference sensor 400 and / or module 500 to quantify knee joint laxity. In some embodiments, the surgeon can use inertial data from a reference sensor 400 and / or module 500 to quantify varus / valgus angles at specific flexion angles. In some embodiments, the surgeon can use inertial data from the reference sensor 400 and / or module 500 to quantify the varus / valgus angle through the range of motion.

[0158] The surgeon can adjust or replace the trial implant. This process may be repeated until the trial implant is satisfactory. The surgeon can position the implant based on the trial implant. In some embodiments, the range of motion of the trial implant or the implant is stored by the surgical orientation device 300. In some embodiments, the range of motion of the trial implant or the implant is transmitted by the surgical orientation device 300 for postoperative comparison.

[0159] Figures 12 to 18 illustrate the femoral preparation system 600 and the tibial preparation system 700. The femoral preparation system 600 may comprise any components of the femoral preparation system 100 described herein. The tibial preparation system 700 may comprise any components of the tibial preparation system 200 described herein. The femoral preparation system 600 and the tibial preparation system 700 may comprise fixtures that enable the placement of the femoral preparation system 600 into the tibial preparation system 700.

[0160] The femoral preparation system 600 may be used to position the reference sensor 400 relative to the femur. The reference sensor 400 may be positioned laterally relative to the distal end of the femur. The reference sensor 400 may be positioned so that the leg is in an extended position. The reference sensor 400 may be positioned at a known distance from an anatomical landmark. The reference sensor 400 may be positioned at a known angle from an anatomical landmark. The reference sensor 400 can transmit inertial sensor data related to position and orientation to the surgical orientation device 300.

[0161] The femoral preparation system 600 is configured to be securely attached to the side of the femur. The femoral preparation system 600 may also include one or more cutting guides to modify the natural femur in a distal femoral resection and to ensure that prosthetic components are securely attached to the distal end of the femur as described herein.

[0162] The femoral preparation system 600 may include a cutting guide rod 602. The cutting guide rod 602 may be coupled to the tibial preparation system 700. The cutting guide rod 602 may include a threaded post 604. The threaded post 604 may engage with a threaded bore of the tibial preparation system 700. The threaded bore may engage with a midline reference probe assembly, as described herein, before the femoral preparation system 600 is mounted thereon. The cutting guide rod 602 may be removable. The cutting guide rod 602 may be rotated to disengage the coupling between the femoral preparation system 600 and the tibial preparation system 700. The cutting guide rod 602 may be rotated to couple the femoral preparation system 600 and the tibial preparation system 700. The cutting guide rod 602 may include a flange 606. The cutting guide rod 602 may include a cap 608.

[0163] The femoral preparation system 600 may include a cutting guide bracket 610. The cutting guide bracket 610 may include a slot 612. The slot 612 may allow adjustment of the cutting guide bracket 610 relative to the tibial preparation system 700. The slot 612 may allow adjustment of the cutting guide bracket 610 relative to the patient's anatomical structure. The cutting guide bracket 610 may slide relative to the cutting guide rod 602. The cutting guide rod 602 may be positioned within the slot 612. The flange 606 may be located below the cutting guide bracket 610. The cap 608 may be located above the cutting guide bracket 610. The cutting guide bracket 610 may slide relative to the cutting guide rod 602. The cutting guide bracket 610 may rotate relative to the cutting guide rod 602. The cutting guide bracket 610 may position the femoral preparation system 600 to the left of the tibial preparation system 700, as shown in the figure. The amputation guide bracket 610 can position the femoral preparation system 600 to the right of the tibial preparation system 700. The amputation guide bracket 610 may be a universal bracket that allows positioning to the left or right of the tibial preparation system 700. The amputation guide bracket 602 may include a step 614. The step 614 can position the amputation guide bracket 602 proximal to the tibial preparation system 700. The step 614 can prevent interference between the amputation guide bracket 610 and other components of the system. The amputation guide bracket 602 may include an opening 616.

[0164] The femoral preparation system 600 may include a swivel post 620. The swivel post 620 may include a flange 622. The swivel post 620 may include a cap 624. An opening may allow the swivel post 620 to rotate relative to the cutting guide bracket 602. An opening 616 may allow the swivel post 620 to rotate relative to the patient's anatomical structure. The swivel post 620 can rotate relative to the cutting guide bracket 610. The swivel post 620 may be positioned within the opening 616 of the cutting guide bracket 602. The flange 622 may be located above the cutting guide bracket 602. The cap 624 may be located below the cutting guide bracket 602.

[0165] The femoral preparation system 600 may include an extension portion 630. The extension portion 630 may be coupled to a swivel post 620. The extension portion 630 and the swivel post 620 may be formed separately. The extension portion 630 and the swivel post 620 may be formed integrally. The extension portion may include an opening 632. The opening 632 may slide to engage with a threaded pin 634. The opening 632 may receive the threaded pin 634. The threaded pin 634 may be an intramedullary pin. The length of the extension portion 630 may be the input to the surgical orientation device 300. The length of the extension portion 630 may be selected based on the patient's anatomical structure. The extension portion 630 may have a fixed length regardless of the patient's anatomical structure. The extension portion 630 may include a groove 636. The groove 636 may be a keyed groove. The groove 636 may be a dovetail groove. The extension portion 630 can be angled toward the patient.

[0166] The femoral preparation system 600 may include a mounting bracket 640. In some embodiments, the mounting bracket 640 may be an L-shaped bracket. The mounting bracket 640 may include a first portion 642. The first portion 642 may be a tapered projection. The first portion 642 may slide against a groove 636 of the extension portion 630. The first portion 642 and the groove 636 may interlock. The first portion 642 and the groove 636 may have 1 degree of freedom. The first portion 642 may be equipped with a scale. The first portion 642 may be equipped with markings to indicate the length relative to the extension portion 630. The first portion 642 may be equipped with markings to indicate the length relative to the pin 634. Distance markings on the first portion 642 may be recorded as input to the surgical orientation device 300. The mounting bracket 640 may include a second portion 644. The first portion 642 and the second portion 644 may be perpendicular. The second part 644 can contain the hub 646.

[0167] The femoral preparation system 600 may be equipped with a push button 650. The push button 650 can slide against the hub 646 of the mounting bracket 640. The femoral preparation system 600 may be equipped with a spring 652. The spring 652 can bias the push button 650.

