Tracking element fixation systems and methods for computer-assisted arthroplasty

Abstract

Disclosed herein are tracking element fixation elements for affixing computer-assisted surgical system (CASS) tracking elements to a patient. Fixation systems provide kinematic coupling or clamping functionality that allows tracking elements (attached to a tracker arm) to be repeatedly and accurately detached and re-attached to facilitate removal when necessary, such as for point probe data collection, during impaction, bone movement, and / or the like. Fixation systems may include a baseplate and a tracker arm configured to be kinematically coupled to the baseplate via a magnet associated with independent ball bearings or contacts extending from a bottom surface of the magnet. The ball bearings or contacts are configured to be received within corresponding grooves of the baseplate. The baseplate may include one or more protrusions extending from a bottom of the baseplate that are configured to be impacted into the cortical bone of the patient.

Description

Attorney Docket No.: 8178.6136WOTRACKING ELEMENT FIXATION SYSTEMS AND METHODS FOR COMPUTER-ASSISTED ARTHROPLASTYRELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 695,459, filed September 17, 2024, entitled “TRACKING ELEMENT FIXATION SYSTEMS AND METHODS FOR COMPUTER-ASSISTED ARTHROPLASTY”, the contents of which are incorporated herein in their entirety.FIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to methods, systems, and apparatuses related to computer-assisted surgical systems that includes various hardware and software components that work together to enhance surgical workflows. More specifically, the present disclosure relates to fixation systems for attaching surgical devices, such as tracker devices, to patient bone anatomy.BACKGROUND

[0002] Computer-assisted surgical (CAS) techniques can provide improved patient outcomes for arthroplasty procedures, such as total knee arthroplasty (TKA) or total hip arthroplasty (THA). For example, CAS can facilitate better implant placement with improved reproducibility when compared to fully manual procedures. CAS, also referred to as “robot-assisted” or “navigated” surgery, relies on registering the geometry and location of patient anatomy (e.g., a bone, a femur, the pelvis, etc.) against a computer model to understand how a subject bone is oriented in space, and the resulting orientation is savedAttorney Docket No.: 8178.6136WO with respect to a tracker or marker attached to the bone. Using the known orientation, robotic orthopedic tools (e.g., saws, burrs, etc.) are able to accurately remove bone according to a preoperative plan, which allows for a more accurate implant fit and functional outcomes as compared with manually performed procedures.

[0003] However, surgical navigation and robotics rely on stable markers to remain in the same position with respect to the bone. Movement of the markers will change the registered orientation of the bone and impact the accuracy of the robotic tool. As a result, inadvertent movements during surgery may negatively impact navigation devices. In addition, limb positioning is typically required during certain arthroplasty procedures (e.g., knee flexion and hip adduction during THA). Such activity may also impinge upon reference markers and, therefore, CAS navigation.

[0004] Available locations for placing reference markers is limited, further complicating CAS navigation, because the markers must be arranged sufficiently close to the area of interest (e.g., a femoral neck cut) in order to provide the required information for the robotic tool to operate. Placing reference markers away from surgical activity (and potential movement) is generally not a viable option because the CAS is not able to obtain sufficient information to operate the surgical tool accurately. Furthermore, certain arthroplasty procedures, such as THA, do not require in-wound (i.e., within the surgical incision area) reference marker placement, but in-would placement is beneficial to achieve optimal accuracy and surgical workflows.

[0005] Conventional systems and techniques are not able to provide CAS navigation using reference markers that are both sufficiently proximate to the surgical field and stableAttorney Docket No.: 8178.6136WO enough to accurately guide robotic tools, particularly within an in-wound area of the patient.SUMMARY

[0006] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

[0007] Disclosed herein are improved systems and methods for affixing tracking elements for computer-assisted surgical systems (CASS) to patients. Tracking element fixation systems described according to various examples in the present disclosure provide kinematic coupling or clamping functionality that allows tracking elements (attached to a tracker arm) to be repeatedly and accurately detached and re-attached to facilitate removal when necessary, such as for point probe data collection, during impaction, bone movement, and / or the like.

[0008] In any preceding or subsequent example, a tracking element fixation system may include a baseplate and a tracker arm configured to be kinematically coupled to the baseplate. The baseplate may include one or more protrusions extending from a bottom of the baseplate that are configured to be impacted into the cortical bone of the patient. One or more threaded holes may be formed in the baseplate to allow for fastener fixation to the patient bone in addition to the protrusions.Attorney Docket No.: 8178.6136WO

[0009] In any preceding or subsequent example, the tracker arm may have a tracker end configured to be coupled to a tracker element. Non-limiting examples of tracker elements may include tracking arrays, markers, and / or any other device or element that may be used to collect or transmit data for a CASS. The tracker arm may include a baseplate connection (or “connection”) end configured to be coupled to the baseplate. The fixation arm may be removably attached to the baseplate via a kinematic coupling element implemented via magnetic structures. In some examples, the kinematic connection may be or may be similar to a Maxwell coupling.

[0010] In any preceding or subsequent example, the fixation arm may include a tracking element end that includes a connector for connecting to a tracking element, such as a tracking array, using connection elements (e g., a ball-and-socket array). The connector and / or connection elements may be configured to allow tracking elements to be positioned to face various directions. In this manner, the position or orientation of a tracking element affixed to the tracker arm may be adjusted to face a camera, IR device, and / or the like to facilitate data collection.

[0011] In any preceding or subsequent example, the fixation arm may be formed as a straight arm (i.e., no or substantially no curve, bend, and / or the like). In any preceding or subsequent example, the fixation may include a curved form, bend, and / or the like (for example, to be positioned around patient anatomy during a procedure).

[0012] In any preceding or subsequent example, the baseplate may be affixed to a femur of a patient. The fixation arm may be coupled to the baseplate and may support a tracking array. In any preceding or subsequent example, the baseplate is affixed on at least a portionAttorney Docket No.: 8178.6136WO of the greater trochanter. In any preceding or subsequent example, the baseplate may be oriented so that the majority of the baseplate rests on the greater trochanter 305.

[0013] In any preceding or subsequent example, the baseplate may have a triangular or substantially triangular shape. In any preceding or subsequent example, the top surface of the baseplate may include one or more fastener holes for fastener fixation of the baseplate to the patient bone.

[0014] In any preceding or subsequent example, the baseplate may include one or more grooves configured to receive ball bearings and / or contacts of the kinematic coupling element. In any preceding or subsequent example, the baseplate may include three grooves.

[0015] In any preceding or subsequent example, divots may be arranged on an upper surface of the baseplate. The divots may be used for point probe data collection. In some examples, the divots may be configured to receive the contacts or ball bearings of the kinematic coupling. In any preceding or subsequent example, the divots may be used for snapshot tracking of the femur, as all three points could be collected simultaneously which would completely define the instantaneous orientation of the femur.

[0016] In any preceding or subsequent example, a kinematic coupling element may include one or more magnets and a corresponding number of ball bearings.

[0017] In any preceding or subsequent example, a kinematic coupling element may be implemented via a magnet and contacts (e.g., ball bearings, spherical contacts, discs, hemispheres, variations thereof, combinations thereof, and / or the like), contacting a bottom surface of the magnet when the kinematic coupling is assembled, that are configured to be received within the corresponding grooves of the baseplate.Attorney Docket No.: 8178.6136WO

[0018] In any preceding or subsequent example, the magnet may be a single magnet having a triangle or wedge shape to correspond to the shape of the housing and the baseplate.

[0019] In any preceding or subsequent example, a tray may be configured to be arranged between the magnet and the baseplate. Holes may be arranged in the tray to allow the contacts to pass through the tray and to be seated within the grooves. One or more tabs, flanges, posts, or other protrusions may extend from an upper surface of the tray. An internal area of the housing may include slots configured to receive the tabs to interlock the tray to the housing.

[0020] In any preceding or subsequent example, one or more tabs, flanges, posts, or other protrusions may extend from an upper surface of the magnet. An inner surface of the internal area of the housing may include slots configured to receive the tabs to interlock the magnet to the housing. In some examples, flanges or other protrusions may extend from the top and bottom surfaces of the magnet. The baseplate may include a notch configured to receive the downward-extending portion of the flange. The housing may include a notch configured to receive the upward-extending portion of the flange.

[0021] In any preceding or subsequent example, a clamp may be used to hold the housing to the baseplate. The clamp may be used in addition to the connection between the tracker arm and the baseplate provided by the kinematic coupling. The clamp may include a pair of arms having handles. Squeezing or pinching together on the handles may actuate a spring pivot configured to move a bottom portion of the arms apart. Releasing the handles causes the spring pivot to force the bottom portion of the arms together. The bottom portion may include a flange or other protrusion configured to be received by a corresponding slotAttorney Docket No.: 8178.6136WO configured on the baseplate. The biasing tension provided by the spring pivot may facilitate holding the tracker arm to the baseplate.

