System and method for navigated reaming of an acetabulum with increased width

Abstract

A system and method for real-time navigation of acetabular reaming are disclosed. A first tracking element is coupled to the reamer. A second tracking element is coupled to or near the acetabulum. The first tracking element may be coupled to an outer casing that surrounds a portion of the shaft of the reamer. The depth and inclination angle of the reamer relative to the acetabulum are determined based on the positions of the first and second tracking elements. Based on the surgical plan, depth, and inclination angle, the volume of bone removed from the acetabulum can also be determined.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 366,654, filed on June 20, 2022, entitled SYSTEMS AND METHODS FOR NAVIGATED REAMING OF THE ACETABULUM, the entire disclosure of which is incorporated herein by reference. (Technical Field)

[0002] The present disclosure generally relates to methods, systems, and apparatuses related to computer - assisted surgical systems, including various hardware and software components that cooperate to enhance a surgical workflow. The disclosed techniques can be applied, for example, to hip arthroplasty.

Background Art

[0003] Total hip arthroplasty (THA) is generally considered to be one of the most successful procedures in orthopedic surgery. However, despite this general reputation, many complications related to the procedure still exist, including aseptic loosening, early dislocation after THA, and malpositioning. Some of these complications may be related to the surgical techniques deployed for THA and the surgeon's ability within the scope of surgical planning.

[0004] Specifically, acetabular reaming is an important step in THA that requires modeling and surgical planning. Even with appropriate planning, the surgeon must employ a high degree of accuracy during reaming to successfully perform the procedure according to the surgical plan.

[0005] In the past, computer-assisted surgical systems have approached acetabular reaming with direct volume sensing. For example, the positions of the tools and the bone may be tracked in 3D space, and their relative positions may be monitored during reaming. The relative 3D positions can be interpreted on a bone model to determine the voxels of bone to be removed during reaming.

[0006] However, tracking and evaluating individual voxels of bone is a complex process that requires more computing resources to perform real-time monitoring. Real-time calculations are important for guiding the surgeon during the reaming procedure. In particular, using tools such as reamers with very large heads can make voxel-by-voxel evaluation overly complex and complicate the real-time monitoring process.

[0007] Furthermore, high accuracy is required at the scale of individual voxels to perform volume tracking adequately. This is especially true during procedures such as reaming where the amount of bone removed is relatively small.

[0008] Surgeons would benefit greatly from real-time guidance and / or navigation tools that determine the path of the reamer and evaluate compliance with the surgical plan. Additionally, safety features that prevent reaming beyond the threshold margins of the surgical plan prevent postoperative complications and increase the overall success and satisfaction of the THA procedure. SUMMARY OF THE INVENTION

[0009] In some embodiments, a method of performing navigated reaming of an acetabulum includes receiving a surgical plan. The surgical plan may include one or more patient-specific parameters related to a total hip arthroplasty. The parameters may further include the location and orientation of a planned implant. The method of performing navigated reaming of the acetabulum further includes receiving a three-dimensional model of at least a portion of the acetabulum, providing a first tracking element associated with a reamer, providing a second tracking element associated with the acetabulum, receiving information associated with the geometric shape of the reamer, determining at least one of a depth and an inclination angle of the reamer with respect to the acetabulum and the location and orientation of a planned implant, and modifying the three-dimensional model based on the position of the first tracking element and at least one of the position of the second tracking element, the information associated with the geometric shape of the reamer, the depth, and the inclination angle.

[0010] In some embodiments, the method further includes comparing the inclination angle to a threshold angle range and automatically stopping or reducing the speed of the reamer in response to the inclination angle being outside the threshold angle range.

[0011] In some embodiments, the method further includes comparing the depth to a threshold depth and automatically stopping or reducing the speed of the reamer in response to the depth exceeding the threshold depth.

[0012] In some embodiments, the method further includes receiving the size of a reamer head.

[0013] In some embodiments, the method further includes generating a three-dimensional model of the reamer head and displaying, on a display device, the three-dimensional model of the reamer head relative to the three-dimensional model of at least a portion of the acetabulum.

[0014] In some embodiments, the method further includes generating an updated three-dimensional model of at least a portion of the acetabulum based on at least a portion of the acetabulum and a three-dimensional model of at least one of depth and inclination angle.

[0015] In some embodiments, the surgical plan includes a three-dimensional model of one or more planned modifications to the acetabulum, and the method further includes comparing the updated three-dimensional model of at least a portion of the acetabulum with the three-dimensional model of one or more planned modifications to the acetabulum, and based on the comparison, displaying a mark on the updated three-dimensional model of at least a portion of the acetabulum.

[0016] In some embodiments, receiving information associated with the geometry of the reamer further includes providing a third tracking element configured to interface with the reamer at a fixed position of the reamer head, and determining information associated with the geometry of the reamer based on the position of the first tracking element relative to the position of the third tracking element.

[0017] In some embodiments, providing a first tracking element associated with the reamer further includes joining the first tracking element to an outer casing of the reamer, the outer casing surrounding a portion of the shaft of the reamer, and the shaft being configured to rotate relative to the outer casing.

[0018] In some embodiments, the reamer is supported using a passive arm.

[0019] In some embodiments, the first tracking element is fixed to the passive arm.

[0020] In some embodiments, a method of performing navigated reaming of an acetabulum includes receiving a surgical plan. The surgical plan may include one or more patient-specific parameters related to a total hip arthroplasty. The parameters may further include the location and orientation of a planned implant. The method further includes providing a first tracking element associated with the reamer, providing a second tracking element registered with respect to the location and orientation of the planned implant, receiving information associated with the geometric shape of the reamer, determining at least one of the depth and tilt angle of the tool with respect to the location and orientation of the planned implant, and based on the position of the first tracking element, including the position of the second tracking element and information associated with the geometric shape of the reamer.

[0021] In some embodiments, a system for performing navigated reaming of an acetabulum includes a navigation tracking system, a reamer, a first tracking element attached to the reamer and configured to be tracked by the navigation tracking system, a second tracking element attached to the acetabulum and configured to be tracked by the navigation tracking system, and a processor in communication with the navigation tracking system. The processor may be configured to receive a surgical plan, the surgical plan including one or more patient-specific parameters related to a total hip arthroplasty, the parameters further including the location and orientation of a planned implant, receive a three-dimensional model of at least a portion of the acetabulum, determine at least one of the depth and tilt angle of the reamer with respect to the acetabulum and the location and orientation of the planned implant, and based on the position of the first tracking element, modify the three-dimensional model based on the position of the second tracking element and information associated with the geometric shape of the reamer, and based on at least one of the depth and tilt angle.

[0022] In some embodiments, the processor is further configured to compare the tilt angle to a threshold angular range and automatically stop or reduce the speed of the reamer in response to a tilt angle outside the threshold angular range.

[0023] In some embodiments, the processor is further configured to compare the depth to a threshold depth and automatically stop or reduce the speed of the reamer in response to a depth that exceeds the threshold depth.

[0024] In some embodiments, the processor is further configured to receive the size of the reamer head.

[0025] In some embodiments, the system further includes a display device. The processor can be further configured to generate a three-dimensional model of the reamer head and display the three-dimensional model of the reamer head relative to the three-dimensional model of at least a portion of the acetabulum on the display device.

[0026] In some embodiments, the processor is further configured to generate an updated three-dimensional model of at least a portion of the acetabulum based on at least a portion of the acetabulum and a three-dimensional model of at least one of the depth and the tilt angle.

[0027] In some embodiments, the surgical plan includes a three-dimensional model of one or more planned revisions to the acetabulum, and the processor is further configured to compare the updated three-dimensional model of at least a portion of the acetabulum with the three-dimensional model of one or more planned revisions to the acetabulum and, based on the comparison, display a mark on the updated three-dimensional model of at least a portion of the acetabulum.

[0028] In some embodiments, the system further includes a third tracking element configured to engage the reamer at a predetermined position of the reamer head. The processor can be further configured to determine information associated with the geometry of the reamer based on the position of the first tracking element relative to the position of the third tracking element. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles, features, and characteristics of the invention.

[0030]

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DETAILED DESCRIPTION OF THE INVENTION

[0031] The present disclosure is not limited to the specific systems, devices, and methods described. This is because they can change. The terms used in the description are for the purpose of describing only specific variations or embodiments and are not intended to limit the scope.

[0032] 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 in this specification have the same meaning as commonly understood by one of ordinary skill in the art. Nothing in this disclosure shall 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".

[0033] Definition For the purposes of the present disclosure, the term "implant" is used to refer to an artificial device or structure manufactured to replace or enhance a biological structure. For example, an artificial acetabular cup (implant) is used to replace or enhance a patient's worn or damaged acetabulum in a total hip arthroplasty. The term "implant" is generally considered to indicate an artificial structure (as opposed to a transplant), but for the purposes of this specification, an implant may include biological tissue or material transplanted to replace or enhance a biological structure.

[0034] For purposes of the present disclosure, the term "real-time" is used to refer to computations or operations that are carried out in situ when an event occurs or an input is received by an operational system. However, the use of the term "real-time" is not intended to exclude operations that introduce some latency between an input and a response, so long as the latency is an unintended result caused by the performance characteristics of the machine.

[0035] Much of the present disclosure refers to surgeons or other medical professionals in particular positions or roles, but nothing in the present disclosure is intended to be limited to a particular position or function. Surgeons or medical professionals can include any physician, nurse, medical professional, or technician. Any of these terms or positions can be used interchangeably with the users of the systems disclosed herein, unless otherwise explicitly specified. For example, references to surgeons can also apply to technicians or nurses in some embodiments.

