Patent Description:
The use of surgical navigation systems for assisting surgeons during surgery is quite common. Such systems are used to track the movement of bony structures to determine a location of the bony structure, and whether it has moved. Typical surgical navigation systems require invasively implanting trackers in the bone of the patient. Invasive implantation of trackers requires additional surgical steps, such as planning the location of the tracker, performing implantation, and performing manual bone registration using a pointer. Additionally, invasive implantation of trackers can potentially cause additional trauma to the patient. Furthermore, to increase accuracy of tracking, conventional systems require a tracking array extending from the bone. Such tracking arrays can reduce visibility of the surgical site and potentially interfere with the surgeon or surgical components of tools in the workspace. Conventional trackers additionally are susceptible to becoming dislodged or inadvertently moved, which in turn can compromise tracking accuracy. Multiple trackers are sometimes attached to the bone to increase tracking accuracy but doing so only amplifies the aforementioned challenges. There is a need in the art for systems and methods to address at least these challenges.

Prior art is found in <CIT> which generally relates to a trauma ultrasound reduction device and in particular to a body profiling system including multiple pivotally connected links and multiple probes. Each of the probes is disposed on one of the links and includes any one or any combination of a transmitter configured to send a signal, a receiver configured to receive the signal, and a transceiver configured to send and receive the signal. <CIT> generally relates to ultrasound imaging of a specular-reflecting target.

This Summary introduces a selection of concepts in a simplified form that are further described in the Detailed Description below. This Summary is not intended to limit the scope of the claimed subject matter nor identify key features or essential features of the claimed subject matter. The invention is according to the independent claim. Preferred embodiments of the invention are according to the dependent claims.

According to a first aspect, a tracking apparatus for tracking a bone of a patient limb is provided. The tracking apparatus includes a body configured to couple to the patient limb, the body including first and second arms each including an exterior surface, an opposing interior surface, and opposing sides connecting the exterior and interior surfaces. The tracking apparatus also includes a wing portion extending from at least one of the sides of at least one of the first and second arms, the wing portion sharing the interior surface of the at least one first and second arm. The tracking apparatus also includes one or more ultrasonic sensors coupled to the interior surface of the body and the interior surface of wing portion, the one or more ultrasonic sensor being configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone. The tracking apparatus also includes one or more trackable elements coupled to the body and the wing portion.

According to a second aspect, a tracking system for tracking a bone of a patient limb is provided. The tracking system includes a tracking apparatus, which includes a body and a wing portion extending from the body. The tracking apparatus includes one or more ultrasonic sensors coupled to the wing portion, the one or more ultrasonic sensor being configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone. The tracking apparatus also includes one or more trackable elements coupled to the wing portion. The tracking system also includes a localizer configured to sense one or more of the trackable elements of the tracking apparatus and one or more controllers configured to determine a position of the bone relative to one or more of the trackable elements and in a coordinate system of the tracking apparatus based on the ultrasonic waves received by the one or more ultrasonic sensors, a position of one or more of the trackable elements in a coordinate system of the localizer based on the sensing of the one or more trackable elements by the localizer, and a position of the bone in a coordinate system of the localizer.

According to a third aspect, a robotic surgical system is provided. The robotic surgical system includes a manipulator including a robotic arm formed of a plurality of links and joints, an end effector coupled to the robotic arm and comprising an energy applicator, and a tracker coupled to one or more of the robotic arm and the end effector. The robotic surgical system also includes a tracking apparatus for tracking a bone of a patient limb, which includes a body and a wing portion extending from the body. The tracking apparatus includes one or more ultrasonic sensors coupled to the wing portion, the one or more ultrasonic sensor being configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone. The tracking apparatus also includes one or more trackable elements coupled to the wing portion. The robotic surgical system also includes a localizer configured to sense one or more of the trackable elements of the tracking apparatus and one or more controllers configured to determine a position of the bone in a coordinate system of the localizer and a position of the energy applicator relative to the bone.

According to a fourth aspect, a tracking apparatus is provided for tracking a patient limb, the tracking apparatus comprising: a body configured to couple to the patient limb and comprising first and second arms each including an exterior surface, an opposing interior surface, and opposing sides connecting the exterior and interior surfaces; a wing portion extending from at least one of the sides of at least one of the first and second arms and the wing portion sharing the interior surface of the at least one first and second arm; one or more ultrasonic sensors coupled to the interior surface of the body and the interior surface of the wing portion and being configured to transmit ultrasonic waves to and receive ultrasonic waves from the patient limb; and one or more trackable elements coupled to the body and the wing portion.

According to a fifth aspect, a tracking apparatus having an ornamental design specifically shown in <FIG> is provided.

According to a sixth aspect, a tracking apparatus for tracking a patient limb is provided. The tracking apparatus includes a body configured to at least partially wrap around the patient limb, the body including an exterior surface, an opposing interior surface, and opposing sides connecting the exterior and interior surfaces. The tracking apparatus also includes a wing portion extending from at least one of the sides of the body, the wing portion sharing the interior surface of the body. The tracking apparatus also includes one or more ultrasonic sensors coupled to the interior surface of the body and the interior surface of the wing portion, the one or more ultrasonic sensor being configured to transmit ultrasonic waves to and receive ultrasonic waves from the patient limb. The tracking apparatus also includes one or more trackable elements coupled to the body.

According to a seventh aspect, a tracking apparatus for tracking a patient limb is provided. The tracking apparatus comprising: a body configured to at least partially wrap around the patient limb and comprising a wing portion integrally extending from the body; one or more ultrasonic sensors coupled to the body and the wing portion and being configured to transmit ultrasonic waves to and receive ultrasonic waves from the patient limb; and one or more trackable elements coupled to the body.

Any of the above aspects can be utilized individually, or in combination.

In one implementation, a space is defined between the interior surfaces of the first and second arms. In one implementation, an axis is defined through the space in a direction extending between the opposing side surfaces of the at least one first and second arms. In one implementation, the wing portion extends along a direction parallel to the axis. In one implementation, the bone comprises a bone axis. In one implementation, the first and second arms are configured to at least partially surround the bone. In one implementation, the axis along which the wing portion extends is configured to be parallel, or substantially parallel with the bone axis. In one implementation, each side has a side surface length. In one implementation, the wing portion has a wing portion length. In one implementation, the wing portion length is less than the side surface length. In one implementation, the at least one first and second arms and the wing portion each include an axial length defined along a direction of the axis. In one implementation, the axial length of the wing portion is greater than or substantially equal to the axial length of the at least one first and second arms.

In one implementation, the one or more trackable elements includes one or more of an optical trackable element configured to be sensed by an optical localizer, a radio frequency (RF) trackable element configured to be sensed by an RF localizer, an electromagnetic (EM) trackable element configured to be sensed by an EM localizer, and a pattern or feature configured to be sensed by a machine-vision camera localizer.

In one implementation, each of the first and second arms and the wing portion has an arcuate configuration.

In one implementation, the first and second arms are spaced apart from one another and are rigid. In one implementation, a hinge connects the first arm and the second arm such that the first arm and the second arm are rotatably moveable relative to one another relative to the hinge. In one implementation, the hinge includes a sensor configured to sense a relationship between the first and second arms. In one implementation, the tracking apparatus comprises one or more controllers configured to determine a relationship between the one or more of the ultrasonic sensors of the first arm and the one or more of the ultrasonic sensors of the second arm.

In one implementation, the one or more controllers are configured to calibrate the one or more ultrasonic sensors based on the relationship between the first and second arms.

In one implementation, the body is flexible to wrap around the patient limb. In one implementation, the first and second arms are integrally connected and are flexible such that the body moves between a closed position and an open position in response to flexing of one or more of the first and second arms. In one implementation, the first and second arms are spaced apart from one another and are flexible and a hinge connects the first arm and the second arm such that the first arm and the second arm are rotatably moveable relative to one another relative to the hinge.

In one implementation, the one or more trackable elements are coupled to the exterior surface of one or more of the first and second arms and coupled to the exterior surface of the wing portion. The tracking elements can be embedded within, disposed atop, or attached to the exterior surface of the arms and/or wing portion.

In one implementation, the wing portion is further defined as a first wing portion. In one implementation, the tracking apparatus comprises a second wing portion extending from the body at a location separated from the first wing portion and the second wing portion sharing the interior surface of at least one of the first and second arm. In one implementation, one or more of the ultrasonic sensors is coupled to the interior surface of the second wing portion. In one implementation, one or more of the trackable elements is coupled to the exterior surface of the second wing portion.

In one implementation, the body includes a first distal end, an opposing second distal end, and a midpoint between the first and the second distal ends. In one implementation, the first wing portion is located between the first distal end and the midpoint of the body. In one implementation, the second wing portion is located between the midpoint and the second distal end of the body. In one implementation, the first distal end and the second distal end of the body are spaced from one another to define an opening configured to receive the patient limb.

In one implementation, the wing portion shares the exterior surface of the at least one first and second arm. In other implementations, the wing portion may extend entirely or partially from the exterior surface. In other implementations, the wing portion may extend entirely or partially from the interior surface.

In one implementation, the tracking apparatus comprises a cushion coupled to the interior surface of the first and second arms and the interior surface of the wing portion. In one implementation, the cushion contacts the patient limb. In one implementation, the tracking apparatus comprises a fluid control unit coupled to the cushion and configured to provide fluid to the cushion. In one implementation, the tracking apparatus comprises a controller configured to determine an integrity of contact between the tracking apparatus and the patient limb based on the ultrasonic waves received by the one or more ultrasonic sensors. In one implementation, the controller is configured to adjust the one or more ultrasonic sensors in response to determining the integrity of contact. In one implementation, the tracking apparatus comprises a cushion coupled to the interior surface of the first and second arms and the interior surface of the wing portion. In one implementation, the cushion contacts the patient limb. In one implementation, a fluid control unit coupled to the cushion and configured to provide fluid to the cushion. In one implementation, the controller is configured to adjust the fluid control unit in response to determining the integrity of contact.

In one implementation, the tracking apparatus comprises a light emitter configured to emit light to the patient limb, an optical sensor configured to sense light reflected from the patient limb, and a controller coupled to the optical sensor and configured to determine an integrity of contact between the tracking apparatus and the patient limb based on the light sensed by the optical sensor.

In one implementation, the tracking apparatus comprises a controller coupled to the one or more ultrasonic sensors and being configured to determine a shape of the bone based on the ultrasonic waves received by the one or more ultrasonic sensors.

In one implementation, the tracking apparatus comprises a non-transitory memory coupled to the controller, the non-transitory memory configured to store the shape of the bone and the controller configured to determine a position of the bone relative to the one or more trackable elements in a coordinate system of the tracking apparatus based on the shape of the bone. In one implementation, the one or more controllers are configured to determine a shape of the bone based on the ultrasonic waves received by the one or more ultrasonic sensors.

