Systems and methods for planning hip arthroplasty

Abstract

Systems and methods for planning a hip arthroplasty for a patient are disclosed. The method includes obtaining a computer model of the patient's hip joint, determining anatomical angles associated with the bony anatomy, determining muscle attachment locations on the bony anatomy, and generating a 3D mathematical model of the hip joint including bony and muscular anatomical properties based on at least the measurements and the muscle attachment locations. The method further includes determining an initial surgical plan including a set of implant parameters based input related to the hip joint. The method further includes identifying differences between the pre-operative and post-operative muscle properties based on the initial surgical plan and the 3D mathematical model, optimizing the implant parameters based on the identified differences, and generating an optimized surgical plan based on the optimized implant parameters.

Description

Attorney Docket No. PT-6005-WO-PCT / D030402 SYSTEMS AND METHODS FOR PLANNING HIP ARTHROPLASTY CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No.63 / 529,032 entitled “Systems and Methods for Planning Hip Arthroplasty,” filed July 26, 2023, which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates generally to methods, systems, and apparatuses related to planning a hip arthroplasty procedure. More particularly, the present disclosure relates to planning placement of a hip implant (e.g., an acetabular cup) in a personalized manner accounting for soft tissue properties. The disclosed techniques may be applied to, for example, hip arthroplasties, but may also apply to shoulder arthroplasties and other surgical interventions. BACKGROUND

[0003] In joint arthroplasties such as total hip arthroplasty (THA), selection and placement of implant components may be planned based on the patient’s anatomy in order to provide satisfactory functioning of the post-operative joint. One of the objectives of THA is to restore normal hip function, including but not limited to mobility and stability of the joint. Currently, THA planning consists of using a 2D frontal x-ray of a joint of a patient and / or computed tomography (CT) scans from the patient to template, size, and position implant components to the patient's anatomy.

[0004] However, proper hip function may also be dependent on proper functioning of the muscles and ligaments spanning the joint. Improper selection or placement of implant components may result in sub-optimal muscle function, undesired muscle injury and / or pain, increased risk of dislocation, and overall increased risk of failure of the procedure, e.g., a need for subsequent surgery.Attorney Docket No. PT-6005-WO-PCT / D030402

[0005] For example, a relatively common muscle-related issue in THA patients is anterior iliopsoas impingement, which may result in groin pain and related symptoms during daily activities that require use of the iliopsoas muscle. Such activities may include straight- leg raising, active flexion of the hip, ascending stairs, lifting the leg into a flat position (e.g., onto a bed), and lifting the leg into a sitting or standing position (e.g., to get into and out of a car). FIG.3 depicts a placement of an acetabular cup that may result in iliopsoas tendinitis. As shown, the acetabular cup may be positioned anterior to the bony acetabulum such that a portion of the cup overhangs the bony anatomy. The iliopsoas tendon may rub against the anteroinferior edge of the acetabular cup, thereby leading to iliopsoas tendinitis. Correct sizing and placement of the cup can avoid such complications.

[0006] In another example, the surgical approach to THA surgery (e.g., anterior, posterior, lateral) may cut through different muscles and / or regions of the hip capsule, thereby reducing the soft tissue tension at least for a period following surgery. The reduced tension may increase the risk of dislocation and / or induce compensatory mechanisms in the patient's biomechanics and produce sub-optimal musculoskeletal strategies to perform daily activities.

[0007] Additionally, placement of implant components can also affect the overall balance of the femur. While preserving native femoral offset has been a point of focus in the past to achieve proper tension of the muscles surrounding the joint, less attention has been paid to the changes in femoral internal rotation (or anterior offset). Recent studies have shown that increased stem anteversion compared to the native femoral anteversion is associated with post- operative increase in internal rotation of the femur. FIG. 4A depicts a pre-operative condition of the hip joint and the internal and external rotator muscles. FIG. 4B depicts the joint when femoral anteversion has been increased through surgical intervention resulting in a posterior shift of the greater trochanter that leads to increased tension in the internal rotator muscles and relaxation of the external rotator muscles. FIG. 4C depicts rotation of the femur internally toAttorney Docket No. PT-6005-WO-PCT / D030402 restore muscle balance, thereby resulting in a new balanced position of the femur. As shown, the changes in tension of the internal and external rotator muscles resulting from sub-optimal placement of the stem may lead to a new balanced position of the femur that affects overall posture of the patient's lower limb.

[0008] Furthermore, studies also indicate that increased internal rotation, together with younger age and leg lengthening, is associated with increased patellar lateral tilt, which is linked to anterior ipsilateral knee pain after THA. Changes in the tension of the biarticular muscles that span both hip and knee (e.g., tensor fascia latae, iliotibial band, and rectus femoris) inevitably affect patellofemoral kinematics. Leg lengthening is often necessary when treating dysplastic patients to avoid leg length discrepancies, but its effect on muscle tension and surrounding joints is currently unknown on a patient-specific level.

[0009] Still further, patients with osteoarthritis are often affected by muscle contractures that affect pre-operative lower leg neutral alignment. Flexion contractures are common and are generally resolved through THA. External rotation contractures might also be present in some instances. Studies suggest that pre-operative pelvic tilt, which is generally used for functional placement of the cup, is affected by flexion contractures and post-operative pelvic tilt will differ after the contracture is resolved during surgery. Therefore, a better understanding of the effect of muscle contractures and their resolution on pre-operative and post-operative leg alignment would benefit THA planning.

[0010] Currently, THA planning tools do not predict or account for post-operative muscle properties. Available tools may reconstruct the pre-operative bony anatomy of the hip (i.e., femur and pelvis) from CT images so that implant component positions may be planned with respect to the joint based on the bony anatomy. Some post-operative properties may be predicted (e.g., center of rotation change, leg length change, femoral offset, and impingement). However, implant selection and placement are planned pre-operatively solely based on femurAttorney Docket No. PT-6005-WO-PCT / D030402 and pelvis anatomy and comparison to the contralateral leg. In some cases, lateral x-rays of the pelvis in functional positions (e.g., standing, sitting, and / or chair exiting) are taken pre- operatively to measure pelvic tilt and spinopelvic mobility in order to enable selection of implant positions in consideration of these measures to account for the functional motion of the patient’s pelvis.

[0011] However, despite the fundamental role of muscles in restoring normal hip function, currently available THA planning tools do not predict or account for post-operative muscle properties, such as moment arm, passive tension, and force-generating capacity.

[0012] As such, it would be advantageous to include soft tissue considerations in the implant selection and placement process. For example, it would be advantageous to have a system for planning acetabular cup placement in hip arthroplasties based on predicted post- operative muscle properties in addition to the bony anatomy. SUMMARY

[0013] A computer-implemented method for planning a hip arthroplasty for a patient is provided. The method comprises obtaining a computer model of a bony anatomy of a hip joint of the patient; determining one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle; determining, based on the computer model, a plurality of muscle attachment locations on the bony anatomy; generating a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations; determining an initial surgical plan comprising one or more implant parameters based on input related to the hip joint; identifying, based on the initial surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post- operative properties of muscles associated with the hip joint; optimizing the one or more implant parameters based on the one or more identified differences; and optimizing the initialAttorney Docket No. PT-6005-WO-PCT / D030402 surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan.

[0014] According to some embodiments, the one or more measurements are selected from the group consisting of a femoral anteversion, a femoral internal rotation, and a lateral patellar tilt for the hip joint.

[0015] According to some embodiments, the one or more measurements comprise, for each hip joint of the patient, the femoral anteversion, the femoral internal rotation, and the lateral patellar tilt.

[0016] According to some embodiments, determining a plurality of muscle attachment locations on the bony anatomy comprises determining the plurality of muscle attachment locations based on a statistical shape model using the computer model. According to additional embodiments, determining the plurality of muscle attachment locations is further based on magnetic resonance imaging (MRI) data for the patient.

[0017] According to some embodiments, the 3D mathematical model comprises one or more Hill-type muscle models.

[0018] According to some embodiments, the one or more implant parameters are selected from the group consisting of an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and an implant liner type.

[0019] According to some embodiments, each of the initial surgical plan and the optimized surgical plan further comprise information associated with at least one of a surgical approach and muscle repair.

[0020] According to some embodiments, each of the one or more differences comprise one of a muscle length and a muscle moment arm.Attorney Docket No. PT-6005-WO-PCT / D030402

[0021] According to some embodiments, optimizing the one or more implant parameters reduces at least one of the one or more identified differences.

[0022] According to some embodiments, the method further comprises displaying the optimized surgical plan on a display device.

[0023] According to some embodiments, the method further comprises outputting the optimized surgical plan to a computer-readable storage device.

[0024] A system for planning a hip arthroplasty for a patient is also provided. The system comprises at least one processor; and a non-transitory, computer-readable medium storing instructions that, when executed, cause the at least one processor to obtain a computer model of a bony anatomy of a hip joint of the patient, determine one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle, determine, based on the computer model, a plurality of muscle attachment locations on the bony anatomy, generate a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations, determine an initial surgical plan comprising one or more implant parameters based on input related to the hip joint, identify, based on the surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post-operative properties of muscles associated with the hip joint, optimize the one or more implant parameters based on the one or more identified differences, and optimize the initial surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan.

[0025] According to some embodiments, the one or more measurements are selected from the group consisting of a femoral anteversion, a femoral internal rotation, and a lateral patellar tilt for the hip joint. According to additional embodiments, the one or moreAttorney Docket No. PT-6005-WO-PCT / D030402 measurements comprise, for each hip joint of the patient, the femoral anteversion, the femoral internal rotation, and the lateral patellar tilt.

[0026] According to some embodiments, the instructions that cause the at least one processor to determine a plurality of muscle attachment locations on the bony anatomy comprise instructions that, when executed, cause the at least one processor to determine the plurality of muscle attachment locations based on a statistical shape model using the computer model. According to additional embodiments, the instructions that cause the at least one processor to determine a plurality of muscle attachment locations on the bony anatomy comprise instructions that, when executed, cause the at least one processor to determine the plurality of muscle attachment locations based further on magnetic resonance imaging (MRI) data for the patient.

[0027] According to some embodiments, the 3D mathematical model comprises one or more Hill-type muscle models.

[0028] According to some embodiments, the one or more implant parameters are selected from the group consisting of an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and an implant liner type.

[0029] According to some embodiments, each of the initial surgical plan and the optimized surgical plan further comprise information associated with at least one of a surgical approach and muscle repair.

[0030] According to some embodiments, each of the one or more differences comprise one of a muscle length and a muscle moment arm.

[0031] According to some embodiments, the instructions that cause the at least one processor to optimize the one or more implant parameters comprise instructions that, whenAttorney Docket No. PT-6005-WO-PCT / D030402 executed, cause the at least one processor to reduce at least one of the one or more identified differences.

[0032] According to some embodiments, the system further comprises a display device, wherein the instructions, when executed, further cause the at least one processor to display the optimized surgical plan on the display device.

[0033] According to some embodiments, the instructions, when executed, further cause the at least one processor to output the optimized surgical plan to a computer-readable storage device.

[0034] A system for planning a hip arthroplasty for a patient is also provided. The system comprises a processor configured to obtain a computer model of a bony anatomy of a hip joint of the patient, determine one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle, determine, based on the computer model, a plurality of muscle attachment locations on the bony anatomy, generate a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations, determine an initial surgical plan comprising one or more implant parameters based on input related to the hip joint, identify, based on the surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post- operative properties of muscles associated with the hip joint, optimize the one or more implant parameters based on the one or more identified differences, and optimize the initial surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the invention and together with the writtenAttorney Docket No. PT-6005-WO-PCT / D030402 description serve to explain the principles, characteristics, and features of the invention. In the drawings:

[0036] FIG.1 depicts an operating theatre including an illustrative computer-assisted surgical system (CASS) in accordance with an embodiment.

[0037] FIG. 2A depicts illustrative control instructions that a surgical computer provides to other components of a CASS in accordance with an embodiment.

[0038] FIG. 2B depicts illustrative control instructions that components of a CASS provide to a surgical computer in accordance with an embodiment.

[0039] FIG. 2C depicts an illustrative implementation in which a surgical computer is connected to a surgical data server via a network in accordance with an embodiment.

[0040] FIG. 3 depicts a placement of an acetabular cup that may result in iliopsoas tendinitis in accordance with an embodiment.

[0041] FIG.4A depicts a pre-operative condition of the hip joint and the internal and external rotator muscles in accordance with an embodiment.

[0042] FIG. 4B depicts the joint of FIG. 4A where femoral anteversion has been increased through surgical intervention in accordance with an embodiment.

[0043] FIG. 4C depicts the joint of FIG. 4B where the femur is rotated internally to restore muscle balance in accordance with an embodiment.

[0044] FIG. 5 depicts a flow diagram of an illustrative method of optimizing a surgical plan for a hip arthroplasty for a patient in accordance with an embodiment.

[0045] FIG. 6 depicts an exemplary workflow for planning a hip arthroplasty in accordance with an embodiment.

[0046] FIG. 7 depicts a flow diagram of an illustrative method of assessing hip joint kinematics of a patient in accordance with an embodiment.Attorney Docket No. PT-6005-WO-PCT / D030402

[0047] FIG.8 depicts an exemplary workflow for assessing hip joint kinematics of a patient in accordance with an embodiment.

[0048] FIG. 9 illustrates a block diagram of an exemplary data processing system in which embodiments are implemented. DETAILED DESCRIPTION

[0049] This disclosure is not limited to the particular systems, devices and methods described, as these may vary. The terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope.