[0036] The systems, methods, and devices disclosed herein are particularly well-suited for surgical procedures that utilize a surgical navigation system, such as the CORI® surgical navigation system. CORI is a registered trademark of SMITH & NEPHEW, INC. of Memphis, Tennessee.

[0037] Overview of the CASS Ecosystem FIG. 1 provides a view of an exemplary computer-assisted surgical system (CASS) 100 according to some embodiments. As will be described in more detail in the following sections, the CASS uses computer, robotics, and imaging technologies to assist a surgeon in performing orthopedic surgeries such as total knee arthroplasty (TKA) or total hip arthroplasty (THA). For example, a surgical navigation system can help a surgeon find a patient's anatomical structure, guide surgical instruments, and implant medical devices with a high degree of accuracy. Surgical navigation systems such as the 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 a surgeon to more accurately plan, track, and navigate the placement of instruments and implants relative to a patient's body, as well as perform pre-operative and intra-operative body imaging.

[0038] The effector platform 105 positions surgical tools relative to a 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 that holds a surgical tool or instrument during use. The end effector 105B can be a handheld device or instrument used by a surgeon (e.g., a CORI™ handpiece or cutting guide or jig), or alternatively, the end effector 105B can include a device or instrument held or positioned by a robotic arm 105A. Although one robotic arm 105A is shown in FIG. 1, in some embodiments, there may be multiple devices. By way of example, there could 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 adjacent to the table T on a floor platform (not shown), mounted on a pole from floor to ceiling, 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 pole from floor to ceiling that is 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 closing the wound. Further, 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.

[0039] The effector platform 105 may include a limb positioner 105C for positioning a patient's limb during surgery. An example of the limb positioner 105C is the SMITH AND NEPHEW SPIDER2 system. The limb positioner 105C may be manually operated by a surgeon or, alternatively, may change the limb position based on instructions received from a surgical computer 150 (described below). Although one limb positioner 105C is shown in FIG. 1, in some embodiments, multiple devices may exist. By way of 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 adjacent to the table T on a floor platform (not shown), mounted on a pole, or mounted to a wall or ceiling of the operating room. In some embodiments, the limb positioner 105C may be used in non-conventional ways such as a retractor or a 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 for assisting in wound closure.

[0040] The effector platform 105 may include tools such as a driver, light, or laser for indicating an axis or plane, a bubble level, a pin driver, a pin pusher, a flat checker, a pointer, a finger, or some combination thereof.

[0041] The resection device 110 (not shown in FIG. 1) performs bone or tissue resection using, for example, mechanical, ultrasonic, or laser technology. Examples of resection devices 110 include drill devices, burring devices, oscillating sawing devices, oscillating impact devices, reamers, ultrasonic bone cutting devices, radio frequency ablation devices, reciprocating devices (such as rasps or broaches), and laser ablation systems. In some embodiments, the resection device 110 is held and operated by a surgeon during surgery. In other embodiments, the effector platform 105 can be used to hold the resection device 110 during use.

[0042] The effector platform 105 may also include a cutting guide or jig 105D that is used to guide a saw or drill used to excise tissue during surgery. Such a cutting guide 105D can be integrally formed as part of the effector platform 105 or the robotic arm 105A, or the cutting guide can be a separate structure that can be fitted and / or removably attached to the effector platform 105 or the robotic arm 105A. The effector platform 105 or the robotic arm 105A can be controlled by the CASS 100 to position the cutting guide or jig 105D adjacent to the patient's anatomical structure according to a surgical plan developed preoperatively or intraoperatively, such that the cutting guide or jig produces accurate bone cuts according to the surgical plan.

[0043] Tracking system 115 uses one or more sensors to collect real-time position data that identifies a patient's anatomical structures 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 speed / acceleration of anatomical structures / measurements that can be used for tool control. In some embodiments, the tracking system 115 can use a tracker array attached to the end effector 105B to determine the location and orientation of 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, as well as 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.

[0044] Any suitable tracking system can be used to track the surgical target and the patient's anatomical structure within the surgical space. For example, a combination of an IR camera and a visible light camera can be used in an array. Various light sources, such as IR LED light sources, can illuminate the scene to enable three-dimensional imaging. In some embodiments, this may include imaging such as stereoscopic, trinocular, or quadrilateral viewing. In some embodiments, in addition to the camera array attached to the cart, additional cameras can be placed throughout the surgical space. For example, a handheld tool or a headset worn by the operator / surgeon can include imaging capabilities that communicate the images to a central processor and correlate those images with the images captured by the camera array. This can result in a more robust image of the environment for modeling using multiple viewpoints. Further, some imaging devices can have a suitable resolution or have a suitable viewpoint with respect to the scene to capture information stored in a quick response (QR) code or barcode. This can help identify certain objects not manually registered in the system. In some embodiments, the camera can be mounted on the robotic arm 105A.

[0045] However, as discussed herein, most of the tracking and / or navigation techniques 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 various reasons. For example, implantation of a standard optical tracker requires tissue resection (e.g., down to the cortex), followed by drilling and driving of cortical pins. Further, since optical trackers require a direct line of sight to the tracking system, the placement of such trackers may need to be far from the surgical site so as not to restrict the movement of the surgeon or medical staff.

[0046] In some embodiments, a particular object can be manually registered pre - or intra - operatively by a surgeon to the system. For example, by interacting with the user interface, the surgeon can identify the starting location of a tool or a bone structure. By tracking fiducial marks associated with that tool or bone structure, or by using other conventional image - tracking modalities, the processor can track the tool or bone in the three - dimensional model as it moves through the environment.

[0047] In some embodiments, specific markers, such as fiducial marks, that identify individuals, important tools, or bones within a space can include passive or active identifiers that can be picked up by a camera or camera array associated with the tracking system. For example, an IR LED can blink a pattern that conveys a unique identifier to the source of that pattern, providing a dynamic identification mark. Similarly, one - dimensional or two - dimensional optical codes (such as barcodes, QR codes, etc.) can be affixed to objects within the space to provide passive identification that can occur based on image analysis. If these codes are arranged asymmetrically on an object, these codes can further be used to determine the orientation of the object by comparing the location of the identifier to the extent of the object in the image. For example, a QR code can be placed at the corner of a tool tray, and the orientation and identity of the tray can be tracked. Other tracking modalities are described throughout. For example, in some embodiments, an augmented - reality headset can be worn by the surgeon and other staff to provide additional camera angles and tracking capabilities.

[0048] In addition to optical tracking, the physical characteristics of an object can be registered and associated with a trackable object such as a fiducial mark fixed to a tool or bone, thereby tracking specific features of the object. For example, a surgeon can perform a manual registration process in which the tracked tool and the tracked bone can be manipulated relative to each other. By pressing the tip of the tool against the surface of the bone, a three-dimensional surface can be mapped onto the bone in relation to its position and orientation relative to the reference frame of the fiducial mark. By optically tracking the position and orientation (pose) of the fiducial mark associated with the bone, the model of the surface can be tracked along with the environment via extrapolation.

[0049] The registration process of registering the CASS 100 to the relevant anatomical structure of the patient can also involve the use of anatomical landmarks such as landmarks on bone or cartilage. For example, the CASS 100 can include a 3D model of the relevant bone or joint, and the surgeon can use a probe connected to the CASS to collect intraoperative data regarding the location of the bone landmark on the patient's actual bone. The bone landmarks can include, for example, the medial and lateral condyles, the ends of the proximal femur and distal tibia, and the center of the hip joint. The CASS 100 can compare and register the location data of the bone landmark collected by the surgeon with the probe to the location data of the same landmark within the 3D model. Alternatively, the CASS 100 can construct a 3D model of the bone or joint using the location data of the bone landmark and the bone surface collected by the surgeon using the CASS probe or other means without preoperative image data. The registration process can also include determining the various axes of the joint. For example, for TKA, the surgeon can use the CASS 100 to determine the anatomical and mechanical axes of the femur and tibia. The surgeon and the CASS 100 can identify the center of the hip joint by moving the patient's leg in a spiral direction (i.e., abduction), thereby enabling the CASS to determine where the center of the hip joint is located.

[0050] The 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 ultrasonic systems.

[0051] The display device 125 provides a graphical user interface (GUI) that displays the images collected by the tissue navigation system 120, as well as other information related to the surgery. For example, in one embodiment, the display device 125 overlays image information collected from various modalities (e.g., CT, MRI, X-ray, fluorescence, ultrasound, etc.) collected preoperatively or intraoperatively to give the surgeon various views of the patient's anatomical structure and real-time condition. The display device 125 may include, for example, one or more computer monitors. As an alternative or supplement to the display device 125, one or more members of the surgical staff may wear an augmented reality (AR) head-mounted device (HMD). For example, in FIG. 1, the surgeon 111 is wearing an AR HMD 155 that may, for example, overlay preoperative image data on the patient or provide suggestions for the surgical plan. Various exemplary uses of the AR HMD 155 in surgical procedures are detailed in the following section.

[0052] Surgical computer 150 provides control instructions for various components of CASS 100, collects data from those components, and provides general processing for various data required during surgery. In some embodiments, surgical computer 150 is a general-purpose computer. In other embodiments, surgical computer 150 can be a parallel computing platform that uses multiple central processing units (CPUs) or graphics processing units (GPUs) to perform processing. In some embodiments, surgical computer 150 is connected to a remote server via one or more computer networks (e.g., the Internet). The remote server can be used, for example, for data storage or execution of computationally intensive processing tasks.