[0022] Examples described in the present disclosure provide numerous advantages over conventional systems and methods. In one non-limiting example advantage, the configuration of the baseplate-fixation arm connection allows the fixation arm to be attached to the baseplate, removed, and then replaced in the exact same position and orientation it was previously attached, providing repeatable static and dynamic measurements. In addition, using a magnetically-attached kinematic coupling allows an impacted tracking element or fixation arm to disengage from the baseplate without pulling excessively on the baseplate. If the fixation arm was rigidly attached to the baseplate, any impact could cause unwanted stress to be transmitted to the bone.

[0023] The tracking element fixation system configured according to some examples provides a magnetic quick-release device that allows a trackable marker (or other device) to be quickly attached or detached as required during surgery. As such, detachment of a marker, tracker, tracker array, etc. is convenient for the surgeon, for instance, if the surgeon’s movements are encumbered by the presence of the tracker array or other device. The magnetic quick-release device is configured to provide well defined, stable, and reproducible positioning of the marker with respect to patient anatomy and / or the bone screws or other surgical elements.

[0024] In another non-limiting example advantage, fixation systems may attach to the bone in-wound and, as such, remain in the field of view of the camera (or other device) when compared to existing trackers attached remotely (for instance, at the distal femur). In aAttorney Docket No.: 8178.6136WO further non-limiting example advantage, fixation devices may be rigidly attached to the bone and do not move around with respect to the femur during a surgery, for example, when compared with conventional “pinless” trackers.

[0025] Tracking systems according to any preceding or subsequent example allow for snapshot (e.g., point probe data collection) and live tracking functionality for a CASS in a single fixation device. In addition, tracking systems according to any preceding or subsequent example allow for improved stability (e.g., three points of contact) and a smaller profile on the bone as compared with existing solutions. Tracking systems according to any preceding or subsequent example allow for assessment of femoral and global offset / lengthening, “direct” LL / OS measurement without a need for the proximal femur landmark, establishing a valid femur registration, registration of all femoral landmarks, axes, etc., verification of broach version, cup navigation and verification, stem verification, and a “femur-first” THA surgical approach.

[0026] For THA, a femoral tracking marker device is fixed in a typical manner on a patient's femur near the greater trochanter. However, the upper femur is less amenable to bone screw attachment. Because of the mechanics of the hip and upper femur, the upper femur experiences very large stress and shearing forces, both in its natural state and after implantation of an artificial hip prosthesis. In extreme cases this stress can actually cause the prosthetic stem to fracture the upper femur. Therefore, in some examples, it is preferable that this device be fixable to the femur in a firm and fully engaged position, which does not allow slippage or rotation, and preferably without the use of bone screws, pins or any other bone damaging devices. Specifically, in some examples, it is extremelyAttorney Docket No.: 8178.6136WO preferable that the marker is attachable to the femur by a device which does not penetrate the outer cortical (hard) shell of the bone, as the penetration could compromise the structural integrity of the bone tissue. For example, to use aggressively textured surfaces, which could include one or more protrusions, spikes, cleats, and / or the like that do not penetrate the outer cortical shell.

[0027] Accordingly, in another non-limiting example advantage, the one or more protrusions of the baseplate permit convenient and quick attachment without fully penetrating the outer cortical (hard) shell of the femur. The baseplate of the tracking element fixation system facilitates continuous or near-continuous, real-time optical tracking of the femur to achieve a desired amount of femoral offset and a desired leg length (for example, substantially matching the native length and offset on the opposite side of the body).

[0028] Other advantages are described in the present disclosure and would be understood by a person of skill in the art in view of the present disclosure.

[0029] Further features and advantages of at least some of the examples described in the present disclosure, as well as the structure and operation of any preceding or subsequent example of the present disclosure, are described in detail below with reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] By way of example, specific examples of the disclosed device will now be described, with reference to the accompanying drawings, in which:Attorney Docket No.: 8178.6136WO

[0031] FIG. 1 depicts an operating theatre including an illustrative computer-assisted surgical system (CASS) in accordance with one or more features of the present disclosure;

[0032] FIGS. 2A and 2B depict a tracking element fixation system in accordance with one or more features of the present disclosure;

[0033] FIGS. 2C and 2D depict illustrative mounting arms of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0034] FIGS. 3A and 3B depict a tracking element fixation system affixed to a portion of a femur in accordance with one or more features of the present disclosure;

[0035] FIGS. 4A and 4B depict a grooved baseplate of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0036] FIGS. 5A and 5B depict a divot-coupling baseplate of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0037] FIG. 6 depicts an example of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0038] FIGS. 7A-7E depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0039] FIGS. 8A-8C depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0040] FIGS. 9A-9D depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure;

[0041] FIG. 10 depicts a femoral clamp in accordance with one or more features of the present disclosure;Attorney Docket No.: 8178.6136WO

[0042] FIG. 11 depicts alternative clamp configurations in accordance with one or more features of the present disclosure;

[0043] FIG. 12 depicts a serrated bone plate in accordance with one or more features of the present disclosure;

[0044] FIG. 13 depicts a slot-mounted tracking element fixation system in accordance with one or more features of the present disclosure;

[0045] FIG. 14 depicts a fixation element in accordance with one or more features of the present disclosure; and

[0046] FIGS. 15A -15C depict femoral screwless tracking element fixation systems in accordance with one or more features of the present disclosure.

[0047] FIG. 16 is a flow chart depicting several operations performed in a method in accordance with one or more features of the present disclosure.

[0048] It should be understood that the drawings are not necessarily to scale and that the disclosed examples are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of the disclosed methods and devices, or which render other details difficult to perceive may have been omitted. It should be further understood that this disclosure is not limited to the particular examples illustrated herein. In the drawings, like numbers refer to like elements throughout unless otherwise noted.Attorney Docket No.: 8178.6136WODETAILED 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 examples 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 examples 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.”

[0051] Various features of an improved tracker element fixation system for use with a computer-assisted surgical system will now be described more fully hereinafter with reference to the accompanying drawings, in which one or more features of the tracker element fixation system will be shown and described. It should be appreciated that the various features may be used independently of, or in combination, with each other. It will be appreciated that a tracker element fixation system as disclosed herein may be embodied in many different forms and should not be construed as being limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will convey certain features of the tracker element fixation system to those skilled in the art.

[0052] Computer-assisted navigation in arthroplasty procedures, such as THA, provides better implant placement with improved reproducibility when compared to manualAttorney Docket No.: 8178.6136WO procedures. Although THA is used in some examples, this is for illustrative purposes only. The described fixation systems can be used for other surgical procedures, including partial hip arthroplasty, revision hip arthroplasty, TKA, revision TKA (rTKA), and / or the like.

[0053] Many advantages of computer-navigated THA have not been realized due to challenges with obtaining a reference plane and reliably attaching a reference array to the femur. During conventional computer-assisted THA, femoral markers are either attached within the surgical incision, free from soft tissue impingement, or pinned percutaneously at sites distant from the exposed areas. Movement of the limb may cause soft tissue impingement and consequently disturb these percutaneously inserted reference markers, causing registration errors, which may not be detected by the operating surgeon intraoperatively.

[0054] Navigated THA relies on registering the geometry of a bone against a computergenerated model, typically generated from a CT image, to understand how that bone is oriented in space. The resulting orientation of the bone is saved with respect to a marker which is attached to the bone. In general, a fixed optical tracking marker is tracked in relation to a fixed reference mark on the same bone, both before and after the surgical procedure. This provides a check (“tracker check”) to detect any errors due to, for example, slippage, drift, or deformation of the apparatus. With this orientation known, robotic surgical orthopedic tools are able to accurately remove bone according to a preoperative plan. This allows for a more accurate implant fit and functional outcomes as compared with a manually performed procedure. However, surgical navigation and robotics require stable markers to remain in the same position with respect to the bone, as any movement of theAttorney Docket No.: 8178.6136WO markers will alter the registered orientation of the bone and thus impact the accuracy of the robotic tools. In particular, limb movements required during THA (e.g., figure-of-four position, knee flexion, and hip adduction) create tension in the rectus femoris and the fascia lata, causing impingement with reference markers.

[0055] It is desirable to have the tracking elements placed in-wound because the camera which is optically tracking the markers is oriented toward the incision, and any trackers which are attached to the femur outside of the field of view of the camera may not be adequately monitored. In-wound tracking using conventional systems is challenging because, as in typical DA and posterior surgical THA techniques, there is little space within the wound site to attach trackers. In addition, subsequent tracking of the femoral broach necessitates that fixation does not violate the intramedullary canal, which further restricts the location for affixing a tracking element on the anterior face of the femur. For example, in a DA approach, the femoral neck is exposed but leaves very little bone stock available for tracking elements to be attached. A typical posterior approach exposes more bone than a DA approach, but still provides limited space for attaching tracking elements, particularly that are not susceptible to movement or impaction during the surgical procedure. In some examples, it is beneficial to have the tracking array connected to an arm, such as fixation arm 222 of FIG. 2 below, via a ball-and-socket connection as it allows a surgeon or other operator to place the camera in the location that makes the most sense for their workflow and still angle the tracker such that line-of-sight between the camera and tracker is maintained. It provides extra flexibility to account for these line-of-sight concerns and gives more power to the surgical team to optimize the workflow to their own preferences.Attorney Docket No.: 8178.6136WO

[0056] Another potential complication associated with in-wound tracking is the movement of the femur itself within the incision. During THA procedures, surgeons often externally and internally rotate the femur, which can lead to parts of the bone which were exposed during the initial incision to disappear under the soft tissue surrounding the hip joint. Consequently, using a pinned solution which cannot be removed would not be technically feasible, given that it would make it very challenging for surgeons to complete the remaining steps in the procedure.

