Joint Extension System

Abstract

A joint extension device and its method of use are disclosed. The joint extension device includes a flexion arm and a load arm having an extension tip and a load tip, respectively, configured for insertion into a joint. The flexion arm is coupled to the load arm so that, during use, the load arm can be adjusted to separate the extension tip and the load tip to apply an extension force to the joint. A strain gauge measures strain applied to the flexion arm based on the applied extension force. The measured strain is used to determine the amount of force applied to the joint. The force data is used during surgical planning to determine the amount of joint laxity when a specific load is applied to the joint.

Description

[Technical Field]

[0001] Related Applications This application claims priority to U.S. Provisional Patent Application No. 62 / 972,930, filed February 11, 2020, entitled "A JOINT TENSIONING DEVICE AND METHODS OF USE THEREOF," which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to joint extension devices and methods of use, and more particularly to devices and methods for applying known forces to a joint for the collection of extension / relaxation data of soft tissue associated with the joint. [Background technology]

[0003] Robotic-assisted total knee arthroplasty offers surgeons the advantage of planning the procedure and visualizing the expected outcome of the procedure before making any bone resections. To achieve this virtual planning, two primary inputs to the system are required: (1) the bony anatomy of the femur and tibia, and (2) the stretch / laxity of the soft tissues within the joint. The bony anatomy can be relatively easily and reliably defined. However, the nature of the surrounding soft tissues is much less objective. This lack of objectivity in one of the primary system inputs has the potential to lead to inconsistent outputs and, ultimately, inconsistent results. Standardizing the collection of the stretch / laxity of the soft tissues within the joint would help resolve this issue.

[0004] During manual total knee arthroplasty, surgeons have limited tools to assess soft tissue laxity before performing resections. While tools and tests such as spacers can be used to attempt to determine the resulting ligament laxity, bone resections are usually already performed. When the knee is out of balance, the likely cause is ligament release. Some systems offer devices designed to stretch the ligaments, but each of these systems requires the completion of tibial resections before stretching.

[0005] During robotic-assisted total knee arthroplasty, the user is given a visual cue to apply varus or valgus stress to the knee throughout the range of motion to activate the system and quantify ligament laxity. This stress is typically applied manually or via a z-retractor between the medial and lateral tibiofemoral articular surfaces. A challenge in quantifying ligament laxity in robotic-assisted total knee arthroplasty is standardizing the amount of varus / valgus force applied to the knee during this step. Summary of the Invention

[0006] This Summary is provided to comply with 37 CFR § 1.73, requiring that the Summary of the Invention briefly indicate the nature and gist of the invention. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the disclosure.

[0007] A joint extension system is provided. The joint extension system includes a joint extension device including a first arm having a first tip having a first geometric shape configured to align with a first location within the joint. A second arm having a second tip having a second geometric shape configured to align with a second location within the joint. The second arm is coupled to the first arm such that the first tip and the second tip are joined together along an axis in a closed position, and during use, the first tip and the second tip are manually separated from each other to an open position to apply an extension force to the joint. A sensor device is located within the first arm and positioned to measure a strain applied to the first tip based on the extension force applied to the joint. The joint extension system further includes a computing device coupled to the sensor device. The computing device is configured to receive the measured strain applied to the first tip from the sensor device. The extension force applied to the joint is determined by manual separation of the first and second extremities based on the received measured strain applied to the first extremity.

[0008] In some embodiments, the first tip and the second tip are configured to contact the knee joint.

[0009] In some embodiments, the first tip is configured to contact the femur and the second tip is configured to contact the tibia to apply a distraction force to the knee joint.

[0010] In some embodiments, the first arm is configured as a PCL retractor.

[0011] In some embodiments, the sensor device comprises one or more strain gauges.

[0012] In some embodiments, one or more strain gauges are embedded within the glass coating.

[0013] In some embodiments, the sensor device comprises a plurality of strain gauges.

[0014] In some embodiments, the first arm is connected to the second arm at a pivot to allow manual separation between the first and second arms to apply an extension force to the joint.

[0015] In some embodiments, the sensor device comprises a strain gauge located a fixed distance from the pivot.

[0016] In some embodiments, the first arm is configured to translate away from the second arm to provide manual separation.

[0017] In some embodiments, the computing device is located within the housing of the joint extension device.

[0018] In some embodiments, the joint extension device further comprises a display interface located on the housing and configured to display the extension force applied to the joint.

[0019] In some embodiments, the computing device receives the measured strain values ​​in real time.

[0020] In some embodiments, the computing device determines the extension force applied to the joint based on a calibration curve of the joint extension device stored on the computing device.

[0021] In some embodiments, the computing device is further configured to receive joint position data. Joint laxity of the joint is determined when an extension force is applied to the joint. [Brief explanation of the drawings]

[0022] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles, nature and characteristics of the invention.

[0023] [Figure 1] 1 illustrates an operating room including an exemplary computer-assisted surgical system (CASS), according to one embodiment. [Figure 2] 1 illustrates an example of an electromagnetic sensor device, according to some embodiments. [Figure 3A] 10 illustrates an alternative example of an electromagnetic sensor device having three vertical coils, according to some embodiments. [Figure 3B] 10 illustrates an alternative example of an electromagnetic sensor device having two non-parallel fixed coils, according to some embodiments. [Figure 3C] 10 illustrates an alternative example of an electromagnetic sensor device having two non-parallel separate coils, according to some embodiments. [Figure 4] 1 illustrates an example of an electromagnetic sensor device and a patient's bone, according to some embodiments. [Figure 5A] 10 illustrates exemplary control instructions that the surgical computer provides to other components of the CASS, according to one embodiment. [Figure 5B]1 illustrates exemplary control instructions that components of a CASS provide to a surgical computer, according to one embodiment. [Figure 5C] 1 illustrates an exemplary implementation in which a surgical computer is connected to a surgical data server via a network, according to one embodiment. [Figure 6] 1 illustrates a surgical patient care system and exemplary data sources, according to one embodiment. [Figure 7A] 1 illustrates an exemplary flow diagram for determining a pre-operative surgical plan, according to one embodiment. [Figure 7B] 1 illustrates an exemplary flow diagram for determining episodes of care, including pre-operative, intra-operative, and post-operative actions, according to one embodiment. [Figure 7C-1] 1 illustrates an exemplary graphical user interface including an image showing implant placement, according to one embodiment. [Figure 7C-2] 1 illustrates an exemplary graphical user interface including an image showing implant placement, according to one embodiment. [Figure 7C-3] 1 illustrates an exemplary graphical user interface including an image showing implant placement, according to one embodiment. [Figure 8] 1 is a perspective, partially schematic, perspective view of an exemplary joint extension device, according to one embodiment. [Figure 9A] FIG. 9 is a side view of the exemplary articulating extension device shown in FIG. 8 in a closed position, according to one embodiment. [Figure 9B] FIG. 9 is a side view of the exemplary articulating extension device shown in FIG. 8 in an open position, according to one embodiment. [Figure 10] 1 illustrates the insertion of an exemplary joint extension device into a knee joint, according to one embodiment. [Figure 11A] 10 illustrates an alternative exemplary configuration of a joint extension device according to an additional embodiment. [Figure 11B] 10 illustrates an alternative exemplary configuration of a joint extension device according to an additional embodiment. [Figure 12]1 illustrates a flowchart of an exemplary method of operating a joint extension device, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present disclosure describes a joint extension device and a method of using the same. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that the embodiments may be practiced without any number of these specific details.

[0025] The present disclosure is not limited to the particular systems, devices, and methods described, as these may vary, and the terminology used in the description is used for the purpose of describing particular variations or embodiments only, and is not intended to limit the scope.

[0026] As used in this document, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Nothing in this disclosure should be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term "comprising" means "including, but not limited to."

[0027] definition For purposes of this disclosure, the term "implant" is used to refer to an artificial device or structure manufactured to replace or reinforce a biological structure. For example, a prosthetic acetabular cup (implant) is used in a total hip replacement to replace or reinforce a patient's worn or damaged acetabulum. Although the term "implant" is generally considered to refer to an artificial structure (as opposed to a transplant), for purposes of this specification, an implant can include biological tissue or material implanted to replace or reinforce a biological structure.

[0028] For purposes of this disclosure, the term "real-time" is used to refer to computations or actions that are performed in real time as an event occurs or an input is received by an operable system. However, the use of the term "real-time" is not intended to exclude actions that incur some degree of latency between input and response, as long as the latency is an unintended consequence caused by machine performance characteristics.

[0029] While much of this disclosure refers to surgeons or other medical professionals by a particular title or role, nothing in this disclosure is intended to be limited to a particular title or function. A surgeon or medical professional can include any doctor, nurse, medical professional, or technician. Any of these terms or titles can be used interchangeably with users of the systems disclosed herein unless expressly specified otherwise. For example, a reference to a surgeon may, in some embodiments, also apply to a technician or nurse.

[0030] The systems, methods, and devices disclosed herein are particularly well suited for surgical procedures utilizing surgical navigation systems, such as the NAVIO® Surgical Navigation System. NAVIO is a registered trademark of BLUE BELT TECHNOLOGIES, INC., Pittsburgh, Pennsylvania, a subsidiary of SMITH & NEPHEW, INC., Memphis, Tennessee.

[0031] CASS Ecosystem Overview FIG. 1 provides a diagram of an exemplary computer-assisted surgical system (CASS) 100, according to some embodiments. As described in further detail in the following sections, CASS uses computers, robotics, and imaging technology to help surgeons perform orthopedic surgical procedures, such as total knee arthroplasty (TKA) or total hip arthroplasty (THA). For example, surgical navigation systems can help surgeons locate a patient's anatomy, guide surgical instruments, and implant medical devices with a high degree of precision. Surgical navigation systems, such as CASS 100, often employ various forms of computing technology to perform a wide range of standard and minimally invasive surgical procedures and techniques. Additionally, these systems enable surgeons to more precisely plan, track, and navigate the placement of instruments and implants relative to a patient's body, as well as perform pre- and intra-operative body imaging.

[0032] The effector platform 105 positions the surgical tool relative to the patient during surgery. The exact components of the effector platform 105 will vary depending on the embodiment employed. For example, for knee surgery, the effector platform 105 may include an end effector 105B, which holds the surgical tool or instrument during use. The end effector 105B may be a handheld device or instrument used by the surgeon (e.g., a NAVIO® handpiece or cutting guide or jig), or alternatively, the end effector 105B may include a device or instrument held or positioned by a robotic arm 105A. While one robotic arm 105A is shown in FIG. 1 , in some embodiments, there may be multiple devices. As an example, there may be one robotic arm 105A on each side of the surgical table T, or two devices on one side of the table T. The robotic arm 105A can be mounted directly to the table T, located next to the table T on a floor platform (not shown), mounted on a floor-to-ceiling pole, or mounted to a wall or ceiling of the operating room. The floor platform can be fixed or movable. In one particular embodiment, the robotic arm 105A is mounted on a floor-to-ceiling pole positioned between the patient's legs or feet. In some embodiments, the end effector 105B can include a suture holder or stapler to assist in wound closure. Additionally, in the case of two robotic arms 105A, the surgical computer 150 can drive the robotic arms 105A to cooperate to suture the wound during closure. Alternatively, the surgical computer 150 can drive one or more robotic arms 105A to staple the wound during closure.

[0033] The effector platform 105 may include a limb positioner 105C for positioning a patient's limb during surgery. An example of a limb positioner 105C is the SMITH AND NEPHEW SPIDER2 system. The limb positioner 105C may be manually operated by the surgeon or, alternatively, may change the limb position based on commands received from a surgical computer 150 (described below). While one limb positioner 105C is shown in FIG. 1 , in some embodiments, there may be multiple devices. As an example, there may be one limb positioner 105C on each side of the surgical table T, or two devices on one side of the table T. The limb positioner 105C may be mounted directly to the table T, located next to the table T on a floor platform (not shown), mounted on a pole, or mounted to the wall or ceiling of the operating room. In some embodiments, the limb positioner 105C may be used in non-traditional ways, such as with a retractor or specific bone holder. The limb positioner 105C may include, by way of example, an ankle boot, a soft tissue clamp, a bone clamp, or a soft tissue retractor spoon such as a hooked, curved, or angled blade. In some embodiments, the limb positioner 105C may include a suture holder to assist in wound closure.

[0034] The effector platform 105 may include tools such as drivers, lights, or lasers to indicate axes or planes, bubble levels, pin drivers, pin pullers, plane checkers, pointers, fingers, or some combination thereof.

[0035] The ablation device 110 (not shown in FIG. 1 ) performs bone or tissue resection, for example, using mechanical, ultrasonic, or laser techniques. Examples of ablation devices 110 include drilling devices, deburring devices, vibratory sawing devices, vibratory impact devices, reamers, ultrasonic bone cutting devices, radio frequency ablation devices, reciprocating devices (such as scrapers or broaches), and laser ablation systems. In some embodiments, the ablation device 110 is held and manipulated by the surgeon during surgery. In other embodiments, the effector platform 105 may be used to hold the ablation device 110 during use.

[0036] The effector platform 105 may also include a cutting guide or jig 105D that is used to guide a saw or drill used to resect tissue during surgery. Such a cutting guide 105D may be integrally formed as part of the effector platform 105 or the robotic arm 105A, or the cutting guide may be a separate structure that may fit and / or be removably attached to the effector platform 105 or the robotic arm 105A. The effector platform 105 or the robotic arm 105A may be controlled by the CASS 100 to position the cutting guide or jig 105D adjacent the patient's anatomy according to a surgical plan developed pre-operatively or intra-operatively, so that the cutting guide or jig will produce precise bone cuts according to the surgical plan.