[0168] The femoral preparation system 600 may include a connector 660. The connector 660 may include a coupling device 662. The connector 660 may include one or more openings 664. The connector 660 may include two openings 664. The openings 664 can receive threaded pins 666. The femoral preparation system 600 may include one or more threaded pins 666. The femoral preparation system 600 may include two threaded pins 666. The two openings 664 can define the trajectory of the threaded pins 666. The coupling device 662 can engage with a reference sensor interface 680 shown in Figure 18. The reference sensor interface 680 can be directly attached to the connector 662 after a portion of the femoral preparation system 600 has been removed.

[0169] The push button 650 can engage with the coupling device 662. The push button 650 can be biased to engage with the coupling device 662. When the push button 650 is pressed, it can disengage a portion of the femoral preparation system 600. When the push button 650 is pressed, it can allow the mounting bracket 640 to be engaged with and disengaged from the connector 660. The push button 650 can be released to engage with and disengage the coupling device 662. The push button 650 can be released to allow the reference sensor interface 680 to be mounted to the connector 662.

[0170] The tibial preparation system 700 may include orthopedic assemblies used to prepare the tibia for prosthetic components. The tibial preparation system 700 may include components for adjusting the posterior / anterior tilt of the surgical orientation device 300. The tibial preparation system 700 may include components for adjusting the posterior / anterior tilt of the cutting block. The tibial preparation system 700 may include and may include components for adjusting the varus / valgus tilt of the surgical orientation device 300. The tibial preparation system 700 may include and may include components for adjusting the varus / valgus tilt of the cutting block.

[0171] The tibial preparation system 700 may include a landmark acquisition assembly 710. The landmark acquisition assembly 710 may include a structure configured to contact and / or acquire information about an anatomical landmark on the human body. The landmark acquisition assembly 710 may include an elongated member 712. The landmark acquisition assembly 710 may include a probe member 714 positioned on at least one end of the elongated member 712. The probe member 714 may be configured to contact an anatomical landmark, such as the ankle joint of a patient. The elongated member 712 may further include a series of markings indicating distance and / or length. The markings may be used, for example, to measure the AP offset of the probe member 714.

[0172] The tibial preparation system 700 may include a midline reference probe assembly. The tibial preparation system 700 may include a threaded bore. The threaded bore can engage with the midline reference probe assembly before the femoral preparation system 600 is mounted on it. The midline reference probe assembly can be positioned in the appropriate anatomical location of the proximal tibia. The midline reference probe assembly may be located at a point immediately posterior to the insertion site of the anterior cruciate ligament (ACL), or at another preferred anatomical landmark. For example, the tip of the midline reference probe assembly may rest on the insertion site of the anterior cruciate ligament of the knee and / or on a soft point at the apex of the tibia, commonly referred to as the A / P point of the mechanical axis. This point is generally located along the intercondylar eminence of the tibia on the tibia and marks the location of the point along the mechanical axis of the leg. Distance markings may be written on the upper surface of the midline reference probe assembly, and the corresponding A / P offset position may be an input to the surgical orientation device 300. The A / P point can correspond to a point on the machine axis. The surgical orientation device 300 can calculate a second point on the machine axis. The surgical orientation device 300 can determine the machine axis vector.

[0173] The tibial preparation system 700 may be equipped with a reference sensor interface 780. The tibial preparation system 700 may be equipped with a surgical orientation device interface 770. The reference sensor 400 can be coupled to the reference sensor interface 780. The surgical orientation device 300 can be coupled to the surgical orientation device interface 770. During tibial alignment, the tibial preparation system 700 is assembled with the reference sensor 400 coupled to the reference sensor interface 780 and the surgical orientation device 300 coupled to the surgical orientation device interface 770. The surgical orientation device 300 may be attached to the movable part of the tibial preparation system 700. The reference sensor 400 may be attached to the fixed part of the tibial preparation system 700. The reference sensor 400 can track the position of the tibia when acquiring landmarks.

[0174] A tibial alignment method may include a step of acquiring landmarks to determine the arrangement of a mechanical axis passing through the tibia. For example, landmarks may be acquired by engaging the probe member 714 of the landmark acquisition assembly 710 first with the medial malleolus and then with the lateral malleolus (or vice versa). Acquisition of other malleolus may similarly be achieved by oscillating one or more parts of the landmark acquisition assembly 710 so that the probe member 714 contacts the other side of the leg. The surgical orientation device 300 can then determine the arrangement of the mechanical axis, for example, by identifying the sagittal and coronal planes through which the mechanical axis passes. In some embodiments, the surgical orientation device 300 can calculate the arrangement of the mechanical axis by assuming that the mechanical axis extends from the point of contact between the proximal tibia and the midline reference probe assembly through a point midway between two malleolus points that contact the probe member of the landmark acquisition assembly 710 on either side of the leg, or through any other suitable point.

[0175] In some embodiments, the user can activate the surgical orientation device 300 by pressing one of the user inputs on the surgical orientation device 300 when acquiring each landmark. After activation, the surgical orientation device 300 can align (e.g., record) its orientation to a reference position (e.g., a first reference position). For example, the surgical orientation device 300 can align and / or calculate its current orientation based on data collected from sensors inside the surgical orientation device 300. The orientation of the surgical orientation device 300 at the first reference position can be used to identify and align the coronal plane orientation including the mechanical axis of the leg, and further to determine a first reference point for identifying the sagittal plane arrangement and / or orientation including this same mechanical axis.

[0176] Next, the user can swing the probe member of the landmark acquisition assembly 710 over the other (e.g., medial) side of the leg, thereby positioning the reference probe 714 adjacent to the other ankle. With each landmark acquisition, the user can palpate the ankle. After the position of the other (e.g., medial) ankle is identified, the user can press one of the user inputs of the surgical orientation device 300 to cause the surgical orientation device 300 to determine its orientation at the second reference position. For example, the surgical orientation device 300 can align and / or calculate its current orientation based on data collected from sensors inside the surgical orientation device 300.

[0177] The orientation of the surgical orientation device 300 at the second reference position may again be used to identify the orientation of the coronal plane penetrating the tibia containing the mechanical axis of the leg, and / or to position a second reference point for identifying the arrangement and / or orientation of the sagittal plane containing the same mechanical axis.

[0178] When using the surgical orientation device 300 to determine the first and second reference positions, the output of the sensor within the surgical orientation device 300 can be monitored with minimal error in the reading. For example, a transition phase can be eliminated in the sensor output to achieve an accurate estimation of a given anatomical landmark.