[0050] As used in this document, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to 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.” Definitions

[0051] For the purposes of this disclosure, the term “implant” is used to refer to a prosthetic device or structure manufactured to replace or enhance a biological structure. For example, in a total hip replacement procedure a prosthetic acetabular cup (implant) is used to replace or enhance a patients worn or damaged acetabulum. While the term “implant” is generally considered to denote a man-made structure (as contrasted with a transplant), for the purposes of this specification an implant can include a biological tissue or material transplanted to replace or enhance a biological structure.

[0052] For the purposes of this disclosure, the term “real-time” is used to refer to calculations or operations performed on-the-fly as events occur or input is received by theAttorney Docket No. PT-6005-WO-PCT / D030402 operable system. However, the use of the term “real-time” is not intended to preclude operations that cause some latency between input and response, so long as the latency is an unintended consequence induced by the performance characteristics of the machine.

[0053] For the purposes of this disclosure, the terms “distract,” “distracting,” or “distraction” are used to refer to displacement of a first point with respect to a second point. For example, the first point and the second point may correspond to surfaces of a joint. In some embodiments herein, a joint may be distracted, i.e., portions of the joint may be separated and / or moved with respect to one another to place the joint under tension. In some embodiments, a first portion of the joint be a surface of a femur and a second portion of the joint may be a surface of a tibia such that separation occurs between the bones of the joint. In additional embodiments, a first portion of the joint may be a first portion of a tibial implant component or a tibial trial implant and a second portion of the joint may be a second portion of the tibial implant component or the tibial trial implant that is movable with respect to the first portion (e.g., a base plate and a superior spacer as described herein). Accordingly, separation may occur between the portions of the tibial implant component or the tibial trial implant (i.e., intra-implant separation). Throughout the disclosure herein, the described embodiments may be collectively referred to as distraction of the joint.

[0054] Although much of this disclosure refers to surgeons or other medical professionals by specific job title or role, nothing in this disclosure is intended to be limited to a specific job title or function. Surgeons or medical professionals can include any doctor, nurse, medical professional, or technician. Any of these terms or job titles can be used interchangeably with the user of the systems disclosed herein unless otherwise explicitly demarcated. For example, a reference to a surgeon also could apply, in some embodiments to a technician or nurse.Attorney Docket No. PT-6005-WO-PCT / D030402

[0055] The systems, methods, and devices disclosed herein are particularly well adapted for surgical procedures that utilize surgical navigation systems, such as the CORI® surgical navigation system. CORI is a registered trademark of SMITH & NEPHEW, INC. of Memphis, TN. CASS Ecosystem Overview

[0056] FIG. 1 provides an illustration of an example computer-assisted surgical system (CASS) 100, according to some embodiments. As described in further detail in the sections that follow, the CASS uses computers, robotics, and imaging technology to aid surgeons in performing orthopedic surgery procedures such as total knee arthroplasty (TKA) or THA. For example, surgical navigation systems can aid surgeons in locating patient anatomical structures, guiding surgical instruments, and implanting 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 variety of standard and minimally invasive surgical procedures and techniques. Moreover, these systems allow surgeons to more accurately plan, track and navigate the placement of instruments and implants relative to the body of a patient, as well as conduct pre-operative and intra-operative body imaging.

[0057] An 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 a knee surgery, the Effector Platform 105 may include an End Effector 105B that holds surgical tools or instruments during their use. The End Effector 105B may be a handheld device or instrument used by the surgeon (e.g., a CORI® hand piece or a cutting guide or jig) or, alternatively, the End Effector 105B can include a device or instrument held or positioned by a robotic arm 105A. While one robotic arm 105A is illustrated in FIG.1, in some embodiments there may be multiple devices. As examples, there may be one robotic arm 105A on each side of an operating table T or two devices on one side of the tableAttorney Docket No. PT-6005-WO-PCT / D030402 T. The robotic arm 105A may be mounted directly to the table T, be located next to the table T on a floor platform (not shown), mounted on a floor-to-ceiling pole, or mounted on a wall or ceiling of an operating room. The floor platform may be fixed or moveable. In one particular embodiment, the robotic arm 105A is mounted on a floor-to-ceiling pole located between the patient's legs or feet. In some embodiments, the End Effector 105B may include a suture holder or a stapler to assist in closing wounds. Further, in the case of two robotic arms 105A, the surgical computer 150 can drive the robotic arms 105A to work together to suture the wound at closure. Alternatively, the surgical computer 150 can drive one or more robotic arms 105A to staple the wound at closure.

[0058] The Effector Platform 105 can include a Limb Positioner 105C for positioning the patient's limbs during surgery. One example of a Limb Positioner 105C is the SMITH AND NEPHEW SPIDER2 system. The Limb Positioner 105C may be operated manually by the surgeon or alternatively change limb positions based on instructions received from the Surgical Computer 150 (described below). While one Limb Positioner 105C is illustrated in FIG.1, in some embodiments there may be multiple devices. As examples, there may be one Limb Positioner 105C on each side of the operating table T or two devices on one side of the table T. The Limb Positioner 105C may be mounted directly to the table T, be located next to the table T on a floor platform (not shown), mounted on a pole, or mounted on a wall or ceiling of an operating room. In some embodiments, the Limb Positioner 105C can be used in non- conventional ways, such as a retractor or specific bone holder. The Limb Positioner 105C may include, as examples, an ankle boot, a soft tissue clamp, a bone clamp, or a soft-tissue retractor spoon, such as a hooked, curved, or angled blade. In some embodiments, the Limb Positioner 105C may include a suture holder to assist in closing wounds.Attorney Docket No. PT-6005-WO-PCT / D030402

[0059] The Effector Platform 105 may include tools, such as a screwdriver, light or laser, to indicate an axis or plane, bubble level, pin driver, pin puller, plane checker, pointer, finger, or some combination thereof.

[0060] Resection Equipment 110 (not shown in FIG. 1) performs bone or tissue resection using, for example, mechanical, ultrasonic, or laser techniques. Examples of Resection Equipment 110 include drilling devices, burring devices, oscillatory sawing devices, vibratory impaction devices, reamers, ultrasonic bone cutting devices, radio frequency ablation devices, reciprocating devices (such as a rasp or broach), and laser ablation systems. In some embodiments, the Resection Equipment 110 is held and operated by the surgeon during surgery. In other embodiments, the Effector Platform 105 may be used to hold the Resection Equipment 110 during use.

[0061] The Effector Platform 105 also can include a cutting guide or jig 105D that is used to guide saws or drills used to resect tissue during surgery. Such cutting guides 105D can be formed integrally as part of the Effector Platform 105 or robotic arm 105A or cutting guides can be separate structures that can be matingly and / or removably attached to the Effector Platform 105 or robotic arm 105A. The Effector Platform 105 or robotic arm 105A can be controlled by the CASS 100 to position a cutting guide or jig 105D adjacent to the patient's anatomy in accordance with a pre-operatively or intraoperatively developed surgical plan such that the cutting guide or jig will produce a precise bone cut in accordance with the surgical plan.

[0062] The Tracking System 115 uses one or more sensors to collect real-time position data that locates the patient's anatomy and surgical instruments. For example, for TKA procedures, the Tracking System may provide a location and orientation of the End Effector 105B during the procedure. In addition to positional data, data from the Tracking System 115 also can be used to infer velocity / acceleration of anatomy / instrumentation, which can be usedAttorney Docket No. PT-6005-WO-PCT / D030402 for tool control. In some embodiments, the Tracking System 115 may 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 may be inferred based on the position and orientation of the Tracking System 115 and a known relationship in three-dimensional space between the Tracking System 115 and the End Effector 105B. Various types of tracking systems may be used in various embodiments of the present invention including, without limitation, Infrared (IR) tracking systems, electromagnetic (EM) tracking systems, video or image based tracking systems, and ultrasound registration and tracking systems. Using the data provided by the tracking system 115, the surgical computer 150 can detect objects and prevent collision. For example, the surgical computer 150 can prevent the robotic arm 105A and / or the End Effector 105B from colliding with soft tissue.

[0063] Any suitable tracking system can be used for tracking surgical objects and patient anatomy in the surgical theatre. For example, a combination of IR and visible light cameras can be used in an array. Various illumination sources, such as an IR LED light source, can illuminate the scene allowing three-dimensional imaging to occur. In some embodiments, this can include stereoscopic, tri-scopic, quad-scopic, etc. imaging. In addition to the camera array, which in some embodiments is affixed to a cart, additional cameras can be placed throughout the surgical theatre. For example, handheld tools or headsets worn by operators / surgeons can include imaging capability that communicates images back to a central processor to correlate those images with images captured by the camera array. This can give a more robust image of the environment for modeling using multiple perspectives. Furthermore, some imaging devices may be of suitable resolution or have a suitable perspective on the scene to pick up information stored in quick response (QR) codes or barcodes. This can be helpful in identifying specific objects not manually registered with the system. In some embodiments, the camera may be mounted on the robotic arm 105A.Attorney Docket No. PT-6005-WO-PCT / D030402

[0064] In some embodiments, specific objects can be manually registered by a surgeon with the system preoperatively or intraoperatively. For example, by interacting with a user interface, a surgeon may identify the starting location for 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, a processor may track that tool or bone as it moves through the environment in a three-dimensional model.

[0065] In some embodiments, certain markers, such as fiducial marks that identify individuals, important tools, or bones in the theater may 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 flash a pattern that conveys a unique identifier to the source of that pattern, providing a dynamic identification mark. Similarly, one- or two-dimensional optical codes (barcode, QR code, etc.) can be affixed to objects in the theater to provide passive identification that can occur based on image analysis. If these codes are placed asymmetrically on an object, they also can be used to determine an orientation of an object by comparing the location of the identifier with the extents of an object in an image. For example, a QR code may be placed in a corner of a tool tray, allowing the orientation and identity of that tray to be tracked. Other tracking modalities are explained throughout. For example, in some embodiments, augmented reality (AR) headsets can be worn by surgeons and other staff to provide additional camera angles and tracking capabilities. In this case, the infrared / time of flight sensor data, which is predominantly used for hand / gesture detection, can build correspondence between the AR headset and the tracking system of the robotic system using sensor fusion techniques. This can be used to calculate a calibration matrix that relates the optical camera coordinate frame to the fixed holographic world frame.

[0066] In addition to optical tracking, certain features of objects can be tracked by registering physical properties of the object and associating them with objects that can beAttorney Docket No. PT-6005-WO-PCT / D030402 tracked, such as fiducial marks fixed to a tool or bone. For example, a surgeon may perform a manual registration process whereby a tracked tool and a tracked bone can be manipulated relative to one another. By impinging the tip of the tool against the surface of the bone, a three- dimensional surface can be mapped for that bone that is associated with a position and orientation relative to the frame of reference of that fiducial mark. By optically tracking the position and orientation (pose) of the fiducial mark associated with that bone, a model of that surface can be tracked with an environment through extrapolation.

[0067] The registration process that registers the CASS 100 to the relevant anatomy of the patient also can involve the use of anatomical landmarks, such as landmarks on a bone or cartilage. For example, the CASS 100 can include a 3D model of the relevant bone or joint and the surgeon can intraoperatively collect data regarding the location of bony landmarks on the patient's actual bone using a probe that is connected to the CASS. Bony landmarks can include, for example, the medial malleolus and lateral malleolus, 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 bony landmarks collected by the surgeon with the probe with the location data of the same landmarks in the 3D model. Alternatively, the CASS 100 can construct a 3D model of the bone or joint without pre-operative image data by using location data of bony landmarks and the bone surface that are collected by the surgeon using a CASS probe or other means. The registration process also can include determining various axes of a joint. For example, for a 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., circumduction) so the CASS can determine where the center of the hip joint is located.

[0068] A Tissue Navigation System 120 (not shown in FIG.1) provides the surgeon with intraoperative, real-time visualization for the patient's bone, cartilage, muscle, nervous,Attorney Docket No. PT-6005-WO-PCT / D030402 and / or vascular tissues surrounding the surgical area. Examples of systems that may be employed for tissue navigation include fluorescent imaging systems and ultrasound systems.

[0069] The Display 125 provides graphical user interfaces (GUIs) that display images collected by the Tissue Navigation System 120 as well other information relevant to the surgery. For example, in one embodiment, the Display 125 overlays image information collected from various modalities (e.g., CT, MRI, X-ray, fluorescent, ultrasound, etc.) collected pre-operatively or intra-operatively to give the surgeon various views of the patient's anatomy as well as real-time conditions. The Display 125 may include, for example, one or more computer monitors. As an alternative or supplement to the Display 125, one or more members of the surgical staff may wear an Augmented Reality (AR) Head Mounted Device (HMD). For example, in FIG.1 the Surgeon 111 is wearing an AR HMD 155 that may, for example, overlay pre-operative image data on the patient or provide surgical planning suggestions. In one embodiment, a tracker array-mounted surgical tool could be detected by both the IR camera and an AR headset (HMD) using sensor fusion techniques without the need for any "intermediate" calibration rigs. This near-depth, time-of-flight sensing camera located in the HMD could be used for hand / gesture detection. The headset's sensor API can be used to expose IR and depth image data and carryout image processing using, for example, C++ with OpenCV. This approach allows the relationship between the CASS and the virtual coordinate frame to be determined and the headset sensor data (i.e., IR in combination with depth images) to isolate the CASS tracker arrays. The image processing system on the HMD can locate the surgical tool in a fixed holographic world frame and the CASS IR camera can locate the surgical tool relative to its camera coordinate frame. This relationship can be used to calculate a calibration matrix that relates the CASS IR camera coordinate frame to the fixed holographic world frame. This means that if a calibration matrix has previously been calculated, the surgical tool no longer needs to be visible to the AR headset. However, a recalculation may be necessary if theAttorney Docket No. PT-6005-WO-PCT / D030402 CASS camera is accidentally moved in the workflow. Various example uses of the AR HMD 155 in surgical procedures are detailed in the sections that follow.