[0037] The tracking system 115 uses one or more sensors to collect real-time position data identifying the patient's anatomy and surgical instruments. For example, for a TKA procedure, the tracking system may provide the location and orientation of the end effector 105B during the procedure. In addition to the position data, data from the tracking system 115 can be further used to estimate the velocity / acceleration of the anatomy / measurements, which can be used for tool control. In some embodiments, the tracking system 115 may determine the location and orientation of the end effector 105B using a tracker array attached to the end effector 105B. The position of the end effector 105B can be inferred based on the position and orientation of the tracking system 115 and the known relationship in three-dimensional space between the tracking system 115 and the end effector 105B. In various embodiments of the present invention, various types of tracking systems may be used, including, but not limited to, infrared (IR) tracking systems, electromagnetic (EM) tracking systems, video or image-based tracking systems, and ultrasonic registration and tracking systems. Using the data provided by the tracking system 115, the surgical computer 150 can detect objects and prevent collisions. For example, the surgical computer 150 can prevent the robotic arm 105A and / or the end effector 105B from colliding with soft tissue.

[0038] Any suitable tracking system can be used to track the surgical subject and patient anatomy within the surgical space. For example, a combination of IR and visible light cameras can be used in an array. Various illumination sources, such as IR LED light sources, can illuminate the scene to enable three-dimensional imaging. In some embodiments, this can include stereoscopic, tripodal, tetrascopic, and other imaging. In some embodiments, in addition to the camera array affixed to the cart, additional cameras can be placed throughout the surgical space. For example, a handheld tool or headset worn by the operator / surgeon can include imaging capabilities that communicate images to a central processor and correlate those images with those captured by the camera array. This can provide a more robust image of the environment for modeling using multiple perspectives. Additionally, some imaging devices can be of appropriate resolution or have an appropriate perspective relative to the scene to capture information stored in a quick response (QR) code or barcode. This can be useful for identifying specific objects not manually registered in the system. In some embodiments, a camera can be mounted on the robotic arm 105A.

[0039] However, as discussed herein, the majority of tracking and / or navigation technologies utilize image-based tracking systems (e.g., IR tracking systems, video or image-based tracking systems, etc.). However, electromagnetic (EM)-based tracking systems are becoming more common for a variety of reasons. For example, implantation of a standard optical tracker requires tissue resection (e.g., down to the cortex) and subsequent drilling and driving of cortical pins. Furthermore, because optical trackers require a direct line of sight with the tracking system, placement of such trackers may need to be far away from the surgical site to avoid restricting the surgeon's or medical personnel's movements.

[0040] Generally, an EM-based tracking device includes one or more wire coils and a reference field generator. The one or more wire coils can be energized (e.g., via a wired or wireless power source). When energized, the coils generate an electromagnetic field that can be detected and measured (e.g., by a reference field generator or additional device) in a manner that can determine the location and orientation of the one or more wire coils. As one skilled in the art will appreciate, a single coil such as that shown in FIG. 2 is limited to detecting a total of five degrees of freedom (DOF). For example, the sensor 200 may be capable of tracking / determining movement in the X, Y, or Z directions, as well as rotation around the Y-axis 202 or Z-axis 201. However, due to the electromagnetic properties of the coils, rotational movement around the X-axis cannot be properly tracked.

[0041] Thus, in most electromagnetic tracking applications, a three-coil system such as that shown in FIG. 3A is used to enable tracking in all six degrees of freedom, allowing a rigid body to move in three-dimensional space (i.e., forward / backward 310, up / down 320, left / right 330, roll 340, pitch 350, and yaw 360). However, the inclusion of two additional coils and the 90° offset angles at which they are positioned may require the tracking device to be much larger. Alternatively, as those skilled in the art know, fewer than three complete coils may be used to track all six degrees of freedom. In some EM-based tracking devices, two coils may be fixed to one another, as shown in FIG. 3B. With this arrangement, the sixth degree of freedom 303B can be determined because the two coils 301B and 302B are not perfectly parallel, but are rigidly fixed to one another and have known positions relative to one another.

[0042] The use of two fixed coils (e.g., 301B and 302B) enables EM-based tracking in 6DOF, but the sensor device is substantially larger in diameter than a single coil due to the additional coil. Thus, practical application of an EM-based tracking system in a surgical environment may require tissue resection and drilling of a portion of the patient's bone to allow for insertion of the EM tracker. Alternatively, in some embodiments, it may be possible to implant / insert a single coil or 5DOF EM tracking device into a patient's bone using only a pin (e.g., without the need to drill or cut out substantial bone).

[0043] Therefore, as described herein, there is a need for a solution that can limit the use of EM tracking systems to devices that are small enough to be inserted / implanted using a small diameter needle or pin (i.e., without the need to create a new incision or a large diameter opening in the bone). Thus, in some embodiments, a second 5DOF sensor that is not attached to the first and therefore has a smaller diameter may be used to track all 6DOF. Referring now to FIG. 3C, in some embodiments, two 5DOF EM sensors (e.g., 301C and 302C) may be inserted into a patient (e.g., the patient's bone) at different locations and at different angular orientations (e.g., angle 303C is not zero).

[0044] Referring now to FIG. 4 , an exemplary embodiment is shown in which a first 5DOF EM sensor 401 and a second 5DOF EM sensor 402 are inserted into a patient's bone 403 using a standard hollow needle 405, which is typical in most ORs. In further embodiments, the first sensor 401 and the second sensor 402 may have an angular offset “α” 404. In some embodiments, the offset angle “α” 404 may be required to be greater than a predetermined value (e.g., a minimum angle of 0.50°, 0.75°, etc.). This minimum value, in some embodiments, may be determined by the CASS and provided to the surgeon or medical professional during surgical planning. In some embodiments, the minimum value may be based on one or more factors, such as, for example, the orientation accuracy of the tracking system, the distance between the first and second EM sensors, the location of the electric field generator, the location of the electric field detector, the type of EM sensor, the quality of the EM sensor, the patient's anatomy, etc.

[0045] Thus, as discussed herein, in some embodiments, one or more EM sensors may be inserted using a pin / needle (e.g., a cannulated mounting needle, etc.). Generally, the pin / needle is a disposable component, while the sensor itself may be reusable. However, it should be understood that this is one potential system, and various other systems may be used in which the pin / needle and / or EM sensor are independently disposable or reusable. In further embodiments, the EM sensor may be secured to the mounting needle / pin (e.g., using a luer lock fitting, etc.), allowing for rapid assembly and disassembly. In additional embodiments, the EM sensor may utilize an alternative sleeve and / or anchor system that allows for minimally invasive placement of the sensor.

[0046] In another embodiment, the system may enable a multi-sensor navigation system capable of detecting and correcting field-of-view distortions that plague electromagnetic tracking systems. It should be understood that field-of-view distortions may result from the movement of any ferromagnetic material within the reference field of view. Thus, as one skilled in the art will appreciate, a typical OR has numerous devices (e.g., operating tables, LCD displays, lighting devices, imaging systems, surgical instruments, etc.) that can cause interference. Furthermore, field-of-view distortions are known to be extremely difficult to detect. The use of multiple EM sensors allows the system to accurately detect field-of-view distortions and / or alert the user that the current position measurement may be inaccurate. Because the sensors are rigidly fixed (e.g., via pins / needles) to the bony anatomical structure, relative measurements of the sensor positions (X, Y, Z) may be used to detect field-of-view distortions. As a non-limiting example, in some embodiments, after the EM sensors are fixed to the bone, the relative distance between the two sensors is known and should remain constant. Therefore, any change in this distance may indicate the presence of field-of-view distortions.

[0047] In some embodiments, a particular object may be manually registered with the system by the surgeon preoperatively or intraoperatively. For example, by interacting with a user interface, the surgeon may identify the starting location of a tool or bone structure. By tracking fiducial marks associated with the tool or bone structure, or by using other conventional image tracking modalities, the processor may track the tool or bone in the three-dimensional model as it moves through the environment.

[0048] In some embodiments, specific markers, such as fiducial marks, that identify individuals, important tools, or bones in space may include passive or active identifiers that can be picked up by a camera or camera array associated with the tracking system. For example, IR LEDs can flash patterns that communicate a unique identifier to the source of the pattern, providing dynamic identification. Similarly, one- or two-dimensional optical codes (e.g., barcodes, QR codes) can be affixed to objects in space to provide passive identification that can occur based on image analysis. If these codes are placed asymmetrically on an object, they can also be used to determine the object's orientation by comparing the location of the identifier to the extent of the object in the image. For example, a QR code may be placed in the corner of a tool tray to track the tray's orientation and identity. Other tracking modalities are described throughout. For example, in some embodiments, augmented reality headsets can be worn by surgeons and other staff to provide additional camera angles and tracking capabilities.

[0049] In addition to optical tracking, specific features of an object can be tracked by registering the object's physical properties and associating them with a trackable object, such as a fiducial mark fixed to a tool or bone. For example, a surgeon can perform a manual registration process in which a tracked tool and a tracked bone can be manipulated relative to each other. By pressing the tip of a tool against the surface of a bone, a three-dimensional surface can be mapped to that bone associated with the position and orientation of that fiducial mark relative to a reference frame. By optically tracking the position and orientation (pose) of the fiducial mark associated with that bone, a model of that surface can be tracked with the environment via extrapolation.

[0050] The registration process of registering CASS100 to the patient's relevant anatomical structures can also involve the use of anatomical landmarks, such as landmarks on bones or cartilage. For example, CASS100 can include a 3D model of the relevant bones or joints, and the surgeon can use a probe connected to the CASS to intraoperatively collect data regarding the locations of bony landmarks on the patient's actual bones. The bony landmarks can include, for example, the medial and lateral malleolus, the ends of the proximal femur and distal tibia, and the center of the hip joint. CASS100 can compare and register the location data of the bony landmarks collected by the surgeon with the probe with the location data of the same landmarks in the 3D model. Alternatively, CASS100 can build a 3D model of the bones or joints without preoperative image data, using the location data of the bony landmarks and bone surfaces collected by the surgeon using the CASS probe or other means. The registration process can also include determining various axes of the joint. For example, for a TKA, the surgeon can use CASS100 to determine the anatomical and mechanical axes of the femur and tibia. The surgeon and CASS 100 identify the hip joint center by moving the patient's leg in a spiral direction (i.e., abduction), which allows the CASS to determine where the hip joint center is located.

[0051] A tissue navigation system 120 (not shown in FIG. 1) provides the surgeon with intraoperative real-time visualization of the patient's bone, cartilage, muscle, nerve, and / or vascular tissue surrounding the surgical area. Examples of systems that may be employed for tissue navigation include fluorescence imaging systems and ultrasound systems.

[0052] Display 125 provides a graphical user interface (GUI) that displays images collected by tissue navigation system 120 as well as other information related to the surgery. For example, in one embodiment, display 125 overlays image information collected from various modalities (e.g., CT, MRI, X-ray, fluorescence, ultrasound, etc.) collected preoperatively or intraoperatively to provide the surgeon with various views of the patient's anatomy and real-time conditions. Display 125 may include, for example, one or more computer monitors. As an alternative or supplement to display 125, one or more members of the surgical staff may wear an augmented reality (AR) head-mounted device (HMD). For example, in FIG. 1 , surgeon 111 is wearing an AR HMD 155 that may, for example, overlay preoperative image data on the patient or provide surgical planning suggestions. Various example uses of AR HMD 155 in surgical procedures are detailed in the following sections.

[0053] The surgical computer 150 provides control instructions for the various components of the CASS 100, collects data from those components, and provides general processing for the various data required during surgery. In some embodiments, the surgical computer 150 is a general-purpose computer. In other embodiments, the surgical computer 150 may be a parallel computing platform that performs processing using multiple central processing units (CPUs) or graphics processing units (GPUs). In some embodiments, the surgical computer 150 is connected to remote servers via one or more computer networks (e.g., the Internet). The remote servers may be used, for example, for storing data or performing computationally intensive processing tasks.

[0054] Various technologies commonly known in the art can be used to connect the surgical computer 150 to the other components of the CASS 100. Additionally, computers may connect to the surgical computer 150 using a combination of technologies. For example, the end effector 105B may connect to the surgical computer 150 via a wired (i.e., serial) connection. The tracking system 115, tissue navigation system 120, and display 125 may also be connected to the surgical computer 150 using wired connections. Alternatively, the tracking system 115, tissue navigation system 120, and display 125 may connect to the surgical computer 150 using wireless technologies such as, but not limited to, Wi-Fi, Bluetooth, near field communication (NFC), or ZigBee.

[0055] Powered Impingement and Acetabular Reamer Device Part of the flexibility of the CASS design described above with respect to FIG. 1 is the ability to add additional or alternative devices to the CASS 100 as needed to support a particular surgical procedure. For example, in the context of hip surgery, the CASS 100 may include a powered impaction device. The impaction device is designed to repeatedly apply an impact force that the surgeon can use to perform activities such as implant alignment. For example, in a total hip arthroplasty (THA), the surgeon often uses an impaction device to insert a prosthetic acetabular cup into the acetabulum of the implant host. While impaction devices are manual in nature (e.g., the surgeon manipulates the impaction device with a mallet), powered impaction devices are generally easier and faster to use in a surgical setting. The powered impaction device may be powered, for example, using a battery attached to the device. Various mounting pieces may be connected to the powered impaction device to direct the impact force in various ways as needed during surgery. Additionally, in the context of hip surgery, CASS 100 may include a powered, robotically controlled end effector that reams the acetabulum to accommodate an acetabular cup implant.