[0053] To connect surgical computer 150 to other components of CASS 100, various techniques generally known in the art can be used. Additionally, the computer can be connected to surgical computer 150 using a combination of techniques. For example, end effector 105B can be connected to surgical computer 150 via a wired (i.e., serial) connection. Tracking system 115, tissue navigation system 120, and display 125 can similarly be connected to surgical computer 150 using a wired connection. Alternatively, tracking system 115, tissue navigation system 120, and display device 125 can be connected to surgical computer 150 using wireless techniques including, but not limited to, Wi-Fi, Bluetooth, near field communication (NFC), or ZigBee.

[0054] Electrical Impact and Wide Acetabular Reamer Device Part of the flexibility of the CASS design described above with respect to FIG. 1 is that additional or alternative devices can be added to the CASS 100 as needed to support certain surgical techniques. For example, in the context of hip surgery, the CASS 100 may include a powered impact device. The impact device is designed to repeatedly apply an impact force that can be used by the surgeon to perform activities such as implant alignment. For example, in total hip arthroplasty (THA), the surgeon often uses an impact device to insert an artificial acetabular cup into the acetabulum of the implant host. Impact devices are typically manual (e.g., the surgeon operates by hitting the impact device with a mallet), but powered impact devices are generally easier and faster to use in a surgical setting. The powered impact device can be powered, for example, using a battery attached to the device. Various attachment pieces can be connected to the powered impact device so that the impact force can be directed in various ways as needed during the surgery. Also, in the context of hip surgery, the CASS 100 may include a motorized robot-controlled end effector for reaming the acetabulum to accommodate an acetabular cup implant.

[0055] In robotic-assisted THA, the patient's anatomical structure can be registered in the CASS 100 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 can be attached to the iliac crest using clamps and / or bone pins, and such trackers can be attached externally through the skin or internally (either posterolateral or anterolateral) through an incision made to perform the THA. For THA, the CASS 100 can utilize one or more femoral cortical screws inserted into the proximal femur as checkpoints to assist with the registration process. The CASS 100 can also utilize one or more checkpoint screws inserted into the pelvis as additional checkpoints to assist with the registration process. The femoral tracker array can be fixed or attached to the femoral cortical screw. The CASS 100 can adopt steps where registration is verified using a probe accurately placed by the surgeon on important regions of the proximal femur and pelvis identified for the surgeon on the display 125. The tracker can be located on the robotic arm 105A or the end effector 105B to register the arm and / or the end effector with the CASS 100. The verification step can also utilize proximal and distal femoral checkpoints. The CASS 100 can utilize color prompts or other prompts to inform the surgeon that the registration process of the relevant bone and the robotic arm 105A or the end effector 105B has been verified with a certain degree of accuracy (e.g., within 1 mm).

[0056] For THA, the CASS 100 can include a broach tracking option using a femoral array that enables the surgeon to capture the position and orientation of the broach during the procedure and calculate the length and offset values of the patient's hip joint. Based on information provided about the patient's hip joint and the position and orientation of the planned implant after broach tracking is complete, the surgeon can modify or adjust the surgical plan.

[0057] Regarding robotic-assisted THA, the CASS 100 may include one or more electric reamers that are connected or attached to the robotic arm 105A or the end effector 105B and prepare the pelvic bone to receive the acetabular implant according to the surgical plan. The robotic arm 105A and / or the end effector 105B can notify the surgeon and / or control the power of the reamer to ensure that the acetabulum is being resected (reamed) according to the surgical plan. For example, if the surgeon attempts to resect bone outside the boundaries of the bone to be resected 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 to turn off or release the robotic control of the reamer. The display 125 can use different colors to indicate the progress of the bone being resected (reamed) compared to the surgical plan. The surgeon can look at the display of the bone being resected (reamed) and guide the reamer to complete the reaming according to the surgical plan. The CASS 100 can provide the surgeon with a visual or audible prompt warning the surgeon that a resection not according to the surgical plan is being performed.

[0058] After learning, the CASS 100 can impact a test implant and a final implant against the acetabulum using a manual or powered impactor that is attached to or connected to the robotic arm 105A or the end effector 105B. The robotic arm 105A and / or the end effector 105B can be used to guide the impactor to impact the test and final implants against the acetabulum according to the surgical plan. The CASS 100 can cause the position and orientation of the test and final implants to occur with respect to the bone being displayed to inform the surgeon how to compare the orientation and position of the test and final implants to the surgical plan when the surgeon is treating the leg and hip joint, and the display device 125 can indicate the position and orientation of the implant. The CASS 100 can provide the surgeon with the option to replan and re-execute the reaming and implant impact by preparing a new surgical plan if the surgeon is not satisfied with the original implant position and orientation.

[0059] Preoperatively, the CASS 100 can develop a proposed surgical plan based on a three-dimensional model of the hip joint, as well as patient-specific other information such as the mechanical and anatomical axes of the leg bone, the superior condylar axis, the femoral neck axis, the dimensions (e.g., length) of the femur and hip joint, the mid-axis of the hip joint, the ASIS axis of the hip joint, and the location of anatomical landmarks such as the lesser trochanter landmark, the distal landmark, and the center of rotation of the hip joint. The surgical plan developed by the CASS can provide the recommended optimal implant size as well as the implant position and orientation based on the three-dimensional model of the hip joint and other patient-specific information. The surgical plan developed by the CASS can include proposed details regarding offset values, tilt and anteversion values, center of rotation, cup size, medialization value, superior-inferior fit value, and the size and length of the femoral stem.

[0060] Regarding THA, the surgical plan developed by CASS can be viewed preoperatively and intraoperatively, and the surgeon can modify the surgical plan developed by CASS preoperatively or intraoperatively. The surgical plan developed by CASS shows the planned resection on the hip joint, and based on the planned resection, the planned implant can be superimposed on the hip joint. CASS 100 can provide the surgeon with options for various surgical workflows based on the surgeon's preferences. For example, the surgeon can select from different workflows based on the number and type of anatomical landmarks to be checked and captured, and / or the location and number of tracker arrays used in the registration process.

[0061] According to some embodiments, the powered impact device used with CASS 100 can operate in a variety of different settings. In some embodiments, the surgeon adjusts the settings through a manual switch or other physical mechanism on the powered impact device. In other embodiments, for example, a digital interface that enables input of settings may be used via the touch screen of the powered impact device. Such a digital interface may be able to change the available settings based on, for example, the type of attachment component connected to the power attachment device. In some embodiments, instead of adjusting the settings of the powered impact device itself, the settings can be changed through communication with a robot or other computer system within CASS 100. Such a connection can be established, for example, using a Bluetooth or Wi-Fi networking module on the powered impact device. In another embodiment, the impact device and the end piece may include features that enable the impact device to recognize which end piece (cup impacter, broach handle, etc.) is attached without the need for action by the surgeon and adjust the settings accordingly. This can be achieved, for example, via a QR code, barcode, RFID tag, or other means.

[0062] Examples of settings that can be used include cup collision settings (e.g., single direction, specified frequency range, specified force and / or energy range), broach collision settings (e.g., bidirectional / vibratory at a specified frequency range, specified force, and / or energy range), femoral head collision settings (e.g., single direction / single blow at a specified force or energy), and stem collision settings (e.g., single direction at a specified frequency with a predetermined force or energy). Further, in some embodiments, the powered collision device includes settings related to the collision of the acetabular liner (e.g., single direction / single blow at a specified force or energy). There can be multiple settings for each type of liner, such as poly, ceramic, oxinium, or other materials. Additionally, the powered collision device can provide settings for different bone qualities based on pre-operative examination / image / knowledge by the surgeon and / or intraoperative evaluation. In some embodiments, the powered impactor device can have a dual function. For example, the powered impactor device can provide a reciprocating motion not only to provide a collision force but also to provide a reciprocating motion for a broach or rasp.

[0063] In some embodiments, the powered collision device includes a feedback sensor that collects data during use of the instrument and transmits the data to a computing device such as a controller within the device or the surgical computer 150. This computing device can then record the data for later analysis and use. Examples of data that can be collected include, but are not limited to, sound waves, the predetermined resonance frequency of each instrument, the reaction force or rebound energy from the patient's bone, the location of the device with respect to imaging (e.g., fluoroscopy, CT, ultrasound, MRI, etc.), and / or external strain gauges on the bone.

[0064] When 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 for THA (depth and / or orientation). Once the information is known, the information may be displayed for the surgeon's review or used to activate haptic or other feedback mechanisms to guide the surgical procedure.

[0065] Furthermore, the data derived from the aforementioned algorithms can be used to drive the operation of the device. For example, during the insertion of an acetabular cup in an electric impact device, the device can automatically extend the impact head (e.g., end effector) that moves the implant to the appropriate location or turn off the power to the device after the implant is fully seated. In one embodiment, the derived information can be used to automatically adjust the bone quality setting such that the electric impact device should use less power to reduce the risk of fracture of the femur / acetabulum / pelvis or damage to surrounding tissue.

[0066] Robot Arm In some embodiments, the CASS 100 includes a robotic arm 105A that functions as an interface for stabilizing and holding various instruments used during the surgical procedure. For example, in the context of hip surgery, these instruments may include, but are not limited to, retractors, sagittal or reciprocating saws, reamer handles, cup impacters, broach handles, and stem inserters. The robotic arm 105A may have multiple degrees of freedom (such as a Spider device) and may have the ability to be locked in place (e.g., by pressing a button, voice activation, the surgeon removing their hand from the robotic arm, or other means).

[0067] In some embodiments, the movement of robotic arm 105A can be caused by the use of a control panel incorporated within the robotic arm system. For example, the display screen may include one or more input sources such as physical buttons or user interfaces having one or more icons that are direct movements of robotic arm 105A. A surgeon or other medical practitioner can engage one or more input sources to position robotic arm 105A when performing a surgical procedure.