[0070] Surgical Computer 150 provides control instructions to various components of the CASS 100, collects data from those components, and provides general processing for various data needed during surgery. In some embodiments, the Surgical Computer 150 is a general-purpose computer. In other embodiments, the Surgical Computer 150 may be a parallel computing platform that uses multiple central processing units (CPUs) or graphics processing units (GPU) to perform processing. In some embodiments, the Surgical Computer 150 is connected to a remote server over one or more computer networks (e.g., the Internet). The remote server can be used, for example, for storage of data or execution of computationally intensive processing tasks.

[0071] Various techniques generally known in the art can be used for connecting the Surgical Computer 150 to the other components of the CASS 100. Moreover, the computers can connect to the Surgical Computer 150 using a mix of technologies. For example, the End Effector 105B may connect to the Surgical Computer 150 over a wired (i.e., serial) connection. The Tracking System 115, Tissue Navigation System 120, and Display 125 can similarly be connected to the Surgical Computer 150 using wired connections. Alternatively, the Tracking System 115, Tissue Navigation System 120, and Display 125 may connect to the Surgical Computer 150 using wireless technologies such as, without limitation, Wi-Fi, Bluetooth, Near Field Communication (NFC), or ZigBee. Robotic Arm

[0072] In some embodiments, the CASS 100 includes a robotic arm 105A that serves as an interface to stabilize and hold a variety of instruments used during the surgical procedure. For example, in the context of a hip surgery, these instruments may include, without limitation, retractors, a sagittal or reciprocating saw, the reamer handle, the cup impactor, the broachAttorney Docket No. PT-6005-WO-PCT / D030402 handle, and the stem inserter. The robotic arm 105A may have multiple degrees of freedom (like a Spider device) and have the ability to be locked in place (e.g., by a press of a button, voice activation, a surgeon removing a hand from the robotic arm, or other method).

[0073] In some embodiments, movement of the robotic arm 105A may be effectuated by use of a control panel built into the robotic arm system. For example, a display screen may include one or more input sources, such as physical buttons or a user interface having one or more icons, that direct movement of the robotic arm 105A. The surgeon or other healthcare professional may engage with the one or more input sources to position the robotic arm 105A when performing a surgical procedure.

[0074] A tool or an end effector 105B attached or integrated into a robotic arm 105A may include, without limitation, a burring device, a scalpel, a cutting device, a retractor, a joint tensioning device, or the like. In embodiments in which an end effector 105B is used, the end effector may be positioned at the end of the robotic arm 105A such that any motor control operations are performed within the robotic arm system. In embodiments in which a tool is used, the tool may be secured at a distal end of the robotic arm 105A, but motor control operation may reside within the tool itself.

[0075] The robotic arm 105A may be motorized internally to both stabilize the robotic arm, thereby preventing it from falling and hitting the patient, surgical table, surgical staff, etc., and to allow the surgeon to move the robotic arm without having to fully support its weight. While the surgeon is moving the robotic arm 105A, the robotic arm may provide some resistance to prevent the robotic arm from moving too fast or having too many degrees of freedom active at once. The position and the lock status of the robotic arm 105A may be tracked, for example, by a controller or the Surgical Computer 150.

[0076] In some embodiments, the robotic arm 105A can be moved by hand (e.g., by the surgeon) or with internal motors into its ideal position and orientation for the task beingAttorney Docket No. PT-6005-WO-PCT / D030402 performed. In some embodiments, the robotic arm 105A may be enabled to operate in a "free" mode that allows the surgeon to position the arm into a desired position without being restricted. While in the free mode, the position and orientation of the robotic arm 105A may still be tracked as described above. In one embodiment, certain degrees of freedom can be selectively released upon input from user (e.g., surgeon) during specified portions of the surgical plan tracked by the Surgical Computer 150. Designs in which a robotic arm 105A is internally powered through hydraulics or motors or provides resistance to external manual motion through similar means can be described as powered robotic arms, while arms that are manually manipulated without power feedback, but which may be manually or automatically locked in place, may be described as passive robotic arms.

[0077] A robotic arm 105A or end effector 105B can include a trigger or other means to control the power of a saw or drill. Engagement of the trigger or other means by the surgeon can cause the robotic arm 105A or end effector 105B to transition from a motorized alignment mode to a mode where the saw or drill is engaged and powered on. Additionally, the CASS 100 can include a foot pedal (not shown) that causes the system to perform certain functions when activated. For example, the surgeon can activate the foot pedal to instruct the CASS 100 to place the robotic arm 105A or end effector 105B in an automatic mode that brings the robotic arm or end effector into the proper position with respect to the patient's anatomy in order to perform the necessary resections. The CASS 100 also can place the robotic arm 105A or end effector 105B in a collaborative mode that allows the surgeon to manually manipulate and position the robotic arm or end effector into a particular location. The collaborative mode can be configured to allow the surgeon to move the robotic arm 105A or end effector 105B medially or laterally, while restricting movement in other directions. As discussed, the robotic arm 105A or end effector 105B can include a cutting device (saw, drill, and burr) or a cutting guide or jig 105D that will guide a cutting device. In other embodiments, movement of the robotic armAttorney Docket No. PT-6005-WO-PCT / D030402 105A or robotically controlled end effector 105B can be controlled entirely by the CASS 100 without any, or with only minimal, assistance or input from a surgeon or other medical professional. In still other embodiments, the movement of the robotic arm 105A or robotically controlled end effector 105B can be controlled remotely by a surgeon or other medical professional using a control mechanism separate from the robotic arm or robotically controlled end effector device, for example using a joystick or interactive monitor or display control device.

[0078] A robotic arm 105A may be used for holding the retractor. For example, in one embodiment, the robotic arm 105A may be moved into the desired position by the surgeon. At that point, the robotic arm 105A may lock into place. In some embodiments, the robotic arm 105A is provided with data regarding the patient's position, such that if the patient moves, the robotic arm can adjust the retractor position accordingly. In some embodiments, multiple robotic arms may be used, thereby allowing multiple retractors to be held or for more than one activity to be performed simultaneously (e.g., retractor holding & reaming).

[0079] The robotic arm 105A may also be used to help stabilize the surgeon's hand while making a femoral neck cut. In this application, control of the robotic arm 105A may impose certain restrictions to prevent soft tissue damage from occurring. For example, in one embodiment, the Surgical Computer 150 tracks the position of the robotic arm 105A as it operates. If the tracked location approaches an area where tissue damage is predicted, a command may be sent to the robotic arm 105A causing it to stop. Alternatively, where the robotic arm 105A is automatically controlled by the Surgical Computer 150, the Surgical Computer may ensure that the robotic arm is not provided with any instructions that cause it to enter areas where soft tissue damage is likely to occur. The Surgical Computer 150 may impose certain restrictions on the surgeon to prevent the surgeon from reaming too far into the medial wall of the acetabulum or reaming at an incorrect angle or orientation.Attorney Docket No. PT-6005-WO-PCT / D030402

[0080] In some embodiments, the robotic arm 105A may be used to hold a cup impactor at a desired angle or orientation during cup impaction. When the final position has been achieved, the robotic arm 105A may prevent any further seating to prevent damage to the pelvis.

[0081] The surgeon may use the robotic arm 105A to position the broach handle at the desired position and allow the surgeon to impact the broach into the femoral canal at the desired orientation. In some embodiments, once the Surgical Computer 150 receives feedback that the broach is fully seated, the robotic arm 105A may restrict the handle to prevent further advancement of the broach.

[0082] The robotic arm 105A may also be used for resurfacing applications. For example, the robotic arm 105A may stabilize the surgeon while using traditional instrumentation and provide certain restrictions or limitations to allow for proper placement of implant components (e.g., guide wire placement, chamfer cutter, sleeve cutter, plan cutter, etc.). Where only a burr is employed, the robotic arm 105A may stabilize the surgeon's handpiece and may impose restrictions on the handpiece to prevent the surgeon from removing unintended bone in contravention of the surgical plan.

[0083] The robotic arm 105A may be a passive arm. As an example, the robotic arm 105A may be a CIRQ robot arm available from Brainlab AG. CIRQ is a registered trademark of Brainlab AG, Olof-Palme-Str. 9 81829, München, 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 No. 10,342,636 to Nowatschin et al., the entire contents of each of which is herein incorporated by reference.Attorney Docket No. PT-6005-WO-PCT / D030402 Surgical Procedure Data Generation and Collection

[0084] The various services that are provided by medical professionals to treat a clinical condition are collectively referred to as an "episode of care." For a particular surgical intervention, the episode of care can include three phases: pre-operative, intra-operative, and post-operative. During each phase, data is collected or generated that can be used to analyze the episode of care in order to understand various features of the procedure and identify patterns that may be used, for example, in training models to make decisions with minimal human intervention. The data collected over the episode of care may be stored at the Surgical Computer 150 or the Surgical Data Server 180 as a complete dataset. Thus, for each episode of care, a dataset exists that comprises all of the data collectively pre-operatively about the patient, all of the data collected or stored by the CASS 100 intra-operatively, and any post- operative data provided by the patient or by a healthcare professional monitoring the patient.

[0085] As explained in further detail, the data collected during the episode of care may be used to enhance performance of the surgical procedure or to provide a holistic understanding of the surgical procedure and the patient outcomes. For example, in some embodiments, the data collected over the episode of care may be used to generate a surgical plan. In one embodiment, a high-level, pre-operative plan is refined intra-operatively as data is collected during surgery. In this way, the surgical plan can be viewed as dynamically changing in real-time or near real-time as new data is collected by the components of the CASS 100. In other embodiments, pre-operative images or other input data may be used to develop a robust plan preoperatively that is simply executed during surgery. In this case, the data collected by the CASS 100 during surgery may be used to make recommendations that ensure that the surgeon stays within the pre-operative surgical plan. For example, if the surgeon is unsure how to achieve a certain prescribed cut or implant alignment, the Surgical Computer 150 can be queried for a recommendation. In still other embodiments, the pre-operative and intra-operativeAttorney Docket No. PT-6005-WO-PCT / D030402 planning approaches can be combined such that a robust pre-operative plan can be dynamically modified, as necessary or desired, during the surgical procedure. In some embodiments, a biomechanics-based model of patient anatomy contributes simulation data to be considered by the CASS 100 in developing preoperative, intraoperative, and post-operative / rehabilitation procedures to optimize implant performance outcomes for the patient.

[0086] Aside from changing the surgical procedure itself, the data gathered during the episode of care may be used as an input to other procedures ancillary to the surgery. For example, in some embodiments, implants can be designed using episode of care data. Example data-driven techniques for designing, sizing, and fitting implants are described in U.S. Patent No. 10,064,686, filed August 15, 2011, and entitled "Systems and Methods for Optimizing Parameters for Orthopaedic Procedures"; U.S. Patent No. 10,102,309, filed July 20, 2012 and entitled "Systems and Methods for Optimizing Fit of an Implant to Anatomy"; and U.S. Patent No. 8,078,440, filed September 19, 2008 and entitled "Operatively Tuning Implants for Increased Performance," the entire contents of each of which are hereby incorporated by reference into this patent application.

[0087] Furthermore, the data can be used for educational, training, or research purposes. For example, using the network-based approach described below in FIG. 2C, other doctors or students can remotely view surgeries in interfaces that allow them to selectively view data as it is collected from the various components of the CASS 100. After the surgical procedure, similar interfaces may be used to "playback" a surgery for training or other educational purposes, or to identify the source of any issues or complications with the procedure.

[0088] Data acquired during the pre-operative phase generally includes all information collected or generated prior to the surgery. Thus, for example, information about the patient may be acquired from a patient intake form or electronic medical record (EMR).Attorney Docket No. PT-6005-WO-PCT / D030402 Examples of patient information that may be collected include, without limitation, patient demographics, diagnoses, medical histories, progress notes, vital signs, medical history information, allergies, and lab results. The pre-operative data may also include images related to the anatomical area of interest. These images may be captured, for example, using Magnetic Resonance Imaging (MRI), Computed Tomography (CT), X-ray, ultrasound, or any other modality known in the art. The pre-operative data may also comprise quality of life data captured from the patient. For example, in one embodiment, pre-surgery patients use a mobile application ("app") to answer questionnaires regarding their current quality of life. In some embodiments, preoperative data used by the CASS 100 includes demographic, anthropometric, cultural, or other specific traits about a patient that can coincide with activity levels and specific patient activities to customize the surgical plan to the patient. For example, certain cultures or demographics may be more likely to use a toilet that requires squatting on a daily basis.

[0089] FIGS. 2A and 2B provide examples of data that may be acquired during the intra-operative phase of an episode of care. These examples are based on the various components of the CASS 100 described above with reference to FIG.1; however, it should be understood that other types of data may be used based on the types of equipment used during surgery and their use.

[0090] FIG.2A shows examples of some of the control instructions that the Surgical Computer 150 provides 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 controlled directly by the Surgical Computer 150. In embodiments where a component is manually controlled by the Surgeon 111, instructions may be provided on the Display 125 or AR HMD 155 instructing the Surgeon 111 how to move the component.

[0091] The various components included in the Effector Platform 105 are controlled by the Surgical Computer 150 providing position commands that instruct the component whereAttorney Docket No. PT-6005-WO-PCT / D030402 to move within a coordinate system. In some embodiments, the Surgical Computer 150 provides the Effector Platform 105 with instructions defining how to react when a component of the Effector Platform 105 deviates from a surgical plan. These commands are referenced in FIG. 2A as "haptic" commands. For example, the End Effector 105B may provide a force to resist movement outside of an area where resection is planned. Other commands that may be used by the Effector Platform 105 include vibration and audio cues.