[0056] In robotic-assisted THA, the patient's anatomy may be registered to CASS100 using CT or other image data, identification of anatomical landmarks, a tracker array attached to the patient's bone, and one or more cameras. The tracker array may be attached to the iliac crest using clamps and / or bone pins, and such trackers may be attached externally through the skin or medially (either posterolaterally or anterolaterally) through an incision made to perform the THA. For THA, CASS100 may utilize one or more femoral cortical screws inserted into the proximal femur as checkpoints to assist the registration process. CASS100 may also utilize one or more checkpoint screws inserted into the pelvis as additional checkpoints to assist the registration process. A femoral tracker array may be secured to or attached to the femoral cortical screws. CASS100 may employ a step in which registration is verified using a probe precisely placed by the surgeon over key areas of the proximal femur and pelvis identified for the surgeon on display 125. A tracker may be located on the robotic arm 105A or end effector 105B to register the arm and / or end effector to CASS 100. The verification step may also utilize proximal and distal femur checkpoints. CASS 100 may utilize color or other prompts to inform the surgeon that the registration process of the associated bone and robotic arm 105A or end effector 105B has been verified with some degree of accuracy (e.g., within 1 mm).

[0057] For THA, CASS100 may include a broach tracking option using a femoral array, allowing the surgeon to capture the position and orientation of the broach intraoperatively and calculate the length and offset of the patient's hip. Based on the information provided about the patient's hip and the planned implant position and orientation after broach tracking is complete, the surgeon can modify or adjust the surgical plan.

[0058] For robotic-assisted THA, the CASS 100 may include one or more powered reamers connected or attached to the robotic arm 105A or end effector 105B to prepare the pelvic bone to receive the acetabular implant according to the surgical plan. The robotic arm 105A and / or end effector 105B can notify the surgeon and / or control the power of the reamer to ensure the acetabulum is reamed according to the surgical plan. For example, if the surgeon attempts to resect bone outside the borders of the bone to be reamed according to the surgical plan, the CASS 100 can turn off the power of the reamer or instruct the surgeon to turn off the power of the reamer. The CASS 100 can provide the surgeon with the option of turning off or disengaging robotic control of the reamer. The display 125 can use different colors to indicate the progress of the bone being reamed compared to the surgical plan. The surgeon can view a representation of the bone being reamed and guide the reamer to complete the reaming according to the surgical plan. CASS 100 can provide visual or audible prompts to the surgeon to alert them that a resection is being performed that is not in accordance with the surgical plan.

[0059] After reaming, CASS 100 can impact the trial and final implants into the acetabulum using a manual or powered impactor attached to or connected to robotic arm 105A or end effector 105B. Robotic arm 105A and / or end effector 105B can be used to guide the impactor to impact the trial and final implants into the acetabulum according to the surgical plan. CASS 100 can cause the position and orientation of the trial and final implants relative to the bone to be displayed, and display 125 can show the implant position and orientation, to inform the surgeon on how the orientation and position of the trial and final implants compare to the surgical plan as they treat the leg and hip. CASS 100 can provide the surgeon with the option to re-plan and re-perform the reaming and implant impaction by preparing a new surgical plan if the surgeon is not satisfied with the original implant position and orientation.

[0060] Preoperatively, CASS100 can develop a suggested surgical plan based on a three-dimensional model of the hip joint and other patient-specific information, such as the mechanical and anatomical axes of the leg bones, the epicondylar axis, the femoral neck axis, femoral and hip joint dimensions (e.g., length), the medial axis of the hip joint, the ASIS axis of the hip joint, and the location of anatomical landmarks, such as the lesser trochanter landmark, distal landmarks, and the hip joint's center of rotation. The CASS-developed surgical plan can provide a recommended optimal implant size and implant position and orientation based on the three-dimensional model of the hip joint and other patient-specific information. The CASS-developed surgical plan can include suggested details regarding offset values, inclination and anteversion values, center of rotation, cup size, medialization values, upper and lower fit values, and femoral stem size and length.

[0061] For THA, the CASS-developed surgical plan can be viewed preoperatively and intraoperatively, and the surgeon can modify the CASS-developed surgical plan preoperatively or intraoperatively. The CASS-developed surgical plan shows the planned resection on the hip joint and, based on the planned resection, can superimpose the planned implant on the hip joint. CASS100 can provide the surgeon with a variety of surgical workflow options that are displayed to the surgeon based on the surgeon's preferences. For example, the surgeon can select from different workflows based on the number and type of anatomical landmarks checked and captured and / or the location and number of tracker arrays used in the registration process.

[0062] According to some embodiments, the powered impaction device used with CASS 100 can operate in a variety of different settings. In some embodiments, the surgeon adjusts settings through a manual switch or other physical mechanism on the powered impaction device. Other embodiments may use a digital interface that allows for setting input, for example, via the touchscreen of the powered impaction device. Such a digital interface may allow for varying available settings based, for example, on the type of attachment connected to the power attachment device. In some embodiments, rather than adjusting settings on the powered impaction device itself, settings can be changed through communication with a robot or other computer system within CASS 100. Such a connection may be established, for example, using a Bluetooth or Wi-Fi networking module on the powered impaction device. In another embodiment, the impaction device and endpiece may include features that allow the impaction device to recognize which endpiece (e.g., cup impactor, broach handle) is attached without any action required by the surgeon and adjust settings accordingly. This may be accomplished, for example, via a QR code, barcode, RFID tag, or other method.

[0063] Examples of settings that may be used include a cup impaction setting (e.g., unidirectional, specified frequency range, specified force and / or energy range), a broach impaction setting (e.g., bidirectional / oscillating with a specified frequency range, specified force and / or energy range), a femoral head impaction setting (e.g., unidirectional / single blow with a specified force or energy), and a stem impaction setting (e.g., unidirectional at a specified frequency with a predetermined force or energy). Additionally, in some embodiments, the powered impaction device includes a setting related to acetabular liner impaction (e.g., unidirectional / single blow with a specified force or energy). There may be multiple settings for each type of liner, such as poly, ceramic, oxinium, or other material. Furthermore, the powered impaction device may provide settings for different bone qualities based on the surgeon's preoperative examination / imaging / knowledge and / or intraoperative assessment. In some embodiments, the powered impactor device may have dual functionality. For example, the powered impactor device may provide a reciprocating motion to provide impact force, but it may also provide a reciprocating motion for a broach or rasp.

[0064] In some embodiments, the motorized impaction device includes feedback sensors that collect data during use of the instruments and transmit the data to a computing device, such as a controller in the device or surgical computer 150. This computing device can then record the data for later analysis and use. Examples of data that may be collected include, but are not limited to, sound waves, the predetermined resonant frequency of each instrument, reaction forces or rebound energy from the patient's bone, the location of the device with respect to imaging (e.g., fluoro, CT, ultrasound, MRI, etc.), and / or external strain gauges on the bone.

[0065] As the data is collected, the computing device may execute one or more algorithms in real time or near real time to assist the surgeon in performing the surgical procedure. For example, in some embodiments, the computing device uses the collected data to derive information such as the appropriate final broach size (femur), when the stem is fully seated (femoral side), or when the cup is seated relative to the THA (depth and / or orientation). Once the information is known, it may be displayed for the surgeon's review or may be used to activate haptic or other feedback mechanisms to guide the surgical procedure.

[0066] Additionally, data derived from the aforementioned algorithms may be used to drive device operation. For example, during insertion of a prosthetic acetabular cup with a powered impaction device, the device may automatically extend the impaction head (e.g., end effector) to move the implant into place, or turn off power to the device after the implant is fully seated. In one embodiment, using the derived information, the powered impaction device may automatically adjust bone quality settings, which should use less power to reduce femoral / acetabular / pelvic fractures or damage to surrounding tissue.

[0067] robotic arm In some embodiments, CASS 100 includes a robotic arm 105A that serves as an interface for stabilizing and holding various instruments used during a surgical procedure. For example, in the context of hip surgery, these instruments may include, but are not limited to, a retractor, a sagittal or reciprocating saw, a reamer handle, a cup impactor, a broach handle, and a stem inserter. Robotic arm 105A may have multiple degrees of freedom (like a Spider device) and may have the ability to be locked into place (e.g., by pressing a button, voice activation, the surgeon removing their hand from the robotic arm, or other methods).

[0068] In some embodiments, movement of the robotic arm 105A can be triggered using a control panel integrated into the robotic arm system. For example, a display screen can include one or more input sources, such as physical buttons or a user interface with one or more icons, that directly move the robotic arm 105A. A surgeon or other medical personnel can engage the one or more input sources to position the robotic arm 105A when performing a surgical procedure.

[0069] Tools or end effectors 105B attached to or incorporated into the robotic arm 105A may include, but are not limited to, burrs, scalpels, cutting devices, retractors, joint extension devices, etc. In embodiments in which an end effector 105B is used, the end effector may be positioned at the end of the robotic arm 105A such that any motor-controlled operations are implemented within the robotic arm system. In embodiments in which a tool is used, the tool may be fixed to the distal end of the robotic arm 105A, but the motor-controlled operations may reside within the tool itself.

[0070] Robotic arm 105A may be internally motorized to stabilize both the robotic arm, thereby preventing it from falling and hitting the patient, operating table, surgical staff, etc., and to allow the surgeon to move the robotic arm without fully supporting its weight. While the surgeon is moving robotic arm 105A, the robotic arm may provide some resistance to prevent it from moving too quickly or from having too many degrees of freedom active at once. The position and locking status of robotic arm 105A may be tracked by, for example, a controller or surgical computer 150.

[0071] In some embodiments, the robotic arm 105A can be moved by hand (e.g., by a surgeon) or with an internal motor into its ideal position and orientation for the task to be performed. In some embodiments, the robotic arm 105A can be operable in a “free” mode, allowing the surgeon to position the arm as desired without constraints. While in free mode, the position and orientation of the robotic arm 105A can still be tracked, as described above. In one embodiment, certain degrees of freedom can be selectively released upon input from a user (e.g., a surgeon) during certain portions of the surgical plan tracked by the surgical computer 150. Designs in which the robotic arm 105A is internally powered through hydraulics or motors, or provides resistance to external manual movement via similar means, can be described as powered robotic arms, while arms that are manually manipulated without power feedback but can be manually or automatically locked into position can be described as passive robotic arms.

[0072] The robotic arm 105A or end effector 105B may include a trigger or other means for controlling the force of the saw or drill. Engagement of the trigger or other means by the surgeon can transition the robotic arm 105A or end effector 105B from a powered alignment mode to a mode in which the saw or drill is engaged and powered on. Additionally, CASS 100 may include a foot pedal (not shown) that, when activated, causes the system to perform a specific function. For example, the surgeon can activate the foot pedal to instruct CASS 100 to place the robotic arm 105A or end effector 105B into an automatic mode, which brings the robotic arm or end effector into the appropriate position relative to the patient's anatomy and performs the required resection. CASS 100 can also place the robotic arm 105A or end effector 105B into a collaborative mode, which allows the surgeon to manually manipulate and position the robotic arm or end effector at a specific location. Collaborative mode may be configured to allow the surgeon to move the robotic arm 105A or end effector 105B medially or laterally while restricting movement in other directions. As discussed, the robotic arm 105A or end effector 105B may include cutting devices (saws, drills, and burrs) or a cutting guide or jig 105D that guides the cutting device. In other embodiments, movement of the robotic arm 105A or robotically-controlled end effector 105B may be controlled entirely by the CASS 100 without, or with only minimal, assistance or input from the surgeon or other medical professional. In still other embodiments, movement of the robotic arm 105A or robotically-controlled end effector 105B may be remotely controlled by the surgeon or other medical professional using a control mechanism separate from the robotic arm or robotically-controlled end effector device, for example, using a joystick or interactive monitor or display control device.

[0073] The following example describes the use of a robotic device in the context of hip surgery, but it should be understood that the robotic arm may have other applications for surgical procedures involving the knee, shoulder, etc. One example of the use of a robotic arm in the context of the creation of an anterior cruciate ligament (ACL) graft tunnel is described in WIPO Publication No. 2020 / 047051, entitled "Robotic Assisted Ligament Graft Placement and Tensioning," filed August 28, 2019, which is incorporated herein by reference in its entirety.

[0074] The robotic arm 105A may be used to hold the retractor. For example, in one embodiment, the robotic arm 105A may be moved by the surgeon to a desired position. At this point, the robotic arm 105A may be locked in place. In some embodiments, the robotic arm 105A is provided with data regarding the patient's position so that if the patient moves, the robotic arm can adjust the retractor position accordingly. In some embodiments, multiple robotic arms may be used, thereby holding multiple retractors or performing multiple activities simultaneously (e.g., holding and reaming retractors).

[0075] The robotic arm 105A may also be used to help stabilize the surgeon's hand while cutting the femoral neck. In this application, the control of the robotic arm 105A may impose certain limits to prevent soft tissue damage. For example, in one embodiment, the surgical computer 150 tracks the position of the robotic arm 105A as it is actuated. If the tracked location approaches an area where tissue damage is predicted, a command may be sent to the robotic arm 105A to stop it. Alternatively, if the robotic arm 105A is automatically controlled by the surgical computer 150, the surgical computer may ensure that no commands are provided to the robotic arm that would cause it to enter an area where soft tissue damage is likely to occur. The surgical computer 150 may impose certain limits on the surgeon to prevent the surgeon from over-reaming into the medial wall of the acetabulum or from reaming at an incorrect angle or orientation.