[0179] Information regarding both the first and second reference positions is acquired and aligned with the surgical orientation device 300, after which the surgical orientation device 300 can determine (e.g., calculate) the placement of a desired plane between the lateral and medial malleolus. The desired plane may correspond to the sagittal plane containing the mechanical axis. The desired plane may vary depending on factors such as the patient's specific anatomical structure, as well as the surgeon's training and experience. For example, the desired plane may be positioned midway between the lateral and medial malleolus, 55% from the lateral malleolus toward the medial malleolus, or in some other predetermined location.

[0180] The user can instruct the surgical orientation device 300 to calculate the sagittal plane placement and / or orientation using one or more user inputs. After the surgical orientation device 300 has calculated where the sagittal plane is located, it can provide the user with orientation feedback indicating that the sagittal plane placement has been calculated, for example, in the form of one or more visual signals on a display.

[0181] A femoral alignment method may include a step of acquiring landmarks to determine the placement of a mechanical axis passing through the femur. The femoral preparation system 600 may comprise an orthopedic assembly for femoral preparation. The femoral preparation system 600 is configured to be securely mounted on the side of the femur. In some embodiments, the femoral preparation system 600 may comprise a cutting guide rod 602, a cutting guide bracket 610, a swivel post 620, an extension 630, a mounting bracket 640, a push button 650, and a connector 660.

[0182] The femoral preparation system 600 can be attached to the tibial preparation system 700. The cutting guide rod 602 can engage with the tibial preparation system 700. The femoral preparation system 600 may be adjustable. The femoral preparation system 600 can be inserted into and fixed to the tibial preparation system 700. The cutting guide bracket 610 can slide relative to the cutting guide rod 602. The swivel post 620 can pivot relative to the cutting guide bracket 610. The extension portion 630 can be positioned relative to the anatomical structure.

[0183] The femoral preparation system 600 can be aligned to the anatomical structure of the patient. In preparation for distal femoral resection, the method may include the step of identifying a distal point that intersects the mechanical axis of the femur. The method may include the step of positioning a threaded pin 634. The threaded pin 634 may be positioned relative to the distal point of the mechanical axis of the femur. The threaded pin 634 may be a midline pin. The threaded pin 634 may be approximately centered in the intercondylar notch. The threaded pin 634 positions the femoral preparation system 600 approximately centered in the distal end portion of the femur. The method may include the step of positioning an extension 630. The extension 630 can pivot via a swivel post 620. The extension 630 may include an opening 632. In some methods, the threaded pin 634 is inserted first, and the extension 630 is positioned relative to the threaded pin 634. Alternatively, the opening 632 may act as a drill guide for inserting a threaded pin 634. In some cases, the mounting bracket 640 is released from the extension 630 when positioning the extension 630.

[0184] In some cases, the mounting bracket 640 is coupled to the connector 660. The push button 650 can be biased. The push button 650 can be coupled to the mounting bracket 640 and the connector 660 to form an integrated structure. In some cases, the mounting bracket 640, the push button 650, and the connector 660 may be pre-assembled.

[0185] In several ways, the mounting bracket 640 can be positioned relative to the extension portion 630. The mounting bracket 640 and the extension portion 630 can form a connection between the tongue and the groove. The method may include the step of sliding the assembled mounting bracket 640 and connector 660 relative to the extension portion 630. The method may include the step of retracting the mounting bracket 640 and connector 660 until the connector 660 aligns with the bone. During this movement of the mounting bracket 630 and connector 660, the extension portion 630 remains fixed to the femur via the threaded pin 634. The positioning of the mounting bracket 640 relative to the extension portion 630 may be an input to the system. The distance the mounting bracket 640 slides relative to the extension portion 630 may be an input to the system.

[0186] The connector 660 may have one or more openings 664. In some ways, one or more openings 664 may act as drill guides for inserting threaded pins 666. The threaded pins 666 are inserted through the openings 664 of the connector 660. The openings 664 may be angled. The openings 644 may be offset. The openings 664 may be angled and offset drill guide holes. The connector 660 can be fixed to the femur via one or more pins 666.

[0187] The mounting bracket 640 can be removed from the connector 660. The push button 650 can be pushed toward the connector 660. The push button 650 can engage and disengage the connector 660. The mounting bracket 640 can slide toward the connector 660 and engage and disengage from it. The mounting bracket 640 can slide toward the extension portion 630 and engage and disengage from it. The extension portion 630 can be removed.

[0188] The cutting guide rod 602, cutting guide bracket 610, swivel post 620, and extension 630 can be removed. The connector 660 remains fixed to the femur. The connector 660 can be coupled to the reference sensor 400. The connector 660 can be coupled to the reference sensor interface 680. The reference sensor 400 can be coupled to the reference sensor interface 680. In some cases, the cutting block is mounted on a threaded pin 634 for excision. In some cases, the threaded pin 634 can be removed.

[0189] The reference sensor device 400 and / or orientation device 300 may be used to determine the relative coordinates of the central pivot point on the femur. By determining the coordinates of the pivot point of the femoral head, the reference sensor device 400 and / or surgical orientation device 300 can calculate the arrangement and / or orientation of the mechanical axis penetrating the femur.

[0190] The leg may be moved (e.g., rocked) to determine the coordinates of the pivot point of the femoral head (i.e., the pivot point of the mechanical axis). For example, with the reference sensor device 400 attached, the leg may be moved in several different directions and / or planes. Readings such as the angular velocity and acceleration of the femur may be acquired by the reference sensor device 400 until the arrangement and / or orientation of the leg and the mechanical axis of the femur ("femoral mechanical axis") is determined. In one embodiment, if one or more multi-axis (e.g., two-axis) accelerometers and gyroscopes are used, the reference sensor data for each movement of the femur can be numerically integrated with respect to time to obtain the trajectory of the position and velocity points (one point for each IMU data). The IMU data may be integrated without imposing any limitations on the plane trajectory for the movement of the femur.

[0191] The acceleration and angular velocity sensed by the reference sensor device 400 during leg movement can be processed while the leg moves around its pivot point. The reference sensor device 400 can provide an output vector representing the center of rotation with respect to the inertial sensor axis of the reference sensor device 400.

[0192] In some embodiments, error correction techniques may be used to remove biases from the surgical orientation device 300 and reference sensor 400 before determining the position and / or orientation of the rotation center of the machine axis. For example, error correction techniques may include evaluating 1) static bias, 2) gyroscope bias, and 3) accelerometer bias in the surgical reference sensor 400 and surgical orientation device 300.