In one implementation, the tracking apparatus comprises a display configured to display the position of the bone in the coordinate system of the localizer and the shape of the bone. In one implementation, the tracking apparatus comprises a controller of the one or more controllers. In one implementation, the one or more controllers comprises a controller remotely coupled to the tracking apparatus.

In one implementation, the tracking apparatus is further defined as a first tracking apparatus for a femur of a patient such that the body of the first tracking apparatus is configured to couple to the femur of the patient. In one implementation, the tracking system comprises a second tracking apparatus for a tibia of the patient such that the body of the second tracking apparatus is configured to couple to the tibia of the patient.

In one implementation, the hinge or hinges of the tracking apparatus may comprise motors for moving a first and/or second arms between an open and/or closed position.

Any of the above implementations can be combined in part, or in whole, with any of the aspects.

Referring to <FIG>, a tracking system <NUM> is illustrated. The tracking system <NUM> is useful for non-invasively tracking and/or assessing a surgical site or an anatomical volume of a patient <NUM>, such as bone or soft tissue. For example, in the instance of <FIG>, the tracking system <NUM> tracks a femur F and/or a tibia T of the patient <NUM>. Other bones, such as the humerus, pelvis, skull, and spine are contemplated.

As shown in <FIG>, the tracking system <NUM> may include a tracking apparatus <NUM> which couples to the patient <NUM>, specifically, a patient limb L, and tracks a bone of the patient limb L. In <FIG>, the tracking system <NUM> includes a first tracking apparatus <NUM>' for tracking the femur F and a second tracking apparatus <NUM>" for tracking the tibia T.

The tracking apparatus <NUM> includes one or more ultrasonic sensors <NUM> coupled to an interior surface INT of the tracking apparatus <NUM>. The ultrasonic sensors <NUM> are configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone of the patient. Furthermore, the tracking apparatus <NUM> includes one or more trackable elements <NUM>, which may be sensed by a localizer of the tracking system <NUM>. In <FIG>, the trackable elements <NUM> are shown as being coupled to an exterior surface EXT of the tracking apparatus <NUM>.

The tracking system <NUM> may also include a navigation system <NUM>, which may include a navigation localizer <NUM>. The navigation localizer <NUM> may be configured to sense elements of the tracking system <NUM>. For example, the navigation localizer <NUM> may be configured to sense the trackable elements <NUM> of the tracking apparatus <NUM>, a tool tracker <NUM> attached to the tool <NUM>, and/or a manipulator tracker <NUM> attached to the manipulator <NUM>.

The tracking system <NUM> also includes one or more controllers <NUM>. The one or more controllers <NUM> may be configured to determine a state of the bone of the patient <NUM> in a (navigation) localizer coordinate system LCLZ. As used herein, the state of an object includes, but is not limited to, data that defines a shape, surface contour, position, and/or an orientation of an object or equivalents/derivatives thereof. Additionally, the state may include linear velocity data, angular velocity data, acceleration, and the like.

For example, the one or more controllers <NUM> may be configured to determine a position of the bone of the patient <NUM> in the localizer coordinate system LCLZ and/or a shape of the bone of the patient <NUM>. In an instance where the one or more controllers <NUM> determines a position of the bone of the patient <NUM>, it may be stated that the one or more controllers <NUM> transform a state of the bone of the patient <NUM> from the tracking apparatus coordinate system TA to the localizer coordinate system LCLZ. Specifically, the one or more controllers <NUM> perform a first transform by determining a position of the bone of the patient <NUM> relative to one or more of the trackable elements <NUM> and in the tracking apparatus coordinate system TA based on ultrasonic waves received by the one or more ultrasonic sensors <NUM>. The one or more controllers <NUM> may then perform a second transform by determining a position of the one or more trackable elements <NUM> in the localizer coordinate system LCLZ based on a sensing of the one or more trackable elements <NUM> by the localizer <NUM>. The one or more controllers <NUM> may then combine the first and second transforms to determine the position of the bone in the localizer coordinate system LCLZ based on the position of the bone of the patient <NUM> in the tracking apparatus coordinate system TA (the first transform) and based on the position of the one or more trackable elements <NUM> in the localizer coordinate system LCLZ (the second transform).

The tracking system <NUM> may also include a display. For example, in the instance of <FIG>, the tracking system <NUM> includes displays <NUM> of the navigation system <NUM>. The displays <NUM> may be configured to display a state of the bone of the patient <NUM>. In the instance of <FIG>, the displays <NUM> may be configured to display data corresponding to a position of the femur F, as well as a shape of the femur F.

As shown in <FIG>, the tracking system <NUM> may be a part of a robotic surgical system <NUM>, the tracking system <NUM> being delineated from the rest of the robotic surgical system <NUM> using a dashed-line box. The robotic surgical system <NUM> may be configured to carry out the surgical procedure based on the state of the bone as determined by the one or more controllers <NUM> of the tracking system <NUM>. However, in some instances, the tracking system <NUM> may be independent of the robotic surgical system <NUM>. In such instances, a surgeon may carry out a surgical procedure while referencing the position or shape of the bone, as displayed by the display <NUM> or as notified by the tracking system <NUM>.

The robotic surgical system <NUM> may be configured to treat the surgical site or the anatomical volume of a patient 12A. In <FIG>, the robotic surgical system <NUM> is shown performing a surgical procedure on the patient <NUM>. The surgical procedure may involve tissue removal or other forms of treatment. Treatment may include cutting, coagulating, lesioning the tissue, other in-situ tissue treatments, or the like. As an example, the surgical procedure may involve partial or total knee replacement surgery. In some examples, the robotic surgical system <NUM> may be designed to cut away material to be replaced by surgical implants, such as knee implants, including unicompartmental, bicompartmental, multicompartmental, or total knee implants. Some of these types of implants are shown in <CIT>, entitled "Prosthetic Implant and Method of Implantation,". The robotic surgical system <NUM> and techniques disclosed herein may be used to perform other procedures, surgical or non-surgical, or may be used in industrial applications or other applications where robotic systems are utilized.

As shown in <FIG>, the robotic surgical system <NUM> may include a manipulator <NUM>. The manipulator <NUM> has a base <NUM> and a plurality of links <NUM>. A manipulator cart <NUM> supports the manipulator <NUM> such that the manipulator <NUM> is fixed to the manipulator cart <NUM>. The links <NUM> collectively form one or more robotic arms R of the manipulator <NUM>. The manipulator <NUM> may have a serial arm configuration (as shown in <FIG>), a parallel arm configuration, or any other suitable manipulator configuration. In other examples, more than one manipulator <NUM> may be utilized in a multiple arm configuration.

In the example shown in <FIG>, the manipulator <NUM> comprises a plurality of joints J and a plurality of joint encoders <NUM> located at the joints J for determining position data of the joints J. For simplicity, only one joint encoder <NUM> is illustrated in <FIG>, although other joint encoders <NUM> may be similarly illustrated. The manipulator <NUM> according to one example has six joints J1-J6 implementing at least six-degrees of freedom (DOF) for the manipulator <NUM>. However, the manipulator <NUM> may have any number of degrees of freedom and may have any suitable number of joints J and may have redundant joints.

The manipulator <NUM> need not require joint encoders <NUM> but may alternatively, or additionally, utilize motor encoders present on motors <NUM> coupled to any number of joints J. Also, the manipulator <NUM> need not require rotary joints, but may alternatively, or additionally, utilize one or more prismatic or linear joints. Any suitable combination of joint types is contemplated.

As shown in <FIG>, the base <NUM> of the manipulator <NUM> is generally a portion of the manipulator <NUM> that provides a fixed reference coordinate system for other components of the manipulator <NUM> or the robotic surgical system <NUM> in general. Generally, the origin of a manipulator coordinate system MNPL is defined at the fixed reference of the base <NUM>. The base <NUM> may be defined with respect to any suitable portion of the manipulator <NUM>, such as one or more of the links <NUM>. Alternatively, or additionally, the base <NUM> may be defined with respect to the manipulator cart <NUM>, such as where the manipulator <NUM> is physically attached to the manipulator cart <NUM>. In one example, the base <NUM> is defined at an intersection of the axes of joints J1 and J2. Thus, although joints J1 and J2 are moving components in reality, the intersection of the axes of joints J1 and J2 can be a virtual fixed reference pose, which provides both a fixed position and orientation reference and which does not move relative to the manipulator <NUM> and/or manipulator cart <NUM>. In other examples, the manipulator <NUM> can be a hand-held manipulator where the base <NUM> is a base portion of a tool (e.g., a portion held free hand by the user), and the tool tip is movable relative to the base portion. The base portion has a reference coordinate system that is tracked, e.g., via the manipulator tracker <NUM>, and the tool tip has a tool tip coordinate system that is computed relative to the reference coordinate system (e.g., via motor and/or joint encoders and forward kinematic calculations). Movement of the tool tip can be controlled to follow the path since its pose relative to the path can be determined.

The manipulator <NUM> and/or manipulator cart <NUM> house a manipulator controller <NUM>, or other type of control unit. The manipulator controller <NUM> may comprise one or more computers, or any other suitable form of controller that directs the motion of the manipulator <NUM>. The manipulator controller <NUM> may have a central processing unit CPU and/or other processors, memory MEM, and storage (not shown). The manipulator controller <NUM> is loaded with software as described below. The processors could include one or more processors to control operation of the manipulator <NUM>. The processors can be any type of microprocessor, multi-processor, and/or multi-core processing system. The manipulator controller <NUM> may additionally, or alternatively, comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein. The term processor is not intended to limit any implementation to a single processor. The manipulator <NUM> may also comprise a user interface UI with one or more displays <NUM> (shown in <FIG>) and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.).

As shown in <FIG>, a tool <NUM> couples to the manipulator <NUM> and is movable relative to the base <NUM> to interact with the anatomy in certain modes. The tool <NUM> is a physical and surgical tool and is or forms part of an end effector EE supported by the manipulator <NUM> in certain embodiments. The end effector EE may include an energy applicator <NUM>, e.g., a bur, a drill bit, a saw blade, an ultrasonic vibrating tip, or the like, designed to contact and remove the tissue of the patient <NUM> at the surgical site. The tool <NUM> may be grasped by the user. One possible arrangement of the manipulator <NUM> and the tool <NUM> is described in <CIT>, entitled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,". The manipulator <NUM> and the tool <NUM> may be arranged in alternative configurations. The tool <NUM> can be like that shown in <CIT>, entitled "End Effector of a Surgical Robotic Manipulator,".