[0068] The tool or end effector 105B attached to or incorporated within robotic arm 105A can include, but is not limited to, a deburring device, scalpel, cutting device, retractor, joint extension device, and the like. In embodiments where end effector 105B is used, the end effector can be positioned at the end of robotic arm 105A such that any motor control operations are performed within the robotic arm system. In embodiments where a tool is used, the tool may be fixed to the distal end of robotic arm 105A, although the motor control operations may be present within the tool itself.

[0069] Robotic arm 105A may be internally motorized to stabilize both robotic arms, thereby preventing the robotic arms from falling and hitting the patient, operating table, surgical staff, etc., and enabling the surgeon to move the robotic arm without fully supporting its weight. While the surgeon is moving robotic arm 105A, the robotic arm can provide some resistance to prevent the robotic arm from moving too fast or having too many degrees of freedom become active at once. The position and locked state of robotic arm 105A can be tracked, for example, by a controller or surgical computer 150.

[0070] In some embodiments, the robotic arm 105A can be moved by hand (e.g., by a surgeon) or along with an internal motor to its ideal position and orientation for the task being performed. In some embodiments, the robotic arm 105A can be made operable in a "free" mode that allows the surgeon to position the arm at a desired location without being restricted. During the free mode, the position and orientation of the robotic arm 105A can still be tracked as described above. In one embodiment, a degree of freedom can be selectively released upon input from a user (e.g., a surgeon) during a particular portion of a surgical plan being tracked by the surgical computer 150. A design 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 a powered robotic arm, while an arm that is manually manipulated without power feedback but can be locked in place manually or automatically can be described as a passive robotic arm.

[0071] The robotic arm 105A or the end effector 105B may include a trigger or other means for controlling the power of the saw or drill. Engagement of the trigger or other means by the surgeon can shift the robotic arm 105A or the end effector 105B from the electric alignment mode to a mode in which the saw or drill is engaged and the power is on. Further, the CASS 100 may include a foot pedal (not shown) that causes the system to perform a particular function when activated. For example, the surgeon can activate the foot pedal to direct the CASS 100 to position the robotic arm 105A or the end effector 105B in an automatic mode that brings the robotic arm or end effector to an appropriate position relative to the patient's anatomical structure and performs the required resection. The CASS 100 can also position the robotic arm 105A or the end effector 105B in a collaborative mode that allows the surgeon to manually manipulate the robotic arm or end effector and position it at a particular location. The collaborative mode can be configured to allow the surgeon to move the robotic arm 105A or the end effector 105B in an inward or lateral direction while restricting movement in other directions. As discussed, the robotic arm 105A or the end effector 105B may include a cutting device (saw, drill, and burr), or a cutting guide or jig 105D that guides the cutting device. In other embodiments, the movement of the robotic arm 105A or the robot-controlled end effector 105B can be fully controlled by the CASS 100 without or with minimal assistance or input from the surgeon or other medical professional. In still other embodiments, the movement of the robotic arm 105A or the robot-controlled end effector 105B can be remotely controlled by the surgeon or other medical professional using, for example, a joystick or an interactive monitor or display control device, or a control mechanism separate from the robotic arm or robot-controlled end effector device.

[0072] The robotic arm 105A can be used to hold a retractor. For example, in one embodiment, the robotic arm 105A can be moved to a desired position by a surgeon. At this point, the robotic arm 105A can be locked in place. In some embodiments, data regarding the patient's position is provided so that the robotic arm 105A can adjust the retractor position accordingly if the patient moves. In some embodiments, multiple robotic arms may be used, thereby holding multiple retractors or performing two or more activities (e.g., holding a retractor and reaming) simultaneously.

[0073] The robotic arm 105A can also be used to assist in stabilizing the surgeon's hand while cutting the femoral neck. In this application, the control of the robotic arm 105A can impose certain limitations to prevent the occurrence of soft tissue damage. For example, in one embodiment, the surgical computer 150 tracks the position of the robotic arm 105A when the robotic arm 105A is activated. If the tracked location approaches an area where tissue damage is predicted, a command may be sent to the robotic arm 105A to stop. Alternatively, if the robotic arm 105A is automatically controlled by the surgical computer 150, the surgical computer can ensure that no commands that would cause the robotic arm to enter an area where soft tissue damage is likely to occur are provided to the robotic arm. The surgical computer 150 can impose certain limitations on the surgeon to prevent the surgeon from over-reaming the inner wall of the acetabulum or reaming at an incorrect angle or orientation.

[0074] In some embodiments, the robotic arm 105A can be used to hold a cup impacter at a desired angle or orientation during cup impact. Once the final position is achieved, the robotic arm 105A can prevent any further seating to prevent damage to the pelvis.

[0075] The surgeon can position the broach handle at a desired location using the robotic arm 105A, and the surgeon can impact the broach into the femur canal in a desired orientation. In some embodiments, when the surgical computer 150 receives feedback that the broach is fully fixed, the robotic arm 105A can limit the handle to prevent further advancement of the broach.

[0076] The robotic arm 105A can also be used for resurfacing applications. For example, the robotic arm 105A can provide certain constraints or limitations to stabilize the surgeon while using conventional instruments and to enable proper placement of implant components (such as guide wire placement, chamfer cutters, sleeve cutters, plunge 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 removing unintended bone in violation of the surgical plan.

[0077] 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, Muenchen, FED REP of GERMANY. In one particular embodiment, the robotic arm 105A is an intelligent holding arm as 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.

[0078] Generation and Collection of Surgical Procedure Data The various services provided by medical professionals to treat a clinical condition are collectively referred to as an "episode of care." For a particular surgical intervention, an episode of care can include three stages: pre-operative, intra-operative, and post-operative. Between each stage, data can be collected or generated to analyze the episode of care to understand the various characteristics of the procedure and identify patterns that can be used, for example, to train models to make decisions with minimal human intervention. The data collected over an episode of care can be stored as a complete data set in the surgical computer 150 or the surgical data server 180. Thus, for each episode of care, there exists a data set that collectively includes all pre-operative data for the patient, all data collected or stored intra-operatively by the CASS 100, and any post-operative data provided by the patient or by medical staff monitoring the patient.

[0079] As will be described in more detail, data collected during a care episode can be used to improve the performance of surgical procedures or to provide an overall understanding of surgical procedures and patient outcomes. For example, in some embodiments, data collected over a care episode can be used to generate a surgical plan. In one embodiment, a high-level preoperative plan is refined during the surgery as data is collected. In this way, the surgical plan can be seen as changing dynamically in real-time or near real-time as new data is collected by the components of the CASS 100. In other embodiments, preoperative images or other input data can be used to develop a robust plan preoperatively that is simply executed during the surgery. In this case, the data collected by the CASS 100 during the surgery can be used to make recommendations to ensure that the surgeon stays within the preoperative surgical plan. For example, if it is unclear how the surgeon is to achieve a particular predetermined cut or implant alignment, the surgical computer 150 can be asked for recommendations. In still other embodiments, the preoperative and intraoperative planning approaches can be combined such that a robust preoperative plan can be dynamically modified during the surgical procedure as needed or desired. In some embodiments, a biomechanics-based model of the patient's anatomical structure contributes to simulation data considered by the CASS 100 in the development of preoperative, intraoperative, and postoperative / rehabilitation procedures to optimize the patient's implant performance outcome.

[0080] Other than changing the surgical procedure itself, data collected during a care episode can be used as input into other procedures associated with the surgery. For example, in some embodiments, an implant can be designed using care episode data. Exemplary data-driven techniques for designing, sizing, and fitting implants are described in U.S. Patent Application No. 13 / 814,531, filed Aug. 15, 2011, entitled "Systems and Methods for Optimizing Parameters for Orthopaedic Procedures," U.S. Patent Application No. 14 / 232,958, filed Jul. 20, 2012, entitled "Systems and Methods for Optimizing Fit of an Implant to Anatomy," and U.S. Patent Application No. 12 / 234,444, filed Sep. 19, 2008, entitled "Operatively Tuning Implants for Increased Performance," the entire contents of each of which are incorporated herein by reference.

[0081] Further, the data can be used for educational, training, or research purposes. For example, using the network-based approach described later in FIG. 5C, other physicians or students can view the surgery remotely through an interface that allows selective viewing of data collected from various components of the CASS 100. After the surgical procedure, a similar interface can be used to "replay" the surgery for training or other educational purposes, or to identify sources of procedural problems or complications.

[0082] Data obtained during the preoperative phase generally includes all information collected or generated prior to surgery. Thus, for example, information regarding the patient can be obtained from the patient's intake form or electronic medical record (EMR). Examples of patient information that can be collected include, but are not limited to, patient demographics, diagnosis, medical history, progress notes, vital signs, historical information, allergies, and clinical test results. Preoperative data can also include images related to the anatomical region of interest. These images can 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 can also include quality of life data captured from the patient. For example, in one embodiment, the preoperative patient uses a mobile application (app) to answer a questionnaire regarding their current quality of life. In some embodiments, the preoperative data used by the CASS 100 includes patient demographics, anthropometrics, culture, or other specific traits regarding the patient that can be used to customize the surgical plan to match the activity level and specific activities of the patient. For example, a particular culture or patient background may be more likely to use a toilet that requires squatting daily.

[0083] Figures 2A and 2B provide examples of data that can be obtained during the intraoperative phase of a care episode. These examples are based on the various components of the CASS 100 described above with reference to FIG. 1, but it should be understood that other types of data can be used based on the type of instruments used during the surgery and their use.