[0092] In some embodiments, the end effectors 105B of the robotic arm 105A are operatively coupled with cutting guide 105D. In response to an anatomical model of the surgical scene, the robotic arm 105A can move the end effectors 105B and the cutting guide 105D into position to match the location of the femoral or tibial cut to be performed in accordance with the surgical plan. This can reduce the likelihood of error, allowing the vision system and a processor utilizing that vision system to implement the surgical plan to place a cutting guide 105D at the precise location and orientation relative to the tibia or femur to align a cutting slot of the cutting guide with the cut to be performed according to the surgical plan. Then, a surgeon can use any suitable tool, such as an oscillating or rotating saw or drill to perform the cut (or drill a hole) with perfect placement and orientation because the tool is mechanically limited 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 a surgeon to drill and screw or pin the cutting guide into place before performing a resection of the patient tissue using the cutting guide. This can free the robotic arm 105A or ensure that the cutting guide 105D is fully affixed without moving relative to the bone to be resected. For example, this procedure can be used to make the first distal cut of the femur during a total knee arthroplasty. In some embodiments, where the arthroplasty is a hip arthroplasty, cutting guide 105D can be fixed to the femoral head or the acetabulum for the respective hip arthroplasty resection. ItAttorney Docket No. PT-6005-WO-PCT / D030402 should be understood that any arthroplasty that utilizes precise cuts can use the robotic arm 105A and / or cutting guide 105D in this manner.

[0093] The Resection Equipment 110 is provided with a variety of commands to perform bone or tissue operations. As with the Effector Platform 105, position information may be provided to the Resection Equipment 110 to specify where it should be located when performing resection. Other commands provided to the Resection Equipment 110 may be dependent on the type of resection equipment. For example, for a mechanical or ultrasonic resection tool, the commands may specify the speed and frequency of the tool. For Radiofrequency Ablation (RFA) and other laser ablation tools, the commands may specify intensity and pulse duration.

[0094] Some components of the CASS 100 do not need to be directly controlled by the Surgical Computer 150; rather, the Surgical Computer 150 only needs to activate the component, which then executes software locally specifying the manner in which to collect data and provide 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.

[0095] The Surgical Computer 150 provides the Display 125 with any visualization that is needed by the Surgeon 111 during surgery. For monitors, the Surgical Computer 150 may provide instructions for displaying images, GUIs, etc. using techniques known in the art. The display 125 can include various portions of the workflow of a surgical plan. During the registration process, for example, the display 125 can show a preoperatively constructed 3D bone model and depict the locations of the probe as the surgeon uses the probe to collect locations of anatomical landmarks on the patient. The display 125 can include information about the surgical target area. For example, in connection with a TKA, the display 125 can depict the mechanical and anatomical axes of the femur and tibia. The display 125 can depictAttorney Docket No. PT-6005-WO-PCT / D030402 varus and valgus angles for the knee joint based on a surgical plan, and the CASS 100 can depict how such angles will be affected if contemplated revisions to the surgical plan are made. Accordingly, the display 125 is an interactive interface that can dynamically update and display how changes to the surgical plan would impact the procedure and the final position and orientation of implants installed on bone.

[0096] As the workflow progresses to preparation of bone cuts or resections, the display 125 can depict the planned or recommended bone cuts before any cuts are performed. The surgeon 111 can manipulate the image display to provide different anatomical perspectives of the target area and can have the option to alter or revise the planned bone cuts based on intraoperative evaluation of the patient. The display 125 can depict how the chosen implants would be installed on the bone if the planned bone cuts are performed. If the surgeon 111 choses to change the previously planned bone cuts, the display 125 can depict how the revised bone cuts would change the position and orientation of the implant when installed on the bone.

[0097] The display 125 can provide the surgeon 111 with a variety of data and information about the patient, the planned surgical intervention, and the implants. Various patient-specific information can be displayed, including real-time data concerning the patient's health such as heart rate, blood pressure, etc. The display 125 also can include information about the anatomy of the surgical target region including the location of landmarks, the current state of the anatomy (e.g., whether any resections have been made, the depth and angles of planned and executed bone cuts), and future states of the anatomy as the surgical plan progresses. The display 125 also can provide or depict additional information about the surgical target region. For a TKA, the display 125 can provide information about the gaps (e.g., gap balancing) between the femur and tibia and how such gaps will change if the planned surgical plan is carried out. For a TKA, the display 125 can provide additional relevant information about the knee joint such as data about the joint's tension (e.g., ligament laxity) and informationAttorney Docket No. PT-6005-WO-PCT / D030402 concerning rotation and alignment of the joint. The display 125 can depict how the planned implants' locations and positions will affect the patient as the knee joint is flexed. The display 125 can depict how the use of different implants or the use of different sizes of the same implant will affect the surgical plan and preview how such implants will be positioned on the bone. The CASS 100 can provide such information for each of the planned bone resections in a TKA or THA. In a TKA, the CASS 100 can provide robotic control for one or more of the planned bone resections. For example, the CASS 100 can provide robotic control only for the initial distal femur cut, and the surgeon 111 can manually perform other resections (anterior, posterior and chamfer cuts) using conventional means, such as a 4-in-1 cutting guide or jig 105D.

[0098] The display 125 can employ different colors to inform the surgeon of the status of the surgical plan. For example, un-resected bone can be displayed in a first color, resected bone can be displayed in a second color, and planned resections can be displayed in a third color. Implants can be superimposed onto the bone in the display 125, and implant colors can change or correspond to different types or sizes of implants.

[0099] The information and options depicted on the display 125 can vary depending on the type of surgical procedure being performed. Further, the surgeon 111 can request or select a particular surgical workflow display that matches or is consistent with his or her surgical plan preferences. For example, for a surgeon 111 who typically performs the tibial cuts before the femoral cuts in a TKA, the display 125 and associated workflow can be adapted to take this preference into account. The surgeon 111 also can preselect that certain steps be included or deleted from the standard surgical workflow display. For example, if a surgeon 111 uses resection measurements to finalize an implant plan but does not analyze ligament gap balancing 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 provided based on the surgeon's preferences or the circumstances of a particularAttorney Docket No. PT-6005-WO-PCT / D030402 surgery. Modules directed to ligament and gap balancing, for example, can include pre- and post-resection ligament / gap balancing, and the surgeon 111 can select which modules to include in their default surgical plan workflow depending on whether they perform such ligament and gap balancing before or after (or both) bone resections are performed.

[0100] For more specialized display equipment, such as AR HMDs, the Surgical Computer 150 may provide images, text, etc. using the data format supported by the equipment. For example, if the Display 125 is a holography device such as the Microsoft HoloLens™ or Magic Leap One™, the Surgical Computer 150 may use the HoloLens Application Program Interface (API) to send commands specifying the position and content of holograms displayed in the field of view of the Surgeon 111.

[0101] In some embodiments, one or more surgical planning models may be incorporated into the CASS 100 and used in the development of the surgical plans provided to the surgeon 111. The term "surgical planning model" refers to software that simulates the biomechanics performance of anatomy under various scenarios to determine the optimal way to perform cutting and other surgical activities. For example, for knee replacement surgeries, the surgical planning model can measure parameters for functional activities, such as deep knee bends, gait, etc., and select cut locations on the knee to optimize implant placement. One example of a surgical planning model is the LIFEMOD™ simulation software from SMITH AND NEPHEW, INC. In some embodiments, the Surgical Computer 150 includes computing architecture that allows full execution of the surgical planning model during surgery (e.g., a GPU-based parallel processing environment). In other embodiments, the Surgical Computer 150 may be connected over a network to a remote computer that allows such execution, such as a Surgical Data Server 180 (see FIG.2C). As an alternative to full execution of the surgical planning model, in some embodiments, a set of transfer functions are derived that simplify the mathematical operations captured by the model into one or more predictor equations. Then,Attorney Docket No. PT-6005-WO-PCT / D030402 rather than execute the full simulation during surgery, the predictor equations are used. Further details on the use of transfer functions are described in WIPO Publication No. 2020 / 037308, filed August 19, 2019, entitled "Patient Specific Surgical Method and System," the entirety of which is incorporated herein by reference.

[0102] FIG.2B shows examples of some of the types of data that can be provided to the Surgical Computer 150 from the various components of the CASS 100. In some embodiments, the components may stream data to the Surgical Computer 150 in real-time or near real-time during surgery. In other embodiments, the components may queue data and send it to the Surgical Computer 150 at set intervals (e.g., every second). Data may be communicated using any format known in the art. Thus, in some embodiments, the components all transmit data to the Surgical Computer 150 in a common format. In other embodiments, each component may use a different data format, and the Surgical Computer 150 is configured with one or more software applications that enable translation of the data.

[0103] In general, the Surgical Computer 150 may serve as the central point where CASS data is collected. The exact content of the data will vary depending on the source. For example, each component of the Effector Platform 105 provides a measured position to the Surgical Computer 150. Thus, by comparing the measured position to a position originally specified by the Surgical Computer 150 (see FIG. 2B), the Surgical Computer can identify deviations that take place during surgery.

[0104] The Resection Equipment 110 can send various types of data to the Surgical Computer 150 depending on the type of equipment used. Example data types that may be sent include the measured torque, audio signatures, and measured displacement values. Similarly, the Tracking Technology 115 can provide different types of data depending on the tracking methodology employed. Example tracking data types include position values for tracked items (e.g., anatomy, tools, etc.), ultrasound images, and surface or landmark collection points orAttorney Docket No. PT-6005-WO-PCT / D030402 axes. The Tissue Navigation System 120 provides the Surgical Computer 150 with anatomic locations, shapes, etc. as the system operates.

[0105] Although the Display 125 generally is used for outputting data for presentation to the user, it may also provide data to the Surgical Computer 150. For example, for embodiments where a monitor is used as part of the Display 125, the Surgeon 111 may interact with a GUI to provide inputs which are sent to the Surgical Computer 150 for further processing. For AR applications, the measured position and displacement of the HMD may be sent to the Surgical Computer 150 so that it can update the presented view as needed.

[0106] During the post-operative phase of the episode of care, various types of data can be collected to quantify the overall improvement or deterioration in the patient's condition as a result of the surgery. The data can take the form of, for example, self-reported information reported by patients via questionnaires. For example, in the context of a knee replacement surgery, functional status can be measured with an Oxford Knee Score questionnaire, and the post-operative quality of life can be measured with a EQ5D-5L questionnaire. Other examples in the context of a hip replacement surgery may include the Oxford Hip Score, Harris Hip Score, and WOMAC (Western Ontario and McMaster Universities Osteoarthritis index). Such questionnaires can be administered, for example, by a healthcare professional directly in a clinical setting or using a mobile app that allows the patient to respond to questions directly. In some embodiments, the patient may be outfitted with one or more wearable devices that collect data relevant to the surgery. For example, following a knee surgery, the patient may be outfitted with a knee brace that includes sensors that monitor knee positioning, flexibility, etc. This information can be collected and transferred to the patient's mobile device for review by the surgeon to evaluate the outcome of the surgery and address any issues. In some embodiments, one or more cameras can capture and record the motion of a patient's body segments during specified activities postoperatively. This motion capture can be compared to a biomechanicsAttorney Docket No. PT-6005-WO-PCT / D030402 model to better understand the functionality of the patient's joints and better predict progress in recovery and identify any possible revisions that may be needed.

[0107] The post-operative stage of the episode of care can continue over the entire life of a patient. For example, in some embodiments, the Surgical Computer 150 or other components comprising the CASS 100 can continue to receive and collect data relevant to a surgical procedure after the procedure has been performed. This data may include, for example, images, answers to questions, "normal" patient data (e.g., blood type, blood pressure, conditions, medications, etc.), biometric data (e.g., gait, etc.), and objective and subjective data about specific issues (e.g., knee or hip joint pain). This data may be explicitly provided to the Surgical Computer 150 or other CASS component by the patient or the patient's physician(s). Alternatively, or additionally, the Surgical Computer 150 or other CASS component can monitor the patient's EMR and retrieve relevant information as it becomes available. This longitudinal view of the patient's recovery allows the Surgical Computer 150 or other CASS component to provide a more objective analysis of the patient's outcome to measure and track success or lack of success for a given procedure. For example, a condition experienced by a patient long after the surgical procedure can be linked back to the surgery through a regression analysis of various data items collected during the episode of care. This analysis can be further enhanced by performing the analysis on groups of patients that had similar procedures and / or have similar anatomies.

[0108] In some embodiments, data is collected at a central location to provide for easier analysis and use. Data can be manually collected from various CASS components in some instances. For example, a portable storage device (e.g., USB stick) can be attached to the Surgical Computer 150 into order to retrieve data collected during surgery. The data can then be transferred, for example, via a desktop computer to the centralized storage. Alternatively, inAttorney Docket No. PT-6005-WO-PCT / D030402 some embodiments, the Surgical Computer 150 is connected directly to the centralized storage via a Network 175 as shown in FIG.2C.

[0109] FIG. 2C illustrates a "cloud-based" implementation in which the Surgical Computer 150 is connected to a Surgical Data Server 180 via a Network 175. This Network 175 may be, for example, a private intranet or the Internet. In addition to the data from the Surgical Computer 150, other sources can transfer relevant data to the Surgical Data Server 180. The example of FIG.2C shows three additional data sources: the Patient 160, Healthcare Professional(s) 165, and an EMR Database 170. Thus, the Patient 160 can send pre-operative and post-operative data to the Surgical Data Server 180, for example, using a mobile app. The Healthcare Professional(s) 165 includes the surgeon and his or her staff as well as any other professionals working with Patient 160 (e.g., a personal physician, a rehabilitation specialist, etc.). It should also be noted that the EMR Database 170 may be used for both pre-operative and post-operative data. For example, assuming that the Patient 160 has given adequate permissions, the Surgical Data Server 180 may collect the EMR of the Patient pre-surgery. Then, the Surgical Data Server 180 may continue to monitor the EMR for any updates post- surgery.