The tool <NUM> may comprise a tool controller <NUM> to control operation of the tool <NUM>, such as to control power to the tool (e.g., to a rotary motor of the tool <NUM>), control movement of the tool <NUM>, control irrigation/aspiration of the tool <NUM>, and/or the like. The tool controller <NUM>, as shown in <FIG>, may be in communication with the manipulator controller <NUM> or other components. The tool <NUM> may also comprise a user interface UI with one or more displays <NUM> (shown in <FIG>) and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.). The manipulator controller <NUM> controls a state (position and/or orientation) of the tool <NUM> (e.g., the tool center point (TCP)) with respect to a coordinate system, such as the manipulator coordinate system MNPL. The manipulator controller <NUM> can control (linear or angular) velocity, acceleration, or other derivatives of motion of the tool <NUM>.

The manipulator controller <NUM> and/or the tool controller <NUM> may control operation of the robotic surgical system <NUM> during a manual mode, which is described in <CIT>. During the manual mode, the user manually directs, and the manipulator <NUM> executes, movement of the tool <NUM> at the surgical site. The user physically contacts the tool <NUM> to apply external force and cause movement of the tool <NUM> in the manual mode. The manipulator controller <NUM> and/or the tool controller <NUM> may control operation of the robotic surgical system <NUM> during a semi-autonomous mode, which is described in <CIT>. During the semi-autonomous mode, the manipulator <NUM> moves the tool <NUM> along a milling path (e.g., the active joints J of the manipulator <NUM> operate to move the tool <NUM> without necessarily requiring external force/torque on the tool <NUM> from the user). In some embodiments, when the manipulator <NUM> operates in the semi-autonomous mode, the manipulator <NUM> is capable of moving the tool <NUM> free of user assistance. Free of user assistance may mean that a user does not physically contact the tool <NUM> to move the tool <NUM>. Instead, the user may use some form of remote control to control starting and stopping of movement. For example, the user may hold down a button of the remote control to start movement of the tool <NUM> and release the button to stop movement of the tool <NUM>.

As shown in <FIG> and <FIG>, the tracking system <NUM> may include a navigation system <NUM>. The navigation system <NUM> may be configured to sense the trackable elements <NUM> for determining a state of the tracking apparatus <NUM> with respect to the (navigation) localizer coordinate system LCLZ. In other instances, the navigation system <NUM> may also be configured to sense other elements for determining a state of the manipulator <NUM> and/or the tool <NUM>. For example, the navigation system <NUM> may track the tool tracker <NUM> for determining a state of the tool <NUM> and/or the manipulator tracker <NUM> for determining a state of the manipulator <NUM>. The navigation system <NUM> may also be configured to directly track an anatomy of the patient <NUM>, e.g., femur F and tibia T, without tracking the tracking apparatus <NUM>. One example of the navigation system <NUM> is described in <CIT>, entitled "Navigation System Including Optical and Non-Optical Sensors,".

As shown in <FIG>, the navigation system <NUM> may include a cart assembly <NUM> that houses a navigation controller <NUM>, and/or other types of control units. A navigation user interface UI may be in operative communication with the navigation controller <NUM>. The navigation user interface may include one or more displays <NUM> (shown in <FIG>). The navigation system <NUM> may be capable of displaying a graphical representation of the relative states of the tracked objects to the user using the one or more displays <NUM>. The navigation user interface UI may further include one or more input devices to input information into the navigation controller <NUM> or otherwise to select/control certain aspects of the navigation controller <NUM>. Such input devices may include interactive touchscreen displays. The input devices may include any one or more of push buttons, a keyboard, a mouse, a microphone (voice-activation), gesture control devices, and the like.

As previously stated, the navigation system <NUM> may also include the navigation localizer <NUM>. In the instance of <FIG>, the localizer <NUM> is an optical localizer and includes a camera unit <NUM>. The camera unit <NUM> has an outer casing <NUM> that houses one or more optical sensors <NUM>. The localizer <NUM> may further comprise a video camera VC and a localizer controller <NUM>, as shown in <FIG>. The localizer controller <NUM> may be configured to control components of the localizer <NUM>, such as the optical sensors <NUM> and/or the video camera VC.

As shown in <FIG>, the localizer <NUM> may be coupled to the navigation controller <NUM>. As such, the localizer <NUM> of the navigation system <NUM> may sense the one or more trackable elements <NUM> of the tracking apparatus <NUM> and the navigation controller <NUM> may determine a state of the tracking apparatus <NUM> based on the sensing performed by the localizer <NUM>. For example, the localizer <NUM> may perform known triangulation techniques to sense the trackable elements <NUM> and communicate tracking information of the trackable elements <NUM> with the navigation controller <NUM> such that the navigation controller <NUM> is able to determine the state of the tracking apparatus <NUM>.

In some instances, the localizer <NUM> of the navigation system <NUM> may be configured to sense objects other than the trackable elements <NUM> of the tracking apparatus <NUM>. For example, in instances where the tracking system <NUM> is a part of the robotic surgical system <NUM>, the localizer <NUM> may also be configured to sense a trackable element attached to the manipulator <NUM>, the tool <NUM>, and/or the anatomy of the patient <NUM> and the navigation controller <NUM> may be configured to determine a state of the manipulator <NUM>, the tool <NUM>, and/or the anatomy of the patient <NUM>. For example, the localizer <NUM> may sense the tool tracker <NUM> attached to the tool <NUM>, the manipulator tracker <NUM> attached to the manipulator <NUM>, and/or patient trackers coupled to the femur F and tibia T using known triangulation techniques. Furthermore, in such instances, the navigation controller <NUM> may be configured to communicate a state of the trackable elements <NUM> to the manipulator controller <NUM> via a wired bus, communication network, as shown in <FIG>, via wireless communication, or otherwise.

The navigation system <NUM> may use any suitable configuration for tracking the manipulator <NUM>, tool <NUM>, and/or the patient <NUM>, in addition to, or instead of, known triangulation techniques. For instance, the navigation system <NUM> and/or localizer <NUM> may be ultrasound-based. In such an instance, the navigation system <NUM> may comprise an ultrasound imaging device coupled to the navigation controller <NUM>. The ultrasound imaging device may image any of the aforementioned objects, e.g., the tracking apparatus <NUM>, the manipulator <NUM>, the tool <NUM>, and/or the patient <NUM>, and generates state signals to the navigation controller <NUM> based on the ultrasound images. The ultrasound images may be <NUM>-D, <NUM>-D, or a combination of both. The navigation controller <NUM> may process the images in near real time to determine states of the objects. The ultrasound imaging device may have any suitable configuration and may be different than the camera unit <NUM> as shown in <FIG>.

In other instances, the navigation system <NUM> may include an optical localizer, a radio frequency (RF) based localizer, an electromagnetically (EM) based localizer, and/or a machine-vision based localizer. In such instances, the navigation system <NUM> may be configured to sense a corresponding type of object. For example, the navigation system <NUM> may be configured to sense an optical trackable element, an RF sensor or emitter, an EM sensor or emitter, and/or an object including a pattern or feature detectable by a machine-vision camera localizer.

The navigation controller <NUM> may comprise one or more computers, or any other suitable form of controller. As shown in <FIG> and <FIG>, the navigation controller <NUM> may include a central processing unit CPU and/or other processors, memory MEM, and storage (not shown). The processors can be any type of processor, microprocessor, or multi-processor system. The navigation controller <NUM> may be loaded with software. The software, for example, may convert signals received from the localizer <NUM> into data representative of a state of objects being tracked. The navigation controller <NUM> may additionally, or alternatively, comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein. The term processor is not intended to limit any implementation to a single processor.

The navigation system <NUM> may have any other suitable components or structure not specifically recited herein. Furthermore, any of the techniques, methods, and/or components described above with respect to the navigation system <NUM> shown may be implemented or provided for any of the other examples of the navigation system <NUM> described herein. For example, the navigation system <NUM> may utilize solely inertial tracking or any combination of tracking techniques, and may additionally, or alternatively, comprise fiber optic-based tracking, machine-vision tracking, and the like.

One implementation of the tracking apparatus <NUM> of the tracking system <NUM> is shown in <FIG> and <FIG>. As shown in <FIG> and <FIG>, the tracking apparatus <NUM> includes a body <NUM>, a wing portion <NUM>, one or more ultrasonic sensors <NUM>, and one or more trackable elements <NUM>.

The body <NUM> is configured to couple to a patient limb L as shown in <FIG>. As shown in <FIG>, the body <NUM> may include a first arm 44A and a second arm 44B. Each of the first and second arms 44A, 44B include an exterior surface EXT, an opposing interior surface INT, and opposing sides S connecting the exterior and interior surfaces. The body <NUM> is configured to couple to the patient limb such that the first and second arms 44A, 44B are configured to at least partially surround the bone of the patient <NUM>.

Referring to <FIG>, a space <NUM> may be defined between the interior surfaces INT of the first and second arms 44A, 44B. An axis AX may be defined through the space <NUM> in a direction extending between the opposing side surfaces S of the first and second arms 44A, 44B. As shown in <FIG>, a bone of the patient limb L, represented as a femur F in <FIG>, may include a bone axis BAX. The first and second arms 44A, 44B are configured to couple to the patient limb L such that the axis AX is parallel or substantially parallel with the bone axis BAX. It is not necessary that the axis AX be perfectly aligned with the bone axis BAX.

As shown in <FIG>, the body <NUM> may include an opening <NUM>. As shown, the body <NUM> includes a first distal end <NUM> and an opposing second distal end <NUM>. The first distal end <NUM> and the second distal end <NUM> are spaced from one another to define the opening <NUM>. The opening <NUM> may be configured to receive the patient limb L such that the body <NUM> may couple to the patient limb L, as shown in <FIG>. The opening <NUM> is sized such that when the body <NUM> is closed, the tracking apparatus <NUM> should remain secured to the limb L. In other words, when the body <NUM> is closed, the opening <NUM> is sized to be narrower than a statistically below average sized patient limb such that the patient limb cannot escape the opening when the body <NUM> is closed. The opening <NUM> is also sized such that when the body <NUM> is fully open, the tracking apparatus <NUM> can secure to any size patient limb. In other words, when the body <NUM> is fully open, the opening <NUM> is sized to be wider than a statistically above average sized patient limb such that the patient limb can easily fit within the opening when the body <NUM> is open.