[0193] In alignment, the surgical orientation device 300 and reference sensor 400 determine the mechanical axes of the tibia and femur in flexion. The surgical orientation device 300 memorizes the mechanical axes. In some methods, the leg is moved to an extended state after both mechanical axes have been acquired. The surgical orientation device 300 and reference sensor 400 are configured to sense changes in orientation. Changes in orientation when the leg is flexed and when the leg is extended can determine the angle of the mechanical axes. Changes in the mechanical axes can determine the varus / valgus angle. Changes in the mechanical axes can determine the flexion / extension angle. Changes in the mechanical axes may be measured in the coronal plane. Changes in the mechanical axes are measured in the sagittal plane. In some methods, leg alignment measurements are performed before resection. The leg is moved to an extended state. Changes in the tibial mechanical axis relative to the femoral mechanical axis are calculated. Limb alignments of the hip, knee, and ankle joints are calculated. The relative positioning of the machine axis can be memorized by a surgical orientation device before resection.

[0194] The surgical orientation device 300 and / or reference sensor 400 can provide guidance to the surgeon on how to position the cutting block on the bone to achieve a cutting plane perpendicular to the bone's load-bearing axis. The surgical orientation device 300 and / or reference sensor 400 can provide guidance to the surgeon on how to position the cutting block on the bone to offset the cutting plane by several degrees from its perpendicular plane, if necessary. The surgical orientation device 300 and / or reference sensor 400 can provide guidance on varus / valgus angles relative to the cutting plane. The surgical orientation device 300 and / or reference sensor 400 can provide guidance on flexion / extension angles relative to the cutting plane.

[0195] In some cases, the cutting guide may be fixed to the bone to be cut, and a reference sensor 400 and / or a surgical orientation device 300 may be coupled to the cutting guide. The tibial preparation system 700 may include a cutting guide. In some cases, one device may be attached to a fixed portion of the tibial preparation system 700 to act as a reference for bone orientation, and the other device may be attached to an articulated arm of the tibial preparation system 700 to provide the surgeon with a means for finding and setting the desired cutting plane. The articulated arm of the tibial preparation system 700 may be restricted to move only in two dimensions, for example, in pitch and yaw (not rotation). These two axes form a plane that can be adjusted to guide the placement of a cutting block that guides a saw to cut the bone on that plane.

[0196] After the mechanical axis is identified, a tibial cutting block may be utilized. The cutting block may be positioned so that it is spaced away from the anterior surface of the tibia. The surgical orientation device 300 and the tibial preparation system 700 may be used to adjust the cutting block to obtain the desired orientation for resection of the tibial apex. For example, the posterior tilt assembly and the varus / valgus assembly of the tibial preparation system 700 may be adjusted independently to change the angle of the cutting block and, subsequently, the angle of the intended resection. During this adjustment, the surgical orientation device 300 may display one or more readings on a display indicating whether the surgical orientation device 300 and the cutting block are aligned with the sagittal and / or coronal planes containing the tibial mechanical axis.

[0197] After the machine axis is identified, a femoral cutting block may be used. The cutting block may be positioned so that it is spaced away from the distal surface of the femur. The reference sensor 400 and the femoral preparation system 600 may be used to adjust the cutting block to obtain the desired orientation for femoral resection. After the reference sensor device 400 and / or surgical orientation device 300 calculate the pivot point of the machine axis as described above and position the machine axis, the user can begin adjusting and orienting the femoral cutting block relative to the position of the machine axis. For example, the surgical orientation device 300 may display the adjustments of varus / valgus and flexion / extension angles required for the cutting block to reach a neutral alignment with the machine axis through which the femoral head passes.

[0198] After the amputation block is positioned, it can be attached to the surface by multiple pins. After the amputation block is attached to the tibia, the proximal portion of the tibia can be resected. After the amputation block is attached to the femur, the distal portion of the femur can be resected.

[0199] Advantageously, the mechanical axis can be verified after resection. In some cases, the leg is placed in an extended position after resection. The implant can be positioned within the knee joint. The placement of the implant can be verified in limb alignment. The varus / valgus angle in the extended position can be verified in limb alignment. The flexion / extension angle in the extended position can be verified in alignment. In some cases, the change in the tibial mechanical axis is determined after resection. In some cases, the change in the femoral mechanical axis is determined after resection. In some embodiments, the placement of a reference sensor device 400 on the femur allows the leg to be moved into an extended position. In extension, the relative positioning of the mechanical axis is determined.

[0200] In some embodiments, the reference sensor device 400 can track the relative position of the femur, thereby allowing the procedure to proceed without immobilizing the leg being operated on. For example, at least one of the reference sensor device 400 and the surgical orientation device 300 can communicate with the other, so that any relative movement of one of these devices can be tracked by the other, and the resulting overall orientation of the reference sensor device 400 and / or the surgical orientation device 300 can be displayed on the display of the surgical orientation device 300. In some embodiments, the reference sensor device 400 can track the movement of the femur. In some embodiments, the surgical orientation device 300 can track the movement of the tibia.

[0201] The surgical orientation device 300 and reference sensor 400 can record any point or axis. The surgical orientation device 300 and reference sensor 400 can store these points and axes during the procedure. The surgical orientation device 300 can refer to these stored mechanical axes after resection. The surgical orientation device 300 and reference sensor 400 can be used to measure and record the placement of anatomical landmarks. The mechanical axis of the leg, as defined herein, generally refers to the line extending from the center of rotation of the proximal head of the femur (e.g., the center of the femoral head), ideally through the approximate center of the knee, to the center of the ankle, i.e., the midpoint. The mechanical axis of the femur is the same axis extending from the center of rotation of the proximal head of the femur through the center of the distal end of the femur (the center of the distal end of the femur is generally described as the center of the intercondylar notch). Generally, the ideal mechanical axis of a patient allows the load to pass from the center of the hip joint, through the center of the knee joint, and to the center of the ankle.

[0202] The surgical orientation device 300 may be used in conjunction with the reference sensor 400 to determine the spatial orientation of the machine axis. In some ways, the surgical orientation device 300 and the reference sensor 400 may be used to determine one, two, or more planes intersecting the machine axis. In some ways, the surgical orientation device 300 and the reference sensor 400 may be used to determine the coronal plane. In some ways, the surgical orientation device 300 and the reference sensor 400 may be used to determine the sagittal plane. The surgical orientation device 300 and the reference sensor 400 may be used before excision to verify the alignment of one or more orthopedic fixation devices or one or more cut surfaces. The surgical orientation device 300 and the reference sensor 400 may be used after excision to verify the alignment of one or more orthopedic fixation devices or one or more cut surfaces. The surgical orientation device 300 and the reference sensor 400 may be used before excision to determine the alignment of the machine axis. The surgical orientation device 300 and reference sensor 400 may be used to determine the alignment of the machine axis after resection. The surgical orientation device 300 and reference sensor 400 may be used to determine the gap measurement after resection.