[0084] Figure 2A shows an example of a portion of the control instructions provided by the surgical computer 150 to other components of the CASS 100, according to some embodiments. Note that the example of FIG. 2A assumes that the components of the effector platform 105 are each directly controlled by the surgical computer 150. In embodiments where the components are manually controlled by the surgeon 111, instructions may be provided on the display device 125 or the AR HMD 155 to instruct the surgeon 111 on how to move the components.

[0085] The various components included in the effector platform 105 are controlled by the surgical computer 150, which provides position commands that instruct the components where to move within the coordinate system. In some embodiments, the surgical computer 150 provides the effector platform 105 with instructions that define how the components of the effector platform 105 should react if they deviate from the surgical plan. These commands are referred to as "haptic" commands in FIG. 2A. 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.

[0086] In some embodiments, the end effector 105B of the robotic arm 105A is operably coupled to a 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 femur or tibia cut to be performed according to the surgical plan. Thereby, the possibility of error can be reduced, and its vision system and processor are utilized to implement the surgical plan, place the cutting guide 105D in the correct location and orientation with respect to the tibia or femur, and align the cutting slot of the cutting guide with the cut to be performed according to the surgical plan. Next, the surgeon can use any suitable tool, such as a vibrating or rotating saw or drill, to cut (or make a hole) in a perfect placement and orientation, since the tool is mechanically restricted by the features of the cutting guide 105D. In some embodiments, the cutting guide 105D may include one or more pin holes that are used by the surgeon to screw or pin the cutting guide with a drill before performing the resection of the patient's tissue using the cutting guide. This can free the robotic arm 105A or ensure that the cutting guide 105D is fully fixed without moving relative to the bone to be resected. For example, this technique can be used to make the first distal cut of the femur during total knee arthroplasty. In some embodiments where the arthroplasty is hip arthroplasty, the cutting guide 105D can be fixed to the femoral head or acetabulum for each hip arthroplasty resection. It should be understood that any arthroplasty that utilizes an accurate cut can use the robotic arm 105A and / or the cutting guide 105D in this way.

[0087] The resection device 110 is provided with various commands for operating on bone or tissue. Similar to the effector platform 105, position information may be provided to the resection device 110 to specify where it should be located when performing a resection. Other commands provided to the resection device 110 may depend on the type of resection device. For example, in the case of a mechanical or ultrasonic resection tool, 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.

[0088] Some components of the CASS 100 do not need to be directly controlled by the surgical computer 150. Rather, the surgical computer 150 may simply activate the components and then locally execute software that specifies a method for collecting data and providing it to the surgical computer 150. In the example of FIG. 2A, there are two components that are operated in this manner, the tracking system 115 and the tissue navigation system 120.

[0089] The surgical computer 150 provides the display device 125 with any visualization required by the surgeon 111 during the surgery. For the monitor, the surgical computer 150 may use techniques known in the art to provide instructions for displaying images, GUIs, etc. The display device 125 may include various parts of the surgical planning workflow. During the registration process, for example, the display 125 can show a 3D bone model constructed preoperatively and can show the location of the probe when the surgeon uses the probe to collect the locations of the patient's anatomical landmarks. The display 125 may include information about the surgical target area. For example, in relation to TKA, the display 125 can show the mechanical and anatomical axes of the femur and tibia. The display 125 can show the varus and valgus angles of the knee joint based on the surgical plan, and the CASS 100 can show how such angles are affected when the intended modifications to the surgical plan are made. Thus, the display device 125 is an interactive interface that can dynamically update and display how changes to the surgical plan affect the procedure of the implant attached to the bone as well as the final position and orientation.

[0090] As the workflow progresses towards preparation for bone cutting or resection, the display device 125 can show the planned or recommended bone cuts before any cuts are made. The surgeon 111 can manipulate the image display to provide different anatomical viewpoints of the target area and can have the option to change or modify the planned bone cuts based on the intraoperative assessment of the patient. The display 125 can show how the selected implant will be attached to the bone if the planned bone cuts are made. If the surgeon 111 selects to change a previously planned bone cut, the display device 125 can show how the modified bone cut will change the position and orientation of the implant when attached to the bone.

[0091] The display device 125 can provide the surgeon 111 with various data and information regarding the patient, the planned surgical intervention, and the implant. It can display various patient-specific information, including real-time data regarding the patient's health, such as heart rate, blood pressure, etc. The display device 125 can also include information regarding the anatomical structure of the surgical target area, including the location of landmarks, the current state of the anatomical structure (e.g., whether any resection has been performed, the depth and angle of planned and executed osteotomies), and the future state of the anatomical structure as the surgical plan progresses. The display device 125 can also provide or indicate additional information regarding the surgical target area. For TKA, the display device 125 can provide information regarding the gap between the femur and the tibia (e.g., gap balance), and how such a gap would change if the planned surgical plan were implemented. For TKA, the display device 125 can provide additional relevant information regarding the knee joint, such as data regarding the tension of the joint (e.g., ligament laxity), and information regarding the rotation and alignment of the joint. The display device 125 can show how the location and position of the planned implant would affect the patient as the knee joint bends. The display device 125 can show how the use of different implants, or different sizes of the same implant, would affect the surgical plan, and can preview how such implants would be positioned on the bone. The CASS 100 can provide such information for each of the planned osteotomies in TKA or THA. In TKA, the CASS 100 can provide robotic control for one or more of the planned osteotomies. For example, the CASS 100 can provide robotic control only for the first distal femoral osteotomy, and 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.

[0092] The display device 125 can adopt different colors to notify the surgeon of the status of the surgical plan. For example, the unexcised bone can be displayed in a first color, the excised bone can be displayed in a second color, and the planned resection can be displayed in a third color. The implant can be superimposed on the bone by the display device 125, and the color of the implant can vary or correspond to different types or sizes of the implant.

[0093] The information and options shown on the display device 125 can vary according to the type of surgical procedure to be performed. Further, the surgeon 111 can request or select a specific surgical workflow display that matches or conforms to the preferences of the surgical plan. For example, for the surgeon 111 who typically performs a tibial cut before a femoral cut in a TKA, the display device 125 and the associated workflow can be adapted taking this preference into account. The surgeon 111 can also pre-select whether a particular step is included in or removed from the standard surgical workflow display. For example, if the surgeon 111 uses resection measurements to finalize the implant plan but does not analyze the ligament gap balance when finalizing the implant plan, the surgical workflow display can be organized into modules, and the surgeon can 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 targeting ligament and gap balance can include, for example, pre- and post-resection ligament / gap balance, and the surgeon 111 can select which modules to include in the workflow of the given surgical plan depending on whether such ligament and gap balance is performed before or after (or both) bone resection.

[0094] For more specialized display devices, such as an AR HMD, the surgical computer 150 may provide images, text, etc. using the data formats supported by the device. For example, if the display device 125 is a holographic device such as Microsoft HoloLens™ or Magic Leap One™, the surgical computer 150 may use the HoloLens application program interface (API) to send commands that specify the position and content of the holograms to be displayed within the field of view of the surgeon 111.

[0095] In some embodiments, one or more surgical planning models may be incorporated into the CASS 100 and used in the development of surgical plans provided to surgeon 111. The term "surgical planning model" refers to software that simulates the performance of biological structures under various scenarios to determine the optimal way to perform cuts and other surgical activities. For example, for knee replacement surgery, the surgical planning model can measure parameters for functional activities such as deep knee flexion, walking, and select the cut location above the knee to optimize implant placement. An example of a surgical planning model is the LIFEMOD™ simulation software from SMITH AND NEPHEW, INC. In some embodiments, the surgical computer 150 includes a computing architecture that enables full execution of the surgical planning model (e.g., a GPU-based parallel processing environment) during surgery. In other embodiments, the surgical computer 150 may be connected via a network to a remote computer that enables such execution, such as a surgical data server. 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, instead of performing all simulations during surgery, the predictor equations are 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 on August 19, 2019, which is hereby incorporated by reference in its entirety.

[0096] FIG. 2B shows an example of some types of data that can 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 the surgery. In other embodiments, the components may queue the data and send it to the surgical computer 150 at set intervals (e.g., every second). The data can 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 may be configured with one or more software applications that enable translation of the data.

[0097] Generally, the surgical computer 150 may function as a central point where CASS data is collected. The exact content of the data varies depending on the source. For example, each component of the effector platform 105 provides the measured position to the surgical computer 150. Thus, by comparing the measured position with the position initially specified by the surgical computer 150 (see FIG. 2B), the surgical computer can identify the deviations that occur during the surgery.

[0098] The ablation device 110 can send various types of data to the surgical computer 150 depending on the type of device used. Exemplary data types that can be sent include measured torque, audio signature, and measured displacement values. Similarly, the tracking technique 115 can provide different types of data depending on the tracking method used. Exemplary tracking data types include the item being tracked (e.g., anatomical structure, tool, etc.), ultrasound images, and position values for the collection points or axes of the surface or landmarks. The tissue navigation system 120 provides the anatomical location, shape, etc. to the surgical computer 150 when the system is operating.

[0099] The display device 125 is generally used to output data for presentation to the user, but can also provide data to the surgical computer 150. For example, in embodiments where a monitor is used as part of the display 125, the surgeon 111 can interact with the GUI to provide inputs that are transmitted to the surgical computer 150 for further processing. In AR applications, the measured position and displacement of the HMD can be transmitted to the surgical computer 150 so that the presented view can be updated as needed.

[0100] One or more surgical parameters can be optimized in the CASS 100. For hip surgery, the surgical parameters can include the location and angle of femoral neck resection, cup tilt angle, cup anteversion angle, cup depth, femoral stem design, femoral stem size, fit of the femoral stem within the canal, femoral offset, leg length, and implant femoral version.