The first and second arms 44A, 44B may include an arcuate configuration. As shown in <FIG>, the arcuate configuration of the first and second arms 44A, 44B may be substantially circular and curved about a center point CP of the tracking apparatus <NUM>. Furthermore, the arcuate configuration of the first and second arms 44A, 44B may be defined between the first distal end <NUM> and the second distal end <NUM>. In the instance of <FIG>, the arcuate configuration of the body <NUM> is curved about the center point CP. Additionally, the tracking apparatus <NUM> is positioned such that an angle between a line <NUM> drawn from the center point CP to the first distal end <NUM> and a line <NUM> drawn from the center point CP to the second distal end <NUM> is approximately <NUM> degrees, as illustrated in <FIG>. In other positions of the tracking apparatus <NUM> (e.g., an open or closed position to be explained herein), an angle between the line <NUM> and the line <NUM> may be any suitable degree. Additionally, in other instances, the arcuate configuration of the first and second arms 44A, 44B may be any suitable arc. For instance, the arcuate configuration of the first and second arms 44A, 44B may be substantially elliptical. Furthermore, it is not necessary to define the arcuate shape of the first and second arms 44A, 44B with respect to the center point CP. Other types of points or references may be defined within the limb L capturing region of the first and second arms 44A, 44B.

The tracking apparatus <NUM> may include any suitable number of bodies <NUM>. In the instance of <FIG>, the tracking apparatus <NUM> includes a single body <NUM>. In other instances, the tracking apparatus <NUM> may include additionally bodies <NUM>, which may be coupled to or integrally formed with one another.

The body <NUM> may include any suitable shape and any suitable configuration. <FIG> illustrate an alternative instance of the body <NUM> of the tracking apparatus <NUM> wherein the body <NUM> includes a polygonal configuration with several planar faces on the interior and exterior surfaces INT, EXT. In other instances, the body <NUM> may include any suitable polygonal configuration or combinations thereof.

As shown in <FIG>, the first and second arms 44A, 44B may be spaced apart from one another and connected to one another by a hinge <NUM>. The hinge <NUM> may connect the first and second arms 44A, 44B such that the first and second arms 44A, 44B are rotatably moveable relative to one another relative to the hinge <NUM>.

Referring to <FIG>, the first and second arms 44A, 44B rotate about the hinge <NUM> to position the tracking apparatus <NUM> in an open position <NUM> and a closed position <NUM> and any position therebetween. Specifically, in this implementation, the first and second arms 44A, 44B rotate about the hinge <NUM> along the circular path <NUM>, to position the tracking apparatus <NUM> in the open position <NUM> and in the closed position <NUM>. In the open position <NUM>, as shown in <FIG>, the first distal end <NUM> is located at a point A' along the circular path <NUM> and the second distal end <NUM> is located at a point A" along the circular path <NUM>. In the closed position <NUM>, as shown in <FIG>, the first distal end <NUM> is located at a point B' along the circular path <NUM> and the second distal end <NUM> is located at a point B" along the circular path <NUM>. In other instances, the first and second distal ends <NUM>, <NUM> may be located at any suitable point along the circular path <NUM> during the open position <NUM> and during the closed position <NUM>. In other examples, the path <NUM> along which the first and second distal ends <NUM>, <NUM> follow may be other than circular. For example, the path <NUM> can be linear or follow other types of curved or irregular paths.

The body <NUM> may include any suitable material. In the examples shown including the hinge <NUM>, the first and second arms 44A, 44B may be comprised of a rigid material. Alternatively, the body <NUM> may include a flexible material, such as a rubber, thin metallic material, polycarbonate, carbon fiber, plastic, or any suitable elastomeric material. In instances where the first and second arms 44A, 44B comprises a flexible material, the tracking apparatus <NUM> may include or omit the hinge <NUM>. In instances where the tracking apparatus <NUM> omits the hinge <NUM>, the first and second arms 44A, 44B may be integrally connected.

<FIG> and <FIG> illustrates an instance where the first and second arms 44A, 44B comprise a flexible material, are integrally connected, and the tracking apparatus <NUM> omits the hinge <NUM>. As shown, for flexible configurations, the body <NUM> may move between the closed position <NUM>, shown in <FIG>, and the open position <NUM>, shown in <FIG>, in response to flexing of one or more of the first and second arms 44A, 44B. In such instances, the body <NUM> may be biased towards the closed position <NUM> and moved towards the open position <NUM> in response to some external force flexing one or more of the first and second arms 44A, 44B. For example, the force can be applied by an operator pulling apart the first and second arms 44A, 44B during installation of the tracking apparatus <NUM> and/or can be applied by the patient limb L pressing against the body <NUM>. Once installed onto the patient limb L, the flexible body <NUM> biases towards the closed position <NUM> thereby securing the body <NUM> to the patient limb L. The body <NUM> can include an adjustment mechanism, such as a mechanical separator between first and second arms 44A, 44B.

In some instances, the body <NUM> of the tracking apparatus <NUM> may comprise modular or multiple linkages that pivotally connected to one another, such as those described in <CIT>. For example, the first and/or second arms 44A, 44B of could be formed of such linkages. Alternatively, any suitable number of linkages may be added to a distal end <NUM>, <NUM> of the body <NUM>. Accordingly, the tracking apparatus <NUM> may include any suitable number of hinges <NUM> coupled between any number of linkages. For example, the linkages may be coupled to the first distal end <NUM> and/or the second distal end <NUM> of the body <NUM> using a coupling mechanism (not shown) to accommodate a larger patient limb L. In one such instance, a plurality of linkages may be coupled to one another to form a series of linkages, as described in <CIT>, and the series of linkages may be coupled to the body <NUM>. As with the first and/or second arms 44A, 44B, the linkages similarly comprise ultrasonic sensors <NUM> and trackable elements <NUM>. At least one of the linkages comprises a wing portion <NUM>. The linkages, when connected, may be "plug-and-play" such that the tracking apparatus <NUM> may operate the ultrasonic sensors <NUM> and trackable elements <NUM> of the connected linkages, determine the number of connected linkages, and determine a relative position of the connected linkages.

In some instances, the tracking apparatus <NUM> may include a sensor configured to sense a relationship between the first and second arms 44A, 44B. The relationship between the first and second arms 44A, 44B may be a distance between the first and second arms 44A, 44B, and/or a position, a relative velocity, a relative acceleration, or an angle and/or orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B, and/or equivalents/derivatives thereof.

In an instance when the sensor senses a distance between the first and second arms 44A, the sensor may include a distance measuring feature. For example, the sensor may include an ultrasonic sensor, an infrared (IR) sensor, a laser distance (LIDAR) sensor, a time-of-flight sensor, or other known features for measuring distance. The sensor may also sense a position, a relative velocity, a relative acceleration, and/or an angle and/or orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B using an above component.

In an instance when the sensor senses a position of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B, the sensor may include a position measuring feature. For example, the sensor may include joint encoders, inductive sensors, capacitive sensors, transducers, or other known features for measuring position. The sensor may also sense a distance between the first and second arms 44A, and/or a relative velocity, a relative acceleration, or an angle and/or orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B using an above component.

In an instance where the sensor senses an angle and/or orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B, the sensor may be disposed within the hinge <NUM>. Such a sensor may include transducers, piezoelectric elements in or connected to a spring of the hinge <NUM>, servo motors as electromechanical angular biasing elements, or other known features for measuring an angle or orientation. In instances where the tracking apparatus <NUM> does not include the hinge <NUM> and the body <NUM> comprises flexible material, the sensor may include a stress/strain measuring feature for sensing a stress and/or strain on the flexible body <NUM> to sense an angle and/or orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B. The stress/strain measuring feature may include a strain gauge, a load cell, a force sensor, or other known features for measuring stress or strain. The sensor may also sense a distance between the first and second arms 44A, and/or a position, a relative velocity, a relative acceleration, or an angle/orientation of one of the first and/or second arms 44A, 44B relative to the other of the first and/or second arms 44A, 44B using an above component.

The sensor configured to sense the relationship between the first and second arms 44A, 44B may be located in any suitable location of the tracking apparatus <NUM>. For example, as previously stated, the sensor may be disposed within the hinge <NUM>. In instances where the tracking apparatus <NUM> does not include the hinge <NUM>, the sensor may be disposed within any other suitable component of the tracking apparatus <NUM>, such as within the first and/or second arms 44A, 44B.

The one or more controllers <NUM> may be configured to determine the relationship between the first and second arms 44A, 44B based on the relationship between the first and second arms 44A, 44B sensed by the sensor. For example, the one or more controllers <NUM> may be configured to determine a relationship between the ultrasonic sensors <NUM> of the first and second arms 44A, 44B and a relationship between the trackable elements <NUM> of the first and second arms 44A, 44B based on the sensed relationship.

The one or more controllers <NUM> may be configured to determine a relationship between the ultrasonic sensors <NUM> of the first and second arms 44A, 44B based on the sensed relationship to calibrate the ultrasonic sensors <NUM> accordingly. For example, in some instances, the one or more controllers <NUM> may be configured to determine a position of the ultrasonic sensors <NUM> of the first arm 44A relative to a position of the ultrasonic sensors <NUM> of the second arm 44B based on the sensed relationship. The one or more controllers <NUM> may then calibrate the ultrasonic sensors <NUM> of the first and second arms 44A, 44B based on the relative position. This configuration of the one or more controllers <NUM> offers an advantage of the tracking system <NUM> as the one or more controllers <NUM> may determine the position of the bone in the tracking apparatus coordinate system TA with increased accuracy.

The one or more controllers <NUM> may be configured to determine a relationship between the trackable elements <NUM> of the first and second arms 44A, 44B based on the sensed relationship to confirm the state of the tracking apparatus <NUM> in the localizer coordinate system LCLZ. For example, as previously stated, the one or more controllers <NUM> may determine the state of the tracking apparatus <NUM> based on the localizer <NUM> sensing the trackable elements <NUM>. Additionally, the one or more controllers <NUM> may determine the state of the tracking apparatus <NUM> based on determining the relationship between the trackable elements <NUM> of the first and second arms 44A, 44B based on the sensed relationship. The one or more controllers <NUM> may then confirm whether the state of the tracking apparatus <NUM> as determined based on sensing by the localizer <NUM> corresponds to the state of the tracking apparatus <NUM> as determined based on the sensed relationship. This configuration of the one or more controllers <NUM> offers an advantage of the tracking system <NUM> as the one or more controllers <NUM> may determine the state of the tracking apparatus <NUM> with greater robustness.