[0076] In some embodiments, the robotic arm 105A may be used to hold the cup impactor at a desired angle or orientation during cup impaction. Once the final position is achieved, the robotic arm 105A may prevent any further seating to prevent damage to the pelvis.

[0077] The surgeon can use the robotic arm 105A to position the broach handle in a desired location, allowing the surgeon to impact the broach into the femoral canal in a desired orientation. In some embodiments, once the surgical computer 150 receives feedback that the broach is fully secured, the robotic arm 105A can limit the handle to prevent further advancement of the broach.

[0078] The robotic arm 105A can also be used in resurfacing applications. For example, the robotic arm 105A can stabilize the surgeon while using conventional instruments and provide certain constraints or restrictions to allow proper placement of implant components (e.g., guidewire placement, chamfer cutters, sleeve cutters, planar cutters, etc.). If only burrs are employed, the robotic arm 105A may stabilize the surgeon's handpiece and can impose constraints on the handpiece to prevent the surgeon from violating the surgical plan and removing unintended bone.

[0079] The robotic arm 105A can be a passive arm. As an example, the robotic arm 105A can be a CIRQ robotic arm available from Brainlab AG. CIRQ is a registered trademark of Brainlab AG, Olof-Palme-Str. 9 81829, Munchen, FED REP of GERMANY. In one particular embodiment, the robotic arm 105A is an intelligent holding arm such as those disclosed in U.S. Patent Application No. 15 / 525,585 to Krinninger et al., U.S. Patent Application No. 15 / 561,042 to Nowatschin et al., U.S. Patent Application No. 15 / 561,048 to Nowatschin et al., and U.S. Patent Application No. 10,342,636 to Nowatschin et al., the entire contents of each of which are incorporated herein by reference.

[0080] Surgical technique data generation and collection The various services provided by a medical professional to treat a clinical condition are collectively referred to as an "episode of care." For a particular surgical intervention, an episode of care may include three phases: preoperative, intraoperative, and postoperative. During each phase, data is collected or generated that can be used to analyze the episode of care to understand various characteristics of the procedure and, for example, identify patterns that can be used in training a model to make decisions with minimal human intervention. The data collected over the episode of care may be stored as a complete dataset on the surgical computer 150 or the surgical data server 180. Thus, for each episode of care, there is a dataset that collectively includes all preoperative data about the patient, all data collected or stored intraoperatively by CASS 100, and any postoperative data provided by the patient or by medical professionals monitoring the patient.

[0081] As will be described in more detail, data collected during an episode of care can be used to improve the performance of a surgical procedure or to provide a holistic understanding of the surgical procedure and patient outcomes. For example, in some embodiments, data collected over an episode of care can be used to generate a surgical plan. In one embodiment, a high-level preoperative plan is refined intraoperatively as data is collected during surgery. In this way, the surgical plan can be viewed as dynamically changing in real time or near real time as new data is collected by the components of CASS 100. In other embodiments, preoperative images or other input data can be used preoperatively to develop a robust plan that is simply executed during surgery. In this case, data collected by CASS 100 during surgery can be used to make recommendations that ensure the surgeon stays within the preoperative surgical plan. For example, if the surgeon is unsure how to achieve a particular predetermined cut or implant alignment, they can ask surgical computer 150 for recommendations. In still other embodiments, preoperative and intraoperative planning approaches can be combined such that a robust preoperative plan can be dynamically modified as needed or desired during the surgical procedure. In some embodiments, a biomechanics-based model of the patient's anatomy contributes simulation data that is considered by CASS100 in the development of pre-operative, intra-operative, and post-operative / rehabilitation procedures to optimize implant performance outcomes for the patient.

[0082] In addition to modifying the surgical procedure itself, data collected during an episode of care can be used as input to other procedures ancillary to the surgery. For example, in some embodiments, an implant can be designed using the episode of care data. Exemplary data-driven techniques for designing, sizing, and fitting implants are described in U.S. patent application Ser. No. 13 / 814,531, entitled "Systems and Methods for Optimizing Parameters for Orthopaedic Procedures," filed Aug. 15, 2011; U.S. patent application Ser. No. 14 / 232,958, entitled "Systems and Methods for Optimizing Fit of an Implant to Anatomy," filed July 20, 2012; and U.S. patent application Ser. No. 12 / 234,444, entitled "Operatively Tuning Implants for Increased Performance," filed Sep. 19, 2008, the entire contents of each of which are incorporated herein by reference.

[0083] Additionally, the data may be used for educational, training, or research purposes. For example, using a network-based approach described below in FIG. 5C, other physicians or students can remotely view the surgery in an interface that allows them to selectively view data collected from various components of CASS 100. After the surgical procedure, a similar interface can be used to "replay" the procedure for training or other educational purposes, or to identify the source of procedural problems or complications.

[0084] Data acquired during the preoperative phase generally includes all information collected or generated before surgery. Thus, for example, information about the patient may be acquired from a patient intake form or an electronic medical record (EMR). Examples of patient information that may be collected include, but are not limited to, patient demographics, diagnosis, medical history, progress notes, vital signs, medical history information, allergies, and laboratory test results. Preoperative data may also include images related to the anatomical region of interest. These images may be captured using, for example, magnetic resonance imaging (MRI), computed tomography (CT), X-ray, ultrasound, or any other modality known in the art. Preoperative data may also include quality of life data captured from the patient. For example, in one embodiment, the preoperative patient completes a questionnaire regarding their current quality of life using a mobile application (app). In some embodiments, the preoperative data used by CASS 100 includes demographics, anthropometry, culture, or other specific traits about the patient, which can be matched to activity level and specific patient activities to customize the surgical plan to the patient. For example, certain cultures or patient backgrounds may be more likely to use toilets that require daily squatting.

[0085] 5A and 5B provide examples of data that may be acquired during the intraoperative phase of an episode of care. These examples are based on the various components of CASS 100 described above with reference to FIG. 1, but it should be understood that other types of data may be used based on the types of instruments used during surgery and their use.

[0086] Figure 5A shows some example control instructions that surgical computer 150 provides to other components of CASS 100, according to some embodiments. Note that the example of Figure 5A assumes that the components of effector platform 105 are each controlled directly by surgical computer 150. In embodiments in which components are manually controlled by surgeon 111, instructions may be provided on display 125 or AR HMD 155 instructing surgeon 111 how to move the components.

[0087] The various components included in the effector platform 105 are controlled by a surgical computer 150, which provides position commands that instruct the components where to move within a coordinate system. In some embodiments, the surgical computer 150 provides instructions to the effector platform 105 that define how to react if the components of the effector platform 105 deviate from the surgical plan. These commands are referred to in FIG. 5A as "haptic" commands. For example, the end effector 105B may provide a force that resists movement outside of the area where resection is planned. Other commands that may be used by the effector platform 105 include vibration and audio cues.

[0088] In some embodiments, the end effector 105B of the robotic arm 105A is operably coupled to the cutting guide 105D. In response to an anatomical model of the surgical scene, the robotic arm 105A can move the end effector 105B and the cutting guide 105D to a position that matches the location of the femoral or tibial cut to be performed according to the surgical plan. This can reduce the possibility of error, and the vision system and processor can be utilized to implement the surgical plan to position the cutting guide 105D in the exact location and orientation relative to the tibia or femur, aligning the cutting guide's cutting slot with the cut to be performed according to the surgical plan. The surgeon can then use any appropriate tool, such as an oscillating or rotary saw or drill, to make the cut (or drill) with perfect placement and orientation, as the tool is mechanically constrained by the features of the cutting guide 105D. In some embodiments, the cutting guide 105D can include one or more pin holes that the surgeon uses to drill or pin the cutting guide before using the cutting guide to perform the resection of the patient's tissue. This allows the robotic arm 105A to be released or ensures that the cutting guide 105D is fully secured without moving relative to the bone being resected. For example, this procedure may be used to make the first distal cut of the femur during a total knee replacement. In some embodiments where the joint arthroplasty is a hip arthroplasty, the cutting guide 105D may be secured to the femoral head or acetabulum for each hip arthroplasty resection. It should be understood that any joint arthroplasty utilizing precision cutting may use the robotic arm 105A and / or cutting guide 105D in this manner.

[0089] The ablation device 110 is provided with various commands to perform bone or tissue manipulation. Similar to the effector platform 105, position information may be provided to the ablation device 110, specifying where it should be positioned when performing the ablation. Other commands provided to the ablation device 110 may depend on the type of ablation device. For example, in the case of mechanical or ultrasonic ablation tools, the commands may specify the speed and frequency of the tool. In radiofrequency ablation (RFA) and other laser ablation tools, the commands may specify the intensity and pulse duration.

[0090] Some components of CASS 100 do not need to be directly controlled by surgical computer 150. Rather, surgical computer 150 only needs to activate the components, which then locally execute software that specifies the procedure that collects data and provides it to surgical computer 150. In the example of Figure 5A, there are two components that operate in this procedure: tracking system 115 and tissue navigation system 120.

[0091] The surgical computer 150 provides on the display 125 any visualizations the surgeon 111 requires during surgery. For monitors, the surgical computer 150 may provide instructions for displaying images, GUIs, etc., using techniques known in the art. The display 125 may include various portions of the surgical planning workflow. During the registration process, for example, the display 125 may show a preoperatively constructed 3D bone model and indicate the location of a probe as the surgeon uses it to gather the locations of the patient's anatomical landmarks. The display 125 may include information about the surgical target area. For example, in connection with TKA, the display 125 may show the mechanical and anatomical axes of the femur and tibia. The display 125 may show the varus and valgus angles of the knee joint based on the surgical plan, and the CASS 100 may show how such angles will be affected if proposed modifications to the surgical plan are made. Thus, the display 125 is an interactive interface that can dynamically update and show how changes to the surgical plan affect the procedure and the final position and orientation of the implant attached to the bone.

[0092] As the workflow progresses to preparing a bone cut or resection, the display 125 can show the planned or recommended bone cut before any cuts are made. The surgeon 111 can manipulate the image display to provide different anatomical perspectives of the target area and can have the option to change or modify the planned bone cut based on intraoperative evaluation of the patient. The display 125 can show how a selected implant will be attached to the bone if the planned bone cut is made. If the surgeon 111 chooses to change a previously planned bone cut, the display 125 can show how the modified bone cut will change the position and orientation of the implant when attached to the bone.

[0093] The display 125 can provide the surgeon 111 with a variety of data and information regarding the patient, the planned surgical intervention, and the implant. It can display a variety of patient-specific information, including real-time data regarding the patient's health, such as heart rate and blood pressure. The display 125 can also include information about the anatomy of the surgical target area, including the location of landmarks, the current state of the anatomy (e.g., whether any resections have been made, the depth and angle of planned and performed bone cuts), and the future state of the anatomy as the surgical plan progresses. The display 125 can also provide or show additional information regarding the surgical target area. For TKA, the display 125 can provide information about the gap between the femur and tibia (e.g., gap balance) and how such gap will change if the planned surgical plan is implemented. For TKA, the display 125 can provide additional relevant information regarding the knee joint, such as data regarding joint tension (e.g., ligament laxity) and information regarding joint rotation and alignment. The display 125 can show how the planned implant locations and positions will affect the patient as the knee flexes. The display 125 can show how the use of different implants, or different sizes of the same implant, will affect the surgical plan and can preview how such implants will be positioned on the bone. The CASS 100 can provide such information for each planned bone resection in a TKA or THA. In a TKA, the CASS 100 can provide robotic control for one or more of the planned bone resections. For example, the CASS 100 can provide robotic control for only the initial distal femoral cut, while the surgeon 111 can manually perform the other resections (anterior, posterior, and chamfer cuts) using conventional means, such as a 4-in-1 cutting guide or jig 105D.

[0094] Display 125 may employ different colors to inform the surgeon of the status of the surgical plan. For example, unresected bone may be displayed in a first color, resected bone may be displayed in a second color, and planned resections may be displayed in a third color. Implants may be overlaid on the bone in display 125, and the color of the implant may vary or correspond to different types or sizes of implant.

[0095] The information and options shown on the display 125 may vary depending on the type of surgical procedure being performed. Additionally, the surgeon 111 may request or select a particular surgical workflow view that matches or is consistent with their surgical planning preferences. For example, for a surgeon 111 who typically performs a tibial cut before a femoral cut in a TKA, the display 125 and associated workflow may be adapted to take this preference into account. The surgeon 111 may also pre-select certain steps to be included or omitted from the standard surgical workflow view. For example, if the surgeon 111 uses resection measurements to finalize implant planning but does not analyze ligament gap balance when finalizing implant planning, the surgical workflow view may be organized into modules, and the surgeon may select which modules to display and the order in which the modules are presented based on the surgeon's preferences or the specific surgical situation. Modules covering ligament and gap balancing can include, for example, pre- and post-resection ligament / gap balancing, and the surgeon 111 can select which modules to include in their default surgical plan workflow depending on whether such ligament and gap balancing is performed before or after bone resection (or both).

[0096] For more specialized display devices, such as AR HMDs, surgical computer 150 may provide images, text, etc. using data formats supported by the device. For example, if display 125 is a holographic device, such as a Microsoft HoloLens™, or Magic Leap One™, surgical computer 150 may use a HoloLens application program interface (API) to send commands specifying the location and content of holograms to be displayed in the field of view of surgeon 111.