[0057] Despite these challenges, it is important to be able to track the femur in a navigated THA procedure, which allows a CASS to more accurately compute information for performing the CAS, such as the change (pre-operatively to post-operatively) in the leg length and offset, navigate the femoral neck cut to the desired plane, navigate the broach, validate the final position of an implant, and generate kinematic data of the femur during intra-operative passive range of motion assessments.

[0058] Existing solutions for in-wound CAS tracking, particularly tracking the femur during THA, have not been able to adequately solve these challenges. For example, in a first existing solution, the relative orientation between the femur and pelvis reference is stored and tracked before and after surgery. However, trackers affixed to the distal femur have the potential for exaggerating the effect of rotational error given that the measurements are made away from the rotational center of the joint. Theoretically, establishing a coordinate system for the femur and the pelvis allows more accurate measurement. Additional reference points on the proximal femur have been used to address this issue to balance rotational differences between the pre- and post-operative legAttorney Docket No.: 8178.6136WO alignment and to compensate for minor movements of the array while measuring leg length and offset changes intra-operatively. However, this requires registration of additional data points around the knee, which is resource-intensive and time consuming.

[0059] In a second existing solution, pins may be placed in the distal femur for tracking the femur during a CAS TKA procedure. In this solution, a pin is driven through a percutaneous incision in the distal femur, and a tracking array is connected to the pins. Although this solution allows for registration of the femur using markers that are not altered during the procedure, the pins in the distal femur are out of the field of view of the tracking camera given the camera’s restricted field of view that is primarily focused on the incision site so that it may track instruments with attached markers. With respect to DA procedures, surgeons would often adduct the operative leg, which would be prevented by the pins.

[0060] A third existing solution uses a non-invasive “pinless” external femoral reference marker array system. This solution consists of a plate, which mimics the anatomical shape of the soft tissue, which is positioned laterally on the distal third of the operative femur and secured within the incision. Subsequently, an array is attached to this plate by a screw. This array is attached distally from the incision such that it is not able to provide an adequate field of view. In addition, this solution has inherent instability with the tracking array because it is prone to skin motion artifacts, which compromises the accuracy of the femoral registration. Passive shifting of relaxed muscles during surgery and debonding of the incision foil can also cause additional loosening of the pinless reference array, which can contribute to the overall inaccuracy of the tracking.Attorney Docket No.: 8178.6136WO

[0061] Both the pin-based and pinless leg length measurement solutions take the preoperative state as a reference for comparing the initial (pre-operative) leg length situation with the intra-operative situation after inserting the trial or final implants. A possible shift of the femoral head during surgery could reduce the precision of this measurement procedure. Furthermore, the femoral pinless navigation technique does not offer navigated preparation of the femoral medullary canal and / or intraoperative control of hip kinematics (range of motion analysis), and it necessitates two additional points to be registered on the proximal greater trochanter to compensate for misalignments in the leg and movement of the pinless array.

[0062] In a fourth existing solution, a tracking system uses a femoral disc attached to the lateral greater trochanter for bony registration during DA and posterior surgical approaches. In the DA case, the femoral disc has a circular track around the circumference of the disc, which may be used with a point probe to trace around to register the femur according to the location of the disc. However, this solution only provides a snapshot view of the femur. A such, surgeons must recollect the track information each time that they need to determine the location of the femur with respect to the pelvis.

[0063] A fifth existing solution fortracking the femur in posterior, anterolateral, and direct anterior THA procedures uses a femoral cortical screw, which is a circular plate with spikes on the bottom that are fixed onto the greater trochanter by a central locking screw. With this plate fixed to the bone, a tracker can be attached to the plate to register the location of the femur. During surgery, all soft tissue must be cleared around the flange region of the cortical screw and movement (toggling) of the cortical screw should be tested uponAttorney Docket No.: 8178.6136WO attaching a tracker. Furthermore, this solution requires a femoral checkpoint to be inserted into the bone for accuracy verification, which adds complexity to the procedure and requires additional resources.

[0064] Accordingly, the technologies described in the present disclosure include tracking element fixation devices that are designed for use in arthroplasty procedures and are able to be used within the field-of-view of a computer-assisted surgical system (CASS), are stable, removable and replaceable in the same position, and prevent stress from being transferred to the patient bone from impaction on the tracking array. Other advantages are described and would be known to those of skill in the art based on the present disclosure.

[0065] The described technology generally relates to a fixation system for attaching CAS system (CASS) tracker elements to a patient. The fixation system is configured to be affixed to patient anatomy “in-wound,” for instance, on a portion of a bone within a surgical incision. In some examples, the patient anatomy is a femur, such as a portion of the femur near the greater trochanter. The fixation system may be used for various types of surgical procedures, such as a total hip arthroplasty (THA) or a total knee arthroplasty (TKA). In some examples, the fixation system may be used for a THA for both real-time femur tracking and / or snapshot views of patient anatomy, such as a portion of the femur in relation to the pelvis. The fixation system may be configured to be used in-wound in various THA approaches, such as a direct anterior (DA) approach or a posterior approach.

[0066] The fixation system includes a baseplate and a fixation arm. The baseplate may be attached to the patient bone via protrusions extending from a bottom of the baseplate that are configured to be impacted into the cortical bone of the patient. One or more threadedAttomey Docket No.: 8178.6136WO holes may be formed in the baseplate to allow for fastener fixation to the patient bone. The fixation arm includes a tracker end configured for supporting a tracker element or array and a baseplate connection (or “connection”) end configured to be coupled to the baseplate. The fixation arm may be removably attached to the baseplate via a kinematic coupling implemented via magnetic structures. In some examples, the kinematic connection may be or may be similar to a Maxwell coupling.

[0067] In general, the configuration of the baseplate-fixation arm connection allows the fixation arm to be attached to the baseplate, removed, and then replaced in the exact same position and orientation it was previously attached, providing repeatable static and dynamic measurements. In addition, using a magnetically-attached kinematic coupling allows an impacted tracking element or fixation arm to disengage from the baseplate without pulling excessively on the baseplate. If the fixation arm was rigidly attached to the baseplate, any impact could cause unwanted stress to be transmitted to the bone. Other advantages are described in the present disclosure.

[0068] In some examples, the fixation system includes a single removable baseplate for computer- or robot-assisted procedures that requires a small incision (for DA and posterior procedures), to enable both static (snapshot) and real-time (live) tracking of the femur with respect to the pelvis. In various examples, the baseplate may be placed onto the femur such that protrusions on the bottom of the baseplate gain purchase in the near cortical bone of the greater trochanter prior to insertion of a central screw being driven through the baseplate, compressing the plate onto the surface of the bone, and preventing it from rotating. In some examples, the baseplate includes additional features such as divots, v-Attorney Docket No.: 8178.6136WO grooves, magnets, slots, dovetails, bayonet fittings, and / or the like, which allow for a tracker to be attached to the baseplate repeatably and for a point probe to be used for data collection.

[0069] The systems, methods, devices, and assemblies disclosed herein may be used with computer-assisted surgical (CAS) procedures, for example, that utilize surgical navigation systems, such as the CORI surgical system provided by Smith & Nephew Inc. of Memphis, Tennessee, United States of America or the NAVIO surgical navigation system provided by Blue Belt Technologies of Pittsburgh, Pennsylvania, United States of America.

[0070] FIG. 1 provides an illustration of an example computer-assisted surgical system (CASS) 100 according to any preceding or subsequent example. 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 knee arthroplasty (e.g., TKA) or total hip arthroplasty (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.

[0071] As shown in FIG. 1, an effector platform 105 positions surgical tools relative to a patient during surgery. The exact components of the effector platform 105 will vary,Attorney Docket No.: 8178.6136WO depending on the example 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 hand piece or a cutting guide or jig of a surgical system, such as the Navio® Surgical System from Blue Belt Technologies of Plymouth, Minnesota, United States of America) or, alternatively, the end effector 105B can include a device or instrument held or positioned by a robotic arm 105 A.

[0072] 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 may be the SPIDER2 system manufactured and sold by Smith & Nephew, Inc. of Cordova, Tennessee, United States of America. 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).

[0073] Resection equipment (not shown in FIG. 1) performs bone or tissue resection using, for example, mechanical, ultrasonic, or laser techniques. Examples of resection equipment may include drilling devices, burring devices, oscillatory sawing devices, vibratory impaction devices, reamers, ultrasonic bone cutting devices, radio frequency ablation devices, and laser ablation systems. In some examples, the resection equipment is held and operated by the surgeon during surgery. In other examples, the effector platform 105 may be used to hold the resection equipment during use.