In some instances, the localizer <NUM> may be unable to sense a suitable number of the trackable elements <NUM> for determining a state of the tracking apparatus <NUM> in the localizer coordinate system LCLZ. In one such instance, the trackable elements <NUM> may be located on either the first arm 44A or the second arm 44B. In another such instance, only the trackable elements <NUM> of one of the first and second arms 44A, 44B may be able to be sensed by the localizer <NUM> (e.g., a barrier exists between the localizer <NUM> and one or more trackable elements <NUM>). In such an instance, the one or more controllers <NUM> may still determine a state of the tracking apparatus <NUM> by determining a relationship between the first and second arms 44A, 44B based on the sensed relationship. For example, in an instance where the first arm 44A includes trackable elements <NUM> and the second arm 44B does not include trackable elements <NUM>, the controller may determine a relationship between the first and second arms 44A, 44B based on the sensor sensing the relationship between the first and second arms 44A, 44B. The controller may then determine a state (e.g., a position) of the second arm 44B based on the localizer <NUM> sensing the trackable elements <NUM> of the first arm 44A and the determined relationship between the first and second arms 44A, 44B. This configuration of the one or more controllers <NUM> offers an advantage of the tracking system <NUM> as the one or more controllers may still determine the state of the tracking apparatus <NUM> in instances where the localizer <NUM> is unable to sense a suitable number of the trackable elements <NUM>.

The one or more controllers <NUM> may determine the relationship between the first and second arms 44A, 44B based on relationship data stored in a memory of the one or more controllers <NUM>. For example, the relationship data may be stored in a lookup table of the memory. The relationship data stored in a lookup table may associate a relationship between the ultrasonic sensor <NUM> of the first and second arms 44A, 44B based on the relationship sensed by the sensor. Additionally, the relationship data may associate a relationship between the trackable elements <NUM> of the first and second arms 44A, 44B based on the relationship sensed by the sensor. As such, the one or more controllers <NUM> may be configured to determine a relationship between the ultrasonic sensors <NUM> of the first and second arms 44A, 44B and a relationship between the trackable elements <NUM> of the first and second arms 44A, 44B based on the sensed relationship.

The tracking apparatus <NUM> may also include a first wing portion 46A and a second wing portion 46B. The first wing portion 46A is shown in <FIG> and delineated from the body <NUM> using a dashed line 70A. The second wing portion 46B is delineated from the body <NUM> using a dashed line 70B. As shown, the first wing portion 46A may extend from a side S of the first and/or second arm 44A, 44B along a direction parallel to the axis AX. As shown in <FIG>, in instances when the tracking apparatus <NUM> is coupled to the patient limb, the first wing portion 46A may extend from the first and/or second arm 44A, 44B in a manner that is substantially parallel or parallel to the bone axis BAX. Referring to <FIG>, the second wing portion 46B may also extend from the first and/or second arm 44A, 44B along the axis AX. As shown in <FIG>, the second wing portion 46B may also extend from the first and/or second arm 44A, 44B in a manner substantially parallel to the bone axis BAX.

While the tracking apparatus <NUM> of <FIG> includes a two first and second wing portions 46A, 46B, in other instances, the tracking apparatus <NUM> may include any suitable number of wing portions. Said differently, the tracking apparatus <NUM> may include a greater or lesser number of wing portions than shown in <FIG>. For example, the tracking apparatus <NUM> may include at least one wing portion extending from the first and/or second arm 44A, 44B. The tracking apparatus <NUM> is configured to operate with wing portion <NUM> so long as the tracking elements <NUM> of the one wing portion <NUM> can be detected by a localizer of the tracking system <NUM>.

The first and second wing portions 46A, 46B may be integrally formed with the first and second arms 44A, 44B. A shown in <FIG>, the wing portion 46A may share the exterior surface EXT and the interior surface INT of the first arm 44A. The wing portion 46B may share the exterior surface EXT and the interior surface INT of the second arm 44B. In other instances, at least one of the first and second wing portions 46A, 46B may be separated from one or more of the first and second arms 44A, 44B and/or coupled to the first and second arms 44A, 44B. Also shown in <FIG>, the first and second wing portions 46A, 46B may share the arcuate configuration of the first and second arms 44A, 44B. In other instances, the first and second wing portions 46A, 46B and the first and second arms 44A, 44B may include differing configurations.

Referring to <FIG>, a size of the first and second wing portions 46A, 46B with respect to the first and second arms 44A, 44B is shown. As shown, the first arm 44A includes an axial length 73A defined along a direction of the axis AX and the second arm 44B includes an axial length 73B defined along a direction of the axis AX. The first and second wing portions 46A, 46B include an axial length 75A, 75B, respectively, defined along the axis AX. As shown, the axial lengths 75A, 75B of the first and second wing portions 46A, 46B are greater than or substantially equal (+/- <NUM> centimeters) to the axial lengths 73A, 73B of the first and second arms 44A, 44B. In some instances, the axial length 75A of the first wing portion 46A may be greater than or less than the axial length 75B of the second wing portion 46B. Furthermore, the axial lengths 73A, 73B, 75A, 75B may vary from the lengths shown in <FIG>.

<FIG> further illustrate a size of the first and second wing portions 46A, 46B with respect to the first and second arms 44A, 44B. As shown, a side S of the first arm 44A includes a side surface length 57A and a side S of the second arm 44B includes a side surface length 57B. The side surface length 57A is defined between the first distal end <NUM> of the body <NUM> and a first proximal end <NUM> of the body <NUM>, the first proximal end <NUM> being proximal to a midpoint M of the body <NUM> located between the first distal end <NUM> and the second distal end <NUM>. The side surface length 57B is defined between the second distal end <NUM> of the body <NUM> and a second proximal end <NUM> of the body <NUM>, the second proximal end <NUM> being proximal to the midpoint M. Additionally, the first wing portion 46A includes first wing portion length 59A between the midpoint M and first distal end <NUM> and the second wing portion 44B includes second wing portion length 59B between the midpoint M and second distal end <NUM>. As shown, the first and second wing portion lengths 59A, 59B are less than the first and second side surface lengths 57A, 57B. In the instance of <FIG>, the first and second side surface lengths 57A, 57B include the first and second wing portion lengths 59A, 59B. In some instances, the first wing portion length 59A may be greater than or less than the second wing portion length 59B. Furthermore, a size of the lengths 57A, 57B, 59A, 59B may vary from the size shown in <FIG>.

In the instance of <FIG>, the first and second arms 44A, 44B are of substantially similar sizes. Similarly, the first and second wing portions 46A, 46B are of substantially similar sizes. However, in other instances, the first and second arms 44A, 44B may be of differing sizes and the first and second wing portions 46A, 46B may be of differing sizes. For example, the side surface length 57A of the first arm 44A may differ from the side surface length 57B of the second arm 44B and the axial length 73A of the first arm 44A may differ from the axial length 73B of the second arm 44B. Similarly, the arcuate length 59A of the first wing portion 46A may differ from the arcuate length 59B of the second wing portion 46B and the axial length 75A of the first wing portion 46A may differ from the axial length 75B of the second wing portion 46B.

In the instance of <FIG>, the first and second wing portions 46A, 46B each include an arcuate configuration. In other instances, the first wing portion 46A, and the second wing portion 46B may include any suitable configuration. Furthermore, the first wing portion 46A, and the second wing portion 46B may include differing configurations.

The first and second wing portions 46A, 46B may extend from the first and/or second arm 44A, 44B at any location along the body <NUM>. Referring to <FIG>, the first wing portion 46A may extend from the first arm 44A at any location between the midpoint M and the first distal end <NUM> and the second wing portion 46B may extend from the second arm 44B at any location between the midpoint M and the second distal end <NUM>. In a more specific instance, the first wing portion 46A may extend from the first and/or second arm 44A, 44B at a location separated from the second wing portion 46B. As shown in <FIG>, the first wing portion 46A may be located halfway between the first distal end <NUM> and the midpoint M and the second wing portion 46B may be located halfway between the midpoint M and the second distal end <NUM> such that the interior surfaces INT of the first and second wing portions 46A, 46B face one another, as shown in <FIG>, for example. In other instances, the first and second wing portions 46A, 46B may be located such that a portion of the interior surfaces INT of the first and second wing portions 46A, 46B face one another or such that the interior surfaces INT of the first and second wing portions 46A, 46B do not face one another. In still other instances, both of the first and second wing portions 46A, 46B may extend from the first and/or second arm 44A, 44B at a location between the first distal end <NUM> and the midpoint M and/or between the midpoint M and the second distal end <NUM>.

Additionally, the first and second wing portions 46A, 46B may be connected to one another. For example, in one instance, the first and second wing portions 46A, 46B may each include a portion perpendicular to the axis AX that are connected to one another such that the first and second wing portions 46A, 46B are connected to one another. In another instance, the tracking apparatus <NUM> may include a second body <NUM> (not shown) and the first and second wing portions 46A, 46B may be connected to one another via the second body <NUM>. Said differently, a side S of the second body <NUM> may be connected to a side S of the first body <NUM> by the first and second wing portions 46A, 46B.

The location of the first and second wing portions 46A, 46B relative to one another offers an advantage of the tracking system <NUM>. As previously stated, the first wing portion 46A extends from the first and/or second arm 44A, 44B at a location separated from the second wing portion 46B. In this way, the tracking apparatus <NUM> includes a window <NUM> between the first wing portion 46A and the second wing portion 46B, as shown in <FIG> and <FIG>. As such, a surgeon is able to view the surgical site and the patient limb without obstruction during a surgical procedure while the tracking apparatus <NUM> is coupled to the patient <NUM>. Advantageously, in instances where the tracking system <NUM> is a part of the robotic surgical system <NUM>, the manipulator <NUM> may be configured to carry out a surgical procedure on the patient limb without obstruction while the tracking apparatus <NUM> is coupled to the patient <NUM>.

The tracking apparatus <NUM> includes one or more ultrasonic sensors <NUM>. As shown in <FIG>, the ultrasonic sensors <NUM> may be coupled to both the interior surface INT of the first and second arms 44A, 44B and the interior surface INT of the first and second wing portions 46A, 46B. The ultrasonic sensors <NUM> are configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone of the patient <NUM>. The ultrasonic sensors <NUM> are located on the interior surface INT such that ultrasonic waves transmitted by the ultrasonic sensors <NUM> are directed towards the patient limb L.

The ultrasonic sensors <NUM> coupled to the first and second wing portions 46A, 46B offer an advantage of the tracking system <NUM>. As previously stated, the first and second wing portions 46A, 46B extend from the first and/or second arm 44A, 44B in a manner substantially parallel (+/- <NUM> degrees) to the bone axis BAX. As such, the first and second wing portions 46A, 46B allow a greater number of ultrasonic sensors <NUM> to transmit ultrasonic waves <NUM> to and receive ultrasonic waves <NUM> from the bone of the patient <NUM>, in comparison to a tracking apparatus <NUM> without the first and second wing portions 46A, 46B. Additionally, the first and second wing portions 46A, 46B allow ultrasonic waves <NUM> to be transmitted to and received from a greater amount of the bone of the patient <NUM>, enabling greater ultrasonic sensing coverage along the length of the bone. As such, the one or more controllers <NUM> coupled to the ultrasonic sensors <NUM> may determine a shape of a greater amount of the bone and a position of a greater amount of the bone.