[0110] At the Surgical Data Server 180, an Episode of Care Database 185 is used to store the various data collected over a patient's episode of care. The Episode of Care Database 185 may be implemented using any technique known in the art. For example, in some embodiments, a SQL-based database may be used where all of the various data items are structured in a manner that allows them to be readily incorporated in two SQL's collection of rows and columns. However, in other embodiments a No-SQL database may be employed to allow for unstructured data, while providing the ability to rapidly process and respond to queries. As is understood in the art, the term "No-SQL" is used to define a class of data stores that are non-relational in their design. Various types of No-SQL databases may generally beAttorney Docket No. PT-6005-WO-PCT / D030402 grouped according to their underlying data model. These groupings may include databases that use column-based data models (e.g., Cassandra), document-based data models (e.g., MongoDB), key-value based data models (e.g., Redis), and / or graph-based data models (e.g., Allego). Any type of No-SQL database may be used to implement the various embodiments described herein and, in some embodiments, the different types of databases may support the Episode of Care Database 185.

[0111] Data can be transferred between the various data sources and the Surgical Data Server 180 using any data format and transfer technique known in the art. It should be noted that the architecture shown in FIG.2C allows transmission from the data source to the Surgical Data Server 180, as well as retrieval of data from the Surgical Data Server 180 by the data sources. For example, as explained in detail below, in some embodiments, the Surgical Computer 150 may use data from past surgeries, machine learning models, etc. to help guide the surgical procedure.

[0112] In some embodiments, the Surgical Computer 150 or the Surgical Data Server 180 may execute a de-identification process to ensure that data stored in the Episode of Care Database 185 meets Health Insurance Portability and Accountability Act (HIPAA) standards or other requirements mandated by law. HIPAA provides a list of certain identifiers that must be removed from data during de-identification. The aforementioned de-identification process can scan for these identifiers in data that is transferred to the Episode of Care Database 185 for storage. For example, in one embodiment, the Surgical Computer 150 executes the de- identification process just prior to initiating transfer of a particular data item or set of data items to the Surgical Data Server 180. In some embodiments, a unique identifier is assigned to data from a particular episode of care to allow for re-identification of the data if necessary.

[0113] Although FIGS.2A-C discuss data collection in the context of a single episode of care, it should be understood that the general concept can be extended to data collectionAttorney Docket No. PT-6005-WO-PCT / D030402 from multiple episodes of care. For example, surgical data may be collected over an entire episode of care each time a surgery is performed with the CASS 100 and stored at the Surgical Computer 150 or at the Surgical Data Server 180. As explained in further detail below, a robust database of episode of care data allows the generation of optimized values, measurements, distances, or other parameters and other recommendations related to the surgical procedure. In some embodiments, the various datasets are indexed in the database or other storage medium in a manner that allows for rapid retrieval of relevant information during the surgical procedure. For example, in one embodiment, a patient-centric set of indices may be used so that data pertaining to a particular patient or a set of patients similar to a particular patient can be readily extracted. This concept can be similarly applied to surgeons, implant characteristics, CASS component versions, etc.

[0114] Further details of the management of episode of care data are described in U.S. Patent Application No. 16 / 847,183, filed April 13, 2020, published as U.S. Publication No. 2020 / 0243199, and entitled "METHODS AND SYSTEMS FOR PROVIDING AN EPISODE OF CARE," the entirety of which is incorporated herein by reference. Methods of Planning Total Hip Arthroplasty Using Muscle Properties

[0115] As discussed herein, it would be advantageous to have a method of planning a THA procedure that accounts for post-operative muscle properties during implant selection and placement. Such methods may enhance planning performance by providing an improved and personalized prediction of the post-operative state of the joint, thereby enabling clinical benefits such as improved patient function and reduced risk of dislocation, failure, injury, pain, and / or re-operation. Inclusion of muscle-related considerations in the planning accounts for patient-specific factors that are often overlooked by a physician using conventional tools. Ideally, a method for planning acetabular cup placement would be configured to model post- operative muscle properties in addition to the bony anatomy based on personalized patientAttorney Docket No. PT-6005-WO-PCT / D030402 data in order to determine differences between the pre-operative muscle properties and post- operative muscle properties, thereby enabling selection and placement of implants to restore normal hip function.

[0116] Turning now to FIG.5, a flow diagram of an illustrative method of optimizing a surgical plan for a hip arthroplasty for a patient is depicted in accordance with an embodiment. The method 500 comprises obtaining 505 a computer model of a bony anatomy of a hip joint of the patient, determining 510 one or more measurements associated with the bony anatomy, determining 515 muscle attachment locations on the bony anatomy, generating 520 a mathematical model of the hip comprising bony and muscular anatomical properties, receiving 525 input associated with one or more implant parameters, determining 530 a surgical plan comprising the one or more implant parameters based on the input, identifying 535 one or more differences between pre-operative properties and post-operative properties of muscles associated with the hip joint, optimizing 540 the one or more implant parameters based on the one or more identified differences, and generating 545 the optimized surgical plan based on the one or more optimized implant parameters.

[0117] In some embodiments, the computer model of the bony anatomy is based on one or more three-dimensional (3D) images of the bony anatomy, e.g., one or more computed tomography (CT) scan images. In some embodiments, obtaining 505 the computer model of the bony anatomy comprises receiving one or more CT images of the bony anatomy and constructing the computer model based on the CT images.

[0118] In some embodiments, the CT images comprise the entire hip joint. In some embodiments, the CT images comprise the operative hip joint (i.e., the hip joint of the patient for which the THA procedure is being planned) and an opposing hip joint (i.e., the second hip joint of the patient). Accordingly, the CT images may comprise the entire pelvis, the proximal extremity of each femur, and the distal extremity of each femur of the patient. Accordingly,Attorney Docket No. PT-6005-WO-PCT / D030402 measurements of the posterior condyle axis and lateral patellar tilt may be determined based on the CT images as further described herein.

[0119] The computer model may be constructed based on the CT images. The computer model may comprise models or portions of a model corresponding to the pelvis, a femur (i.e., the femur of the operative hip joint), and a patella (i.e., the patella of the leg associated with the operative hip joint). The computer model may depict the bony anatomy of the pelvis, the femur, and the patella. In some embodiments, the computer model may construct the entire pelvis, femur, and / or patella from sparse data obtained from the CT images using statistical shape modeling. For example, sparse data of the proximal and distal extremities of the femur may be obtained from the CT images and used to infer full geometries of the entire femur based on statistical shape modeling.

[0120] Determining 510 one or more measurements associated with the bony anatomy may comprise determining one or more anatomical angles associated with the bony anatomy. In some embodiments, the one or more measurements comprise an anteversion of a femur of the hip, i.e., an angle between the femoral neck axis and posterior intercondylar line projected on the transverse plane. In some embodiments, the one or more measurements comprise a femur internal rotation, i.e., an angle between a line joining the posterior inferior iliac spines and a posterior intercondylar line. In some embodiments, the one or more measurements comprise a lateral patellar tilt, i.e., an angle between a line joining the medial and lateral extremes of the patella and a posterior intercondylar line. In some embodiments, the one or more measurements are selected from the group consisting of femoral anteversion, femoral internal rotation, and lateral patellar tilt. In some embodiments, the one or more measurements comprise femoral anteversion, femoral internal rotation, and lateral patellar tilt. In some embodiments, the measurements are collected for both legs, i.e., the leg associated with the operative hip joint and the leg associated with the opposing hip joint. It should beAttorney Docket No. PT-6005-WO-PCT / D030402 understood that the one or more measurements are performed in the pre-operative state such that the measurements reflect a pre-operative bony anatomy of the patient.

[0121] The muscle attachment locations on the bony anatomy may be determined 515 based on the computer model of the bony anatomy. In some embodiments, determining 515 the muscle attachment locations comprises using statistical shape modeling. For example, morphing or non-rigid registration algorithms may be used to morph a 3D bone geometry of an annotated template to identify muscle attachments on the computer model of the bony anatomy of the patient.

[0122] Utilizing the computer model, the muscle attachment locations, and / or the one or more measurements, the mathematical model of the hip may be generated to model the bony and muscular anatomy of the patient and properties thereof. In some embodiments, the mathematical model is a 3D mathematical model. In some embodiments, the mathematical model comprises one or more mathematical equations generated based on the computer model, the muscle attachment locations, and / or the one or more measurements. It should be understood that these models may utilize patient-specific images such as MRI images, statistical models that relate bone morphology to muscle attachment locations, or a combination thereof.

[0123] The 3D mathematical model may describe the bony and muscular anatomy of the patient in a variety of manners. Generally, 3D unidimensional or volumetric models of the muscles spanning the hip are used to describe the muscular dynamics of the hip joint. In some embodiments, large muscles (e.g., the gluteus medius) are divided into a plurality of musculotendon units to more accurately describe a force application distribution on the muscle attachment locations.

[0124] In some embodiments, each musculotendon unit may be defined by a Hill- type muscle model that describes the musculotendon unit as a force-generating cable-like element with active and passive properties controlled by, for example, the following fourAttorney Docket No. PT-6005-WO-PCT / D030402 parameters: optimal fiber length, tendon slack length, maximum isometric force, and pennation angle. In some embodiments, the four parameters are scaled to a size application to the patient based on historical anatomical data. In some embodiments, the historical anatomical data comprises cadaver dissection average data. In some embodiments, the historical anatomical data comprises historical patient data. In some embodiments, the historical anatomical data comprises a combination of cadaver dissection average data and historical patient data.

[0125] In some embodiments, the 3D mathematical model includes and accounts for additional dynamics of the muscles with respect to the bony anatomy. For example, the 3D mathematical model may account for sliding of muscles on underlying geometries, e.g., bones and other muscles. Wrapping of muscles on underlying anatomical structures may also be included.

[0126] In some embodiments, receiving 525 input associated with one or more implant parameters for the surgical plan comprises receiving input from a user (e.g., a surgeon) through an input device. For example, a surgeon may select or adjust one or more implant parameters based on a review of the CT images, the computer model, the one or more measurements, and / or other collected data as described herein. In additional embodiments, receiving 525 input comprises receiving stored information related to surgical planning. For example, the input may comprise stored preferences for a surgeon, a surgical group, a hospital, or other default standards that are pre-selected for planning of a THA procedure.

[0127] In some embodiments, the input is related to one or more of an implant model and an implant size. In some embodiments, the input relates to one or more of an acetabular cup implant and a femoral implant. In some embodiments, the input may further relate to a head of the femoral implant, e.g., a head size and / or a neck length. In some embodiments, the input may further relate to a liner to be used with the implant components.Attorney Docket No. PT-6005-WO-PCT / D030402

[0128] In some embodiments, determining 530 a surgical plan comprising the one or more implant parameters based on the input comprises determining each of an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and / or a type of implant liner. Where surgeon selection of one or more parameters is provided, the implant parameter may be determined by the selection of the surgeon. Where surgeon selection of one or more parameters is not provided, the implant parameter may be determined 530 based on stored preferences, default standards, and / or one or more calculations performed by a processor (e.g., the surgical computer 150 of FIG. 1 as described herein) and / or a machine learning algorithm. In some embodiments, the surgical plan may include additional information about the procedure. For example, the surgical plan may include a planned surgical approach (e.g., anterior, posterior, lateral), which may imply or include information about particular muscles to be cut during the procedure. The surgical plan may further include planned muscle repair, e.g., whether a cut muscle is planned to be repaired during the procedure and / or the planned method of repair.

[0129] In some embodiments, differences between pre-operative properties and post- operative properties of muscles associated with the hip joint are identified 535 using the 3D mathematical models. In some embodiments, the differences in muscle properties may comprise a muscle length and / or a muscle moment arm. Muscle length and / or muscle moment arm may be relevant to identifying changes in passive tension and force-generating capacity of the muscle. The 3D mathematical models may be used to assess muscular properties in the pre- operative state as well as muscular properties in the post-operative state by incorporating one or more changes to the bony and / or muscular anatomy associated with the surgical plan.

[0130] In one example, the surgical approach (e.g., anterior, posterior, lateral) may cut through different muscles and / or regions of the hip capsule, thereby reducing the soft tissue tension at least for a period following surgery. Accordingly, the 3D mathematical model mayAttorney Docket No. PT-6005-WO-PCT / D030402 incorporate the cuts in one or more muscles and the planned repair to the one or more muscles associated with a planned surgical approach. For example, if a posterolateral approach is planned, absence or weakness of the hip external rotators is simulated by the 3D mathematical models to provide an accurate depiction of the post-operative joint. In some embodiments, the level of muscle weakness simulated is based on whether muscle repair is planned and / or the planned method of repair according to the surgical plan.

[0131] In another example, muscle contractures may exist in the hip joint pre- operatively. For example, if external rotation contractures are present before the THA procedure, their release will increase post-operative internal rotation. Accordingly, the 3D mathematical model may incorporate pre-operative muscle contractures to provide an accurate depiction of the pre-operative joint, and thus an accurate depiction of differences in the post- operative joint based on the surgical plan.