[0203] The surgical orientation device 300 may be attached to the tibial preparation system 700 during tibial alignment. The surgical orientation device 300 may remain attached to the tibial preparation system 700 during femoral alignment. The surgical orientation device 300 may remain attached to the tibial preparation system 700 when the leg is extended for limb alignment and / or gap measurement. The surgical orientation device 300 may remain attached to the tibial preparation system 700 to determine one or more angles between mechanical axes. The surgical orientation device 300 may remain attached to the tibial preparation system 700 during and after resection. The surgical orientation device 300 may remain attached to the tibial preparation system 700 during post-resection limb alignment measurement.

[0204] In some cases, the reference sensor 400 may be mounted on the tibial preparation system 700 during tibial alignment. The reference sensor 400 may be moved in the femoral preparation system 600 during femoral alignment. The reference sensor 400 may remain mounted on the femoral preparation system 600 during limb alignment and / or gap balancing measurements. The reference sensor 400 may remain mounted on the femoral preparation system 600 when the leg is extended. The reference sensor 400 may remain mounted on the femoral preparation system 600 to determine one or more angles between machine axes. The reference sensor 400 may remain mounted on the femoral preparation system 600 during and after resection. In some cases, the reference sensor 400 may be returned to the tibial preparation system 700 during and after resection. In some cases, the reference sensor 400 may be returned to the tibial preparation system 700 for calibration. The reference sensor 400 can be returned to the femoral preparation system 600 when measuring limb alignment after resection.

[0205] Limb alignment measurement can include the angle of the tibial and femoral mechanical axes when the leg is extended. Limb alignment measurement may be useful in partial knee arthroplasty. Limb alignment measurement may be useful in total knee arthroplasty. Limb alignment measurement can improve the lifespan of any implant. Limb alignment measurement can determine the mechanical axes that penetrate the patient's hip, knee, and ankle joints. Limb alignment measurement can determine the varus / valgus angle between the tibia and femur mechanical axes. Limb alignment measurement can determine angles in the coronal plane. Limb alignment measurement can determine the flexion / extension angle between the tibia and femur mechanical axes. Limb alignment measurement can determine angles in the sagittal plane.

[0206] Limb alignment measurement can provide verification of amputation. The surgeon can perform the resection. The resection may be a neutral resection. The resection may be at an angle to the coronal plane. The resection may be at an angle to the sagittal plane. In total knee arthroplasty, the resection may include proximal-distal resection. In total knee arthroplasty, the resection may include medial and lateral compartment resection. In partial knee arthroplasty, the resection does not include proximal-distal resection. In partial knee arthroplasty, the resection may include one compartment. Implants can alter the overall alignment of the mechanical axis of the leg. Implants can alter the varus / valgus angle. Implants can alter the flexion / extension angle. Implants can alter the gap. Limb alignment measurement can determine the relative orientation of the mechanical axis after implant placement. Limb alignment measurement can determine whether the implant provides correction in the coronal plane. Limb alignment measurement can determine whether the implant provides correction in the sagittal plane. Limb alignment measurements can determine whether the measured angles correlate with the preoperative angles determined from imaging techniques. These measurements can provide information on whether soft tissue release is necessary. These measurements can also determine the lift-off of the implant.

[0207] Limb alignment measurement can determine how the mechanical axis of the tibia rotates around the mechanical axis of the femur. Limb alignment measurement may be performed after the mechanical axis has been acquired. Limb alignment measurement may be performed after the mechanical axis has been memorized. Limb alignment measurement may be performed after the surgical orientation device 300 and reference sensor 400 have been calibrated. Limb alignment measurement may be performed before resection. Limb alignment measurement may be performed after resection. Limb alignment measurement may be performed when the leg is in an extended position. Limb alignment measurement may be performed after the implant has been positioned. Limb alignment measurement may be performed at any time during the surgical procedure.

[0208] In several ways, force is applied to the knee. The surgical orientation device 300, in conjunction with the reference sensor 400, can perform gap balancing evaluation. During gap evaluation, the reference sensor 400 is attached to the femur. During gap evaluation, the surgical orientation device 300 is attached to the tibia. In several ways, the surgical orientation device 300 and the reference sensor 400 perform gap balancing before limb alignment measurement. In several ways, the surgical orientation device 300 and the reference sensor 400 perform gap balancing after limb alignment measurement. In several ways, the surgical orientation device 300 and the reference sensor 400 perform gap balancing when the leg is extended. In several ways, gap balancing is performed using at least one implant positioned between the tibia and femur. The angle between the surgical orientation device 300 and the reference sensor 400 can be determined with the condyles in contact. This angle can be aligned as 0 degrees. The tibia and femur can be moved through a range of motion. In some embodiments, a varus force is applied to the tibia. In some embodiments, a valgus force is applied to the tibia. The angle between the surgical orientation device 300 on the tibia and the reference sensor 400 on the femur can be determined. In some methods, the user applies a varus torque. In some methods, the user applies a valgus torque.

[0209] The intercondylar distance can be known. The intercondylar distance can be determined from images, such as X-ray images. The intercondylar distance can be measured during surgery. This distance can be used as input to the surgical orientation device 300. In the example shown, the intercondylar distance is 55 mm. The gap due to varus force can be determined based on a geometric relationship between a known applied varus force and the intercondylar distance. The gap due to valgus force can be determined based on a geometric relationship in the same manner as the gap due to varus force. The gap can be calculated by applying a force and measuring the change in angle between the femoral mechanical axis and the tibial mechanical axis. This angle and the intercondylar distance can yield an estimate of the gap.

[0210] One or more of the surgical orientation device 300 and reference sensor 400 can calculate the gap distance. The gap distance is the product of the measured angles between the tibia and femur. The gap distance is the product of the known intercondylar distances. In some embodiments, the dynamic gap height provides insight into medial / lateral ligament tension. The gap height can provide insight into soft tissue balancing. The gap measurement can determine whether further soft tissue release is needed. The gap measurement can be determined before resection. The gap measurement can be determined after resection. The gap can be evaluated before and after resection. The gap can be evaluated using multiple implants or trial implants.