[0074] The effector platform 105 can also 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 canAttorney Docket No.: 8178.6136WO be formed integrally as part of the effector platform 105 or robotic arm 105 A, or cutting guides can be separate structures that can be matingly and / or removably attached to the effector platform 105 or robotic arm 105 A. The effector platform 105 or robotic arm 105 A 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.

[0075] 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 115 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 can also be used to infer velocity / acceleration of anatomy / instrumentation, which can be used for tool control. In some examples, 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 some examples of the present disclosure including, without limitation, Infrared (IR) tracking systems, electromagnetic (EM) tracking systems, video or image-based tracking systems, and ultrasound registration and tracking systems.Attorney Docket No.: 8178.6136WO

[0076] 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 light emitting diode (LED) light source, can illuminate the scene allowing three-dimensional imaging to occur. In some examples, this can include stereoscopic, tri-scopic, quad-scopic, etc. imaging. In addition to the camera array, which in some examples 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.

[0077] In some examples, 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.

[0078] In some examples, certain markers, such as fiducial marks that identify individuals, important tools, or bones in the theater may include passive or active identifiers that canAttorney Docket No.: 8178.6136WO 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 (e.g., 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 can also 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 examples, augmented reality headsets can be worn by surgeons and other staff to provide additional camera angles and tracking capabilities.

[0079] 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 be 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.

[0080] The registration process that registers the CASS 100 to the relevant anatomy of the patient can also involve the use of anatomical landmarks, such as landmarks on a bone orAttorney Docket No.: 8178.6136WO 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 can also 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.

[0081] A Tissue navigation system (not shown in FIG. 1) provides the surgeon with intraoperative, real-time visualization for the patient’s bone, cartilage, muscle, nervous, 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.

[0082] The display 125 provides graphical user interfaces (GUIs) that display images collected by the Tissue navigation system as well other information relevant to the surgery.Attorney Docket No.: 8178.6136WOFor example, in some examples, 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. Various example uses of the AR HMD 155 in surgical procedures are detailed in the sections that follow.

[0083] 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 examples, the surgical computer 150 is a general-purpose computer. In some examples, 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 examples, 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.

[0084] 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, theAttorney Docket No.: 8178.6136WO end effector 105B may connect to the surgical computer 150 over a wired (i.e., serial) connection. The tracking system 115, Tissue navigation system, and display 125 can similarly be connected to the surgical computer 150 using wired connections. Alternatively, the tracking system 115, Tissue navigation system, and display 125 may connect to the surgical computer 150 using wireless technologies such as, without limitation, Wi-Fi, Bluetooth, Near Field Communication (NFC), and / or ZigBee.

[0085] Part of the flexibility of the CASS design described above with respect to FIG. 1 is that additional or alternative devices can be added to the CASS 100 as necessary to support particular surgical procedures.

[0086] In some examples, 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. The robotic arm 105 A may have multiple degrees of freedom (e.g., like a SPIDER2 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).

[0087] In some examples, movement of the robotic arm 105 A 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 105 A. The surgeon or other healthcare professional may engage with the one or more input sources to position the robotic arm 105 A when performing a surgical procedure.

[0088] A tool or an end effector 105B attached or integrated into a robotic arm 105 A may include, without limitation, a burring device, a scalpel, a cutting device, a retractor, a jointAttorney Docket No.: 8178.6136WO tensioning device, or the like. In some examples in which an end effector 105B is used, the end effector may be positioned at the end of the robotic arm 105 A such that any motor control operations are performed within the robotic arm system. In some examples 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.

[0089] The robotic arm 105 A 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 105 A, 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 105 A may be tracked, for example, by a controller or the surgical computer 150.

[0090] In some examples, the robotic arm 105 A can be moved by hand (e.g., by the surgeon) or with internal motors into its ideal position and orientation for the task being performed. In some examples, the robotic arm 105 A 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 105 A may still be tracked as described above. In some examples, 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 105 A is internally powered through hydraulics or motors or provides resistance to external manual motion through similar means can be described as powered robotic arms, whileAttorney Docket No.: 8178.6136WO 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.

[0091] A robotic arm 105 A 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 105 A 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 105 A 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 can also place the robotic arm 105 A 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 105 A or end effector 105B medially or laterally, while restricting movement in other directions. As discussed, the robotic arm 105 A 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 some examples, movement of the robotic arm 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 any preceding or subsequent example, the movement of the robotic arm 105 A or robotically controlled end effector 105B can be controlled remotely by a surgeon or otherAttorney Docket No.: 8178.6136WO 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.

[0092] The examples below describe uses of the robotic device in the context of a hip surgery; however, it should be understood that the robotic arm may have other applications for surgical procedures involving knees, shoulders, etc.

[0093] A robotic arm 105 A may be used for holding the retractor. For example, in some examples, the robotic arm 105 A may be moved into the desired position by the surgeon. At that point, the robotic arm 105 A may lock into place. In some examples, the robotic arm 105 A 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 examples, 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).

[0094] The robotic arm 105 A 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 105 A may impose certain restrictions to prevent soft tissue damage from occurring. For example, in some examples, the surgical computer 150 tracks the position of the robotic arm 105 A as it operates. If the tracked location approaches an area where tissue damage is predicted, a command may be sent to the robotic arm 105 A causing it to stop. Alternatively, where the robotic arm 105 A 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 mayAttorney Docket No.: 8178.6136WO 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.

[0095] The robotic arm 105 A may also be used for resurfacing applications. For example, the robotic arm 105 A 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 105 A 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.

[0096] 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 a surgical data server or other data store (not shown) as a complete dataset. Thus, for each episode of care, a dataset exists that includes 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.Attorney Docket No.: 8178.6136WO

[0097] 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 examples, the data collected over the episode of care may be used to generate a surgical plan. In some examples, 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 some examples, 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 any preceding or subsequent example, the pre-operative and intra-operative 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 examples, 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.

[0098] 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 examples, implants can be designed using episode of care data. ExampleAttorney Docket No.: 8178.6136WO data-driven techniques for designing, sizing, and fitting implants are described in U.S. Patent Application No. 13 / 814,531 filed August 15, 2011 and entitled “Systems and Methods for Optimizing Parameters for Orthopaedic Procedures”; U.S. Patent Application No. 14 / 232,958 filed July 20, 2012 and entitled “Systems and Methods for Optimizing Fit of an Implant to Anatomy”; U.S. Patent Application No. 12 / 234,444 filed September 19, 2008 and entitled “Operatively Tuning Implants for Increased Performance,” and U.S. Patent Application No. 17 / 265,675 filed February 3, 2021 and entitled “Patella Tracking Method and System” the entire contents of each of which are hereby incorporated by reference into the present disclosure.

[0099] 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). 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 include quality of life data captured from the patient. For example, in some examples, pre-surgery patients use a mobile application (“app”) to answer questionnaires regarding their current quality of life. In some examples, preoperative data used by the CASS 100 includes demographic,Attorney Docket No.: 8178.6136WO 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.

[0100] FIGS. 2A and 2B depict a tracking element fixation system in accordance with one or more features of the present disclosure. More specifically, FIG. 2A depicts a front view of a tracking element fixation system (“fixation system”) 200 and FIG. 2B depicts a side perspective view of the fixation system 200.

[0100] As shown in FIGS. 2A and 2B, a fixation system 200 may include a baseplate 210 (see FIGS. 4A-5B for a detailed depiction of some examples of the baseplate 210) and a fixation arm 222. The baseplate 210 may include one or more protrusions 211 configured to be inserted into the cortical bone of the femur of a patient. Although the baseplate 210 may include multiple protrusions 211, only one is labeled to simplify the figure.

[0101] The fixation arm 222 may include a tracking element end 251 that includes a connector 223 for connecting to a tracking element (not shown), such as a tracking array, using connection elements 240 (e.g., a ball-and-socket array or other suitable connection element now known or later discovered). The connector 223 and / or connection elements 240 may be configured to allow tracking elements to be positioned to face various directions. In this manner, the position or orientation of a tracking element affixed to the tracker arm 222 may be adjusted to face a camera, IR device, and / or the like to facilitate data collection.

[0102] The fixation arm 222 may include a connection end 220 configured to be coupled to the baseplate 210. The connection end 220 may include a housing 221 configured to engage a top portion of the baseplate. In some examples, the fixation arm 222 may beAttorney Docket No.: 8178.6136WO attached to the baseplate via various coupling configurations, including a kinematic coupling, flanges, and / or clamps (see, for example, FIGS. 6, 7A, 8 A, and 9A). The fixation arm 222 may be removably coupled to the baseplate 210. For example, an operator may remove the fixation arm 222 from the baseplate 210 via manual force (e.g., pulling or lifting). In another example, inadvertent impaction of the fixation arm 222 may be sufficient to disengage the fixation arm 222 from the baseplate 210 (e.g., overcoming the magnetic force and / or flange coupling holding the fixation arm 222 to the baseplate 210).