[0132] In some embodiments, optimizing 540 the one or more implant parameters based on the one or more identified differences may be performed to minimize and / or eliminate potential issues in the surgical plan. For example, a potential issue may be rubbing of the iliopsoas muscle on the acetabular cup implant component in a neutral position and / or during activities of daily living that involve use of the muscle, e.g., straight-leg raising, active flexion of the hip, ascending stairs, lifting the operated leg into bed, and lifting the leg to get into and out of a car). In another example, a potential issue may be a change in femoral internal rotation due to increased tension in the internal rotator muscles and relaxation of the external rotator muscles, which may result in post-operative in-toeing. In yet another example, a potential issue may be a change in tension of biarticular muscles (e.g., tensor fascia latae, iliotibial band, and rectus femoris) due to leg lengthening and other posture and anatomical modifications. Changes in the tension of the biarticular muscles may cause increased tensioning in the lateral patellar retinaculum and increased lateral patellar tilt, which is associated with anterior kneeAttorney Docket No. PT-6005-WO-PCT / D030402 pain. Accordingly, optimizing 540 the one or more implant parameters may comprise identifying one or more potential issues based on the identified differences between the pre- operative properties and the post-operative properties of the muscles, and adjusting the one or more implant parameters to reduce or eliminate the one or more potential issues. As such, optimizing 540 may comprise performing iterations of adjusting the one or more implant parameters and re-performing step 535, i.e., identifying differences between pre-operative properties and post-operative properties of muscles associated with the hip joint. In some embodiments, a plurality of iterations are performed. However, it should be understood that any number of iterations may be performed until a satisfactory set of optimized implant parameters is obtained (i.e., wherein all assessed issues in the post-operative joint are eliminated, minimized, and / or reduced to an acceptable degree as would be known and understood by a person having an ordinary level of skill in the art).

[0133] In some embodiments, the optimizing 540 operation comprises optimizing the acetabular cup size and / or the acetabular cup placement or reducing or eliminating overhang of the acetabular cup, thereby reducing the risk of iliopsoas tendinosis. In some embodiments, the optimizing 540 operation comprises optimizing a femoral stem size and / or a femoral stem placement to retain or restore pre-operative muscle properties, femur internal rotation, and lateral patellar tilt. However, it should be understood that any of the implant parameters in the surgical plan may be optimized 540.

[0134] The optimized implant parameters may be used to modify the surgical plan thereby generating 545 the optimized surgical plan. In some embodiments, the method 500 further comprises displaying the surgical plan on a display device, e.g., to allow a surgeon to view the optimized surgical plan. In some embodiments, the method 500 further comprises outputting the surgical plan to a computer-readable storage device, e.g., a server, a portable storage device, and / or a memory of another computing device, to allow the optimized surgicalAttorney Docket No. PT-6005-WO-PCT / D030402 plan to be accessed, viewed, and / or otherwise used by additional parties, including but not limited to a surgeon performing the THA procedure on the patient at a different time and / or place.

[0135] The devices, systems, and methods as described herein are not intended to be limited in terms of the particular embodiments described, which are intended only as illustrations of various features. Many modifications and variations to the devices, systems, and methods can be made without departing from their spirit and scope, as will be apparent to those skilled in the art.

[0136] As described herein, the method 500 enables augmentation of a 3D anatomic model of a patient's hip created pre-operatively from CT reconstruction. The model can be used to identify potential rubbing of the iliopsoas tendon on the cup anterior edge during simulation of activities of daily living associated with groin pain. Cup placement can be adjusted accordingly to avoid rubbing.

[0137] The model can also be used to predict changes in length, moment arm, and / or tension of the main internal and external rotators of the hip (e.g., piriformis, gemelli, obturator, quadratus femoris, gluteus medius and minimus, and / or adductor brevis). Stem component selection and placement may be adjusted to restore pre-operative, contralateral, or healthy muscle properties. However, it should be understood that contralateral and / or healthy muscle properties may not be ideal for the post-operative joint depending on the pre-operative condition of the joint. For example, muscles may remodel and change properties to adjust to the new joint, which may be preferred over a pre-operative state. Accordingly, aiming for contralateral muscle quantities may disrupt the new equilibrium and require more muscle adaptation. As such, contralateral and / or healthy muscle properties may be applied in particular cases.Attorney Docket No. PT-6005-WO-PCT / D030402

[0138] A model as described herein that includes the patellofemoral joint and ligaments may further be used to predict post-operative tension in the biarticular muscles that affect patellar kinematics (e.g., tensor fascia latae, iliotibial band, and rectus femoris). Implant selection and placement may be adjusted to avoid risk of excessive tension and anterior knee pain.

[0139] While the methods described herein refer to 3D mathematical models incorporating a Hill-type muscle model, it should be understood that additional types of physiological muscle models known and understood to a person having an ordinary level of skill in the art may be utilized herein with minor modifications.

[0140] It should be understood that the steps of the method 500 may be performed in a variety of manners. In some embodiments, the steps of the method 500 are performed in sequence as described herein. In additional embodiments, the steps of the method 500 are performed out of sequence. Furthermore, several steps or series of steps may be performed simultaneously or in parallel, especially when implemented by a processor. For example, FIG.6 depicts an exemplary workflow for planning a hip arthroplasty in accordance with the principles of the method 500.

[0141] In additional embodiments of the present subject matter, the method 500 may be implemented in a system configured to perform each of the described steps. For example, a system may comprise at least one processor and a memory or computer-readable storage medium comprising instructions that, when executed, cause the at least one processor to perform the method 500. In some embodiments, the system may further comprise an input device configured to receive the input from a user as described herein and transmit the input to the at least one processor. The input device may be implemented in any manner as would be apparent to a person having an ordinary level of skill in the art. In some embodiments, the system may further comprise a display device configured to be operated by the at least oneAttorney Docket No. PT-6005-WO-PCT / D030402 processor to display the optimized surgical plan as described herein. The display device may be implemented in any manner as would be apparent to a person having an ordinary level of skill in the art. Methods of Assessing Hip Joint Kinematics Using Muscle Properties

[0142] As discussed herein, it would also be advantageous to have systems and methods for simulating different motor activities using predicted post-operative muscle properties. Ideally, these systems and methods would be useful for simulation of activities of daily living in order to provide information related to a risk of dislocation and / or impingement in the post-operative joint (e.g., a hip joint following total hip arthroplasty) during such activities. Accordingly, acetabular cup placement and / or other parameters for the THA procedure could be planned or adjusted based on the information to provide improved outcomes.

[0143] Referring now to FIG.7, a flow diagram of an illustrative method of assessing hip joint kinematics of a patient is depicted in accordance with an embodiment. The method comprises obtaining 705 a computer model of a bony anatomy of the hip joint, determining 710 one or more measurements associated with the bony anatomy, determining 715 muscle attachment and hip capsule attachment locations on the bony anatomy, generating 720 a mathematical model of the post-operative hip comprising bony and muscular anatomical properties, optionally conditioning 725 the mathematical model based on a spinopelvic condition of the patient, altering 730 the mathematical model based on a surgical plan, performing 735 at least one simulation of one or more daily living activities with the mathematical model, determining 740 hip joint kinematic information based on the at least one simulation, and optimizing 745 the surgical plan based on the hip joint kinematic information. In some embodiments, the hip joint kinematic information may be used to assess several proposed parameters for a surgical plan for the patient including one or more implants (e.g.,Attorney Docket No. PT-6005-WO-PCT / D030402 make, model, and / or size) and / or one or more implant placements (e.g., position and / or orientation).

[0144] It should be understood that obtaining 705 the computer model of the bony anatomy may be similar to obtaining 505 the computer model of the bony anatomy in the method 500 of FIG. 5 as disclosed herein. Accordingly, the computer model may be obtained 705 in any manner as disclosed herein with respect to obtaining 505 the computer model of the bony anatomy in the method 500. In some embodiments, the computer model of the bony anatomy is based on one or more three-dimensional (3D) images of the bony anatomy, e.g., one or more computed tomography (CT) scan images. In some embodiments, the CT images comprise the entire hip joint. In some embodiments, the CT images comprise the operative hip joint (i.e., the hip joint of the patient for which the THA procedure is being planned) and an opposing hip joint (i.e., the second hip joint of the patient). Accordingly, the CT images may comprise the entire pelvis, the proximal extremity of each femur, and the distal extremity of each femur of the patient. Accordingly, measurements of the posterior condyle axis and lateral patellar tilt may be determined based on the CT images as further described herein. The computer model may depict the bony anatomy of the pelvis, the femur, and / or the patella of the operative leg. In some embodiments, the computer model may construct the entire pelvis, femur, and / or patella from sparse data obtained from the CT images using statistical shape modeling. For example, sparse data of the proximal and distal extremities of the femur may be obtained from the CT images and used to infer full geometries of the entire femur based on statistical shape modeling.

[0145] It should be understood that determining 710 one or more measurements associated with the bony anatomy may be similar to determining 510 one or more measurements associated with the bony anatomy in the method 500 of FIG. 5 as disclosed herein. Accordingly, the one or more measurements may be determined 710 in any manner asAttorney Docket No. PT-6005-WO-PCT / D030402 disclosed herein with respect to determining 510 the one or more measurements in the method 500. For example, the one or more measurements may comprise anatomical angles, e.g., an anteversion of a femur of the hip, a femur internal rotation, and / or a lateral patellar tilt. In some embodiments, the measurements are collected for both the operative leg and the opposing leg. It should be understood that the one or more measurements are performed in the pre-operative state such that the measurements reflect a pre-operative bony anatomy of the patient.

[0146] The muscle attachment and hip capsule locations on the bony anatomy may be determined 715 based on the computer model of the bony anatomy. In some embodiments, determining 715 the muscle attachment and hip capsule attachment locations comprises using statistical shape modeling. For example, morphing or non-rigid registration algorithms may be used to morph a 3D bone geometry of an annotated template to identify muscle attachments and hip capsule attachments on the computer model of the bony anatomy of the patient. It should be understood that determining 715 attachment locations may be similar to determining 515 attachment locations in the method 500 of FIG. 5 as disclosed herein. Accordingly, the attachment locations for the muscles and / or the hip capsule may be determined 715 in any manner as disclosed herein with respect to determining 515 the muscle attachment locations in the method 500.

[0147] Utilizing the computer model, the muscle attachment and hip capsule attachment locations, and / or the one or more measurements, the mathematical model of the hip may be generated 720 to model the bony and muscular anatomy of the patient and properties thereof. It should be understood that generating 720 the mathematical model may be similar to generating 520 the mathematical model in the method 500 of FIG. 5 as disclosed herein. Accordingly, the mathematical model may be generated 720 in any manner as disclosed herein with respect to generating 520 the mathematical model in the method 500.Attorney Docket No. PT-6005-WO-PCT / D030402

[0148] As described with respect to the method 500, the mathematical model may be a 3D mathematical model comprising one or more mathematical equations generated based on the computer model, the muscle attachment locations, the hip capsule attachment locations, and / or the one or more measurements. The mathematical model may utilize patient-specific images such as MRI images, statistical models that relate bone morphology to muscle attachment and / or hip capsule attachment locations, or a combination thereof.

[0149] As described with respect to the method 500, the 3D mathematical model may utilize 3D unidimensional or volumetric models to describe muscles spanning the hip, e.g., one or more musculotendon unit defined by a Hill-type muscle model. In some embodiments, each musculotendon unit may have active and passive properties controlled by, for example, the following four parameters: optimal fiber length, tendon slack length, maximum isometric force, and pennation angle. Likewise, the hip capsule may be described by a biomechanical model comprising one or more 3D unidimensional or volumetric units (e.g., one or more musculotendon unit defined by a Hill-type muscle model) extending along the circumference of the hip joint. For example, the hip capsule may be described by a plurality of unidimensional units, e.g., non-linear springs, extending along the circumference of the joint. In another example, the biomechanical model of the hip capsule comprises that a fully connected 3D layer comprising hyper-elastic material properties. Accordingly, the muscular dynamics of the hip joint are simulated by the 3D mathematical model comprising muscles spanning the hip and the hip capsule.

[0150] In some embodiments, the 3D mathematical model includes and accounts for additional dynamics of the muscles with respect to the bony anatomy. For example, the 3D mathematical model may account for sliding of muscles on underlying geometries, e.g., bones and other muscles. Wrapping of muscles on underlying anatomical structures may also be included.Attorney Docket No. PT-6005-WO-PCT / D030402

[0151] In some embodiments, the method 700 optionally comprises conditioning 725 the mathematical model based on a spinopelvic condition of the patient. Conditioning 725 the mathematical model based on a spinopelvic condition of the patient may comprise receiving 725A input related to a spinopelvic condition of the patient (e.g., one or more of a spinopelvic balance and a spinopelvic mobility), classifying 725B the spinopelvic condition of the patient based on the input, and modifying 725C the mathematical model based on the spinopelvic condition.

[0152] The input related to the spinopelvic condition of the patient may take a variety of forms. In some embodiments, receiving 725A input related to the spinopelvic condition of the patient comprises obtaining one or more lateral 2D images (e.g., x-rays) of the spinopelvic joint of the patient. For example, the input may include a lateral 2D image of the patient in a standing position and / or a lateral 2D image of the patient in a sitting position.