[0097] In some embodiments, one or more surgical planning models may be incorporated into CASS 100 and used to develop the surgical plan provided to surgeon 111. The term “surgical planning model” refers to software that simulates the performance of anatomy under various scenarios to determine the optimal way to perform amputations and other surgical activities. For example, for knee replacement surgery, the surgical planning model may measure parameters for functional activities such as deep knee flexion and walking and select amputation locations on the knee to optimize implant placement. One example of a surgical planning model is LIFEMOD™ simulation software from SMITH AND NEPHEW, INC. In some embodiments, surgical computer 150 includes a computing architecture that enables full execution of the surgical planning model (e.g., in a GPU-based parallel processing environment) during surgery. In other embodiments, surgical computer 150 may be connected via a network to a remote computer that enables such execution, such as surgical data server 180 (see FIG. 5C ). As an alternative to full execution of the surgical planning model, in some embodiments, a series of transfer functions are derived that simplify the mathematical operations captured by the model into one or more predictor equations. Then, rather than running all the simulations during surgery, a predictor equation is used. Further details regarding the use of transfer functions are described in WIPO Publication No. 2020 / 037308, entitled "Patient Specific Surgical Method and System," filed August 19, 2019, which is incorporated herein by reference in its entirety.

[0098] 5B shows examples of some types of data that may be provided to the surgical computer 150 from various components of the CASS 100. In some embodiments, the components may stream data to the surgical computer 150 in real time or near real time during surgery. In other embodiments, the components may queue data and send it to the surgical computer 150 at set intervals (e.g., every second). Data may be communicated using any format known in the art. Thus, in some embodiments, all components transmit data to the surgical computer 150 in a common format. In other embodiments, each component may use a different data format, and the surgical computer 150 is configured with one or more software applications that allow for the interpretation of the data.

[0099] In general, surgical computer 150 may serve as a central point from which CASS data is collected. The exact content of the data varies depending on the source. For example, each component of effector platform 105 provides measured positions to surgical computer 150. Thus, by comparing the measured positions with positions originally specified by surgical computer 150 (see FIG. 5B), the surgical computer can identify deviations that occur during surgery.

[0100] The resection device 110 can transmit various types of data to the surgical computer 150 depending on the type of device used. Exemplary data types that may be transmitted include measured torque, audio signatures, and measured displacement values. Similarly, the tracking technology 115 can provide different types of data depending on the tracking method used. Exemplary tracking data types include position values ​​for tracked items (e.g., anatomical structures, tools, etc.), ultrasound images, and collected points or axes of surfaces or landmarks. The tissue navigation system 120 provides anatomical locations, shapes, etc. to the surgical computer 150 as the system operates.

[0101] The display 125 is generally used to output data for presentation to a user, but may also provide data to the surgical computer 150. For example, for embodiments in which a monitor is used as part of the display 125, the surgeon 111 may interact with the GUI to provide input that is sent to the surgical computer 150 for further processing. In AR applications, the measured position and displacement of the HMD may be sent to the surgical computer 150 so that the presented view can be updated as needed.

[0102] During the postoperative phase of an episode of care, various types of data can be collected to quantify the overall improvement or deterioration of the patient's condition as a result of the surgery. Data can take the form of self-reported information reported by the patient, for example, via questionnaires. For example, in the context of knee replacement surgery, functional status can be measured using the Oxford Knee Score questionnaire, and postoperative quality of life can be measured using the EQ5D-5L questionnaire. Other examples in the context of hip replacement surgery can include the Oxford Hip Score, Harris Hip Score, and WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index). Such questionnaires can be administered, for example, by a healthcare professional directly in the clinical setting or using a mobile app that allows the patient to respond directly to questions. In some embodiments, the patient can be equipped with one or more wearable devices that collect data related to the surgery. For example, after knee surgery, the patient can be equipped with a knee brace that includes sensors that monitor knee positioning, flexibility, etc. This information can be collected and transferred to the patient's mobile device for review by the surgeon to evaluate the outcome of the surgery and address any issues. In some embodiments, one or more cameras can capture and record the movement of the patient's body segments during designated post-operative activities. This movement capture can be compared to a biomechanical model to better understand the functionality of the patient's joints, better predict recovery progress, and identify any possible modifications that may be required.

[0103] The postoperative phase of an episode of care can continue throughout the patient's lifetime. For example, in some embodiments, surgical computer 150 or other components, including CASS 100, can continue to receive and collect data related to a surgical procedure after the procedure is performed. This data can include, for example, images, answers to questions, "normal" patient data (e.g., blood type, blood pressure, conditions, medications, etc.), biometric data (e.g., gait, etc.), and objective and subjective data regarding specific issues (e.g., knee or hip pain). This data can be explicitly provided to surgical computer 150 or other CASS components by the patient or their physician. Alternatively, or additionally, surgical computer 150 or other CASS components can monitor the patient's EMR and retrieve relevant information as it becomes available. This longitudinal view of the patient's recovery allows surgical computer 150 or other CASS components to provide a more objective analysis of patient outcomes and measure and track the success, or lack thereof, of a given procedure. For example, a condition a patient experiences long after a surgical procedure can be linked back to the surgery through a regression analysis of various data items collected during the episode of care. This analysis can be further strengthened by performing the analysis on groups of patients who have similar procedures and / or similar anatomies.

[0104] In some embodiments, data is collected at a central location to provide easier analysis and use. In some instances, data can be collected manually from various CASS components. For example, a portable storage device (e.g., a USB stick) can be attached to the surgical computer 150 to capture data collected during surgery. The data can then be transferred to centralized storage, for example, via a desktop computer. Alternatively, in some embodiments, the surgical computer 150 is directly connected to the central storage via a network 175, as shown in FIG. 5C.

[0105] FIG. 5C illustrates a “cloud-based” implementation in which the surgical computer 150 is connected to the surgical data server 180 via a network 175. This network 175 may be, for example, a private intranet or the Internet. In addition to data from the surgical computer 150, other sources may transfer relevant data to the surgical data server 180. The example of FIG. 5C illustrates three additional data sources: the patient 160, medical personnel 165, and the EMR database 170. Thus, the patient 160 may send pre-operative and post-operative data to the surgical data server 180, for example, using a mobile app. The medical personnel 165 include the surgeon and their staff, as well as any other professionals working with the patient 160 (e.g., primary care physician, rehabilitation specialist, etc.). Note also that the EMR database 170 may be used for both pre-operative and post-operative data. For example, assuming the patient 160 has provided appropriate permission, the surgical data server 180 may collect the patient's pre-operative EMR. The surgical data server 180 can then continue to monitor the EMR for any updates post-operatively.

[0106] The surgical data server 180 uses an episode of care database 185 to store various data collected over a patient's episodes of care. The episode of care database 185 may be implemented using any technology known in the art. For example, in some embodiments, an SQL-based database may be used where all of the various data items are structured such that they can be easily incorporated into two SQL sets of rows and columns. However, in other embodiments, a No-SQL database may be used to allow for unstructured data while providing the ability to quickly process and respond to queries. As understood in the art, the term "No-SQL" is used to define a class of data storage that is non-relational in design. Various types of No-SQL databases may generally be grouped according to their underlying data model. These groupings may include databases that use a column-based data model (e.g., Cassandra), a document-based data model (e.g., MongoDB), a key-value-based data model (e.g., Redis), and / or a graph-based data model (e.g., Allego). Any type of No-SQL database may be used to implement the various embodiments described herein, and in some embodiments, different types of databases may support the episode of care database 185.

[0107] Data may be transferred between the various data sources and the surgical data server 180 using any data format and transfer technique known in the art. Note that the architecture shown in FIG. 5C allows for transmission of data from data sources to the surgical data server 180, as well as retrieval of data by the data sources from the surgical data server 180. For example, as described in more detail below, in some embodiments, the surgical computer 150 may use data from past surgeries, machine learning models, etc. to help guide the surgical procedure.

[0108] In some embodiments, the surgical computer 150 or surgical data server 180 may perform a de-identification process to ensure that data stored in the episode of care database 185 meets Health Insurance Portability and Accountability Act (HIPAA) standards or other requirements mandated by law. HIPAA provides a list of specific identifiers that must be removed from data during de-identification. The de-identification process described above may scan for these identifiers in data being transferred to the episode of care database 185 for storage. For example, in one embodiment, the surgical computer 150 performs the de-identification process immediately before initiating the transfer of a particular data item or set of data items to the surgical data server 180. In some embodiments, a unique identifier is assigned to data from a particular episode of care to allow for re-identification of the data if necessary.

[0109] While Figures 5A-5C discuss data collection in the context of a single episode of care, it should be understood that the general concept may be extended to data collection from multiple episodes of care. For example, surgical data may be collected across an entire episode of care each time a procedure is performed on CASS 100 and stored in surgical computer 150 or surgical data server 180. As described in further detail below, a robust database of episodes of care data enables the generation of optimized values, measurements, distances, or other parameters and other recommendations related to the surgical procedure. In some embodiments, various data sets are indexed in a database or other storage medium in a manner that allows for rapid retrieval of relevant information during the surgical procedure. For example, in one embodiment, a patient-centric index set may be used to allow for easy extraction of data regarding a particular patient or a set of patients similar to a particular patient. This concept may similarly be applied to surgeons, implant characteristics, CASS component versions, etc.

[0110] Further details of managing episodes of care data are described in U.S. Patent Application No. 62 / 783,858, filed December 21, 2018, entitled "Methods and Systems for Providing an Episode of Care," which is incorporated herein by reference in its entirety.

[0111] Open vs. Closed Digital Ecosystems In some embodiments, CASS100 is designed to operate as a self-contained or "closed" digital ecosystem. Each component of CASS100 is specifically designed for use in the closed ecosystem, and data generally cannot be accessed by devices outside the digital ecosystem. For example, in some embodiments, each component includes software or firmware that implements proprietary protocols for activities such as communication, storage, and security. The concept of a closed digital ecosystem may be desirable for companies that want to control all components of CASS100 to ensure that they meet certain compatibility, security, and reliability standards. For example, CASS100 may be designed so that new components cannot be used in the CASS unless certified by the company.

[0112] In other embodiments, CASS 100 is designed to operate as an "open" digital ecosystem. In these embodiments, components may be manufactured by a variety of different companies according to standards for activities such as communication, storage, and security. Using these standards, any company can then freely build independent, compliant components of the CASS platform. Data may be transferred between components using publicly available application programming interfaces (APIs) and open, shareable data formats.

[0113] To illustrate one type of recommendation that can be implemented using CASS 100, a technique for optimizing surgical parameters is disclosed below. The term "optimization" in this context refers to the selection of parameters that are optimal based on certain specified criteria. In extreme cases, optimization can refer to selecting optimal parameters based on data from an entire episode of care, including any preoperative data, the state of the CASS data at a given time point, and postoperative goals. Additionally, optimization can be implemented using historical data, such as data generated during previous surgical procedures involving the same surgeon, previous patients with similar physical characteristics to the current patient, etc.

[0114] The optimized parameters may depend on the portion of the patient's anatomy being operated on. For example, for knee surgery, the surgical parameters may include femoral and tibial component positioning information, including, but not limited to, rotational alignment (e.g., varus / valgus rotation, external rotation, flexion rotation of the femoral component, posterior slope of the tibial component), resection depth (e.g., genu varum, genu varum), and implant type, size, and position. Positioning information may further include combined implant surgical parameters, such as overall limb alignment, combined tibiofemoral hyperextension, and combined tibiofemoral resection. Additional examples of parameters that may be optimized for a given TKA femoral implant by CASS 100 include the following: [Table 1]

[0115] Additional examples of parameters that may be optimized for a given TKA tibial implant by CASS100 include: [Table 2]

[0116] For hip surgery, surgical parameters may include femoral neck resection location and angle, cup inclination angle, cup anteversion angle, cup depth, femoral stem design, femoral stem size, femoral stem fit within the canal, femoral offset, leg length, and femoral version of the implant.

[0117] Shoulder parameters may include, but are not limited to, humeral resection depth / angle, humeral stem version, humeral offset, glenoid version and inclination, and reverse shoulder parameters such as humeral resection depth / angle, humeral stem version, glenoid inclination / version, glenosphere orientation, glenosphere offset and offset direction.

[0118] Various conventional techniques exist for optimizing surgical parameters. However, these techniques are typically computationally intensive, and therefore, parameters often need to be determined preoperatively. As a result, surgeons have limited ability to modify optimized parameters based on potential issues during surgery. Furthermore, conventional optimization techniques typically operate as a "black box," with little or no explanation regarding the recommended parameter values. Thus, if a surgeon decides to deviate from the recommended parameter values, they typically do so without fully understanding the impact that deviation will have on the rest of the surgical workflow or the patient's postoperative quality of life.

[0119] Surgical Patient Care System The general concept of optimization can be extended to the entire episode of care using a surgical patient care system 620 that uses surgical data and other data from the patient 605 and medical personnel 630 to optimize outcomes and patient satisfaction, as shown in FIG.