[0103] In some examples, as depicted in FIGS. 2A and 2B, the fixation arm 222 may be formed as a straight arm (i.e., no curve, or substantially no curve, bend, and / or the like). In some examples, fixation arm 222 may include a curved form, bend, and / or the like. The different types of tracker arms 222 may be used for various surgical approaches. For example, a straight fixation arm 222 may be used for a THA posterior approach. In another example, a bent or curved fixation arm 222 may be configured to bend around soft tissue in an AD approach. However, examples are not so limited, as straight or curved tracker arms 222 may be used in various surgical approaches.

[0104] FIGS. 2C and 2D depict illustrative mounting arms of a tracking element fixation system in accordance with one or more features of the present disclosure. In the examples of FIGS. 2C and 2D, the tracker arm 222 includes a bend or curve, for example, to allow the tracker arm 222 to bend around soft tissue (e.g., in AD approach), thus allowing the tracker to be rotated slightly. In some examples, the tracker arm 222 and the housing 221 are a single integral unit. In other examples, the tracker arm 222 is removably coupled to the housing 221. For example, the tracker arm 222 may include a coupling element 252Attorney Docket No.: 8178.6136WO configured to be coupled to a corresponding coupling element 253 on the housing 221. In this manner, the tracker arm 222 (and, therefore, a tracking element attached to the tracker arm 222) may be differentially orientated by positioning the tracker arm 222 in the coupling element 253. Coupling elements 252 and 253 may include grooves, slots, friction fit elements, fasteners, and / or the like configured to attach the tracker arm 222 to the housing 221. For example, the tracker arm 222 may be rotated to a desired orientation and then rigidly coupled to the housing 221 via coupling elements 252 and 253.

[0105] FIGS. 3A and 3B depict a tracking element fixation system affixed to a portion of a femur in accordance with one or more features of the present disclosure. As shown in FIGS. 3 A and 3B, a baseplate 210 may be affixed to a femur 301 of a patient. The fixation arm 222 is coupled to the baseplate 210 and supports a tracking array 243. The tracking array 243 is attached to the fixation arm 222 via connector 223. In some examples, the connection elements 240 include a fastener that can be tightened to keep the tracking array 243 stationary or loosened so that the tracking array 243 can be maneuvered, turned, removed, or placed back into the connector 223 (e.g., returned to the socket joint).

[0106] The femur 301 includes a shaft 302, head 303, neck 304, and greater trochanter 305 region. In some examples, for example, in a DA approach, the baseplate 210 is affixed on at least a portion of the greater trochanter 305. In some examples, the baseplate 210 may be oriented so that the majority of the baseplate 210 rests on the greater trochanter 305, with one or more screw holes 214, 215 lateral to the intramedullary canal, such that that the screw could be placed without interfering during broaching. The protrusions 211 are to be placed such that they rest on top of the intramedullary canal, but it would not be longAttorney Docket No.: 8178.6136WO enough to pierce the near cortex and interfere with broaches or stems during the procedure. An inserter tool or other impactor may be used to press the protrusions into the femur 301. In some examples, with the impactor still on top of the baseplate 210, a predrill may be performed before a screw is used to fix the baseplate 210 to the bone. In a posterior approach, the baseplate 210 could be fixed to the lateral side of the greater trochanter 305 in an orientation that is easiest for a surgeon, as the screws and the protrusions 211 would not be at risk of breaching the intramedullary canal.

[0107] FIGS. 4A and 4B depict a grooved baseplate of a tracking element fixation system in accordance with one or more features of the present disclosure. As shown in FIGS. 4A and 4B, a baseplate 210 may have a triangular or substantially triangular shape, with a short side 206 and two long sides 207, 208. The baseplate 210 may have a bottom surface 262 configured to be placed in contact with the patient bone and a top surface 261 configured to engage the tracker arm 221.

[0108] The baseplate 210 may include one or more protrusions 211 configured to be inserted into the cortical bone of the patient. In some examples, the protrusions 211 may be or may include spikes, prongs, points, pins, or other forms capable of penetrating patient bone. In some examples, the protrusions 211 may be pointed. In other examples, the protrusions 211 may be rounded, for example, to reduce or even eliminate any unnecessary stress concentration in the near cortex that could lead to a peri-prosthetic fracture during impaction. The baseplate 210 may include one protrusion 211, two protrusions 211, three protrusions, four protrusions, five protrusions, or ten protrusions 211 (or any value or range between any two of these values). In some examples, the protrusions may be about 3Attorney Docket No.: 8178.6136WO millimeters (mm) to about 6 mm (or any value or range between any two of these values, including endpoints). In other examples, the protrusions may be about 1 mm to about 10 mm (or any value or range between any two of these values, including endpoints).

[0109] In some examples, the top surface 261 of the baseplate 210 may include one or more screw holes 214, 215. For example, the baseplate 210 may include a first screw hole 214 located centrally and a second screw hole 215 located near the top edge 206 of the baseplate 210. In some examples, one or more of the screw holes 214, 215 may be countersunk screw holes. In various examples, one or more of the screw holes 214, 215 may be designed to accept 2.87 and 3.5 mm self-tapping cortical screws, which can also be used as self-drilling screws. Alternatively, surgeons can use a predrill once the baseplate 210 is impacted into the greater trochanter, which can be followed with a self-trapping screw.

[0110] The baseplate 210 may include one or more grooves 230. Although the baseplate 210 may include multiple grooves 230, only one is labeled to simplify the figure. The grooves 230 may include sidewalls 231 and a bottom surface 232. The grooves 230 may be configured to receive ball bearings, hemispheres, kinematic protrusions, or other elements of a kinematic coupling (see, for example, FIGS. 6, 7D, and 8C).

[0111] In some examples, the baseplate 210 includes three v-grooves for use as the base for a kinematic coupling to the tracker arm 221. In general, a kinematic coupling works by exactly constraining two parts with respect to one another, providing a certainty of the relative location of one part to another. In some examples, the kinematic coupling configured for the fixation system 200 is or is substantially similar to a Maxwell coupling,Attorney Docket No.: 8178.6136WO for instance, involving three ball bearings being placed within three v-grooves. The configuration of the three grooves and three ball bearings constrains all six degrees of freedom of the system, preventing trackers from moving once the tracking array is mounted onto the baseplate 210. The configuration of the fixation system 200 allows the tracker arm 221 to be attached to the baseplate 210, removed, and then replaced in the exact same position and orientation it was previously attached, providing repeatable static and dynamic measurements.

[0112] In some examples, divots 233 are arranged at the end of the grooves 230. Although the baseplate 210 may include multiple divots 233, only one is labeled to simplify the figure. The divots 233 may be configured to be used by a point probe device. For example, the divots 233 may be used to capture the tip of a point probe (for instance, a 2 mm or similar sized point probe). In some examples, the divots 233 may be used for snapshot tracking of the femur, as all three points could be collected simultaneously which would completely define the instantaneous orientation of the femur. In various examples, divot snapshot tracking may be used in a DA approach and the kinematic coupling live tracking may be used in a posterior approach currently. However, examples are not so limited as divot snapshot tracking and live tracking may be used in either a DA approach or a posterior approach.

[0113] FIGS. 5A and 5B depict a divot-coupling baseplate of a tracking element fixation system in accordance with one or more features of the present disclosure. As shown in FIGS. 5A and 5B, a baseplate 219 may include divots 238 that may be used for point probe data collection (e.g., for snapshot functions) and as a seat for ball bearings or kinematicAttorney Docket No.: 8178.6136WO protrusions of a corresponding kinematic coupling (see, for example, 611 of FIG. 6, 721 of FIG. 7D, or 821 of FIG. 8C).

[0114] Referring to FIG. 5B, in some examples, the protrusions 211 may be configured as a cylinder (not shown, internal to the protrusion 211) with different chamfers 212, 213 applied to the top and bottom of the cylinder. In some examples, the chamfer 212 at the top of the protrusion 211 may have an outside surface with a greater angle compared with the bottom chamfer 213. In some examples, the larger chamfer 212 may prevent the baseplate 210 from bottoming out on the bone while allowing the protrusion 210 to still penetrate the bone and provide sufficient fixation, for instance, to prevent rotations or other unwanted movement.

[0115] FIG. 6 depicts an example of a tracking element fixation system in accordance with one or more features of the present disclosure. More specifically, FIG. 6 depicts a side perspective view of a fixation system 200 with a transparent housing 221 to show the internal features of a kinematic coupling between the tracker arm 222 and the baseplate 210. As shown in FIG. 6, a kinematic coupling element 601 may include one or more magnets 610 and a corresponding number of ball bearings 611. Although the coupling element 601 may include multiple magnets 610 and ball bearings 611, only one of each is labeled to simplify the figure. In some examples, the magnets 610 may be cylindrical magnets. In various examples, the magnets 610 may include three magnets (i.e., one for each groove 230 of the baseplate 210).

[0116] Magnets, such as magnets 610, 720, 820, and 920, may be made of various magnetic materials, for example, capable of forming a permanent or semi -permanentAttorney Docket No.: 8178.6136WO magnet. In some examples, magnets may be formed of iron or iron alloys, neodymium, cobalt, alnico, ferrite, variations thereof, alloys thereof, combinations thereof, and / or the like.