[0101] Obtaining High Resolution of Important Areas During Hip Surgery Using a Point Probe The use of a point probe is described in U.S. Patent Application No. 14 / 955,742, entitled "Systems and Methods for Planning and Performing Image Free Implant Revision Surgery", the entire disclosure of which is incorporated herein by reference. Briefly, an optically tracked point probe can be used to map the actual surface of the target bone that requires a new implant. The mapping is performed after removal of a defective or worn implant and also after removal of any diseased or otherwise undesirable bone. Multiple points are collected on the bone surface by brushing or scraping the entire remaining bone with the tip of the point probe. 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 a basis for planning the procedure and the required implant size. Alternative techniques for determining the 3D model using X-rays are described in U.S. Patent Application No. 16 / 387,151, entitled "Three-Dimensional Selective Bone Matching", filed on April 17, 2019, and U.S. Patent Application No. 16 / 789,930, entitled "Three-Dimensional Selective Bone Matching", filed on February 13, 2020, the entire disclosure of each of these applications being incorporated herein by reference.

[0102] In hip joint applications, high-resolution data can be obtained in important areas such as the acetabular rim and acetabular fossa using a point probe painting. This can enable the surgeon to obtain a detailed view prior to the start of reaming. For example, in one embodiment, the point probe can be used to identify the floor (fossa) of the acetabulum. As is well understood in the art, in hip joint surgery, it is important to ensure that the floor of the acetabulum is not damaged during reaming to avoid destruction of the medial wall. If the medial wall is inadvertently damaged, 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, the CASS 100 can automatically stop the reamer when it reaches the floor or when the reamer is within a threshold distance.

[0103] As an additional protection means, the thickness of the region between the acetabulum and the medial wall can be estimated. For example, once the acetabular rim and acetabular fossa are painted and registered to the preoperative 3D model, the thickness can be easily estimated by comparing the location of the surface of the acetabulum with the location of the medial wall. Using this knowledge, the CASS 100 can provide a warning or other response if any surgical activity is predicted to protrude through the acetabular wall during reaming.

[0104] The point probe 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 landmarks on the pelvic plane such as the ASIS and pubic symphysis, the surgeon can use the point probe to paint the bone to represent the true pelvic plane. Considering a more complete view of these landmarks, the registration software has more information for orienting the 3D model.

[0105] The point probe can also be used to collect high-resolution data that describes proximal femur 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 generally used as a reference point for aligning the femoral component during hip arthroplasty. Alignment depends greatly on the proper location of the GT. Thus, in some embodiments, the point probe is 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 in selecting a stem that maximizes the ability to achieve a press-fit during surgery, prevents minor movement 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 depends greatly on the correct location of the relevant anatomical structures. Thus, it may be advantageous to paint the LT to provide a high-resolution view of the area.

[0106] In some embodiments, the point probe is used to paint the femoral neck to provide high-resolution data that enables the surgeon to better understand where to cut the neck. The navigation system can then guide the surgeon when performing the neck cut. For example, as understood in the art, the angle of the femoral neck is measured by placing one line at the center of the femoral shaft and a second line at the center of the femoral neck. Thus, a high-resolution view of the femoral neck (and optionally, the femoral shaft) will provide a more accurate calculation of the femoral neck angle.

[0107] High-resolution femoral head and neck data can also be used in navigated resurfacing procedures where software / hardware assists the surgeon in the preparation of the proximal femur and the placement of femoral components. As is generally understood in the art, during resurfacing of the hip joint, the head and neck of the femur are not removed; rather, the head is trimmed and covered with a smooth metal coating. In this case, it would be advantageous for the surgeon to paint the femoral head and cap, such that an accurate assessment of the respective geometric shapes can be understood and used to guide the trimming and placement of the femoral components.

[0108] Registration of Preoperative Data to the Patient's Anatomical Structure Using a Point Probe As described above, in some embodiments, a 3D model is developed during the preoperative phase 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 prior to the surgical procedure. The registered 3D model can be used to track and measure the patient's anatomical structure and surgical tools during the surgery.

[0109] During the surgical procedure, fiducials are acquired to facilitate registration of this preoperative 3D model to the patient's anatomical structure. For knee procedures, these points can include the center of the femoral head, points on the distal femoral axis, the medial and lateral condyles, the medial and lateral epicondyles, points on the proximal tibial mechanical axis, and the tibial A / P orientation. For hip procedures, these points can include the anterior superior iliac spine (ASIS), the pubic symphysis, points along the acetabular rim and within the hemisphere, the greater trochanter (GT), and the lesser trochanter (LT).

[0110] In a revision surgery, the surgeon may paint a specific area, including an anatomical defect, to enable better visualization and navigation of implant insertion. These defects can be identified based on the analysis of preoperative images. For example, in one embodiment, each preoperative image is compared to a library of images showing "healthy" anatomical structures (i.e., without defects). Some significant deviations between the patient's image and the healthy image can be flagged as potential defects. During the surgery, the surgeon may then be warned about the possibility of a defect via a visual alert on the display device 125 of the CASS 100. The surgeon can then paint the area and provide further details regarding the potential defect to the surgical computer 150.

[0111] In some embodiments, the surgeon may use a non-contact method for the registration of the internal incision of the bone's anatomical structure. For example, in one embodiment, a laser scan is employed for registration. The laser stripe is projected onto the anatomical area of interest, and the deformation of the height of the area is detected as a change in the line. Other non-contact optical methods such as white light interferometry or ultrasonic methods can alternatively be used for surface height measurement or registration of the anatomical structure. For example, ultrasonic technology is beneficial when there is soft tissue between the registration points and the bone to be registered (e.g., ASIS, symphysis pubis in hip surgery), thereby enabling a more accurate definition of the anatomical plane.

[0112] Navigated Reaming of the Acetabulum As discussed herein, images of the acetabulum can be collected preoperatively or intraoperatively using MRI, CT, X-ray, ultrasound, or any other modality known in the art. Alternatively, a point probe can be used to map the actual surface of the acetabulum. Using data collected from one or a combination of the above techniques, a three-dimensional model of at least a portion of the acetabulum may be generated.

[0113] Figure 3 shows an exemplary graphical user interface 300 for configuring an implant placement for THA according to one embodiment. The graphical user interface 300 may depict an implant interfaced to a three-dimensional model of the acetabulum from one or more views. The views may include a plan view or a three-dimensional view. One or more of the views may be interactive to enable a surgeon to move the implant relative to the acetabulum. The graphical user interface 300 may depict variables associated with the implant (e.g., cup diameter) and the hip (e.g., abduction, flexion, and torsion). The system may provide an optimal placement and / or sizing of the implant. The implant placement may include the position and orientation of the implant. The variables associated with the implant may be configurable by the surgeon. The variables associated with the hip joint may be given values recommended by the surgeon and the system may use them to provide an optimized implant position and / or sizing. Information generated by the system and / or surgeon interfacing with the graphical user interface 300 may be compiled into a surgical plan. The surgical plan may include a modified version of the three-dimensional model including the planned resection of bone.

[0114] Figure 4 shows an environment 400 for navigated acetabular reaming according to one embodiment. The reamer may comprise a shaft 403 configured to drive a reamer head 402. The shaft 403 may be joined to a surgical drill (not shown). In some embodiments, the reamer may further comprise an outer casing 404 of the shaft 403. The outer casing 404 may be configured to remain stationary while the shaft 403 is rotating. The surgical drill may be manually operated by a surgeon. The surgical drill may be joined to a robot and / or a passive arm. As an example, the robot and / or passive arm may partially limit the manual movement of the surgical drill along a predetermined plane, line, or zone relative to the acetabulum 401 based on the position of the reamer head 402 defined in the surgical plan and determined using the methods herein.

[0115] Within the environment 400, at least two tracking elements may be provided, with at least one tracking element 405 attached to the patient's anatomical structure at or near the acetabulum 401 and at least one tracking element 406 attached to the reamer. The tracking element 406 attached to the reamer may be attached to any non-rotating part of the reamer, such as the base, handle, outer casing 404, and / or robot / passive arm, as long as the spatial relationship with the reamer head 402 is known. The element 406 is preferably positioned and oriented so as not to cause interference during reaming, i.e., to avoid contacting each other and the patient's anatomical structure, the surgical drill, the reamer, and / or other objects within the surgical environment. Although an optical tracker is shown, any tracking method (e.g., EM, optical code, fiber optic) or combination thereof may be used.

[0116] The reamer may communicate with the CASS 100 via any known means including wired (e.g., universal serial bus) and wireless (e.g., 802.11 or Bluetooth®) communication systems.

[0117] The CASS 100 may also receive information related to the geometric shape of the reamer, including the position of the tracking element 406 relative to the distal end of the reamer head 402. The information may further include the size of the reamer head 402. A portion of the information may be specified in the surgical plan and / or provided during the surgery. A portion of the information may be manually input through the user interface or collected by other techniques. As an example, the CASS 100 may scan an element (e.g., barcode, QR code, or RFID chip) associated with the reamer, which may refer the system to a database entry encoding or storing the information. In another embodiment, the CASS 100 may identify the reamer through image recognition technology and search for information in the database.

[0118] During the procedure, the CASS 100 may determine the depth 412 of the reamer relative to the acetabulum 401 based on the respective positions of the tracking elements 405 / 406, the three-dimensional model of the acetabulum 401, and the geometric information regarding the reamer. The depth 412 may measure the distance that the distal end of the reamer head 402 has been reamed into the acetabulum 401. The depth 412 may be measured along the axis of the shaft 403 of the reamer.