[0153] Based on the lateral 2D images, the spinopelvic balance and / or spinopelvic mobility of the patient may be classified 725B. For example, sacral slope (also referred to as sacral tilt) may be used to classify 725B the spinopelvic condition of the patient. Sacral slope (SS) or sacral tilt (ST), which is defined as the angle between the endplate of the S1 vertebra and the horizontal plane, may be determined from the lateral 2D images and used to classify 725B the spinopelvic balance and / or spinopelvic mobility of the patient. In some embodiments, sacral slope may be determined in each 2D image by landmarking the 2D images. In some embodiments, landmarking comprises identifying a location of a superior / posterior S1 endplate, a location of an inferior / anterior S1 endplate, a hip center, a posterior acetabulum, and / or an anterior acetabulum. Additional or alternate anatomical landmarks may be identified during landmarking as would be apparent to one having an ordinary level of skill in the art. Thereafter, the landmarks may be used to calculate the sacral slope.Attorney Docket No. PT-6005-WO-PCT / D030402

[0154] In some embodiments, spinopelvic balance may be classified as "stuck standing," "stuck sitting," kyphotic, or normal. However, additional medically recognized conditions related to spinopelvic balance may be included in the user input as would be apparent to a person having an ordinary level of skill in the art. Furthermore, in some embodiments, spinopelvic mobility may be classified as fused, stiff, hypermobile, or normal. However, additional medically recognized conditions related to spinopelvic mobility may be included in the user input as would be apparent to a person having an ordinary level of skill in the art.

[0155] Each of the described classifications of spinopelvic balance may be defined by the sacral slope in the standing position and / or the sitting position. In some embodiments, the "stuck standing" classification is defined by a sacral slope of greater than 30° in both the standing position and the sitting position. In some embodiments, the "stuck sitting" classification is defined by a sacral slope of less than 30° in both the standing position and the sitting position. In some embodiments, the kyphotic classification is defined by a sacral slope of less than 5° in the sitting position. In some embodiments, the normal classification is defined by any sacral slopes that do not fall in the remaining spinopelvic balance classifications. However, it is contemplated that the definitions of each classification may be varied and the methods described herein may be carried out in substantially the same manner with minor modifications as would be apparent to a person having an ordinary level of skill in the art. Accordingly, a sacral slope of the patient in a standing position and / or a sacral slope of the patient in a sitting position may be used to classify 725B the spinopelvic balance of the patient.

[0156] Each of the described classifications of spinopelvic mobility may be defined by a difference or change in the sacral slope between the standing position and the sitting position. In some embodiments, the fused classification is defined by a change in sacral slope of less than or equal to 5°. In some embodiments, the stiff classification is defined by a changeAttorney Docket No. PT-6005-WO-PCT / D030402 in sacral slope of greater than 5°, but less than or equal to 10°. In some embodiments, the hypermobile classification is defined by a change in sacral slope of greater than 30°. In some embodiments, the normal classification is defined by any change in sacral slope that does not fall in the remaining spinopelvic mobility classifications (e.g., greater than 10°, but less than or equal to 30°). However, it is contemplated that the defined ranges for each classification may be varied and the methods described herein may be carried out in substantially the same manner with minor modifications as would be apparent to a person having an ordinary level of skill in the art. Accordingly, a sacral slope of the patient in a standing position and a sacral slope of the patient in a sitting position may be used to classify 725B the spinopelvic mobility of the patient based on a change in the sacral slope.

[0157] Modifying 725C the mathematical model based on the spinopelvic condition may comprise adjusting the mathematical model and / or mathematical equations to represent the spinopelvic condition of the patient (i.e., the pathological behavior associated with the classification of the spinopelvic condition of the patient). For example, conditioning 725C the mathematical model may comprise adjusting the mathematical equations representing hip motion to account for limited motion of the spinopelvic joint consistent with the spinopelvic balance and the spinopelvic mobility of the patient. For example, the motion of the spinopelvic joint may be limited to the range between the sacral slopes of the standing position and the sitting position. For example, the motion of the spinopelvic joint may be limited to a range that is typical for an individual with the indicated spinopelvic condition (e.g., average values) and / or to a customized range measured based on patient data (e.g., the 2D images of the spinopelvic joint).

[0158] Further details related to conditioning a model based on a spinopelvic condition of the patient are described in International Patent Application No.Attorney Docket No. PT-6005-WO-PCT / D030402 PCT / US2021 / 051435, filed September 22, 2021, entitled "Systems and Methods for Hip Modeling and Simulation," the entirety of which is incorporated herein by reference.

[0159] Referring once again to FIG. 7, the mathematical model may be altered 730 based on a surgical plan to predict the post-operative state of the hip joint. It should be understood that altering 730 the mathematical model may be similar to alterations to the mathematical models in operations 530 and 535 in the method 500 of FIG. 5 as disclosed herein. Accordingly, the mathematical model may be altered 730 in any manner as disclosed herein with respect to the method 500.

[0160] In some embodiments, the surgical plan includes one or more implant parameters such as an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and / or a type of implant liner that may affect the kinematics of the joint in a post-operative state. Accordingly, the mathematical model may be altered 730 based on determined implant parameters.

[0161] Furthermore, in some embodiments, the surgical plan includes additional information about the procedure such as a planned surgical approach (e.g., anterior, posterior, lateral), which may cut through different muscles and / or regions of the hip capsule, thereby reducing the soft tissue tension at least for a period following surgery. Accordingly, the 3D mathematical model may incorporate the cuts in one or more muscles and / or the hip capsule. The surgical plan may further include planned muscle repair, e.g., whether a cut muscle is planned to be repaired during the procedure and / or the planned method of repair. In some embodiments, the level of muscle weakness simulated is based on whether muscle repair is planned and / or the planned method of repair according to the surgical plan. Accordingly, the mathematical model may be altered 730 based on a surgical approach and / or planned repairs in order to more closely describe the state of the musculature and the resulting kinematics of the joint in the post-operative state.Attorney Docket No. PT-6005-WO-PCT / D030402

[0162] In some embodiments, the mathematical model may be altered 730 to account for muscle and / or flexion contractures that may exist in the hip joint pre-operatively and / or post-operatively. Accordingly, the 3D mathematical model may incorporate muscle and / or flexion contractures to provide an accurate depiction of the pre-operative joint. For example, the value of using pre-operative pelvic tilt as a cup orientation target has been questioned because the pelvic position will be affected by release of hip contractures during surgery. If contractures are present pre-operatively, they may cause an unnatural anterior tilt of the pelvis in the standing position and lack of hip mobility from standing to sitting. In order to more accurately reflect the post-operative joint, hip flexion contractures may be included in the pre- operative model of the patient as an excessive tightness of hip flexors (e.g., the iliopsoas). Consequently, release of the hip flexors in the post-operative model can accounted for to calculate the actual tilt of the pelvis after surgery. In additional embodiments, data-driven models can be used to predict post-operative pelvis orientation from pre-operative pelvic tilt.

[0163] Performing 735 at least one simulation of one or more daily living activities with the mathematical model may take a variety of forms. In some embodiments, the mathematical model may be used to simulate 735 daily living activities including but not limited to sitting down, standing up, laying down, rising up from a laying position, walking on a flat surface, walking on an inclined and / or declined surface, walking up a flight of stairs, walking down a flight of stairs, crouching, bending over, and / or kneeling. The at least one simulation may account for the post-operative condition of the joint after it is altered 730 due to the surgical plan, spinopelvic mobility, and / or muscle contractures, and / or post-operative pelvic tilt.

[0164] In some embodiments, the movement of the hip joint through each activity may be assessed, i.e., a relative orientation of the pelvis segment and the upper leg segment may be determined. Accordingly, the computer model may be used to determine a range ofAttorney Docket No. PT-6005-WO-PCT / D030402 motion associated with each daily living activity under the limitations of the spinopelvic condition.

[0165] In some embodiments, the at least one simulation may be performed 735 based on motion capture marker data. In some embodiments, motion capture data may be collected from one or more subjects as part of an experimental setup in a motion capture laboratory. The motion capture data may be used to develop the biomechanics of the computer model based on the principles of inverse kinematics, thereby enabling the use of the computer model to simulate patient-specific biomechanics based on an indicated spinopelvic condition. However, additional methodologies may be used to collect patient motion data and drive the computer model simulations including, but not limited to, video-fluoroscopy, stereo-radiography, goniometers, skin stretch sensors, inertial measurement units, accelerometers, and gyroscopes. Patient motion collected with these methodologies may be used to drive the whole computer model or a portion of it. Further details related to simulating 735 daily living activities are described in International Patent Application No. PCT / US2021 / 051435, which has been incorporated herein by reference.

[0166] In some embodiments, determining 740 hip joint kinematic information based on the at least one simulation comprises determining risks to the joint. The hip joint kinematic information may include a range of motion associated with one or more daily living activities, a composite range of motion associated with a plurality of daily living activities (e.g., all simulated daily living activities or a subset of the simulated daily living activities pertinent to a patient). The hip joint kinematic information may further comprise muscle and / or foot-ground forces and may predict joint contact forces. In some embodiments, determining 740 hip joint kinematic information comprises determining poses that cause impingement within the range of motion of the post-operative joint. In some embodiments, determining 740 hip joint kinematic information further comprises calculating a jump distance and / or energy required toAttorney Docket No. PT-6005-WO-PCT / D030402 overpower the resistance of muscle and capsule forces to dislocate the joint and a given impingement pose. Further details related to determining a jump distance and / or energy required for dislocation are described in International Patent Application No. PCT / US / 2022 / 048821 entitled "System and Method for Determining Optimal Placement of Hip Implants," filed November 3, 2022, the entirety of which is incorporated herein by reference. In some embodiments, determining 740 hip joint kinematic information further comprises determining and / or quantifying a risk of dislocation for the joint. In some embodiments, the risk of dislocation may be determined based on the number and / or location of the impingement poses in the range of motion of the joint, the jump distance and / or energy required to dislocate the joint based on a given impingement pose, and / or the frequency and / or likelihood of obtaining the impingement pose in the daily living activities.

[0167] The surgical plan may be optimized 745 based on the hip joint kinematic information. In some embodiments, the hip joint kinematic information may be used to assess parameters of a surgical plan, such as a position and orientation of an implant (e.g., an acetabular cup). For example, the system may assess one or more implant parameters based on the hip joint kinematic information. The post-operative range of motion associated with the implant parameters may be compared to the outputted joint kinematic information to determine whether the required range of motion for daily living activities of the patient is permitted by the implant parameters and / or how much of the required range of motion of the patient is permitted by the implant parameters. Furthermore, the risk of dislocation as described may be used to assess the proposed implant parameters. In some embodiments, several proposed implant parameters (e.g., position and / or orientation of an implant) may be assessed in this manner, and the surgical plan may be optimized 745 based on the hip joint kinematic information. For example, the position and / or orientation of the implants may be modified. In additional embodiments, additional implant parameters (e.g., implant model, implant size, andAttorney Docket No. PT-6005-WO-PCT / D030402 the like) and / or other portions of the surgical plan (e.g., surgical approach and / or planned repairs) may be modified to improve the hip joint kinematics and thus optimize 745 the surgical plan.

[0168] It should be understood that optimizing 745 the surgical plan may be similar to identifying 535 differences between pre-operative properties and post-operative properties of muscles associated with the hip joint, optimizing 540 implant parameters, and / or generating 545 an optimized surgical plan in the method 500 of FIG. 5 as disclosed herein. Accordingly, the surgical plan may be optimized 745 in any manner as disclosed herein with respect to the method 500.

[0169] In some embodiments, the optimized surgical plan may be outputted in a computer-readable format to a local device or a remote device. In some embodiments, the optimized surgical plan may be outputted to a computer-readable storage medium, a computer (e.g., a laptop computer or a desktop computer), a server, a database, a surgical system (e.g., CASS 100 of FIG. 1), a surgical planning system, or any other device. In some embodiments, the optimized surgical plan may be outputted by any known transmission means including, but not limited to, a wired connection, a wireless connection (e.g., Bluetooth, WiFi, etc.), a local area network, the Internet, and / or a cellular network.

[0170] In some embodiments, outputting the optimized surgical plan may comprise displaying the optimized surgical plan on a display device. For example, the optimized surgical plan may be displayed on a display device such as a display of a personal computer, a mobile device, a tablet, the display 125 of the CASS 100 of FIG. 1, and the like. Accordingly, a user may be able to view the hip joint kinematic information to evaluate a surgical plan, select an implant model and / or size, select and implant position and / or orientation, view the optimized surgical plan, and the like.Attorney Docket No. PT-6005-WO-PCT / D030402

[0171] It should be understood that the presently disclosed method is advantageous over conventional methods because the optimized surgical plan carries a reduced risk of impingement and / or dislocation based on an approximated required range of motion that accounts for the post-operative condition of the joint of the patient including the surrounding musculature.

[0172] In additional embodiments of the present subject matter, the method 700 may be implemented in a system configured to perform each of the described steps. For example, a system may comprise at least one processor and a computer-readable storage medium comprising instructions configured to, when executed, cause the at least one processor to perform the method 700 as described herein. In some embodiments, the system may further comprise an input device configured to receive input related to one or more operations of the method 700 and transmit the input to the at least one processor. The input device may be implemented in any manner as would be apparent to a person having an ordinary level of skill in the art. In some embodiments, the system may further comprise a display device for displaying the hip joint kinematic information, the optimized surgical plan, and / or other information related to the method 700 as described herein. The display device may be implemented in any manner as would be apparent to a person having an ordinary level of skill in the art.

[0173] The devices, systems, and methods as described herein are not intended to be limited in terms of the particular embodiments described, which are intended only as illustrations of various features. Many modifications and variations to the devices, systems, and methods can be made without departing from their spirit and scope, as will be apparent to those skilled in the art.

[0174] It should be understood that the steps of the method 700 may be performed in a variety of manners. In some embodiments, the steps of the method 700 are performed inAttorney Docket No. PT-6005-WO-PCT / D030402 sequence as described herein. In additional embodiments, the steps of the method 700 are performed out of sequence. Furthermore, several steps or series of steps may be performed simultaneously or in parallel, especially when implemented by a processor. For example, FIG. 8 depicts an exemplary workflow for assessing hip joint kinematics of a patient in accordance with the principles of the method 700.