[0117] The tracker arm 222 uses the magnets 610 in contact with embedded ball bearings 611 to magnetize the tracker arm 222 to the baseplate 210. When the tracker arm 222 is coupled to the baseplate 210, the ball bearings 611 are seated within the grooves 230.

[0118] In some examples, the ball bearings 611 may be recessed at least partially within a bottom surface of the magnets 610. For instance, the bottom surface of each of the magnets 610 may include a cavity, depression, concavity, or other recess configured to receive at least a portion of a corresponding ball bearing 611. The ball bearings 611 are retained within the recess and are able to rotate within the recess of the magnets 610.

[0119] In various examples, instead of using free-standing ball bearings 611, the magnets 610 may include contacts (e.g., protrusions, detents, hemispheres, or combinations thereof; see for example, 721 of FIG. 7D and 821 of FIG. 8C) extending from a bottom surface thereof that are sized and shaped to be received by a corresponding number and arrangement of grooves 230. In some examples, the contacts may also extend from a bottom portion of the housing 221 .

[0120] The three ball bearings 611 (or contacts in alternative examples) and the three corresponding grooves 230 result in a true kinematic mount because the six degrees of freedom of the tracker arm 222 are constrained by six points of contact.

[0121] In some examples, portions of the tracker arm 222 and the baseplate 210 are formed of magnetic materials including, without limitation, at least a portion of the tracker armAttorney Docket No.: 8178.6136WO222, the housing 221, the ball bearings 611, any trays (see, for example, 710 of FIG. 7A) arranged between a magnet and the baseplate, and the baseplate 210 itself. Non-limiting examples of magnetic materials may include stainless steel, martensitic stainless steel, magnetic martensitic ferrous stainless-steel, chromium steel, steel alloys such as 17-4 H900, 440C, 420, 410, 431, 430, variations thereof, combinations thereof, alloys thereof, and / or the like. In some examples, at least a portion of the housing 221 may be made from non-magnetic materials. Non-limiting examples of non-magnetic materials may include non-magnetic steel, non-magnetic austenitic ferrous stainless-steel, steel alloys such as 303, 304, 316, variations thereof, combinations thereof, alloys thereof, and / or the like.

[0122] In some examples, the alloy materials used to form portions of the fixation system 200 are selected to improve the magnetic coupling between the tracker arm 222 and the baseplate 210 components. For example, with the tracker arm 222, ball bearings 611, and baseplate 210 made of magnetic materials (e.g., magnetic stainless steel) and the housing 221 made of non-magnetic material (e g., non-magnetic stainless-steel), the magnetic flux is forced to flow from the magnets 610, through the ball bearings 611 and into the baseplate 210. The magnetic flux may then return to the top of the magnet 610 through the posts 229 (or, in some examples, tabs 711 of FIG. 7A, tab 81 1 or flange 812 of FIG. 8A), which provide a path back to the tracker arm 222. As a result of this magnetic configuration, the ball bearings 611 are magnetic and allows the tracker arm-baseplate assembly to self-orient itself, for instance, as the ball bearings 611 will move along the curved surface of the baseplate to find a stable orientation in the v-grooves 230 and provide a strength of retention of the tracker arm 222 to the baseplate 210.Attorney Docket No.: 8178.6136WO

[0123] FIGS. 7A-7E depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure. FIG. 7A depicts a side perspective view of a fixation system 200 with a transparent housing 221 and magnet 720 to show the internal features of a kinematic coupling between the tracker arm 222 and the baseplate 210. FIG. 7B depicts a side perspective view of the magnet 720 and a tray 710. FIGS. 7C and 7D depict exploded top and bottom perspective views, respectively, of the fixation system 200. FIG. 7E depicts a bottom perspective view of a housing 221.

[0124] As shown in FIGS. 7A-7E, the fixation system 200 includes a kinematic coupling element 701 implemented via a magnet 720 and contacts 721. In some examples, the contacts 721 are formed as protrusions, detents, hemispheres, combinations thereof, and / or the like extending from a bottom surface 782 of the magnet 720 (and / or, in various examples, extending from the housing 221). In various examples, the contacts 721 are separate elements from the magnet 720, for instance, ball bearings, spherical contacts, hemispherical contacts, discs (e.g., with a rounded bottom surface), rods, and / or the like. The contacts 721 are configured to be received within the corresponding grooves 230 of the baseplate 210. In various examples, the magnet 720 may be a single magnet having a triangle or wedge shape to correspond to the shape of the housing 221 and the baseplate 210. In some examples, the contacts 721 may be an integrated part of the magnet 720. In some examples, the contacts 721 may be individual elements extending into corresponding recesses in the magnet 720 or contacting the bottom planar surface of the magnet 720 when the kinematic coupling element 701 is assembled.Attorney Docket No.: 8178.6136WO

[0125] In various examples, the tray 710 may be configured to be arranged between the magnet 720 and the baseplate 210. Holes 712 may be arranged in the tray 710 to allow the contacts 721 to pass through the tray 710 and to be seated within the grooves 230. One or more tabs, flanges, posts, or other protrusions 711 may extend from an upper surface 761 of the tray 710. Referring to FIG. 7E, an internal area 224 of the housing 221 may include slots 225 configured to receive the tabs 711 to interlock the tray 710 to the housing 221.

[0126] FIGS. 8A-8C depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure. FIG. 8A depicts a side perspective view of a fixation system 200 with a transparent housing 221 and magnet 820 to show the internal features of a kinematic coupling between the tracker arm 222 and the baseplate 210. FIGS. 8B and 8C depict exploded top and bottom perspective views, respectively, of the fixation system 200.

[0127] As shown in FIGS. 8A-8C, the fixation system 200 includes a kinematic coupling element 801 implemented via a magnet 820 and contacts 821. In some examples, the contacts 821 extend from a bottom surface 862 of the magnet 820 (and / or, in various examples, extend from the housing 221). In various examples, the contacts 821 are separate elements from the magnet 720, for instance, ball bearings, spherical contacts, hemispherical contacts, discs (e.g., with a rounded bottom surface), rods, and / or the like. The contacts 821 are configured to be received within the corresponding grooves 230 of the baseplate 210. In various examples, the magnet 820 may be a single magnet having a triangle or wedge shape to correspond to the shape of the housing 221 and the baseplate 210. In some examples, the contacts 821 may be an integrated part of the magnet 820. InAttorney Docket No.: 8178.6136WO other examples, the contacts 821 may be individual elements extending into corresponding recesses in the magnet 820 or contacting the bottom planar surface of the magnet 820 when the kinematic coupling element 801 is assembled.

[0128] In various examples, one or more tabs, flanges, posts, or other protrusions 811 may extend from an upper surface 861 of the magnet 810. An inner surface of the internal area 224 of the housing 221 may include slots 225 configured to receive the tabs 811 to interlock the magnet 820 (and therefore, the kinematic coupling) to the housing 221. In some examples, flanges or other protrusions 812 may extend from the top and bottom surfaces 861, 862 of the magnet 820. The baseplate 210 may include a notch 227 configured to receive the downward-extending portion of the flange 812. The housing 221 may include a notch 226 configured to receive the upward-extending portion of the flange 812.

[0129] FIGS. 9A-9D depict an example of a tracking element fixation system in accordance with one or more features of the present disclosure. FIG. 9A depicts a side perspective view of a clamped fixation element 200 and FIG. 9B depicts a side perspective view of an unclamped fixation element 200, exposing the internal area 224 of the housing 221.

[0130] In some examples, a clamp 940 may be used to hold the housing 221 to the baseplate 210. The clamp 940 may be used in addition to the connection between the tracker arm 222 and the baseplate 210 provided by the kinematic coupling implemented via the magnet 920. The magnet 920 may be configured the same or similar to magnets 720 and / or 820. FIGS. 9C and 9D depict top and bottom perspective views of the magnet 920 showing the contacts 941 and tabs 942 extending from a top surface 961. In someAttorney Docket No.: 8178.6136WO examples, tabs 942 may operate the same or similar to tabs 711 and / or 811 in combination with corresponding slots (now shown) of housing 221.

[0131] The clamp 940 may include a pair of arms 945 having handles 942. Squeezing or pinching together on the handles 942 may actuate a spring pivot 944 configured to move a bottom portion 946 (or “jaws”) of the arms 945 apart. Releasing the handles 942 causes the spring pivot 944 to force the bottom portion 946 of the arms 945 together. The bottom portion 946 may include a flange or other protrusion 947 configured to be received by a corresponding slot 228 configured on the baseplate 210. The biasing tension provided by the spring pivot 944 may facilitate holding the tracker arm 222 to the baseplate 210.