[0120] Traditionally, preoperative diagnosis, preoperative surgical planning, intraoperative execution of the prescribed plan, and postoperative management for total joint arthroplasty are based on personal experience, published literature, and the surgeon's training knowledge base (ultimately, the individual surgeon's tribal knowledge and "network" of peers and journal publications), as well as their inherent ability to use guides and visual cues to perform accurate intraoperative tactile identification of "balance" and accurate manual execution of planar resections. This existing knowledge base and execution are limited in optimizing outcomes for patients requiring care. For example, limitations exist in accurately diagnosing patients for appropriate minimally invasive prescribed care; aligning dynamic patient, health economic, and surgeon preferences with the patient's desired outcome; executing surgical plans that result in appropriate bone alignment and balance; and receiving data from disparate sources with different biases that are difficult to align within a holistic patient framework. Therefore, data-driven tools that more accurately model anatomical responses and guide surgical planning can improve upon existing approaches.

[0121] The surgical patient care system 620 is designed to utilize patient-specific data, surgeon data, medical facility data, and historical outcome data to develop algorithms that propose or recommend optimal overall treatment plans for the patient's entire episode of care (preoperative, perioperative, and postoperative) based on desired clinical outcomes. For example, in one embodiment, the surgical patient care system 620 tracks adherence to the proposed or recommended plan and adjusts the plan based on patient / healthcare provider performance. Once a surgical treatment plan is completed, collected data is logged by the surgical patient care system 620 into a historical database. This database is accessible for future patient and future treatment plan development. In addition to leveraging statistical and mathematical models, simulation tools (e.g., LIFEMOD®) can be used to simulate outcomes, alignment, kinematics, etc. based on the preliminary or proposed surgical plan and reconfigure the preliminary or proposed plan to achieve desired or optimal results according to the patient's profile or surgeon's preferences. The surgical patient care system 620 ensures that each patient receives individualized surgical and rehabilitation care, thereby improving the likelihood of a successful clinical outcome and reducing the financial burden on the institution associated with short-term revisions.

[0122] In some embodiments, the surgical patient care system 620 employs data collection and management methods to provide a detailed surgical case plan with distinct steps that are monitored and / or executed using the CASS 100. User performance is calculated upon completion of each step and may be used to suggest changes to the next step in the case plan. The generation of the case plan relies on a set of input data stored in a local or cloud storage database. The input data may be associated with both the current patient receiving treatment and historical data from patients undergoing similar treatments.

[0123] The patient 605 provides inputs, such as current patient data 610 and historical patient data 615, to the surgical patient care system 620. Various methods commonly known in the art can be used to collect such inputs from the patient 605. For example, in some embodiments, the patient 605 fills out a paper or digital survey that is parsed by the surgical patient care system 620 to extract patient data. In other embodiments, the surgical patient care system 620 may extract patient data from existing sources, such as electronic medical records (EMRs), medical history files, and payer / provider history files. In still other embodiments, the surgical patient care system 620 may provide an application program interface (API) that allows external data sources to push data to the surgical patient care system. For example, the patient 605 may have a cell phone, wearable device, or other portable device that collects data (e.g., heart rate, pain or discomfort level, exercise or activity level, or patient-submitted responses to the patient's adherence to any number of pre-operative planning criteria or conditions) and provides that data to the surgical patient care system 620. Similarly, the patient 605 may have digital applications on their mobile or wearable device that allow them to collect and transmit data to the surgical patient care system 620.

[0124] Current patient data 610 may include, but is not limited to, activity level, pre-existing conditions, comorbidities, prehab performance, health and fitness level, preoperative expectations (related to hospital, surgery, and recovery), Metropolitan Statistical Area (MSA)-driven score, genetic background, previous injuries (sports, trauma, etc.), previous arthroplasty, previous trauma procedures, previous sports medicine procedures, treatment of the contralateral joint or limb, gait or biomechanical information (back and ankle issues), pain or discomfort level, care infrastructure information (payer coverage type, home health infrastructure level, etc.), and an indication of the expected ideal outcome of the procedure.

[0125] Historical patient data 615 may include, but is not limited to, activity level, pre-existing conditions, comorbidities, prehab performance, health and fitness level, preoperative expectations (related to hospital, surgery, and recovery), MSA-driven scores, genetic background, previous injuries (sports, trauma, etc.), previous arthroplasty, previous trauma procedures, previous sports medicine procedures, treatment of the contralateral joint or limb, gait or biomechanical information (back and ankle issues), pain or discomfort level, care infrastructure information (payer coverage type, home health infrastructure level, etc.), expected ideal outcome of the procedure, actual outcome of the procedure (patient-reported outcomes [PROs], implant survival, pain level, activity level, etc.), size of implant used, position / orientation / alignment of implant used, soft tissue balance achieved, etc.

[0126] The healthcare professional 630 performing the procedure or treatment may provide various types of data 625 to the surgical patient care system 620. This healthcare professional data 625 may include, for example, known or preferred surgical techniques (e.g., cruciate retention (CR) vs. posterior stabilization (PS), upsizing vs. downsizing, tourniquet vs. no tourniquet, femoral stem style, preferred approach for THA, etc.), the healthcare professional's 630 level of training (e.g., years, fellowship trained, where trained, what techniques are emulated), previous success levels (outcomes, patient satisfaction) including historical data, and expected ideal outcomes in terms of range of motion, recovery days, and device survival. The healthcare professional data 625 may be captured, for example, in a paper or digital survey provided to the healthcare professional 630, via entry into a mobile application by the healthcare professional, or by extracting relevant data from an EMR. Additionally, the CASS 100 may provide data such as profile data (e.g., a patient-specific knee instrument profile) or a history log describing the use of the CASS during surgery.

[0127] Information regarding the facility where the procedure or treatment will be performed may be included in the input data, including but not limited to: ambulatory surgery center (ASC) vs. hospital, facility trauma level, comprehensive care for joint replacement programs (CJR) or bundle candidates, MSA-driven score, community vs. metro, academic vs. non-academic, post-operative network access (skilled nursing facility [SNF] only, home health, etc.), medical professional availability, implant availability, and surgical equipment availability.

[0128] These facility inputs may be captured, for example, but not limited to, by surveys (paper / digital), surgery scheduling tools (e.g., apps, websites, electronic medical records [EMRs], etc.), databases of hospital information (on the internet), etc. Relevant health economic related input data may also be captured, including, but not limited to, the patient's socioeconomic profile, the expected level of reimbursement the patient will receive, and if the treatment is patient-specific.

[0129] These health economic inputs may be captured, for example, but not limited to, surveys (paper / digital), direct payer information, socioeconomic status databases (on the internet, including zip codes), etc. Finally, data derived from a simulation of the procedure is captured. Simulation inputs include implant size, location, and orientation. Simulations may be performed using custom or commercially available anatomical modeling software programs (e.g., LIFEMOD®, AnyBody, or OpenSIM). Note that the above data inputs may not be available for all patients, and treatment plans are generated using available data.

[0130] Prior to surgery, patient data 610, 615 and medical professional data 625 may be captured and stored in a cloud-based or online database (e.g., surgical data server 180 shown in FIG. 5C ). Procedure-related information is provided to the computing system via wireless data transfer or manually through the use of portable media storage. The computing system is configured to generate a case plan for use with CASS 100. The generation of the case plan is described below. Note that the system can access historical data from previous patients undergoing treatment, including implant size, placement, and orientation, as generated by a computer-assisted, patient-specific knee instrumentation (PSKI) selection system or automatically by CASS 100 itself. To accomplish this, case log data is uploaded to the historical database by a surgical sales representative or case engineer using an online portal. In some embodiments, data transfer to the online database is wireless and automated.

[0131] The historical data set from the online database is used as input to a machine learning model, such as a recurrent neural network (RNN) or other form of artificial neural network. As commonly understood in the art, an artificial neural network functions similarly to a biological neural network and is composed of a series of nodes and connections. The machine learning model is trained to predict one or more values ​​based on the input data. For the following sections, it is assumed that the machine learning model has been trained to generate predictor equations. These predictor equations can be optimized to determine the optimal size, location, and orientation of the implant to achieve the best outcome or satisfaction level.

[0132] Once the procedure is complete, all patient data and available outcome data, including implant size, position, and orientation as determined by CASS100, are collected and stored in a historical database. Any subsequent calculation of the target equation via the RNN includes data from previous patients in this manner, allowing for continuous improvement of the system.

[0133] In addition to, or as an alternative to, determining implant positioning, in some embodiments, predictor equations and associated optimization can be used to generate a resection plane for use with the PSKI system. When used with a PSKI system, calculation and optimization of the predictor equations is completed preoperatively. The patient's anatomy is estimated using medical imaging data (x-ray, CT, MRI). Global optimization of the predictor equations can provide the ideal size and position of the implant components. The Boolean intersection of the implant components and the patient's anatomy is defined as the resection volume. The PSKI can be created to remove the optimized resection envelope. In this embodiment, the surgeon cannot change the surgical plan intraoperatively.

[0134] The surgeon may modify the surgical case plan at any time before or during the procedure. If the surgeon chooses to deviate from the surgical case plan, the modified size, position, and / or orientation of the components is locked, and the global optimization is updated (using the techniques described above) based on the new size, position, and / or orientation of the components to find new ideal positions for the other components and the corresponding resections that need to be performed to achieve the newly optimized size, position, and / or orientation of the components. For example, if the surgeon determines that the size, position, and / or orientation of a femoral implant in a TKA needs to be updated or revised intraoperatively, the femoral implant position would be locked relative to the anatomy, and a new optimized position for the tibia would be calculated (via global optimization) to account for the surgeon's changes to the size, position, and / or orientation of the femoral implant. Furthermore, if the surgical system used to implement the case plan is robotically assisted (e.g., as with NAVIO® or MAKO Rio), bone removal and bone morphology can be monitored in real time during surgery. If the resections made during the procedure deviate from the surgical plan, the subsequent placement of additional components may be optimized by the processor, taking into account the actual resections already made.

[0135] FIG. 7A illustrates how a surgical patient care system 620 can be adapted to implement a case plan matching service. In this example, data is captured related to a current patient 610 and compared to all or a portion of a historical database of patient data and associated outcomes 615. For example, a surgeon may choose to compare the current patient's plan against a subset of the historical database. The data in the historical database may be filtered to include, for example, only data sets with favorable outcomes, data sets corresponding to historical surgeries of patients with the same or similar profile as the current patient's profile, data sets corresponding to a particular surgeon, data sets corresponding to specific elements of the surgical plan (e.g., only surgeries in which a particular ligament is preserved), or any other criteria selected by the surgeon or medical professional. For example, if the current patient data matches or correlates with that of a previous patient who experienced a favorable outcome, the previous patient's case plan can be accessed and adapted or adopted for use with the current patient. The predictor equations may be used in combination with intraoperative algorithms that identify or determine actions associated with the case plan. Based on relevant and / or preselected information from the historical database, the intraoperative algorithm determines a recommended course of action for the surgeon to perform. Each execution of the algorithm generates the next action in the case plan. When the surgeon performs the action, the results are evaluated. The results of the surgeon's execution of the action are used to refine and update the input to the intraoperative algorithm for generating the next step in the case plan. Once the case plan is fully executed, all data associated with the case plan, including any deviations implemented from the actions recommended by the surgeon, are stored in a database of historical data. In some embodiments, the system utilizes preoperative, intraoperative, or postoperative modules in a partial manner, as opposed to the entire continuum of care. In other words, the caregiver can prescribe any combination of replacement or treatment modules, including the use of a single module. These concepts are illustrated in FIG. 7B and may be applied to any type of surgery utilizing CASS 100.

[0136] Display of surgical process As described above with respect to FIGS. 1 and 5A-5C, the various components of CASS 100 generate detailed data records during surgery. CASS 100 can track and record the surgeon's various movements and activities during each step of the surgery and compare the actual activities to the pre-operative or intra-operative surgical plan. In some embodiments, software tools may be employed to process this data into a format in which the surgery can be effectively "played back." For example, in one embodiment, one or more GUIs may be used that show all of the information presented on display 125 during surgery. This may be supplemented with graphs and images showing data collected by different tools. For example, a GUI providing a visual depiction of the knee during tissue resection may provide the measured torque and displacement of the resection device adjacent to the visual depiction to better understand any deviations that occurred from the planned resection area. The ability to review a replay of the surgical plan, or to toggle between different stages of the actual surgery and the surgical plan, may benefit the surgeon and / or surgical staff, allowing them to identify any flaws or difficult stages of the surgery so that they can be corrected in future surgeries. Similarly, in an academic setting, the aforementioned GUI may be used as an educational tool to train future surgeons and / or surgical staff. Additionally, because the dataset effectively records many elements of a surgeon's activities, it may also be used for other reasons (e.g., legal or compliance reasons) as evidence of the correct or incorrect performance of a particular surgical procedure.

[0137] Over time, as more surgical data is collected, a rich library of data can be obtained describing surgical procedures performed on various types of anatomical structures (knees, shoulders, hips, etc.) by different surgeons on different patients. Additionally, information such as implant type and dimensions, patient demographics, etc. can be further used to enhance the overall dataset. Once the dataset is established, it can be used to train a machine learning model (e.g., an RNN) to make predictions about how the surgery will proceed based on the current state of CASS100.

[0138] Training of the machine learning model may be performed as follows: The overall state of CASS 100 may be sampled over multiple time periods during surgery. A machine learning model may then be trained to convert the current state at a first time period into a future state at a different time period. By analyzing the entire state of CASS 100 rather than individual data items, any causal relationships between interactions between different components of CASS 100 may be captured. In some embodiments, multiple machine learning models may be used rather than a single model. In some embodiments, the machine learning model may be trained using not only the state of CASS 100 but also patient data (e.g., captured from the EMR) and identities of surgical staff members. This allows the model to make predictions with even greater specificity. Furthermore, surgeons may selectively make predictions based solely on their own surgical experience, if desired.