[0175] In some embodiments, the patient bone anatomy is derived without CT images. For example, MRI and / or ultrasound images may be utilized to derive the patient bone anatomy. In some embodiments, the patient bone anatomy is derived without 3D images. For example, 2D images such as x-rays may utilized. In such embodiments, machine learning algorithms and / or statistical shape modeling processes may be used to reconstruct 3D bone geometries from the radiographic silhouettes in the x-rays and / or from other 2D images.

[0176] In some embodiments, imaging techniques may be used to derive muscle attachment locations, hip capsule attachment locations, and / or muscle volume. For example, MRI and / or ultrasound data may be used to determine muscle attachment locations, hip capsule attachment locations, and / or muscle volume.

[0177] In some embodiments, personalized muscle architecture properties, (e.g., fascicle length and orientation) may be determined using diffusion tensor imaging, tractography algorithms, Laplacian flow simulations, and / or combinations thereof. Accordingly, the mathematical model may be improved to more accurately depict the musculature surround the hip joint in the patient.

[0178] While the mathematical models are described herein as utilizing the Hill-type model, it should be understood that other types of muscle mathematical models may instead be utilized, e.g., Huxley model and / or 3D finite element models including hyperelastic material properties and / or motor units distributed on the muscle surface.Attorney Docket No. PT-6005-WO-PCT / D030402

[0179] While various steps of the methods 500 and 700 are described herein as being performed by at least one processor, it should be understood that various steps may be carried out manually and / or with human input. In some embodiments, the methods 500 and / or 700 may be performed as part of a surgical planning pipeline in which experienced engineers contribute to the planning. For example, engineers or other professionals may receive imaging scans and / or patient data, reconstruct anatomical structures, position the implant components, and / or communicate a surgical plan or optimized surgical plan to a surgeon.

[0180] In some embodiments, data from modeling and simulation in the procedures and / or methods described herein may be used to generate artificial intelligence or machine learning-based implant selection and / or placement clusters. For example, data from a plurality of patients may be utilized to develop artificial intelligence or machine learning-based implant selection and / or placement clusters that may be improved continually with new patient data from additional procedures. The clusters may be representative of surgeon planning philosophies or techniques, which may be used to provide initial placement and selection within the planning tool that better align with particular surgeon preferences. The clusters may also be used to correlate implant selections and placements with post-operative implant survival and patient reported outcomes, thereby informing patient-specific surgical plans to optimize implant survival, outcomes, function, and / or other post-operative measures.

[0181] While the systems and methods herein are described with respect to acetabular cup placement, it should be understood that the systems and methods may be adapted to additional use cases with modifications that would be apparent to a person having an ordinary level of skill in the art. For example, the modeling and simulation analyses as described herein may be adapted for additional surgical applications, e.g., femoroacetabular impingement, periacetabular osteotomy, and / or fracture repair.Attorney Docket No. PT-6005-WO-PCT / D030402 Data Processing Systems for Implementing Embodiments Herein

[0182] FIG.9 illustrates a block diagram of an exemplary data processing system 900 in which embodiments are implemented. The data processing system 900 is an example of a computer, such as a server or client, in which computer usable code or instructions implementing the process for illustrative embodiments of the present invention are located. In some embodiments, the data processing system 900 may be a server computing device. For example, data processing system 900 can be implemented in a server or another similar computing device operably connected to a surgical system 100 as described above. The data processing system 900 can be configured to, for example, transmit and receive information related to a patient and / or a related surgical plan with the surgical system 100.

[0183] In the depicted example, data processing system 900 can employ a hub architecture including a north bridge and memory controller hub (NB / MCH) 901 and south bridge and input / output (I / O) controller hub (SB / ICH) 902. Processing unit 903, main memory 904, and graphics processor 905 can be connected to the NB / MCH 901. Graphics processor 905 can be connected to the NB / MCH 901 through, for example, an accelerated graphics port (AGP).

[0184] In the depicted example, a network adapter 906 connects to the SB / ICH 902. An audio adapter 907, keyboard and mouse adapter 908, modem 909, read only memory (ROM) 910, hard disk drive (HDD) 911, optical drive (e.g., CD or DVD) 912, universal serial bus (USB) ports and other communication ports 913, and PCI / PCIe devices 914 may connect to the SB / ICH 902 through bus system 916. PCI / PCIe devices 914 may include Ethernet adapters, add-in cards, and PC cards for notebook computers. ROM 910 may be, for example, a flash basic input / output system (BIOS). The HDD 911 and optical drive 912 can use an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. A super I / O (SIO) device 915 can be connected to the SB / ICH 902.Attorney Docket No. PT-6005-WO-PCT / D030402

[0185] An operating system can run on the processing unit 903. The operating system can coordinate and provide control of various components within the data processing system 900. As a client, the operating system can be a commercially available operating system. An object-oriented programming system, such as the JavaTMprogramming system, may run in conjunction with the operating system and provide calls to the operating system from the object-oriented programs or applications executing on the data processing system 900. As a server, the data processing system 900 can be an IBM® eServerTMSystem®running the Advanced Interactive Executive operating system or the Linux operating system. The data processing system 900 can be a symmetric multiprocessor (SMP) system that can include a plurality of processors in the processing unit 903. Alternatively, a single processor system may be employed.

[0186] Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as the HDD 911, and are loaded into the main memory 904 for execution by the processing unit 903. The processes for embodiments described herein can be performed by the processing unit 903 using computer usable program code, which can be located in a memory such as, for example, main memory 904, ROM 910, or in one or more peripheral devices.

[0187] A bus system 916 can be comprised of one or more busses. The bus system 916 can be implemented using any type of communication fabric or architecture that can provide for a transfer of data between different components or devices attached to the fabric or architecture. A communication unit such as the modem 909 or the network adapter 906 can include one or more devices that can be used to transmit and receive data.

[0188] Those of ordinary skill in the art will appreciate that the hardware depicted in FIG. 9 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash memory, equivalent non-volatile memory, or optical disk drives may beAttorney Docket No. PT-6005-WO-PCT / D030402 used in addition to or in place of the hardware depicted. Moreover, the data processing system 900 can take the form of any of a number of different data processing systems, including but not limited to, client computing devices, server computing devices, tablet computers, laptop computers, telephone or other communication devices, personal digital assistants, and the like. Essentially, data processing system 900 can be any known or later developed data processing system without architectural limitation.

[0189] While various illustrative embodiments incorporating the principles of the present teachings have been disclosed, the present teachings are not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the present teachings and use its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which these teachings pertain.

[0190] In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the present disclosure are not meant 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. It will be readily understood that various features of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0191] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various features. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods andAttorney Docket No. PT-6005-WO-PCT / D030402 apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0192] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0193] It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (for example, 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 “includes but is not limited to,” et cetera). While various compositions, methods, and devices are described in terms of “comprising” various components or steps (interpreted as meaning “including, but not limited to”), the compositions, methods, and devices also can “consist essentially of” or “consist of” the various components and steps, and such terminology should be interpreted as defining essentially closed-member groups.

[0194] In addition, even if a specific number is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / orAttorney Docket No. PT-6005-WO-PCT / D030402 A, B, and C together, et cetera). In those instances where a convention analogous to “at least one of A, B, or C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, et cetera). It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, sample embodiments, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0195] In addition, where features of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0196] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, et cetera. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, et cetera. As will also be understood by one skilled in the art all language such as “up to,” “at least,” and the like include the number recited and refer to ranges that can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.Attorney Docket No. PT-6005-WO-PCT / D030402

[0197] The term “about,” as used herein, refers to variations in a numerical quantity that can occur, for example, through measuring or handling procedures in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of compositions or reagents; and the like. Typically, the term “about” as used herein means greater or lesser than the value or range of values stated by 1 / 10 of the stated values, e.g., ±10%. The term “about” also refers to variations that would be recognized by one skilled in the art as being equivalent so long as 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 the embodiment of the stated absolute value or range of values. Whether or not modified by the term “about,” quantitative values recited in the present disclosure include equivalents to the recited values, e.g., variations in the numerical quantity of such values that can occur, but would be recognized to be equivalents by a person skilled in the art.

[0198] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.

Claims

Attorney Docket No. PT-6005-WO-PCT / D030402 CLAIMS What is claimed is:

1. A computer-implemented method for planning a hip arthroplasty for a patient, the method comprising: obtaining a computer model of a bony anatomy of a hip joint of the patient; determining one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle; determining, based on the computer model, a plurality of muscle attachment locations on the bony anatomy; generating a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations; determining an initial surgical plan comprising one or more implant parameters based on input related to the hip joint; identifying, based on the initial surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post-operative properties of muscles associated with the hip joint; optimizing the one or more implant parameters based on the one or more identified differences; and optimizing the initial surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan.

2. The computer-implemented method of claim 1, wherein the one or more measurements are selected from the group consisting of a femoral anteversion, a femoral internal rotation, and a lateral patellar tilt for the hip joint.Attorney Docket No. PT-6005-WO-PCT / D030402 3. The computer-implemented method of claim 1, wherein the one or more measurements comprise, for each hip joint of the patient, the femoral anteversion, the femoral internal rotation, and the lateral patellar tilt.

4. The computer-implemented method of any one of claims 1-3, wherein determining a plurality of muscle attachment locations on the bony anatomy comprises determining the plurality of muscle attachment locations based on a statistical shape model using the computer model.

5. The computer-implemented method of claim 4, wherein determining the plurality of muscle attachment locations is further based on magnetic resonance imaging (MRI) data for the patient.

6. The computer-implemented method of any one of claims 1-5, wherein the 3D mathematical model comprises one or more Hill-type muscle models.

7. The computer-implemented method of any one of claims 1-6, wherein the one or more implant parameters are selected from the group consisting of an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and an implant liner type.

8. The computer-implemented method of any one of claims 1-7, wherein each of the initial surgical plan and the optimized surgical plan further comprise information associated with at least one of a surgical approach and muscle repair.

9. The computer-implemented method of any one of claims 1-8, wherein each of the one or more differences comprise one of a muscle length and a muscle moment arm.Attorney Docket No. PT-6005-WO-PCT / D030402 10. The computer-implemented method of any one of claims 1-9, wherein optimizing the one or more implant parameters reduces at least one of the one or more identified differences.

11. The computer-implemented method of any one of claims 1-10, further comprising displaying the optimized surgical plan on a display device.

12. The computer-implemented method of any one of claims 1-11, further comprising outputting the optimized surgical plan to a computer-readable storage device.

13. A system for planning a hip arthroplasty for a patient, the system comprising: at least one processor; and a non-transitory, computer-readable medium storing instructions that, when executed, cause the at least one processor to: obtain a computer model of a bony anatomy of a hip joint of the patient, determine one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle, determine, based on the computer model, a plurality of muscle attachment locations on the bony anatomy, generate a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations, determine an initial surgical plan comprising one or more implant parameters based on input related to the hip joint, identify, based on the initial surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post-operative properties of muscles associated with the hip joint,Attorney Docket No. PT-6005-WO-PCT / D030402 optimize the one or more implant parameters based on the one or more identified differences, and optimize the initial surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan.

14. The system of claim 13, wherein the one or more measurements comprise, for each hip joint of the patient, the femoral anteversion, the femoral internal rotation, and the lateral patellar tilt.

15. The system of any one of claims 13-14, wherein the instructions that cause the at least one processor to determine a plurality of muscle attachment locations on the bony anatomy comprise instructions that, when executed, cause the at least one processor to determine the plurality of muscle attachment locations based on a statistical shape model using the computer model.

16. The system of claim 15, wherein the instructions that cause the at least one processor to determine a plurality of muscle attachment locations on the bony anatomy comprise instructions that, when executed, cause the at least one processor to determine the plurality of muscle attachment locations based further on magnetic resonance imaging (MRI) data for the patient.

17. The system of any one of claims 13-16, wherein the 3D mathematical model comprises one or more Hill-type muscle models.

18. The system of any one of claims 13-17, wherein the one or more implant parameters are selected from the group consisting of an acetabular cup size, an acetabular cup position, a femoral implant size, a femoral implant position, a head size, a neck length, and an implant liner type.Attorney Docket No. PT-6005-WO-PCT / D030402 19. The system of any one of claims 13-18, wherein each of the initial surgical plan and the optimized surgical plan further comprise information associated with at least one of a surgical approach and muscle repair.

20. The system of any one of claims 13-19, wherein each of the one or more differences comprise one of a muscle length and a muscle moment arm, and wherein the instructions that cause the at least one processor to optimize the one or more implant parameters comprise instructions that, when executed, cause the at least one processor to reduce at least one of the one or more identified differences.

21. A system for planning a hip arthroplasty for a patient, the system comprising a processor configured to: obtain a computer model of a bony anatomy of a hip joint of the patient, determine one or more measurements associated with the bony anatomy, each measurement comprising an anatomical angle, determine, based on the computer model, a plurality of muscle attachment locations on the bony anatomy, generate a three-dimensional (3D) mathematical model of the hip joint comprising bony and muscular anatomical properties based on at least the one or more measurements and the plurality of muscle attachment locations, determine an initial surgical plan comprising one or more implant parameters based on input related to the hip joint, identify, based on the initial surgical plan and the 3D mathematical model, one or more differences between pre-operative properties and post-operative properties of muscles associated with the hip joint,Attorney Docket No. PT-6005-WO-PCT / D030402 optimize the one or more implant parameters based on the one or more identified differences, and optimize the initial surgical plan based on the one or more optimized implant parameters, thereby generating an optimized surgical plan.

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