[0211] The surgical orientation device 300 may be equipped with a display. The surgical orientation device 300 is positioned in the surgical field when measuring limb alignment. The surgical orientation device 300 is positioned in the surgical field when measuring gaps. The display can be sized so that the user can easily read the numbers, lettering, and / or symbols displayed on the display screen while performing the procedure. The display can facilitate the positioning of the cutting guide during resection. The display can provide information for verifying the position of the machine axis after resection. The display can provide information regarding limb alignment. The display can provide information regarding gap balancing.

[0212] The surgical orientation device 300 can store measured or calculated data. The surgical orientation device 300 can store data entered by the user. The surgical orientation device 300 can store distance measurements corresponding to the mounting bracket 640 with respect to the extension portion 630. The surgical orientation device 300 can store the length and / or angle of the extension portion 630. The surgical orientation device 300 can store the orientation of the femoral preparation system 600. The surgical orientation device 300 may further comprise at least one user input device. At least one user input device may comprise a plurality of buttons located adjacent to the display. The buttons can be activated, for example, by a finger, hand, and / or instrument, to input data. The data may include distance measurements related to anatomical landmarks. The surgical orientation device 300 comprises a user interface that allows clinicians to interact with it during procedures.

[0213] The surgical orientation device 300 and the reference sensor 400 can acquire and store position and orientation-related data. The surgical orientation device 300 includes an electrical system. The electrical system may comprise one or more features, including one or more sensors, an electronic control unit communicating with one or more sensors, one or more visual alignment indicators, a power supply, a display, memory, one or more user input devices, one or more processors, program logic, other board configurations representing data and instructions, controller circuits, processor circuits, processors, general-purpose single-chip or multi-chip microprocessors, digital signal processors, embedded microprocessors, microcontrollers, other output devices, and / or one or more input / output ("I / O") ports. In certain embodiments, the electronic control unit may be configured to convert electronic data from machine-readable to human-readable format for presentation on the display of the surgical orientation device 300. The electronic control unit can communicate with internal and / or external memory to retrieve and / or store data and / or program instructions for software and / or hardware. Internal and external memory may include random access memory ("RAM"), such as static RAM, for temporary storage of information, and / or read-only memory ("ROM"), such as flash memory, for more persistent storage of information. Generally, the sensor may be configured to provide continuous real-time data to one or more processors. An electronic control unit may be configured to receive real-time data from the sensor and to use the sensor data to determine, estimate, and / or calculate the orientation or position of the surgical orientation device 300 and / or the orientation or position of the reference sensor 400.

[0214] In some embodiments, in addition to or alternative to the surgical orientation device 300, the system may include an external display. The electronic equipment may include one or more handheld devices such as a computer, desktop computer, laptop computer, or tablet computer such as an iPad®. In some embodiments, the display is positioned within the surgical field. In some embodiments, the display is positioned outside the surgical field. In some embodiments, the reference sensor device 400 may include a display. In some embodiments, in addition to or alternative to the surgical orientation device 300, the electronic equipment may include at least one user input device. The user input device may be activated, for example, by a finger, hand, and / or instrument. The electronic equipment may include software and / or hardware for the system described herein. The electronic equipment may include external memory for the system described herein. The surgical orientation device 300 and / or the reference sensor device 400 may be connected to the Internet. The surgical orientation device 300 and / or the reference sensor device 400 may transmit or receive information from the Internet. The surgical orientation device 300 and / or the reference sensor device 400 may be connected to the cloud. The surgical orientation device 300 and / or reference sensor device 400 can transmit or receive information from the cloud.

[0215] In some configurations, one or more sensors of the surgical orientation device 300 and / or reference sensor device 400 may include at least one orientation sensor configured to provide an electronic control unit with real-time data relating to the motion, orientation, and / or position of the surgical orientation device 300 and / or reference sensor device 400. For example, the sensor module may include at least one gyro sensor, accelerometer, tilt sensor, magnetometer, and / or other similar one or more devices configured to measure the orientation of the surgical orientation device 300 and / or reference sensor device 400 and / or to facilitate the determination of the orientation. In some embodiments, the sensor may be configured to provide measurements relative to a reference point, line, plane, and / or zero gravity. Zero gravity as referred herein generally refers to an orientation where the axis of the sensor is perpendicular to the force of gravity, thereby not producing an angular offset with respect to the gravity vector, e.g., tilt, pitch, roll, or yaw. In other embodiments, the sensor may be configured to provide measurements for use in dead reckoning or inertial navigation systems.

[0216] In various embodiments, the sensor includes one or more accelerometers for measuring the static acceleration of the surgical orientation device 300 and / or reference sensor device 400 due to gravity. For example, the accelerometers may be used as tilt sensors for detecting the rotation of the surgical orientation device 300 and / or reference sensor device 400 around one or more axes. One or more accelerometers may include a two-axis accelerometer (capable of measuring rotation around two axes of rotation) or a three-axis accelerometer (capable of measuring rotation around three axes of rotation). The change in orientation around the axis of the accelerometer may be determined relative to zero gravity and / or a reference plane aligned during the tibial or femoral preparatory procedure described herein.

[0217] In certain embodiments, a multi-axis accelerometer (such as the ADXL203CE MEMS accelerometer available from Analog Devices, Inc. or the LIS331DLH accelerometer available from ST Microelectronics) detects changes in orientation around two rotation axes. For example, the multi-axis accelerometer can detect changes in the angular position of the surgical orientation device 300 and / or reference sensor device 400 from the horizontal plane (e.g., forward / backward rotation) as well as changes in the angular position of the surgical orientation device 300 and / or reference sensor device 400 from the vertical plane (e.g., roll rotation). Changes in the angular position of the surgical orientation device 300 and / or reference sensor device 400 from the horizontal and vertical planes (as measured by the sensors) can also be used to determine changes in the inward / outward orientation of the surgical orientation device 300 and / or reference sensor device 400 (e.g., inversion / eversion rotation).

[0218] In some configurations, the sensor comprises at least one single-axis or multi-axis gyroscope sensor and at least one single-axis or multi-axis accelerometer sensor. For example, the sensor may include a three-axis gyroscope sensor (or three gyroscope sensors) and a three-axis accelerometer sensor (or three accelerometer sensors) to provide position and orientation measurements for all six degrees of freedom of the surgical orientation device 300 and / or reference sensor device 400. In some embodiments, the sensor provides an inertial navigation or estimation system that continuously calculates the position, orientation, and velocity of the surgical orientation device 300 and / or reference sensor device 400 without requiring an external reference.