[0139] In some embodiments, predictions or recommendations made by the aforementioned machine learning models may be directly integrated into the surgical workflow. For example, in some embodiments, the surgical computer 150 may run machine learning models in the background, making predictions or recommendations for future actions or surgical states. Thus, multiple states may be predicted or recommended for each time period. For example, the surgical computer 150 may predict or recommend states for the next five minutes in 30-second increments. Using this information, the surgeon may utilize a “process display” view of the surgery, allowing them to visualize future states. For example, FIG. 7C illustrates a series of images that may be displayed to the surgeon showing an implant placement interface. The surgeon can cycle through these images by, for example, entering a specific time into the display 125 of the CASS 100 or using haptic, oral, or other commands to instruct the system to advance or rewind the display by specific time increments. In one embodiment, the process display may be presented above the surgeon's field of view in the AR HMD. In some embodiments, the process display may be updated in real time. For example, as the surgeon moves the resection tool around the planned resection area, the process display can be updated so that the surgeon can see how their movements affect other factors in the surgery.

[0140] In some embodiments, rather than simply using the current state of CASS 100 as input to the machine learning model, the input to the model may include a planned future state. For example, a surgeon may indicate that he or she plans to make a particular bone resection in the knee joint. This indication may be manually entered into surgical computer 150, or the surgeon may provide the indication verbally. Surgical computer 150 can then create a filmstrip showing the predicted effect of the cut on the surgery. Such a filmstrip may show, for example, at specific time increments, how the surgery will be affected if the proposed course of action is performed, including changes in the patient's anatomy, changes in implant position and orientation, and changes related to surgical interventions and instruments. A surgeon or medical professional can launch or request this type of filmstrip at any point during surgery to preview how the proposed course of action will affect the surgical plan if the proposed action is performed.

[0141] Furthermore, with a well-trained machine learning model and robotic CASS, various elements of the surgery can be automated so that the surgeon only needs to be minimally involved, for example, by providing approval for various steps of the surgery. For example, robotic control using an arm or other means may be gradually integrated into the surgical workflow over time, gradually reducing the surgeon's involvement in manual interaction compared to robotic manipulation. In this case, the machine learning model can learn what robotic commands are required to achieve specific states of the CASS implementation plan. Ultimately, the machine learning model can be used to create a filmstrip or similar view or display that can predict and preview the entire surgery from an initial state. For example, an initial state can be defined, including patient information, surgical plan, implant characteristics, and surgeon preferences. Based on this information, the surgeon can preview the entire surgery to confirm that the CASS-recommended plan meets the surgeon's expectations and / or requirements. Furthermore, since the output of the machine learning model is the state of the CASS 100 itself, commands can be derived to control CASS components to achieve each predicted state. In extreme cases, the entire surgery can therefore be automated based solely on initial state information.

[0142] Using a point probe to obtain high resolution of critical areas during hip surgery The use of point probes is described in U.S. Patent Application No. 14 / 955,742, entitled "Systems and Methods for Planning and Performing Image-Free Implant Revision Surgery," which is incorporated herein by reference in its entirety. Briefly, an optically tracked point probe can be used to map the actual surface of a target bone requiring a new implant. Mapping is performed after removal of a defective or worn implant, as well as removal of any diseased or otherwise undesired bone. Multiple points are collected on the bone surface by brushing or scraping the tip of the point probe across the remaining bone. This is referred to as tracing or "painting" the bone. The collected points are used to create a three-dimensional model or surface map of the bone surface within a computerized planning system. The created 3D model of the remaining bone is then used as the basis for planning the procedure and the required implant size. Alternative techniques for determining 3D models using X-rays are described in U.S. patent application Ser. No. 16 / 387,151, entitled "Three-Dimensional Selective Bone Matching," filed April 17, 2019, and U.S. patent application Ser. No. 16 / 789,930, entitled "Three-Dimensional Selective Bone Matching," filed February 13, 2020, each of which is incorporated by reference in its entirety.

[0143] In hip joint applications, point probe painting can be used to obtain high-resolution data in critical areas such as the acetabular rim and acetabular fossa. This can enable the surgeon to obtain a detailed view before reaming begins. For example, in one embodiment, a point probe can be used to identify the acetabular floor (fossa). As is well understood in the art, in hip joint surgery, it is important to ensure that the acetabular floor is intact during reaming to avoid destruction of the medial wall. If the medial wall is inadvertently destroyed, the surgery requires an additional step of bone grafting. With this in mind, information from the point probe can be used to provide surgical guidelines to the acetabular reamer during the surgical procedure. For example, the acetabular reamer can be configured to provide haptic feedback to the surgeon when the surgeon reaches the floor or otherwise deviates from the surgical plan. Alternatively, CASS 100 can automatically stop the reamer when the floor is reached or when the reamer is within a threshold distance.

[0144] As an added safeguard, the thickness of the area between the acetabulum and the medial wall can be estimated. For example, once the acetabular rim and acetabular fossa have been painted and registered to the preoperative 3D model, thickness can be easily estimated by comparing the location of the acetabular surface to the location of the medial wall. Using this knowledge, CASS100 can provide a warning or other response if any surgical activity during reaming is predicted to protrude through the acetabular wall.

[0145] Point probes can also be used to collect high-resolution data of common reference points used to orient the 3D model to the patient. For example, for pelvic plane landmarks such as the ASIS and pubic symphysis, the surgeon can use a point probe to paint the bones to represent the true pelvic plane. With a more complete view of these landmarks, the registration software has more information to orient the 3D model.

[0146] Point probes can also be used to collect high-resolution data describing proximal femoral reference points, which can be used to enhance the accuracy of implant placement. For example, the relationship between the tip of the greater trochanter (GT) and the center of the femoral head is commonly used as a reference point for aligning femoral components during hip arthroplasty. Alignment is highly dependent on the proper location of the GT. Therefore, in some embodiments, point probes are used to paint the GT to provide a high-resolution view of the area. Similarly, in some embodiments, it may be useful to have a high-resolution view of the lesser trochanter (LT). For example, during hip arthroplasty, the Dorr classification helps select a stem that maximizes the ability to achieve a press-fit intraoperatively, prevents micromotion of the femoral component postoperatively, and ensures optimal bone ingrowth. As understood in the art, the Dorr classification measures the ratio between the canal width at the LT and the canal width 10 cm below the LT. The accuracy of the classification is highly dependent on the correct location of relevant anatomical structures. Therefore, it may be advantageous to paint the LT to provide a high-resolution view of the area.

[0147] In some embodiments, a point probe is used to paint the femoral neck, providing high-resolution data that allows the surgeon to better understand where to cut the neck. The navigation system can then guide the surgeon as they perform the neck cut. For example, as understood in the art, the femoral neck angle is measured by placing one line through the center of the femoral shaft and a second line through the center of the femoral neck. Thus, a high-resolution view of the femoral neck (and possibly the femoral shaft) will provide a more accurate calculation of the femoral neck angle.

[0148] High-resolution femoral head and neck data can also be used in navigated resurfacing procedures, where software / hardware assists the surgeon in preparing the proximal femur and placing the femoral component. As is commonly understood in the art, during hip resurfacing, the head and neck of the femur are not removed; rather, the head is trimmed and capped with a smooth metal coating. In this case, it would be advantageous for the surgeon to paint the femoral head and cap so that an accurate assessment of their respective shapes can be obtained and used to guide the trimming and placement of the femoral component.

[0149] Registration of preoperative data to patient anatomy using point probes As described above, in some embodiments, the 3D model is developed during the preoperative stage based on 2D or 3D images of the anatomical region of interest. In such embodiments, registration between the 3D model and the surgical site is performed before the surgical procedure. The registered 3D model can be used to track and measure the patient's anatomical structures and surgical tools intraoperatively.

[0150] During the surgical procedure, landmarks are acquired to facilitate registration of this preoperative 3D model to the patient's anatomy. For knee procedures, these points may include the center of the femoral head, a point on the distal femoral axis, the medial and lateral epicondyles, the medial and lateral malleolus, a point on the proximal tibial mechanical axis, and the tibial A / P direction. For hip procedures, these points may include the anterior superior iliac spine (ASIS), the pubic symphysis, points along and within the acetabular rim, the greater trochanter (GT), and the lesser trochanter (LT).

[0151] In revision surgery, the surgeon may paint specific areas containing anatomical defects to allow for better visualization and navigation of implant insertion. These defects may be identified based on analysis of preoperative images. For example, in one embodiment, each preoperative image is compared to a library of images showing "healthy" anatomy (i.e., without defects). Any significant deviations between the patient image and the healthy image may be flagged as potential defects. Then, during surgery, the surgeon may be alerted to the possible defects via a visual alert on the display 125 of the CASS 100. The surgeon can then paint the area to provide further details about the potential defects to the surgical computer 150.

[0152] In some embodiments, surgeons may use non-contact methods for registering internal incisions of bony anatomical structures. For example, in one embodiment, laser scanning is employed for registration. A laser stripe is projected onto the anatomical region of interest, and height variations in the region are detected as line changes. Other non-contact optical methods, such as white light interferometry or ultrasound, may alternatively be used for surface height measurement or anatomical structure registration. For example, ultrasound techniques are beneficial when there is soft tissue between the registration point and the bone being registered (e.g., the ASIS, the pubic symphysis in hip surgery), thereby providing a more accurate definition of the anatomical plane.

[0153] 8-10 , there is shown an exemplary joint extension device 10. The joint extension device 10 may be used in a robotic assistance system such as a CASS 100. The joint extension device 10 includes a bending arm 12, a load arm 14, force-sensing electronics 16, and a communication interface 18, although the joint extension device may include other types and / or numbers of elements in other combinations.

[0154] The relative position between the flexion arm 12 and the load arm 14 is manually adjustable. The joint extension device 10 advantageously allows for the manual application of a known force to a joint, such as a knee joint, that is adjustable by the user. The force data can be used as input to the CASS 100. For example, the force data can be used in conjunction with other data collected by the CASS 100, including position data, to provide data demonstrating how a joint responds to a particular load, the amount of joint laxity when a given load is applied, or other relevant information. By applying force at two known locations or contact points provided by the flexion arm 12 and the load arm 14, the applied force can be calculated more accurately. The joint extension device 10 allows for the magnitude of the applied extension force to be standardized in order to quantify joint laxity.

[0155] Referring again to FIGS. 8-10 , the flexion arm 12 includes an extension tip 20 and a handle 22. In this example, the extension tip 20 of the flexion arm 12 is shaped similarly to a PCL retractor, although the extension tip may have any other configuration or geometry, varying based on the joint in which the extension tip is intended to be used. The extension tip 20 is configured for insertion into a joint, such as a knee joint, as shown in FIG. 10 . The geometry of the extension tip 20 may be configured based on the geometry of the contacting bone to provide a more precise contact point within the joint than standard geometries. A more precise contact point allows for more accurate force measurements, as described below. The extension tip 20 includes a first extension surface 24 configured to contact a portion of the joint to apply a load or extension force to the joint. In the example of a knee joint, the first extension surface 24 is configured to be positioned in contact with the patient's femur to apply a load or extension force to the knee joint. A handle 22 is attached to and covers a portion of the bending arm 12. The handle 22 houses the sensing electronics 16 and communication interface 18 of the joint extension device 10, although the sensing electronics may be located elsewhere within the device.

[0156] The load arm 14 includes a load tip 26 and a load lever 28. The load tip 26 is configured for insertion into a joint, such as a knee joint. The load tip 20 includes a second extension surface 30 located opposite the first extension surface 24 of the extension tip 20, configured to contact a portion of the joint during use to apply a load or extension force to the joint. In the example of a knee joint, as shown in FIG. 10 , the second extension surface 30 is configured to be positioned in contact with the patient's tibia to apply a load to the knee joint. In this example, the load arm 14 is connected to the extension arm 12 at a pivot 32. The pivot 32 allows for manual separation of the extension tip 20 and the load tip 26 to allow a user to manually apply a load to the joint during operation of the joint extension device 10. Separation of the extension tip 20 and the load tip 26 is achieved using the load lever 28. Figure 9A shows the articulating extension device 10 in a closed position prior to separation of the extension tip 20 and the loading tip 26, while Figure 9B shows these elements in a separated or open position via manipulation of the pivot 32, which would be utilized to provide loading to the joint during use of the articulating extension device. As shown in Figure 9A, when the articulating extension device is in the closed position, the extension tip 20 and the loading tip 26 are aligned along a common axis.

[0157] The sensing electronics 16 may be positioned within the handle 22 of the bend arm 12. In this example, the sensing electronics 16 includes a strain gauge 34 attached to the bend arm 12, although other methods can be used to detect strain applied to the bend arm 12 during operation. By way of example only, the sensing electronics 16 may include other sensor devices, such as optical, pressure, magnetic, or electrical sensors, configured to determine the torque applied to the bend arm 12 of the joint extension device 10. The strain gauge 34 is configured to detect strain applied to the bend arm 12 during operation based on the load applied to the joint, although other types of sensor devices can be used to determine the force applied by the joint extension device. In one example, the strain gauge 34 is a solid-state strain gauge stored on a metal tip that can be welded to the joint extension device 10. In some examples, the strain gauge 34 can be stored in a glass coating to avoid the use of any adhesives. In this example, the strain gauge 34 advantageously has improved resistance to autoclaving. The strain gauge 34 is located at a fixed location from the pivot 32 between the flexion arm 12 and the load arm 14, so that the torque applied about the pivot can be approximated based on the strain data. As described in further detail below, the applied torque, along with an approximation of the contact location of the extension tip 20 and the load tip 26, can be used to quantify the force applied to the joint. In another example, multiple strain gauges can be used to provide an improved approximation of the contact point of the extension tip 20 and the load tip 26, as well as the direction of the load applied to the joint.