The tracking apparatus <NUM> may include any suitable number of ultrasonic sensors <NUM>. For illustrative purposes, four ultrasonic sensors <NUM> are shown in the tracking apparatus <NUM> of <FIG>. In other instances, the tracking apparatus <NUM> may include one, two, five, ten, or fifty ultrasonic sensors <NUM>. The tracking apparatus <NUM> may include a number of ultrasonic sensors <NUM> suitable for adequate ultrasonic sensing of the bone of the patient <NUM>.

The ultrasonic sensors <NUM> may be arranged in any suitable fashion. For example, as shown in <FIG>, the ultrasonic sensors <NUM> may be arranged in two one-dimensional arrays. As shown in <FIG>, the ultrasonic sensors <NUM> may be arranged in a two-dimensional array. As shown in <FIG>, the ultrasonic sensors <NUM> may be arranged in an offset two-dimensional array. The ultrasonic sensors <NUM> may also be arranged in a predetermined arrangement, such as a checkerboard arrangement. The ultrasonic sensors <NUM> may also be arranged in a random arrangement.

The ultrasonic sensors <NUM> are configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone and patient soft tissue adjacent to the bone. Referring to <FIG>, the ultrasonic sensors <NUM>, which are located on the interior surface INT of the first and second arms 44A, 44B are shown transmitting and receiving ultrasonic waves <NUM> to and from the patient limb, including the bone. As such, the one or more controllers <NUM> coupled to the ultrasonic sensors <NUM> may be configured to determine a position of the bone and/or a shape of the bone based on the ultrasonic waves <NUM> received by the ultrasonic sensors <NUM> in the tracking apparatus coordinate system TA. Additionally, or alternatively, the one or more controller <NUM> coupled to the ultrasonic sensors <NUM> may be configured to identify soft tissue adjacent to the bone to monitor physiological activity of the soft tissue. For instance, the one or more controllers <NUM> may track motion of the blood vessels of the soft tissue, identify debris entering the blood stream, and/or monitor motion or strain of ligaments.

A model of the bone or a surface of the bone is generated by the one or more controller <NUM> from the ultrasonic sensor <NUM> information. The one or more controllers <NUM> can use any suitable image processing and/or segmentation technique to generate the model. In one instance, the model can be formed using machine learning algorithms. In one example, the surface of the bone can be detected by segmenting the ultrasonic imaging data using a convolutional neural network, as described in <CIT>, entitled "Ultrasound Bone Registration with Learning-Based Segmentation and Sound Speed Calibration".

The ultrasonic sensors <NUM> may be configured to transmit the ultrasonic waves <NUM> using beam forming and beam steering techniques. In this way, the ultrasonic sensor <NUM> may transmit the ultrasonic waves <NUM> in a manner that maximizes information response. For example, the ultrasonic sensors <NUM> may be configured to steer and form a beam to produce an ultrasonic wave front that conforms to the surface of the bone of the patient <NUM>. For example, <FIG> illustrates an instance where the ultrasonic sensors <NUM> transmit ultrasonic waves <NUM> with wave fronts WF1-WF6. As shown, the wave fronts WF1-WF6 conform to various surfaces along the femur F. In this way, the ultrasonic sensors <NUM> maximize the intensity of the ultrasonic waves <NUM> reflected off the femur F, enabling the one or more controllers <NUM> coupled to the ultrasonic sensors <NUM> to more accurately determine a shape of the bone and a position of the bone. The ultrasonic sensors <NUM> can be spatially calibrated to reflect a variation in propagation speed of the ultrasound waves through the bone by comparing steered frames of the ultrasound imaging. The ultrasonic sensors <NUM> can also be temporally calibrated by creating a point cloud of the surface and calculating a set of projection values of the point cloud to a vector. These calibration techniques are described in <CIT>, entitled "Ultrasound Bone Registration with Learning-Based Segmentation and Sound Speed Calibration".

As shown throughout the Figures, the tracking apparatus <NUM> includes trackable elements <NUM>. As shown in <FIG>, for example, the trackable elements <NUM> are coupled to, fixed, or otherwise or located on, the exterior surface EXT of the body <NUM> and the exterior surface EXT of the first and second wing portions 46A, 46B. The navigation localizer <NUM> of the navigation system <NUM> is configured to track the tracking apparatus <NUM> by tracking the trackable elements <NUM>. The one or more controller <NUM> may then determine a position of the tracking apparatus <NUM> and a position of the bone of the patient <NUM> in the localizer coordinate system LCLZ based on the navigation localizer <NUM> tracking the trackable elements <NUM>.

The trackable elements <NUM> coupled to the first and second wing portions 46A, 46B offer an advantage of the tracking system <NUM>. As previously stated, the first and second wing portions 46A, 46B extend from the first and/or second arm 44A, 44B along the bone axis BAX. As such, the first and second wing portions 46A, 46B allow a greater number of trackable elements <NUM> to be coupled to the tracking apparatus <NUM> and tracked by the localizer <NUM>, in comparison to a tracking apparatus <NUM> without the first and second wing portions 46A, 46B. Since these trackable elements <NUM> are on/in the first and second wing portions 46A, 46B, greater tracking accuracy is achieved since the trackable elements <NUM> cover a greater length of the bone along the bone axis BAX. As such, the one or more controllers <NUM> coupled to the navigation localizer <NUM> may determine the position of the tracking apparatus <NUM> in the localizer coordinate system LCLZ with increased accuracy.

The tracking apparatus <NUM> may include any suitable number of trackable elements <NUM>. In the instance of <FIG>, six trackable elements <NUM> are shown on the second arm 44B and one trackable element <NUM> is shown on the second wing portion 46B. In other instances, the tracking apparatus <NUM> may include a total of one, two, five, ten, or fifty trackable elements <NUM> arranged on the body <NUM> and the first and second wing portions 46A, 46B.

The trackable elements <NUM> may be arranged in any suitable manner. In the instance of <FIG>, the six trackable elements <NUM> of the second arm 44B are arrange in a <NUM>-by-<NUM> array. In other instances, the trackable elements <NUM> may be arranged in any suitable m-by-n array, with "m" and "n" being greater than or equal to one. For example, in <FIG>, the trackable elements <NUM> are arranged in a <NUM>-by-<NUM> array, a <NUM>-by-<NUM> array, and a <NUM>-<NUM> array along the first arm 44A and the first wing portion 46A. The trackable elements <NUM> may also be arranged in any predetermined fashion to provide adequate tracking of the tracking apparatus <NUM> by the localizer <NUM>. For example, in <FIG>, the trackable elements <NUM> are arranged along a perimeter of the first arm 44A and the first wing portion 46A.

The trackable elements <NUM> may be located on exterior surface EXT of the body <NUM> and the exterior surface EXT of the first and second wing portions 46A, 46B in any suitable manner. For example, the trackable elements <NUM> may be rigidly fixed to the exterior surface EXT, located atop the exterior surface EXT, embedded below the exterior surface EXT, or the like. Alternatively, the trackable elements <NUM> can be located underneath the exterior surface EXT such that the trackable elements <NUM> are enclosed by the housing of the body <NUM>. Additionally, the trackable elements <NUM> may be located on any other suitable component of the tracking apparatus <NUM>. For example, in <FIG>, the trackable elements are located on a side S of the first arm 44A and on the hinge <NUM> of the tracking apparatus <NUM>.

The trackable elements <NUM> may be any suitable type of trackable element. For example, the trackable elements <NUM> may be any optical trackable element configured to be sensed by an optical localizer, such as the navigation localizer <NUM>. As one example, any one or more of the trackable elements <NUM> may include active markers. The active markers may include light emitting diodes (LEDs). Alternatively, or additionally, the trackable elements <NUM> may have passive markers, such as reflectors, which reflect light emitted from the navigation localizer <NUM>. Furthermore, other suitable markers not specifically described herein may be utilized.

In one example, the trackable elements <NUM> may be radio frequency (RF) sensors or emitters which can be detected by an RF localizer <NUM>. In such an example, the navigation system <NUM> and/or localizer <NUM> may be RF-based. For example, the navigation system <NUM> may comprise an RF transceiver coupled to the navigation controller <NUM>. The tracking apparatus <NUM>, the manipulator <NUM>, the tool <NUM>, and/or the patient <NUM> may comprise RF emitters or transponders attached thereto. The RF emitters or transponders may be passive or actively energized. The RF transceiver may transmit an RF tracking signal and generate state signals to the navigation controller <NUM> based on RF signals received from the RF emitters. The navigation controller <NUM> may analyze the received RF signals to associate relative states thereto. The RF signals may be of any suitable frequency. The RF transceiver may be positioned at any suitable location to sense the objects using RF signals effectively. Furthermore, the RF emitters or transponders may have any suitable structural configuration that may be much different than the trackable elements <NUM> of the tracking apparatus <NUM>.

In another example, the trackable elements <NUM> may be electromagnetic (EM) sensors or emitters which can be detected by an EM localizer <NUM>. In such an example, the navigation system <NUM> and/or localizer <NUM> may be electromagnetically based. For example, the navigation system <NUM> may comprise an EM transceiver coupled to the navigation controller <NUM>. The tracking apparatus <NUM>, the manipulator <NUM>, the tool <NUM>, and/or the patient <NUM> may comprise EM components attached thereto, such as any suitable magnetic tracker, electro-magnetic tracker, inductive tracker, or the like. The trackers may be passive or actively energized. The EM transceiver may generate an EM field and generate state signals to the navigation controller <NUM> based upon EM signals received from the trackers. The navigation controller <NUM> may analyze the received EM signals to associate relative states thereto. Again, such examples of the navigation system may have structural configurations that are different than the navigation system <NUM> configuration shown in <FIG>.

In yet another example, the trackable elements <NUM> may include patterns or features (e.g., barcodes, QR codes, perturbations, surface markings, etc.) on the exterior surface EXT which can be detected by a machine-vision camera localizer <NUM>. In such an example, the navigation system <NUM> may be a machine-vision based. For example, the machine-vision camera localizer <NUM> may include a machine-vision camera configured to detect the patterns or features of the trackable elements <NUM>. The patterns or features may be passive or actively energized. The machine-vision camera may generate state signals to the navigation controller <NUM> based upon detecting the patterns or features of the trackable elements <NUM>. The navigation controller <NUM> may analyze the patterns or features to associate relative states thereto. Again, such examples of the navigation system <NUM> may have structural configurations that are different than the navigation system <NUM> configuration shown in <FIG>.