[0219] The reference sensor 400 may include any of the features of the surgical orientation device 300. In one embodiment, the surgical orientation device 300 and / or the reference sensor 400 may include one or more sensors that together form an inertial measuring unit (IMU). In particular, the IMU comprises a first sensor for determining acceleration and a second sensor for determining gyro positioning. As described herein, the first sensor may be an accelerometer and the second sensor may be a gyroscope sensor. The reference sensor 400 also includes a transmitter for transmitting data from the sensor to the electrical system of the surgical orientation device 300. Information received from the reference sensor 400 may be supplied to an input port, or alternatively, the electronic control unit of the surgical orientation device 300 itself may receive the information wirelessly. Information from the reference sensor 400 may, for example, correspond to the position and / or orientation of the reference sensor 400 and may be used by the surgical orientation device 300 to determine the overall, relative, or global position and / or orientation of the surgical orientation device 300 and / or the reference sensor device 400.

[0220] The surgical orientation device 300 and / or reference sensor device 400 may be used to measure and record the alignment of anatomical landmarks, such as the alignment of mechanical axes of the leg, tibia, and femur. Further details regarding systems, devices, sensors, and methods are all incorporated herein by reference in their entirety for all purposes, in Patent Document 6 filed on 9 June 2004, Patent Document 7 filed on 15 July 2009, Patent Document 8 filed on 10 September 2009, Patent Document 1 filed on 24 July 2009, Patent Document 2 filed on 21 January 2011, Patent Document 3 filed on 24 May 2011, Patent Document 4 filed on 5 November 2014, Patent Document 5 filed on 14 November 2014, Patent Document 9 filed on 13 March 2013, Patent Document 10 filed on 10 March 2015, Patent Document 11 filed on 11 August 2017, Patent Document 12 filed on 13 March 2018, Patent Document 13 filed on 13 March 2018, and Patent Document 14 filed on 8 December 2020.

[0221] While these inventions have been disclosed in the context of specific preferred embodiments and examples, it will be understood by those skilled in the art that this application extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the invention, as well as obvious modifications and equivalents thereof. In addition, although many variations of the invention are illustrated and described in detail, other modifications within the scope of the invention will be readily apparent to those skilled in the art based on this disclosure. Furthermore, it is intended that various combinations or partial combinations of the specific features and aspects of these embodiments may be implemented and fall within the scope of this application. For example, this application intends that the connection hub may include another embodiment, either alone or in combination with any of the other modules. Or, one or a combination of those modules may be directly connected to an umbrella hub or overhead support to form another distinct embodiment. Thus, it should be understood that various features and aspects of the disclosed embodiments may be combined with each other or used instead to form various forms of the disclosed embodiments. Therefore, the scope of the invention disclosed herein is not intended to be limited by the specific embodiments disclosed above, but rather to be determined solely by reading the following claims fairly.

[0222] Similarly, this method of disclosure should not be interpreted as reflecting an intention that any claim requires features beyond those expressly stated in that claim. Rather, as reflected in the following claims, the embodiments of the invention consist of combinations of features fewer than all of the single disclosed embodiments. Thus, the claims following “Modes for Carrying Out the Invention” are thus explicitly incorporated into this “Modes for Carrying Out the Invention,” and each claim stands independently as an independent embodiment. [Explanation of Symbols]

[0223] 10 axes 15. Excision site, plateau 20 axes 20. Tibial mechanical axis, electronically controlled unit 25. Plateau of the tibia 100 Femoral Preparation System 102 Femoral fixture assembly, pin 104 Reference sensor device interface, pin 106 Surgical Orientation Device Interface 108 Fixing pins 200 Tibial preparation system 202 Tibial Fixture Assembly 204 Reference Sensor Device Interface 206 Surgical Orientation Device Interface 210 Midline Reference Probe Assembly 212 probe assembly 214 Elongated member 216 Probe member 250 Module Interface 300 Surgical Orientation Devices 400 reference sensors, reference sensor devices 500 modules 600 Femoral Preparation System 602 Cutting guide rod 604 Screw-type post 606 Flange 608 Cap 610 Cutting Guide Bracket 612 slots 614 steps 616 Opening 620 Swivel Post 622 Flange 624 Cap 630 Extension part 632 Opening 634 Threaded pin 636 Groove 640 Mounting Bracket 642 Part 1 644 Part 2 646 Hub 650 push buttons 652 Spring 660 connector 662 Connectors, Couplers 664 openings 666 Threaded Pin 680 Reference Sensor Interface 700 Tibial Preparation System 710 Landmark Acquisition Assembly 712 Elongated member 714 Probe component 770 Surgical Orientation Device Interface 780 Reference Sensor Interface

Claims

1. A system for limb alignment, A first orientation device configured to be joined to the tibia before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A second orientation device configured to be joined to the femur before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A femoral preparation system configured to be attached to the side of the femur, Equipped with, The first or second orientation device comprises a processor configured to receive inertial sensor data, the processor configured to determine the femoral and tibial mechanical axes during flexion, the system for limb alignment is configured to store the relative positioning of the femoral and tibial mechanical axes before resection, and the processor is configured to calculate the angle between the femoral and tibial mechanical axes when the first orientation device is coupled to the tibia before resection and the second orientation device is coupled to the femur before resection.

2. The system according to claim 1, further comprising a tibial preparation system comprising a probe member.

3. The system according to claim 1, further comprising a tibial preparation system comprising a midline reference probe assembly.

4. The system according to claim 1, further comprising a tibial preparation system comprising a first device interface configured to be coupled to the first orientation device, and a second device interface configured to be coupled to the second orientation device.

5. The system according to claim 1, wherein the femoral preparation system comprises a device interface configured to be coupled to the second orientation device.

6. The system according to claim 1, wherein the femoral preparation system comprises an extension portion configured to be positioned relative to a threaded pin attached to a portion of the distal femur.

7. The system according to claim 1, wherein the femoral preparation system comprises a connector configured to be attached to the outer portion of the femur.

8. The system according to claim 1, wherein the femoral preparation system comprises a connector having a device interface configured to be coupled to the second orientation device.

9. The system according to claim 1, wherein the processor is configured to determine the femoral mechanical axis and the tibial mechanical axis at least in part based on the arrangement of anatomical landmarks.

10. The system according to claim 1, wherein the processor is configured to determine the femoral mechanical axis and the tibia mechanical axis at least in part based on the movement of the femur.

11. The system according to claim 1, wherein the processor is configured to determine the varus / valgus angles of the femoral mechanical axis and the tibial mechanical axis.

12. The system according to claim 1, wherein the processor is configured to determine the flexion / extension angles of the femoral mechanical axis and the tibial mechanical axis.