[0158] The sensing electronics 16 may include additional electronics necessary to capture strain data from the strain gauges 34, such as, for example, an analog-to-digital converter. In one example, the strain data may be transmitted via the communications interface 18 for remote processing, such as on the surgical computer 150 of the CASS 100, while in other examples, the sensing electronics 16 may include a highly integrated microcontroller device having various on-board hardware capabilities, such as analog-to-digital converters, digital-to-analog converters, a serial bus, general-purpose I / O pins, RAM and ROM, a processor, or configurable hardware logic configured to process the strain data within the joint extension device 10. In this example, the microcontroller device may be located within the housing of the joint extension device 10, such as in the handle 22. In this example, the sensing electronics 16 may be coupled to a display interface located on the handle 22 to display force information derived from the strain data, so that the joint extension device 10 may operate as a standalone device. In one example, the microcontroller device onboard the surgical computer 150 of the CASS 100 or the joint extension device 10 includes stored calibration data for the strain gauges 34 or other sensing devices used. For example, the calibration data may include a zero offset for the strain gauge 34, which indicates the electrical output of the strain gauge 34 when no load is applied to the joint extension device 10. The zero offset may vary depending on the strain gauge 34 used. The zero offset is used to set the no-load condition to a zero value for the tension applied to the joint. The calibration data also includes a calibration curve that correlates the measured strain value to the force applied to the joint by the joint extension device 10. In one example, the curve is a linear approximation between the measured strain and the applied force.

[0159] The communication interface 18 is coupled to the sensing electronics 16 by a bus 36 or other communication link to receive strain data collected by the strain gauges 34. In this example, the communication interface 18 operatively couples and communicates between the sensing electronics 16 of the joint extension device 10 and another computing device, such as the surgical computer 150 of the CASS 100, although in other examples, the joint extension device 10 may communicate information directly, such as on a display interface on the joint extension device 10, without using the communication interface 18. In this example, the communication interface 18 is a USB port configured to provide a wired connection to the surgical computer 150, although other communication protocols using other types and / or numbers of communication interfaces, including wireless communication protocols, may be used.

[0160] Although the exemplary joint extension device 10 is described as having a flexion arm 12 and a load arm 14 connected via a pivot 32, other configurations between the flexion arm 12 and the load arm 14 can be utilized to manually apply a load to the joint. By way of example only, and referring now to FIGS. 11A and 11B , in other examples, the flexion arm 12 is configured to translate away from the load arm 14 to provide separation between the flexion arm 12 and the load arm 14 and thereby apply a load force to the joint during use. These examples have the same structure and operation as the joint extension device 10, except as described below. In these examples, the flexion arm 12 remains parallel to the load arm 14 during translation. FIG. 11A illustrates a pair of parallel jaw pliers, providing an exemplary configuration of the joint extension device in this embodiment. FIG. 11B illustrates an exemplary ligament balancing device having a sliding or ratcheting mechanism that provides translational movement of the flexion arm 12 away from the load arm 14 to apply a load to the joint during use. In both examples, sensing electronics 16 may be positioned on flexion arm 12 to measure the amount of force applied to the joint. Flexion arm 12 and load arm 14 advantageously provide two contact points that may be utilized to more accurately measure the force applied to the joint using sensing electronics 16, as described below.

[0161] Referring to FIG. 12 , a flowchart of an exemplary operation of the joint extension device 10 is shown. In step 1200 of this example, a user (e.g., a surgeon or other medical professional) inserts the extension tip 20 and the load tip 26 into a joint area. In one example, the joint is a knee joint, as shown in FIG. 10 . The extension tip 20 is inserted so that the first extension surface 24 contacts the patient's fibula, while the load tip 26 is inserted so that the second extension surface 30 contacts the patient's tibia. Although a knee joint is shown and described, the joint extension device 10 can be utilized in other joints and configured accordingly. The joint extension device 10 is inserted in a closed configuration, as shown in FIG. 9A .

[0162] In step 1202, the user manually adjusts the articular extension device 10 to apply an extension force to the joint. As shown in FIG. 9B , the user adjusts the articular extension device using the load lever 28 to separate the extension tip 20 and the load tip 26 within the joint area. In this configuration, the articular extension device 10 applies a load or extension force to the joint based on manual manipulation of the load lever 28 and based on the contact point of the first extension surface 24 and the second extension surface 30. The amount of extension force can be manually varied by the user based on movement of the load lever 28, although extension force can be applied in other directions, such as by use in the configuration of FIGS. 11A and 11B .

[0163] In step 1204, the strain gauges 34 collect strain measurements based on the strain on the bending arm 12 resulting from the extension force applied to the joint. The strain measurements are obtained in real time. The sensing electronics 16 collects the strain measurements from the strain gauges 34 for further processing, including, for example, converting the analog strain measurements to digital signals. In one example, the strain measurements are processed within the joint extension device 10 by an integrated microcontroller or configurable hardware logic. Alternatively, the strain measurements can be communicated via the communications interface 18 to another computing device, such as the surgical computer 150 of the CASS 100, for processing.

[0164] In step 1206, the strain measurements are processed to determine the amount of force or load applied to the joint by the joint extension device 10 based on manual manipulation of the extension device. The strain gauge 34 is located at a fixed location from the pivot 32 between the flexion arm 12 and the load arm 14, so that the torque applied about the pivot can be approximated based on the strain data. As described in further detail below, the applied torque, along with an approximation of the location of contact of the extension tip 20 and the load tip 26, can be used to quantify the force applied to the joint. In one example, a model is utilized that estimates the force applied to the joint based on the applied torque and the location of contact of the extension tip 20 and the load tip 26. The applied force is provided to a user so that, in use, the joint extension device 10 can be used to apply a more accurate and repeatable load to a joint, such as a knee joint, than would be possible if the load were applied using an uninstrumented tool.

[0165] In one example, the extension device 10 may be utilized in a TKA procedure with a system such as the CASS 100, which also captures the position of the tibia and femur in real time. In this example, the surgeon is presented with data based on data obtained from the extension device 10, showing how the knee responds to specific loads, the amount of joint laxity when a given load is applied at certain positions, or other relevant information. The display 125 of the CASS 100 can provide additional relevant information about the knee joint, such as data about joint tension (e.g., ligament laxity) and information about joint rotation and alignment. The display 125 can also provide information about the amount of force applied to the knee from the extension device 10, showing how the planned implant location and position will affect the patient as the knee flexes, resulting in increased accuracy during the preoperative phase.

[0166] As described and illustrated by examples herein, the present technology advantageously provides a device that can be utilized to apply precise, repeatable, manually applied loads to a joint. For example, the ability to quantify the amount of force applied to a joint by a user through a tensioning device during ligament laxity acquisition provides more consistent input to a robotic surgical system. Standardizing this input reduces intraoperative interaction between the surgeon and planning software, ultimately resulting in a more efficient procedure with less variability in surgical outcomes. Use of the present device reduces the likelihood of recutting or resizing the tibial polyinsert, reducing over- or under-stressing of the joint during the ligament release phase, which can falsely indicate that the joint is too tight or too loose, leading to over- or under-cutting during bone resection.

[0167] While various illustrative embodiments incorporating principles of the present teachings have been disclosed, the present teachings are not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the present teachings and use their general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which these teachings pertain.

[0168] In the above detailed description, reference is made to the accompanying drawings, which form a part of this specification. In the drawings, like symbols typically identify like components unless context dictates otherwise. The exemplary embodiments described in this disclosure are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. The various features of the present disclosure, as generally described herein and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are expressly contemplated herein.

[0169] The present disclosure is not limited in terms of the specific embodiments described in this application, which are intended as illustrations of various features. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope thereof. Functionally equivalent methods and apparatuses within the scope of the present disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing description. It is to be understood that the present disclosure is not limited to particular methods, reagents, compounds, compositions, or biological systems, as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0170] With respect to the use of virtually any plural and / or singular term herein, those skilled in the art can translate from plural to singular and / or singular to plural as appropriate to the context and / or application. Various singular / plural arrangements may be expressly set forth herein for clarity.

[0171] In general, those skilled in the art will understand that the terms used herein are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including, but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "including, but not limited to," etc.). Although various compositions, methods, and devices are described in terms of "comprising" (interpreted as meaning "including, but not limited to") various components or steps, compositions, methods, and devices can also "consist essentially of" or "consist of" various components and steps, and such terms should be interpreted as defining essentially closed member groups.

[0172] Furthermore, even if a particular number is explicitly enumerated, one of ordinary skill in the art will recognize that such enumeration should be interpreted to mean at least the enumerated number (e.g., the bare enumeration of "two enumerations" without other qualifiers means at least two enumerations, or more than two enumerations). Furthermore, when a convention similar to "at least one of A, B, and C, etc." is used, such a structure is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Where a convention similar to "at least one of A, B, or C, etc." is used, such construction is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those skilled in the art that virtually any discrete word and / or phrase presenting two or more alternative terms, whether in the description, sample embodiments, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" would be understood to include the possibilities of "A" or "B," or "A and B."

[0173] Furthermore, where features of the present disclosure are described in terms of a Markush group, those skilled in the art will recognize that the present disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0174] As one skilled in the art would understand, for any and all purposes, such as providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of those subranges. Some recited ranges can be readily recognized as sufficiently descriptive and allow for the same range to be divided into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily divided into lower, middle, and upper thirds, etc. As one skilled in the art would also understand, all language, such as "up to," "at least," and the like, includes the recited numbers and refers to a range that can subsequently be effectively divided into subranges, as discussed above. Finally, as one skilled in the art would understand, a range includes each individual member. Thus, for example, a group having 1 to 3 members refers to a group having 1, 2, or 3 members. Similarly, a group having 1 to 5 members refers to a group having 1, 2, 3, 4, or 5, etc. members.

[0175] As used herein, the term "about" refers to variations in numerical values ​​that may occur through real-world measurement or handling procedures, for example, due to inadvertent errors in these procedures, differences in the manufacture, source, or purity of compositions or reagents, and the like. Typically, as used herein, the term "about" means greater or less than the stated value or range of values ​​by 1 / 10 of the stated value (e.g., ±10%). The term "about" also refers to variations that are recognized by those of ordinary skill in the art as equivalents, unless such variations encompass known values ​​practiced by the prior art. Each value or range of values ​​preceded by the term "about" is also intended to encompass embodiments of the stated absolute value or range of values. Whether modified by the term "about," quantitative values ​​recited in this disclosure include equivalents to the recited value, for example, variations in the numerical values ​​of such values ​​that may occur but would be recognized as equivalents by those of ordinary skill in the art.

[0176] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications, and various presently unforeseen or unanticipated substitutions, modifications, variations, or improvements therein may be made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.

Claims

1. 1. A joint extension system comprising: a joint extension device, the joint extension device comprising: a first arm having a first tip with a first geometry configured to align with a first location within the joint; a second arm having a second tip having a second geometry configured to align with a second location within the joint, the second arm coupled to the first arm such that the first tip and the second tip are joined together along an axis in a closed position and, in use, the first tip and the second tip are manually separated from one another to an open position to apply an extension force to the joint; a sensor device located within the first arm and positioned to measure a strain applied to the first tip based on the extension force applied to the joint; a computing device coupled to the sensor device, the computing device comprising: receiving the measured strain applied to the first tip from the sensor device; determining the extension force applied to the joint due to the manual separation of the first tip and the second tip based on the received measured strain applied to the first tip; receiving position data of the joint; and determining joint laxity of the joint using the joint position data when the extension force is applied to the joint across a contact surface provided by the first arm and the second arm; The joint extension system is configured to:

2. The joint extension system of claim 1 , wherein the first extremity and the second extremity are configured to contact a knee joint.

3. The joint extension system of claim 2 , wherein the first tip is configured to contact the femur and the second tip is configured to contact the tibia to apply the extension force to the knee joint.

4. 10. The joint extension system of any one of the preceding claims, wherein the first arm is configured as a PCL retractor.

5. 10. A joint extension system according to any one of the preceding claims, wherein the sensor device comprises one or more strain gauges.

6. The joint extension system of claim 5 , wherein the one or more strain gauges are embedded in a glass coating.

7. The joint extension system of claim 5 , wherein the sensor device comprises a plurality of strain gauges.

8. 10. The joint extension system of any one of the preceding claims, wherein the first arm is connected to the second arm at a pivot to allow manual separation between the first arm and the second arm to apply the extension force to the joint.

9. The joint extension system of claim 8 , wherein the sensor device comprises a strain gauge located a fixed distance from the pivot.

10. The joint extension system of any one of claims 1 to 7, wherein the first arm is configured to translate away from the second arm to provide the manual separation.

11. 10. The joint extension system of any one of the preceding claims, wherein the computing device is located within a housing of the joint extension device.

12. The joint extension system of claim 11 , wherein the joint extension device further comprises a display interface located on the housing and configured to display the extension force applied to the joint.

13. 10. A joint extension system according to any one of the preceding claims, wherein the computing device receives the measured strain values ​​in real time.

14. 10. The joint extension system of claim 1, wherein the computing device determines the extension force applied to the joint based on a calibration curve of the joint extension device stored on the computing device.

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