[0119] During the procedure, the CASS 100 may determine the inclination angle 411 of the reamer. The inclination angle 411 may be determined with respect to any plane 410 based on the respective positions of the tracking elements 405 / 406, the three-dimensional model of the acetabulum 401, and the geometric information regarding the reamer. The plane may be pre-determined by the surgeon as part of the surgical plan or may be selected by the CASS 100. In some embodiments, the plane 410 may be translated based on the depth 412. By way of example, the plane 410 may be the anteroposterior plane. In another example, the plane 410 may be a plane parallel to the anteroposterior plane defined by the adjacency of the plane to the distal point of the reamer head 402. In a third example, the plane 410 may be a plane that intersects the acetabulum 401 and / or is randomly pre-selected near the acetabulum 401. Determining the inclination angle 411 may include projecting the axis of the shaft 403 of the reamer onto the plane 410 and calculating the angle between the axis of the shaft 403 and the projection line.

[0120] Based on the depth 412 and the inclination angle 411 of the reamer with respect to the acetabulum 401, the CASS 100 may determine the volume of bone removed from the three-dimensional model. FIG. 5 shows an exemplary graphical user interface 500 for navigated acetabular reaming according to one embodiment. The graphical user interface 500 may depict a portion of the three-dimensional model of the acetabulum 501. The graphical user interface 500 may depict the position of the reamer head 502 with respect to the three-dimensional model 501.

[0121] The region 510 of the three-dimensional mode 501 can be coded based on the volume of bone removal required at a location based on a surgical plan. The coding may be based on color, symbol, and / or pattern. As an example, if region 510 requires a relatively large amount of reaming to reach the target depth of the region based on the surgical plan, region 510 may be green. The region may change color through the yellow, orange, and red spectra as the region approaches the target depth. In another embodiment, region 510 may be a stripe, and the density of the stripe correlates with the change in depth required to reach the target depth of the surgical plan. One skilled in the art will recognize that any color, symbol, or pattern can be used to specify the remaining volume of the three-dimensional model 501 that requires reaming. Additional information may also be coded for each region. As an example, color, symbol, and / or pattern may visually depict the estimated bone density of the region.

[0122] The thresholds between the various coding colors, symbols, and / or patterns may be based on a predetermined distance between the surface of the three-dimensional model and the planned modification of the surgical plan. In response to a change in the threshold and / or contact between the bone and the reamer, the CASS 100 can warn the surgeon. The warning may be audible, visual, and / or tactile.

[0123] Based on the determined depth of the reamer, the inclination angle of the reamer, and the shape of the reamer, the reamer head 502 can be continuously tracked relative to the acetabulum. The CASS 100 can operate assuming that the estimated volume occupied by the reamer head 502 overlaps with the volume of the three-dimensional model 501 from which the bone overlap volume has been removed in the patient. The three-dimensional model 501 may be modified based on the reamer head 502 and the estimated overlap of the three-dimensional model 501. The modification may include removing the volume of the model 501 within the overlap.

[0124] The graphical user interface 500 may feature one or more interface elements. Exemplary elements may include a manual input from the reamer diameter and one or more inputs 522 for manipulating the perspective of the three-dimensional model 501 (i.e., field of view, pan, and zoom). Those skilled in the art will note that due to the low processing requirements of the method for positioning the reamer relative to the acetabulum, the display may depict the real-time status (i.e., volume) and relative position of the acetabulum and the reamer.

[0125] Figure 6 shows an exemplary graphical user interface for navigated acetabular reaming, according to one embodiment. The graphical user interface 600 may depict a portion of the three-dimensional model of the acetabulum 501. The graphical user interface 600 may depict the position of the reamer head 502 relative to the three-dimensional model 501.

[0126] Regions of the three-dimensional mode 501 may be coded based on the surgical plan and based on the volume of bone removal required at a given location. The coding may be based on color, symbols, and / or patterns, as described above with reference to FIG. 5. The three-dimensional model 501 may be modified based on the reamer head 502 and the estimated overlap of the three-dimensional model 501. The modification may include removing the volume of the model 501 within the overlap.

[0127] As the region approaches a depth specified by the surgical plane, region 601 can be coded to identify that the region does not require additional bone removal. As an example, region 601 may be red. Separate coding may exist to alert the surgeon that region 602 is at and / or beyond a threshold depth specified within the surgical plan. As an example, region 602 may be black. In a scenario where the reamer head 502 contacts region 602 at and / or beyond the threshold depth, the reamer can be automatically stopped, its speed reduced, and / or its movement restricted. For example, the CASS 100 can deactivate the surgical drill and / or reamer 502 to prevent further reaming in such a region 602. In some embodiments, in response to a region approaching, reaching, and / or exceeding the threshold depth, the CASS 100 can provide a warning to the surgeon. The warning may be audible, visual, and / or tactile.

[0128] In certain embodiments, the three-dimensional model may be an atlas model selected from a database. The atlas model can be selected based on a comparison of one or more features of the patient's anatomical structure. The atlas model may be selected using a machine learning algorithm. The atlas model can be transformed to more accurately match the patient's anatomical structure based on data collected through standard imaging, MRI, CT, X-ray, ultrasound, a point probe, and / or manual input. As an example, an atlas model similar to the patient's anatomical structure may be selected based on landmarks detected by X-ray. The model can then be scaled to match the patient's dimensions. The scaled model can be used to determine implant placement. Next, the scaled model may be further modified during the procedure using a point probe to accurately model the bone that requires reaming.

[0129] In certain embodiments, a three-dimensional model of the acetabulum may not be available. Tracking elements 405 attached to the patient's anatomical structure may be registered to the planned implant placement. The volume of bone that requires resection beyond the planned implant placement may be captured during the procedure (i.e., using imaging and / or a point probe).

[0130] During the procedure, the CASS 100 may determine the depth 412 of the reamer relative to the planned implant position based on the respective positions of the tracking elements 405 / 406 and the geometric information regarding the reamer. The depth 412 may measure the distance between the distal end of the reamer head 402 and the surface of the planned implant position. The depth 412 may be measured along the axis of the reamer shaft 403.

[0131] During the procedure, the CASS 100 may determine the inclination angle 411 of the reamer. The inclination angle 411 may be determined with respect to any plane 410 based on the respective positions of the tracking elements 405 / 406, the planned implant position, and the geometric information regarding the reamer. The plane may be predetermined by the surgeon as part of the surgical plan or may be selected by the CASS 100. In some embodiments, the plane 410 may translate based on the depth 412. By way of example, the plane 410 may be the anteroposterior plane. In another example, the plane 410 may be a plane parallel to the anteroposterior plane defined by the adjacency of the plane to the distal point of the reamer head 402. In a third example, the plane 410 may be a plane that intersects the acetabulum 401 and / or is randomly preselected near the acetabulum 401. Determining the inclination angle 411 may include projecting the axis of the reamer shaft 403 onto the plane 410 and calculating the angle between the shaft 403 axis and the projection line.

[0132] In certain embodiments, CASS 100 may not have information associated with bone volume exceeding the planned implant placement. In further embodiments, CASS 100 may determine the position of the bone based on the torque applied to the reamer when interacting with the bone. As an example, prior to contacting the bone with the reamer, the display may depict the position of the reamer head relative to the planned implant position. After detecting the torque on the reamer, the display may be updated to reflect information similar to that described with reference to FIGS. 5 and 6.

[0133] In other embodiments, the display may depict colors, symbols, and / or patterns on the area of the planned implant placement in response to the reamer head reaching the planned implant placement and / or at a threshold near the planned implant placement.

[0134] FIG. 7 shows an exemplary environment 700 with boundaries for the control of a reamer during navigated acetabular reaming, according to one embodiment. One or more boundaries may be established to manage the control of the reamer. In response to the surgeon reaching a boundary, CASS 100 may deactivate and / or activate the reamer, reduce the rotational speed of the reamer, limit the movement of the reamer, and / or alert the surgeon. The alert may be audible, visual, and / or tactile. Boundaries of any shape (e.g., sphere, hemisphere, cube, etc.) may be established in the surgical plan. As described herein, based on the method of positioning the reamer head 402 relative to the acetabulum 401, a cone may be a boundary established with minimal processing requirements. The cone may be defined based on a pair of angles 701 from a reference plane 410 and a maximum depth 702 away from the surface of the acetabulum 401. Appropriate definition of the boundary may help determine when bone is being removed as opposed to when the reamer is being adjusted or repositioned. One of ordinary skill in the art will note that the boundary may include the shape and / or combination of shapes of the open end. For example, a cone may be defined by an angle but not a maximum depth.

[0135] FIG. 8A shows an exemplary reamer head 800 according to one embodiment. The diameter of the reamer head 800 can be identified by any of the methods described herein. Alternatively, the CASS 100 may read a label 802 that uses imaging and optical character recognition (OCR) to provide information related to the diameter of the reamer head 800.

[0136] The reamer head 800 may be characterized by an interface element 801 configured to facilitate connecting the reamer head 800 to the drill shaft 403. For example, many reamer heads 800 feature a cross-shaped interface. FIG. 8B shows an exemplary tracking element 810 configured to replace the reamer head 800 for calibration according to one embodiment. The tracking element 810 may include an interface element 801 similar to that characterized on the reamer head 800. Before attaching the reamer head 800, the tracking element 810 may be joined to the reamer shaft 403. The position of the end of the shaft 403 can be determined by registering the position of the tracking element 810 with another tracking element attached to the reamer, such as an outer casing 404 or a tracking element 406 attached elsewhere on the reamer. Although an optical tracker is illustrated, any tracking method (e.g., EM, optical code, optical fiber) or combination thereof may be used.

[0137] The systems and methods described herein refer to the hip joint, but those skilled in the art will understand that similar systems and methods may be applicable to other joints such as the shoulder.