[0132] FIG. 10 depicts a femoral clamp in accordance with one or more features of the present disclosure. In some examples, a femoral clamp 1000 may be configured that does not require any screw or other protrusion fixation in order to be affixed to a bone surface. In various examples, the femoral clamp 1000 may be configured to grab onto the bone via paddles, for example, below a desired location of a femoral neck cut (for example, approximating the region from the greater trochanter to the lesser trochanter). The paddles 1010, 1011 may include spikes, serrations, or other projections that may facilitate the femoral clamp 1000 gripping onto the patient bone.

[0133] A button nut 1004 may allow for an adjustment screwl006 to be disengaged and for the femoral clamp 100 to coarsely slide into place around the bone. The button nut 1004 could then disengaged and the adjustment screw 1006 could be used to finely adjust the femoral clamp 100 until it is fully clamped onto the bone. A first paddle 1010 may be fixed with a shoulder screw 1012, allowing the paddle 1010 to rotate and contour to the bone.Attorney Docket No.: 8178.6136WOThe femoral clamp 100 may be configured to provide access to locate the femoral clamp 100 around the circumference of the bone within a small surgical incision (e g., 1-2 inches). In some examples, the femoral clamp 1000 may be used in combination with a cerclage wire or other similar tensioning element to secure the femoral clamp 1000 to the patient bone (see, for example, FIGS. 15A-15C).

[0134] FIG. 11 depicts alternative clamp configurations in accordance with one or more features of the present disclosure. FIG. 11 depicts clamp geometries 1101-1103 that may be adapted to provide fixation to patient bone, for instance, to clamp between the greater trochanter and the lesser trochanter or between the anterior and posterior face of the greater trochanter. The clamp geometries 1101-1102 may be used in combination with any examples provided in the present disclosure.

[0135] FIG. 12 depicts a serrated bone plate in accordance with one or more features of the present disclosure. Alternative to using the clamping forces of paddles or other elements to provide temporary fixation to a bone, a serrated bone plate 1200 may be configured to penetrate (or “bite”) into a top surface of the bone. The bone plate 1200 may be split into two separate segments 1215, 1216 and is pulled together using lag screws 1208.

[0136] In some examples, the bone plate 1200 may include inwardly pointing spikes 1202 to penetrate into the opt portion of the bone. For example, the bone plate 1200 may be placed on top of the bone and pressed down into it before the adjustment screws 1208 may be used to clamp the two plates 1204 together. As the two plates 1204 are brought together, the spikes 1202 penetrate into the bone and hold the bone plate 1200 in place. In oneAttorney Docket No.: 8178.6136WO example, one central lag screw 1208 may be sufficient to generate enough pressure to grip onto the bone, for example, in the greater trochanter. In various examples, the lag screws 1208 could be engaged using a powered tool that can fit inside the surgical incision site. In some examples, the bone plate 1200 may be used in combination with a cerclage wire or other similar tensioning element to secure the bone plate 1200 to the patient bone (see, for example, FIGS. 15A and 15B).

[0137] FIG. 13 depicts a slot-mounted tracking element fixation system in accordance with one or more features of the present disclosure. In some examples, a fixation system 1300 may include a baseplate 1310 that, instead of using a kinematic coupling to interface between the tracking arm 222 and the baseplate 1310, a slot 1330 is used to hold the tracking arm 222 and the baseplate 1310together. A magnet (not shown) could be used at the end of the slot to hold the tracking arm 222 and the baseplate 1310 together. Accordingly, a tracking element could be coupled and decoupled from the same location with respect to the femur geometry.

[0138] FIG. 14 depicts a fixation element in accordance with one or more features of the present disclosure. In some examples, a concentric fastener (or spike) 1400 may include a chamfered taper 1410 near the end along with two circumferentially concentric rings 1415, 1416 near the bottom of the spike 1400. The spike 1400 could be used to affix plates or other fixation elements onto the bone, alone or in combination with cables or other structures.

[0139] FIGS. 15A and 15B depict femoral screwless tracking element fixation systems in accordance with one or more features of the present disclosure. In some examples, fixationAttorney Docket No.: 8178.6136WO systems may be configured that avoid insertion of bone screws into the femur to reduce the risk of injury or mechanical compromise of the highly stressed upper femur. This lessens the likelihood of post-operative complications due to femoral fracture. In some examples, a fixation system 1500 may include a horse-shoe collar or baseplate 1510 with two slots 1514 located superior and inferior to the femoral head of a femur 301 for inserting a tensioning device 1520. In some examples, the tensioning device 1520 may be a cerclage wire, cable, ligature, and / or the like.

[0140] In some examples, a range of baseplates 1510 of varying sizes may be used by a surgeon to accommodate various patients. Examples of baseplates 1510 may include baseplates the same or similar to the fixation systems of FIGS. 10 or 12. The dimensions of the baseplate 1510 may range from 30 mm to 45 mm (major axis) and 20 mm to 35 mm (minor axis). Other shapes could be used, including ellipsoidal, “U,” or irregular shapes. The fixation system 1500 may also include an in-wound femoral tracking marker, securely attachable the patient’s femur by a non-penetrating ligature and is trackable by the locating system to detect changes in leg length and femoral offset.

[0141] In some examples, the fixation system 1500 may be used via a cable or tensioning system which involves wrapping the tension element 520 around the upper femur and tightening the tension element 520, thereby tightening the fixation system 1500 (or “clamp”) around the femur 301 to pull the collar 1510 tightly against the greater trochanter.

[0142] The approach provided by the fixation system 1500 offers independent tensioning members, which wrap around the femoral greater trochanter, running above and below the projection of the lesser trochanter to secure the placement of the baseplate to the surface ofAttorney Docket No.: 8178.6136WO the bone while avoiding axial slippage. The tensioning members 1520 pull the horse-shoe shaped collar 1510 onto the projection of the greater trochanter. Given the irregular shape of the greater trochanter, the collar 1510 will seek a stable position vis-a-vis the greater trochanter, which position is maintained firmly by the tensioning members 1520. Different elastomeric straps, fibers, cords, mesh, wire, adhesives or ligatures could be employed in connection with the tracking system as the tensioning members 1520 or in combination with the tensioning members 1520. The tensioning members 1520 are constructed such that they are capable of exerting sufficient force to firmly attach the marker device, but are not so strong that a crushing force could be accidentally exerted on the femur.

[0143] In some examples, a surgeon threads the tensioning members 1520 through a slot 1512, encircling the femur 301, and threads the tensioning members 1520 through an opposing slot 1512 pulling the tensioning members 1520 to an appropriate tension and finally attaching a clamp (not shown) to hold the tensioning members 1520 in tension. Suitable clamps are available from Poly 4 Medical, but other means of holding the members in tension could be used, such as various hooks or staples.

[0144] A tracker check procedure can also be performed with the fixation system 1500 to check the fixation of a screwless femoral tracking marker associated with the fixation system 1500. For example, during initialization, the surgeon can make a reference mark on the femur, for instance, via cauterization or an equivalent process, to check for slippage by finding the coordinates of the reference mark in the reference frame of the femoral tracking marker.Attorney Docket No.: 8178.6136WO

[0145] In various examples, an optical marker can be attached to the baseplate 1510 after tensioning to the bone. The shaft of the optical tracker may optionally have a bend, articulation, or joint to allow the marker to be oriented in a better aspect for optical tracking for different surgical approaches. In some examples, the baseplate 1510 may have an inward facing bevel (for instance, at approximately a 45-degree angle) defining an angled shoulder which is preferably knurled or otherwise textured to grip the trochanter in a positive manner. A bevel may also allow a clamped cable to be loosened and retightened and repositioned without deforming the cable.

[0146] FIG. 15C depicts the baseplate 1510 is FIG. 15A with the fixation arm 222 attached thereto. The functions of the baseplate 1510 and fixation arm 222 are the same as above, however, the baseplate 1510 is not screwed or bolted into the bone.

[0147] FIG. 16 is a flow chart depicting example operations performed in a method 1600 for computer assisted knee arthroplasty. As shown at block 1602, the method 1600 includes attaching a baseplate to a bone of a patient, wherein the baseplate includes one or more protrusions extending from a bottom thereof, wherein the one or more protrusions are configured to be impacted into the bone of the patient. As shown at block 1604, the method 1600 includes coupling a tracker arm to the baseplate using a kinematic coupling device.

[0148] As shown at block 1606, the method 1600 includes attaching a tracking array to the tracker arm for collecting tracking data for a surgical system, wherein the tracking array is detachably coupled to a connector of the tracker arm, the connector configured to allow the tracking array to be adjusted to face a plurality of directions.Attorney Docket No.: 8178.6136WO

[0149] In some examples, the connector includes one or more of: a ball-and-socket connector; an adjustable fastener; magnetic ball connectors; a magnetic swivel connector; a hinged connector with a locking mechanism; or a threaded pivot connector. In some examples, the connector includes the ball-and-socket connector, wherein the method 1600 further comprises adjusting a fastener of the ball-and-socket connector to face tracking array in a specified direction.