13. The system according to claim 1, wherein the processor is configured to determine a gap measurement.

14. A system for limb alignment, A first sensor configured to be attached to the tibia before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A second sensor configured to be attached to the femur before resection, the second sensor including at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A processor configured to receive output from one or more of the first and second sensors, wherein the processor is configured to determine the femoral and tibial mechanical axes during flexion, the system for limb alignment is configured to store the relative positioning of the femoral and tibial mechanical axes before resection, and the processor is configured to calculate the position and / or orientation of the femoral and tibial mechanical axes during movement when the first sensor is connected to the tibia before resection and the second sensor is connected to the femur before resection. A femoral preparation system configured to be attached to the side of the femur, A system equipped with these features.

15. The system according to claim 14, wherein the processor is configured to determine the varus / valgus angle.

16. The system according to claim 14, wherein the processor is configured to determine the inversion angle at different bending angles.

17. The system according to claim 14, wherein the processor is configured to determine axial rotation.

18. The system according to claim 14, wherein the processor is configured to determine the bending angle.

19. The system according to claim 14, wherein the processor is configured to determine the extension angle.

20. The system according to claim 14, wherein the processor is configured to provide recommendations for trial implants.

21. The system according to claim 14, wherein the processor is configured to determine the gap between the tibial plateau and the femoral plateau.

22. The system according to claim 14, wherein the processor is configured to determine the angle between the tibial plateau and the femoral plateau.

23. A system for limb alignment, A first orientation device configured to be joined to the tibia before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A second orientation device configured to be joined to the femur before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A femoral preparation system configured to be attached to the side of the femur, Equipped with, The first orientation device and the second orientation device determine the mechanical axes of the femur and tibia during flexion, and the system for limb alignment is configured to store the relative positions of the mechanical axes of the femur and tibia before resection. The first orientation device and the second orientation device are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is in an extended position, when the first orientation device is connected to the tibia before resection and the second orientation device is connected to the femur before resection.

24. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is in an extended state before resection.

25. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is in an extended state after resection.

26. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is in an extended state and the implant is positioned between the tibia and the femur.

27. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to calculate the relative orientation between the femoral mechanical axis and the tibial mechanical axis when the leg is in an extended state and a force is applied.

28. The system according to claim 23, wherein the cutting block is positioned with respect to the mechanical axis of the femur.

29. The system according to claim 23, wherein the cutting block is positioned with respect to the tibial mechanical axis.

30. The system according to claim 23, wherein the second orientation device is configured to be connected to the femur at a fixed, known point.

31. The system according to claim 23, wherein the second orientation device is configured to connect with the femur when the leg moves from a flexed state to an extended state.

32. The system according to claim 23, wherein the femoral mechanical axis and the tibia mechanical axis are two vectors in a three-dimensional coordinate system.

33. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine the angle at the joint.

34. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine the mechanical axis of the leg.

35. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine an angle in the sagittal plane.

36. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine an angle in the coronal plane.

37. The system according to claim 23, wherein the first orientation device is configured to calculate the tibial mechanical axis.

38. The system according to claim 23, wherein the first orientation device is configured to determine at least two points on the tibial mechanical axis.

39. The system according to claim 23, wherein the second orientation device is configured to calculate the femoral mechanical axis.

40. The system according to claim 23, wherein the second orientation device is configured to determine at least two points on the femoral mechanical axis.

41. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to bond with the tibia for calibration.

42. The system according to claim 23, further comprising a device interface configured to connect to the lateral portion of the femur.

43. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine the varus / valgus angles of the femoral mechanical axis and the tibial mechanical axis.

44. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine the flexion / extension angles of the femoral mechanical axis and the tibial mechanical axis.

45. The system according to claim 23, wherein the first orientation device and the second orientation device are configured to determine a gap measurement.

46. A system for limb alignment, A first orientation device configured to be joined to the tibia before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A second orientation device configured to be joined to the femur before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A femoral preparation system configured to be attached to the side of the femur, Equipped with, The first orientation device and the second orientation device determine the mechanical axes of the femur and tibia during flexion, and the system for limb alignment is configured to store the relative positions of the mechanical axes of the femur and tibia before resection. The first orientation device and the second orientation device are configured to calculate changes in position, orientation, or movement between the femoral mechanical axis and the tibial mechanical axis when the first orientation device is joined to the tibia before resection and the second orientation device is joined to the femur before resection.

47. The system according to claim 46, wherein the first orientation device and the second orientation device provide cutting verification.

48. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate an angle with respect to the coronal plane when the implant is positioned between the tibia and the femur.

49. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate an angle with respect to the sagittal plane when the implant is positioned between the tibia and the femur.

50. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate the varus / valgus angle when the implant is positioned between the tibia and the femur.

51. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate the flexion / extension angle when the implant is positioned between the tibia and the femur.

52. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate soft tissue balancing when the implant is positioned between the tibia and the femur.

53. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to calculate a gap measurement when the implant is positioned between the tibia and the femur.

54. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to verify the angle measurement with respect to the preoperative measurement.

55. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to verify angle measurements against preoperative measurements using imaging technology.

56. The system according to claim 46, wherein the first orientation device and the second orientation device are configured to verify the correction of deformation when the implant is positioned between the tibia and the femur.

57. A system for limb alignment, A first orientation device configured to be joined to the tibia before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A second orientation device configured to be joined to the femur before resection, comprising at least one inertial sensor for evaluating the characteristics of the knee joint before resection, A femoral preparation system configured to be attached to the side of the femur, Equipped with, The first orientation device and the second orientation device determine the mechanical axes of the femur and tibia during flexion, and the system for limb alignment is configured to store the relative positions of the mechanical axes of the femur and tibia before resection. The first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis when the first orientation device is coupled to the tibia before resection and the second orientation device is coupled to the femur before resection.

58. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis in the sagittal plane.

59. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis in the coronal plane.

60. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis as an inversion / eversion angle between the tibial mechanical axis and the femoral mechanical axis.

61. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis as a flexion / extension angle between the tibial mechanical axis and the femoral mechanical axis.

62. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis after resection.

63. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis while the implant is positioned between the tibia and the femur.

64. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis and compare it with an angle determined preoperatively.

65. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis and measure the gap.

66. The system according to claim 57, wherein the first orientation device and the second orientation device are configured to calculate the rotation of the tibial mechanical axis around the femoral mechanical axis to measure soft tissue balancing.

67. The system according to claim 57, wherein the second orientation device is configured to be coupled to the tibia for calibration.

Images