The tracking apparatus <NUM> may include a tracking apparatus controller <NUM>, or other type of control unit. Referring to <FIG>, the tracking apparatus controller <NUM> may be a controller of the one or more controllers <NUM>. The tracking apparatus controller <NUM> may comprise one or more computers, or any other suitable form of controller configured to determine a shape of a bone of the patient <NUM> and/or a position of a bone of the patient <NUM>. The tracking apparatus controller <NUM> may have a central processing unit CPU and/or other processors, memory MEM, and storage (not shown). The tracking apparatus controller <NUM> is loaded with software as described below. The processors could include one or more processors to control operation of the tracking apparatus <NUM>, such as an operation of the ultrasonic sensors <NUM> and/or the trackable elements <NUM>. The processors can be any type of microprocessor, multi-processor, and/or multi-core processing system. The tracking apparatus controller <NUM> may additionally, or alternatively, comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein. The term processor is not intended to limit any implementation to a single processor. The tracking apparatus <NUM> may also comprise a user interface UI with one or more displays <NUM> (shown in <FIG>) and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.).

The tracking system <NUM> may include more than one tracking apparatus <NUM>. For example, referring to <FIG>, the tracking system <NUM> includes a first tracking apparatus <NUM>', and a second tracking apparatus <NUM>". The first tracking apparatus <NUM>' is configured to track the femur F of the patient <NUM> such that the body <NUM> of the first tracking apparatus <NUM>' is configured to couple to the femur F of the patient <NUM>. The second tracking apparatus <NUM>" is configured to track the tibia T of the patient <NUM> such that the body <NUM> of the second tracking apparatus <NUM>'' is configured to couple to the tibia T of the patient <NUM>. In this way, the tracking system <NUM> may track both the femur F and the tibia T of the patient <NUM>.

Referring to <FIG>, the tracking system <NUM> includes one or more controllers <NUM>. In the instance of <FIG> and <FIG>, the one or more controllers <NUM> includes the tracking apparatus controller <NUM> of the tracking apparatus <NUM> and the navigation controller <NUM> of the navigation system <NUM>. Additionally, the one or more controllers <NUM> of the tracking system <NUM> may include the manipulator controller <NUM> and/or the tool controller <NUM>. The one or more controllers <NUM> may be configured to communicate via a wired bus or communication network, as shown in <FIG>, via wireless communication, or otherwise.

The one or more controllers <NUM> further includes one or more software programs and software modules shown in <FIG>. The software modules may be part of the program or programs that operate on the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, the tool controller <NUM>, or any combination thereof, to process data to assist with tracking a bone of a patient limb with the tracking system <NUM>. The software programs and/or modules include computer readable instructions stored in non-transitory memory MEM on the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, the tool controller <NUM>, or any combination thereof, to be executed by one or more processors MEM of the controllers <NUM>, <NUM>, <NUM>, <NUM>. The memory MEM may be any suitable configuration of memory, such as RAM, non-volatile memory, etc., and may be implemented locally or from a remote database. Additionally, software modules for prompting and/or communicating with the user may form part of the program or programs and may include instructions stored in memory MEM on the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, the tool controller <NUM>, or any combination thereof. The user may interact with any of the input devices of the navigation user interface UI or other user interface UI to communicate with the software modules. The user interface software may run on a separate device from the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, the tool controller <NUM>, or any combination thereof.

The one or more controllers <NUM> may comprise any suitable configuration of input, output, and processing devices suitable for carrying out the functions and methods described herein. The one or more controllers <NUM> may comprise one or more of the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, and the tool controller <NUM>. Additionally, these controllers <NUM>, <NUM>, <NUM>, <NUM> may communicate via a wired bus or communication network, as shown in <FIG>, via wireless communication, or otherwise. For example, the tracking apparatus controller <NUM> may receive ultrasound data from the ultrasonic sensors <NUM> and transmit the ultrasound data to the navigation controller <NUM> via wireless communication such that the navigation controller <NUM> may process the ultrasound data and determine the position of the bone of the patient <NUM>. In another example, the navigation controller <NUM> may track the trackable elements <NUM> and transmit tracking data to the tracking apparatus controller <NUM> via wireless communication such that the tracking apparatus controller <NUM> may process the tracking data and determine the position of the bone of the patient <NUM>. As used herein, the term "one or more controllers <NUM>" may refer to any one or all of the tracking apparatus controller <NUM>, the navigation controller <NUM>, the manipulator controller <NUM>, the tool controller <NUM>, or any combination thereof. The one or more controllers <NUM> may comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, sensors, displays, user interfaces, indicators, and/or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein.

The one or more controllers <NUM> of the tracking system <NUM> are configured to perform steps <NUM>-<NUM> shown in <FIG> and <FIG>. Generally, steps <NUM>-<NUM> describe a configuration of the tracking system <NUM> to transform a state of a bone of a patient <NUM> from the tracking apparatus coordinate system TA to the localizer coordinate system LCLZ.

As shown in <FIG>, the one or more controllers <NUM> are coupled to the ultrasonic sensors <NUM> of the tracking apparatus <NUM> and to the localizer <NUM>. Specifically, in the instance of <FIG>, the one or more controllers <NUM> include the tracking apparatus controller <NUM>, which is coupled to the ultrasonic sensors <NUM>, and the navigation controller <NUM>, which is coupled to the localizer <NUM>.

Referring to <FIG>, during step <NUM>, the ultrasonic sensors <NUM> are configured to transmit ultrasonic waves <NUM> to and receive ultrasonic waves <NUM> from the bone. As shown in <FIG>, the ultrasonic sensors <NUM> are configured to transmit ultrasonic waves <NUM> to the femur F and receive ultrasonic waves <NUM> reflected off the femur F during step <NUM>.

Referring to <FIG>, during step <NUM>, the one or more controllers <NUM> are configured to determine a state of the bone relative to one or more of the trackable elements <NUM> in the tracking apparatus coordinate system TA based on the ultrasonic waves <NUM> received by the ultrasonic sensor <NUM>. This is performed using a first transform T1 from the bone to coordinate system of the tracking apparatus <NUM>. Specifically, the location of the ultrasonic sensors <NUM> on the tracking apparatus <NUM> are defined according to a predetermined configuration, which can be stored in memory of the controller(s) <NUM>. Moreover, the location of the trackable elements <NUM> on the tracking apparatus <NUM> are defined according to a predetermined configuration, which can be stored in memory of the controller(s) <NUM>. Accordingly, the location of each ultrasonic sensor <NUM> can be known relative to each trackable element <NUM> according to this fixed data. In the instance of <FIG>, the tracking apparatus controller <NUM> determines, during step <NUM>, the position of the bone (e.g., femur F) relative to the trackable elements <NUM> in the tracking apparatus coordinate system TA based on the ultrasonic waves <NUM> received by the ultrasonic sensors <NUM>. In instances where the one or more controllers <NUM> do not include the tracking apparatus controller <NUM>, any other controller <NUM> may perform step <NUM>.

Referring to <FIG>, during step <NUM>, the localizer <NUM> is configured to sense one or more of the trackable elements <NUM>. During step <NUM>, the one or more controllers <NUM> are configured to determine a state of one or more of the trackable elements <NUM> in the localizer coordinate system LCLZ based on the localizer <NUM> tracking the one or more trackable elements <NUM> during step <NUM>. This is performed using a second transform T2, shown in <FIG>, from the tracking elements <NUM> of the tracking apparatus <NUM> to the localizer <NUM>. In the instance of <FIG>, the navigation controller <NUM> determines, during step <NUM>, the position of the trackable elements <NUM> in the localizer coordinate system LCLZ based on the localizer <NUM> tracking the trackable elements <NUM>. In instances where the one or more controllers <NUM> do not include the navigation controller <NUM>, any other controller <NUM> may perform step <NUM>.

Referring to <FIG>, during step <NUM>, the one or more controllers <NUM> are configured to determine a state of the bone in the localizer coordinate system LCLZ. This is performed by combining the first transform T1 with the second transform T2 to transform the position of the femur F from the tracking apparatus coordinate system TA to the localizer coordinate system LCLZ. This combination of transforms T1, T2 is illustrated as "T1 + T2" in <FIG>. During step <NUM>, the one or more controllers <NUM> combines the position of the femur F in the tracking apparatus coordinate system TA (an output of the first transform T1), as determined by the tracking apparatus controller <NUM> in step <NUM>, and the position of the trackable elements <NUM> in the localizer coordinate system LCLZ (an output of the second transform T2), as determined by the navigation controller <NUM> in step <NUM>, to determine the position of the femur F in the localizer coordinate system LCLZ. In some instances, the tracking apparatus controller <NUM> may communicate with the navigation controller <NUM> and one of the tracking apparatus controller <NUM> and the navigation controller CPU performs step <NUM>. In instances where the one or more controllers <NUM> do not include the navigation controller <NUM> and/or the tracking apparatus controller <NUM>, any other controller <NUM> may perform step <NUM>.

In instances where the tracking system <NUM> is a part of the robotic surgical system <NUM>, the controller(s) <NUM> may be configured to further transform the position of the bone of the patient <NUM> from the localizer coordinate system LCLZ to the manipulator coordinate system MNPL, shown in <FIG>. The robotic surgical system <NUM> may then control the manipulator <NUM> based on the position of the bone in the manipulator coordinate system MNPL. For example, the manipulator controller <NUM> and/or the tool controller <NUM> may control the robotic surgical system <NUM> during the manual mode or the semi-autonomous mode based on the position of the bone in the manipulator coordinate system MNPL. In some instances, the tracking apparatus controller <NUM> and/or the navigation controller <NUM> may perform the transformation of the position of the bone from the localizer coordinate system LCLZ to the manipulator coordinate system MNPL. The tracking apparatus controller <NUM> and/or the navigation controller <NUM> may then communicate the position of the bone in the manipulator coordinate system MNPL to the manipulator controller <NUM>. In some instances, the tracking apparatus controller <NUM> and/or the navigation controller <NUM> may be configured to communicate the position of the bone in the localizer coordinate system LCLZ to the manipulator controller <NUM>, which transforms to determine the position of the bone from the localizer coordinate system LCLZ to the manipulator coordinate system MNPL.