[0138] Although various exemplary embodiments incorporating the principles of the present teachings are disclosed, the present teachings are not limited to the embodiments of the present disclosure. Instead, this application is intended to cover any variations, uses, or adaptations of the present teachings and to use its general principles. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice in the technical field to which these teachings pertain.

[0139] In the foregoing detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like reference numerals typically identify like components unless the context dictates otherwise. The exemplary embodiments described herein are not intended to be limiting. Other embodiments may be used 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 may generally be arranged, substituted, combined, separated, and designed in a variety of different configurations as described herein and shown in the figures, all of which are explicitly contemplated herein.

[0140] The present disclosure is not limited to 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 its spirit and scope. In addition to those listed herein, functionally equivalent methods and apparatuses within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. It should be understood that the present disclosure is not limited to a particular method, device, or system, but that they may vary. It should also be understood that the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0141] Regarding the use of substantially any plural and / or singular terms herein, those skilled in the art can translate from plural to singular and / or from singular to plural as appropriate to the context and / or application. Various singular / plural arrangements may be explicitly set forth herein for clarity.

[0142] Generally, 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.), which would be understood by those skilled in the art. Various compositions, methods, and devices are described from the perspective of “comprising” various components or steps (interpreted as meaning “including, but not limited to”), but the 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.

[0143] Furthermore, even if a specific number is explicitly recited, one of ordinary skill in the art will recognize that such a recitation should be construed as meaning at least the recited number (e.g., a bare recitation of "two recitations" without other modifiers means at least two recitations, or two or more recitations). Further, when a convention similar to "at least one of A, B, and C" is used, generally, such a construction is intended in the sense that one of ordinary skill in the art will understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, a system having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together). When a convention similar to "at least one of A, B, or C" is used, generally, such a construction is intended in the sense that one of ordinary skill in the art will understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, a system having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together). In substantially any discrete word and / or phrase presenting two or more alternative terms, in any of the description, sample embodiments, or drawings, it will be further understood by one of ordinary skill in the art that it is intended to contemplate the possibility of including either, or both, of the terms. For example, the phrase "A or B" will be understood to include the possibility of "A" or "B", or "A and B".

[0144] Moreover, when features of the present disclosure are described in terms of Markush groups, one of ordinary skill in the art will recognize that the present disclosure thereby also describes any individual member or subgroup of members of the Markush group.

[0145] As will be understood by those skilled in the art, for any and all purposes, such as providing a written description, all ranges disclosed herein also include any and all possible sub-ranges, as well as combinations of those sub-ranges. Some of the recited ranges are readily recognizable as being sufficiently described and enabling the same range to be divided, for example, into at least equal halves, thirds, quarters, fifths, tenths, and the like. By way of non-limiting example, each range discussed herein can be readily divided, for example, into a lower third, middle third, and upper third. Also, as will be understood by those skilled in the art, all language such as "up to," "at least," and the like includes the recited number and refers to a range that can be substantially divided later into sub-ranges as discussed above. Finally, as will be understood by those skilled in the art, a range includes each individual member. Thus, for example, a group having 1 to 3 components refers to a group having 1, 2, or 3 components. Similarly, a group having 1 to 5 components refers to a group having 1, 2, 3, 4, or 5 components, and so on.

[0146] As used herein, the term "about" refers to variations in numerical values that may occur through real-world measurements or handling techniques, such as errors due to inadvertence in these procedures, differences in the manufacture, source, or purity of a composition or reagent, and the like. Typically, as used herein, the term "about" means greater than or less than the recited value or range of values by up to 1 / 10 of the recited value (e.g., ±10%). The term "about" also refers to variations that are recognized by those skilled in the art as being equivalent, provided that such variations do not 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 recited absolute value or range of values. Whether or not modified by the term "about", the quantitative values recited in this disclosure include equivalents of the recited values, e.g., numerical variations that may occur but would be recognized by those skilled in the art as being equivalent.

[0147] The various features and functions disclosed above, as well as alternatives thereof, may be combined in many other different systems or applications. Various presently unforeseen or unexpected alternatives, modifications, variations, or improvements thereof may then be made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.

Claims

**Claim 1** A system for performing navigated reaming of an acetabulum, comprising a navigation tracking system, a reamer, a first tracking element attached to the reamer and configured to be tracked by the navigation tracking system, a second tracking element attached to the acetabulum and configured to be tracked by the navigation tracking system, a processor in communication with the navigation tracking system, the processor receiving a surgical plan that includes one or more patient-specific parameters related to total hip arthroplasty, the one or more patient-specific parameters including the location and orientation of a planned implant, receiving a three-dimensional model of at least a portion of the acetabulum, determining at least one of the depth and tilt angle of the reamer with respect to the acetabulum and the location and orientation of the planned implant based on information associated with the position of the first tracking element, the position of the second tracking element, and the geometric shape of the reamer, a system configured to modify the three-dimensional model based on at least one of the depth and the tilt angle. **Claim 2** The processor compares the tilt angle to a threshold angle range, and is further configured to automatically stop or decrease the speed of the reamer in response to the tilt angle being outside the threshold angle range. The system according to claim 1. **Claim 3** The processor compares the depth to a threshold depth, and is further configured to automatically stop or decrease the speed of the reamer in response to the depth exceeding the threshold depth. The system according to claim 1. **Claim 4** The processor receives the size of the reamer head, and is further configured to determine the position of the reamer head based on the size of the reamer head and the position of the first tracking element. The system according to claim 1. **Claim 5** Further comprising a display device, The processor generates a three-dimensional model of the reamer head, and is further configured to display the three-dimensional model of the reamer head on the display device with respect to the three-dimensional model of at least a portion of the acetabulum. The system according to claim 3. **Claim 6** The system according to claim 3, wherein the processor is further configured to generate an updated three-dimensional model of at least a portion of the acetabulum based on at least a portion of the acetabulum and at least one of the depth and the tilt angle of the three-dimensional model.

7. The surgical plan includes a three-dimensional model of one or more planned revisions to the acetabulum, The processor, compares the updated three-dimensional model of at least a portion of the acetabulum with the three-dimensional model of the one or more planned revisions to the acetabulum, The system according to claim 6, further configured to display a mark on the updated three-dimensional model of at least a portion of the acetabulum based on the comparison.

8. further comprising a third tracking element configured to engage the reamer in place of the reamer head, The system according to claim 1, wherein the processor is further configured to determine the information associated with the geometric shape of the reamer based on the position of the first tracking element relative to the position of the third tracking element.

9. A method for performing navigated reaming of an acetabulum, comprising: receiving a surgical plan, the surgical plan including one or more patient-specific parameters related to total hip arthroplasty, the one or more patient-specific parameters including the location and orientation of a planned implant; receiving a three-dimensional model of at least a portion of the acetabulum; providing a first tracking element associated with the reamer; providing a second tracking element associated with the acetabulum; receiving information associated with the geometric shape of the reamer; determining at least one of the depth and the tilt angle of the reamer relative to the acetabulum and the location and orientation of the planned implant based on the position of the first tracking element, the position of the second tracking element, and the information associated with the geometric shape of the reamer; modifying the three-dimensional model based on at least one of the depth and the tilt angle.

10. comparing the tilt angle with a threshold angle range, The method according to claim 9, further comprising automatically stopping or reducing the speed of the reamer in response to the inclination angle being outside the threshold range.

11. comparing the depth with a threshold depth; The method according to claim 9, further comprising automatically stopping or reducing the speed of the reamer in response to the depth exceeding the threshold depth.

12. receiving the size of the reamer head; The method according to claim 9, further comprising determining the position of the reamer head based on the size of the reamer head and the position of the first tracking element.

13. generating a three-dimensional model of the reamer head; The method according to claim 12, further comprising displaying the three-dimensional model of the reamer head on a display device with respect to the three-dimensional model of at least a part of the acetabulum.

14. The method according to claim 12, further comprising generating an updated three-dimensional model of at least a part of the acetabulum based on a three-dimensional model of at least a part of the acetabulum, the size of the reamer head, and at least one of the depth and the inclination angle.

15. wherein the surgical plan includes a three-dimensional model of one or more planned modifications to the acetabulum, and the method comprises: comparing the updated three-dimensional model of at least a part of the acetabulum with the three-dimensional model of one or more of the planned modifications to the previous acetabulum; The method according to claim 14, further comprising displaying a mark on the updated three-dimensional model of at least a part of the acetabulum based on the comparison.

16. receiving information associated with the geometric shape of the reamer, providing a third tracking element configured to engage the reamer instead of the reamer head; The method according to claim 9, comprising determining the information associated with the geometric shape of the reamer based on the position of the first tracking element with respect to the position of the third tracking element.

17. providing a first tracking element associated with the reamer; joining the first tracking element to an outer casing of the reamer, the outer casing surrounding a portion of a shaft of the reamer, the shaft configured to rotate relative to the outer casing; and, the method of claim 9 including the joining

18. The method of claim 9, wherein the reamer is supported using a passive robotic arm

19. The method of claim 18, wherein the first tracking element is secured to the passive arm

20. A method of performing navigated reaming of an acetabulum, the method comprising receiving a surgical plan, the surgical plan including one or more patient-specific parameters related to a total hip arthroplasty, the one or more patient-specific parameters including a location and orientation of a planned implant; receiving providing a first tracking element associated with the reamer providing a second tracking element registered with respect to the location and orientation of the planned implant receiving information associated with a geometric shape of the reamer determining at least one of a depth and an inclination angle of the reamer relative to the location and orientation of the planned implant based on a position of the first tracking element, a position of the second tracking element, and the information associated with the geometric shape of the reamer; the method

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