In some instances, the one or more controllers <NUM> may receive and store a shape of the bone of the patient <NUM> prior to determining a position of the bone. For instance, the one or more controllers <NUM> may store a shape of a femur F in a non-transitory memory, such as memory MEM. The shape of the femur F may be specific to the patient <NUM> to undergo the surgical procedure. The shape of the femur F may be derived by utilizing an algorithm to compare the ultrasonic imaging data to a statistical model or atlas of bone data from one or more populations. The ultrasonic sensors <NUM> may then transmit ultrasonic waves <NUM> using beam forming and beam steering techniques based on the stored shape of the femur F to maximize information response. For example, the ultrasonic sensors <NUM> may be configured to steer and form a beam to produce an ultrasonic wave front that conforms to the surface of the femur F the patient <NUM> based on the stored shape of the femur F. In this way, the ultrasonic sensors <NUM> maximize the intensity of the ultrasonic waves <NUM> reflected off the bone, allowing for a controller <NUM> coupled to the ultrasonic sensors <NUM> to more accurately determine a shape of the bone and a position of the bone.

In some instances, the tracking apparatus <NUM> may include a cushion <NUM>. As shown in <FIG>, the cushion may be coupled to the interior surface INT of the body <NUM>, and optionally, the interior surface INT of the first and second wing portions 46A, 46B. When the body <NUM> is coupled to the patient <NUM>, the cushion <NUM> contacts the skin of the patient limb. The cushion <NUM> is configured to maintain contact integrity between the patient limb and the interior surface INT, which allows for improved transmission and reception of the ultrasonic waves <NUM> and reduced interference. Advantageously, the cushion <NUM> is configured to maintain contact integrity between the interior surface INT and patient limbs of a variety of shapes and sizes.

The cushion <NUM> may include any suitable shape for maintaining contact integrity between the patient limb and the interior surface INT. For example, the cushion may include an arcuate planar surface as shown in <FIG>. As another example, the cushion may include any other contoured surface. The cushion <NUM> may include any suitable material for maintaining contact integrity between the patient limb and the interior surface INT. For example, the cushion <NUM> may include a gel material, a fibrous material, a fluid material, and/or a polyurethane material, or the like.

As shown in <FIG>, the tracking apparatus <NUM> may include a fluid control unit <NUM> coupled to the cushion <NUM>. The fluid control unit <NUM> may be configured to provide fluid, such as air, water, and/or ultrasonic gel, to the cushion <NUM>. The fluid control unit <NUM> may provide or remove fluid to the cushion <NUM> such that the cushion <NUM> expands or contracts, to enable the cushion <NUM> to maintain contact integrity between the interior surface INT and a patient limb and to provide additional comfort for the patient. Additionally, during some surgical procedures, it may be advantageous for the cushion <NUM> to act as a tourniquet. During such surgical procedures, the fluid control unit <NUM> may provide fluid to the cushion <NUM> such that the cushion <NUM> expands to apply sufficient pressure to the patient limb for restricting blood flow.

The fluid control unit <NUM> may be coupled to, or a part of the one or more controllers <NUM> either locally coupled to or remotely located from the tracking apparatus <NUM>. In this way, the one or more controllers <NUM> may control the amount of fluid provided to the cushion <NUM> by the fluid control unit <NUM>, the speed by which fluid is provided to the cushion <NUM> by the fluid control unit <NUM>, an amount of fluid drained from the cushion <NUM> by the fluid control unit <NUM>, and/or a type of fluid provided to the cushion by the fluid control unit <NUM>. In the instance of <FIG>, the tracking apparatus controller <NUM> of the one or more controllers <NUM> is coupled to the fluid control unit <NUM> and controls an amount of ultrasonic gel provided to the cushion <NUM> by the fluid control unit <NUM>. Additionally, the fluid control unit <NUM> may include a user interface UI (not shown) with one or more displays <NUM> (not shown) and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.).

In some instances, the one or more controllers <NUM> of the tracking apparatus <NUM> may be configured to determine an integrity of contact between the patient limb and the interior surface INT of the body <NUM> and the interior surface INT of the first and second wing portions 46A, 46B. In the instance of <FIG>, the tracking apparatus controller <NUM> determines the integrity of contact.

The one or more controllers <NUM> may determine the integrity of contact between the patient limb and the interior surface INT of the body <NUM> and the interior surface INT of the first and second wing portions 46A, 46B using a variety of techniques. In one instance, the tracking apparatus controller <NUM> may determine the integrity of contact based on the ultrasonic waves <NUM> received by the ultrasonic sensors <NUM>. In another instance, the tracking apparatus <NUM> may include a light emitter <NUM> configured to emit light to the patient limb. In such an instance, the tracking apparatus <NUM> may also include an optical sensor <NUM> configured to sense light reflected from the patient limb. The tracking apparatus controller <NUM> may be coupled to the optical sensor <NUM> and configured to determine the integrity of contact based on the reflected light sensed by the optical sensor <NUM>. For example, the tracking apparatus controller <NUM> may determine the integrity of contact based on an intensity, a propagation-direction, a frequency, or a wavelength spectrum and polarization of the reflected light. Integrity of contact alternatively can be determined using pressure or distance sensors, or the like, the readings from which can be compared by the one or more controllers <NUM> to a threshold pressure or distance.

The tracking apparatus <NUM> may be configured to respond in a variety of ways to the integrity of contact determined by the one or more controllers <NUM>. For example, the tracking apparatus <NUM> may be configured to adjust the ultrasonic sensors <NUM> in response to determining the integrity of contact. In one such instance, the tracking apparatus controller <NUM> may be configured to prevent an ultrasonic sensor <NUM> from transmitting and receiving ultrasonic waves <NUM> based on poor integrity of contact. In another instance, the tracking apparatus controller <NUM> may be configured to control the ultrasonic sensors <NUM> to steer and form a beam to produce an ultrasonic wave front based on the integrity of contact. As another example, the tracking apparatus controller <NUM> may be configured to control the fluid control unit <NUM> based on the integrity of contact. In one such instance, the tracking apparatus <NUM> may be configured to control an amount of fluid provided to the cushion <NUM> to achieve a suitable integrity of contact. As yet another example, the tracking apparatus <NUM> may be configured to notify a surgeon of the integrity of contact. In one such instance, the tracking apparatus <NUM> may be configured to notify a surgeon that the integrity of contact is acceptable or unacceptable using a user interface UI of the tracking system <NUM>.

The tracking apparatus <NUM> may also be motorized to move the first and/or second arms 44A, 44B between the open and closed positions <NUM>, <NUM> and any position therebetween. This may be done to simplify installation of the tracking apparatus <NUM> to the patient limb L without user assistance. The tracking apparatus <NUM> may comprise a motor at any one or more of the hinges <NUM>. The one or more controllers <NUM> may be configured to control the motor based on the integrity of contact as determined by any of the aforementioned sensors. The one or more controllers <NUM> may initialize motor movement in response to any automated, semi-automated, or manually initiated control signal. The one or more controllers <NUM> may control the motor to move the first and/or second arms 44A, 44B based on the acceptability or unacceptability of the integrity of contact as determined by any of the aforementioned sensors.

The one or more controller <NUM> may also be configured to control the tracking apparatus <NUM> and/or any components of the robotic surgical system <NUM> based on monitoring physiological activity of soft tissue. As previously stated, the one or more controllers <NUM> may be configured to identify soft tissue adjacent to the bone to monitor physiological activity of the soft tissue. As an example, the one or more controllers <NUM> may be configured to control the fluid control unit <NUM> such that the cushion <NUM> applies sufficient pressure and restricts blood flow based on the one or more controllers <NUM> identifying that debris has entered the blood stream. As another example, the one or more controllers <NUM> may control the tool <NUM> (e.g., stopping or slowing the tool <NUM>) based on the one or more controllers <NUM> identifying that debris has entered the blood stream. The one or more controllers <NUM> may also control the display <NUM> of a user interface UI to display a warning based on the one or more controllers <NUM> identifying that debris has entered the blood stream.

The tracking apparatus <NUM> may also be used for assessing a joint of the patient. This may include joint balancing, joint laxity, joint range of motion, or any other assessment involving kinematics of a joint. The tracking apparatus <NUM> may do so by tracking the bone, soft tissue, and/or physiological activity of the patient limb L. For instance, ligaments could be identified, and motion or strain of the ligaments could be monitored as part of the joint balancing. In one example, the femur F could be rigidly secured, e.g., to the table or to a joint positioner, while the tracking apparatus <NUM> is attached to the tibia T. A user could then manipulate the tibia T to assess the joint. Data from the tracking apparatus <NUM> could be provided to a software program, e.g., a software program implemented by the navigation system <NUM>. The software program could display real-time data involving joint balancing, joint laxity, joint range of motion, or any other assessment involving kinematics of a joint to the user. Alternatively, a tracking apparatus <NUM> may be placed on the femur F and the tibia T to determine relative motion therebetween for any of the above-described purposes.

The above-described tracking apparatus <NUM> provides several advantages over conventional means of tracking. The tracking apparatus <NUM> avoids the need for invasively implanting trackers in the bone of the patient or potential trauma to the patient because the tracking apparatus <NUM> externally wraps about the skin of the patient limb. The tracking apparatus <NUM> can be an intelligent component with controllers, calibration, and registration, which avoids the need for additional surgical steps, such as planning the location of the tracker, performing implantation, and performing manual bone registration using a pointer. The tracking apparatus <NUM> avoids bulky tracking arrays extending out of the surgical site from the bone. The tracking apparatus <NUM> provides increased visibility of the surgical site and avoids interfere with the surgeon or surgical components of tools in the workspace. For example, the wing portion being to the side of the patient limb provides a "window" of visibility at the top of the joint where surgery is performed. By having a large surface area contact with the patient limb, as well as means for locking or keeping the tracking apparatus <NUM> in place, the tracking apparatus <NUM> is less susceptible to becoming dislodged or inadvertently moved, which in turn can compromise tracking accuracy. The ultrasound and tracking elements in/on the wing portion of the tracking apparatus <NUM> provides a greater tracking length along the bone thereby increasing accuracy. In view of the above description, those having skill in the art can appreciate other advantages not specifically described herein.

Claim 1:
A tracking apparatus (<NUM>) for tracking a bone of a patient limb, the tracking apparatus (<NUM>) comprising:
a body (<NUM>) configured to couple to the patient limb and comprising first and second arms (44A, 44B) each including an exterior surface (EXT), an opposing interior surface (INT), and opposing sides (S) connecting the exterior and interior surfaces (EXT, INT);
a wing portion (<NUM>) integrally formed with the body (<NUM>) and extending from at least one of the opposing sides (S) of at least one of the first and second arms (44A, 44B) wherein the interior surface (INT) is integrally shared among the at least one first and second arm (44A, 44B) and the wing portion (<NUM>);
one or more ultrasonic sensors (<NUM>) coupled to the interior surface (INT) of the body (<NUM>) and the interior surface (INT) of the wing portion (<NUM>) and being configured to transmit ultrasonic waves to and receive ultrasonic waves from the bone; and
one or more trackable elements (<NUM>) coupled to the body (<NUM>) and the wing portion (<NUM>).