[0150] In some examples, attaching the baseplate to the bone of the patient includes attaching the baseplate to at least a portion of a greater trochanter of the patient. In some examples, a top surface of the baseplate includes a set of grooves or divots arranged thereon; wherein the set of grooves or divots is configured to receive contacts of the kinematic coupling device for attaching the tracker arm to the baseplate; and wherein the kinematic coupling device comprises a magnet and a set of ball bearings positioned between the magnet and the top surface of the baseplate, wherein the set of ball bearings are the contacts and are configured to be seated in the set of grooves or divots on the top surface of the baseplate.

[0151] In some examples of the method 1600, the kinematic coupling device incudes a tray arranged between the magnet and the baseplate; and wherein the tray includes a set of holes configured such that the set of ball bearing sits within a corresponding one of the set of holes and touches a groove or divot through the corresponding hole.

[0152] In some examples, the kinematic coupling device includes a housing configured to enclose the magnet and at least a portion of the tray on the top surface of the baseplate. In some examples, one or more tabs, flanges, posts or protrusions extend from an upperAttorney Docket No.: 8178.6136WO surface of the magnet to be received by first slots of an internal area of the housing. In some examples, one or more tabs, flanges, posts, or protrusions extend from an upper surface of the tray to be received by second slots of the internal area of the housing. In some examples, the tracker arm extends from a top surface of the housing of the kinematic coupling device.

[0153] In some examples, the method 1600 further includes enclosing the baseplate with a housing, the tracker arm extending from a top surface of the housing. The method 1600 may further include attaching the housing onto the baseplate using at least a clamp, the clamp comprising a pair of arms having handles, wherein applying a force on the handles actuates a spring pivot configured to move a bottom portion of the arms apart. In some examples, removing the force on the handles causes the spring pivot to force the bottom portion of the arms together. In such an example, the bottom portion of the arms includes a flange configured to be received by a corresponding slot on the baseplate. In some examples, a biasing tension provided by the spring pivot facilitates holding the tracker arm to the baseplate.

[0154] The foregoing description has broad application. While the present disclosure refers to certain some examples, numerous modifications, alterations, and changes to the described examples are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described examples. Rather these examples should be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the disclosure are to be considered within the scope of theAttorney Docket No.: 8178.6136WO disclosure. The present disclosure should be given the full scope defined by the language of the following claims, and equivalents thereof. The discussion of any example is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples. In other words, while illustrative examples of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs.

[0155] Directional terms such as top, bottom, superior, inferior, medial, lateral, anterior, posterior, proximal, distal, upper, lower, upward, downward, left, right, longitudinal, front, back, above, below, vertical, horizontal, radial, axial, clockwise, and counter-clockwise) and the like may have been used herein. Such directional references are only used for identification purposes to aid the reader’s understanding of the present disclosure. For example, the term “distal” may refer to the end farthest away from the medical professional / operator when introducing a device into a patient, while the term “proximal” may refer to the end closest to the medical professional when introducing a device into a patient. Such directional references do not necessarily create limitations, particularly as to the position, orientation, or use of this disclosure. As such, directional references should not be limited to specific coordinate orientations, distances, or sizes, but are used to describe relative positions referencing particular examples. Such terms are not generallyAttorney Docket No.: 8178.6136WO limiting to the scope of the claims made herein. Any example or feature of any section, portion, or any other component shown or particularly described in relation to any preceding or subsequent example of similar sections, portions, or components herein may be interchangeably applied to any other similar example or feature shown or described herein.

[0156] It should be understood that, as described herein, an “example” (such as illustrated in the accompanying Figures) or “example” (such as “in some examples”) may refer to an illustrative representation of an environment or article or component in which a disclosed concept or feature may be provided or embodied, or to the representation of a manner in which just the concept or feature may be provided or embodied. However, such illustrated examples are to be understood as examples (unless otherwise stated), and other manners of embodying the described concepts or features, such as may be understood by one of ordinary skill in the art upon learning the concepts or features from the present disclosure, are within the scope of the disclosure. Furthermore, references to “one example” of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations, configurations, and / or examples that also incorporate the recited features.

[0157] In addition, it will be appreciated that while the Figures may show one or more examples of concepts or features together in a single example of an environment, article, or component incorporating such concepts or features, such concepts or features are to be understood (unless otherwise specified) as independent of and separate from one another and are shown together for the sake of convenience and without intent to limit to being present or used together. For instance, features illustrated or described as part of oneAttorney Docket No.: 8178.6136WO example can be used separately, or with another example to yield a still further example. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0158] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. It will be further understood that the terms “comprises” and / or “comprising,” or “includes” and / or “including” when used herein, specify the presence of stated features, regions, steps, elements and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and / or groups thereof.

[0159] The phrases “at least one,” “one or more,” and “and / or,” as used herein, are open- ended expressions that are both conjunctive and disjunctive in operation. The terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.

[0160] Connection references (e.g., engaged, attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative to movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative to sizes reflected in the drawings attached hereto may vary.Attorney Docket No.: 8178.6136WO

[0161] The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more examples or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain some examples or configurations of the disclosure may be combined in alternate examples or configurations. Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate example of the present disclosure.

Claims

Attorney Docket No.: 8178.6136WOCLAIMSWhat is claimed is:

1. A tracking element fixation system comprising: a baseplate comprising one or more protrusions extending from a bottom surface thereof, wherein the one or more protrusions are configured to be impacted into a bone of a patient, and wherein the baseplate includes a through hole configured to allow for fastener fixation of the baseplate to the bone of the patient; and a tracker arm configured to be kinematically coupled to the baseplate, the tracker arm comprising a tracker end having a connector configured to be detachably coupled to a tracker element, the connector configured to allow the tracker element to be adjusted to face a plurality of directions.

2. The tracking element fixation system of claim 1, wherein the tracker arm further comprises a connection end configured to be coupled to the baseplate, wherein the tracker arm is removably attachable to the baseplate via a kinematic coupling device.

3. The tracking element fixation system of claim 2, wherein the kinematic coupling device comprises a Maxwell coupling.

4. The tracking element fixation system of claim 1, wherein the connector includes one or more of:Attorney Docket No.: 8178.6136WO a ball-and-socket connector; an adjustable fastener; magnetic ball connectors; a magnetic swivel connector; a hinged connector with a locking mechanism; or a threaded pivot connector.

5. The tracking element fixation system of claim 1, wherein the tracker arm includes a curve or a bend.

6. The tracking element fixation system of claim 1, wherein the baseplate is configured to be affixed on at least a portion of a greater trochanter of the patient.

7. The tracking element fixation system of claim 1, wherein a top surface of the baseplate includes a fastener hole for fastener fixation of the baseplate to the bone of the patient; wherein the tracker arm being kinematically coupled to the baseplate includes the tracker arm being magnetically coupled to the top surface of the baseplate.

8. The tracking element fixation system of claim 1, wherein a top surface of the baseplate includes a set of grooves or divots arranged thereon;Attorney Docket No.: 8178.6136WO wherein the set of grooves or divots is configured to receive contacts of a kinematic coupling device for attaching the tracker arm to the baseplate.

9. The tracking element fixation system of claim 8, wherein the kinematic coupling device comprises a magnet and a set of ball bearings positioned between the magnet and the top surface of the baseplate, wherein the set of ball bearings are the contacts and are configured to be seated in the set of grooves or divots on the top surface of the baseplate.

10. The tracking element fixation system of claim 9, wherein the kinematic coupling device incudes a tray arranged between the magnet and the baseplate; and wherein the tray includes a set of holes configured such that the set of ball bearing sits within a corresponding one of the set of holes and touches a groove or divot through the corresponding hole.

11. The tracking element fixation system of claim 10, wherein the kinematic coupling device includes a housing configured to enclose the magnet and at least a portion of the tray on the top surface of the baseplate; wherein one or more tabs, flanges, posts or protrusions extend from an upper surface of the magnet to be received by first slots of an internal area of the housing; wherein one or more tabs, flanges, posts, or protrusions extend from an upper surface of the tray to be received by second slots of the internal area of the housing; andAttorney Docket No.: 8178.6136WO wherein the tracker arm extends from a top surface of the housing of the kinematic coupling device.

12. The tracking element fixation system of claim 1, further comprising a housing configured to enclose the baseplate, the tracker arm extending from a top surface of the housing; wherein the housing is configured to be held onto the baseplate using at least a clamp, the clamp comprising a pair of arms having handles, wherein applying a force on the handles actuates a spring pivot configured to move a bottom portion of the arms apart; wherein removing the force on the handles causes the spring pivot to force the bottom portion of the arms together; wherein the bottom portion of the arms includes a flange configured to be received by a corresponding slot on the baseplate; and wherein a biasing tension provided by the spring pivot facilitates holding the tracker arm to the baseplate.

13. A method comprising: attaching a baseplate to a bone of a patient, wherein the baseplate includes one or more protrusions extending from a bottom thereof, wherein the one or more protrusions are configured to be impacted into the bone of the patient; coupling a tracker arm to the baseplate using a kinematic coupling device; andAttorney Docket No.: 8178.6136WO attaching a tracking array to the tracker arm for collecting tracking data for a surgical system, wherein the tracking array is detachably coupled to a connector of the tracker arm, the connector configured to allow the tracking array to be adjusted to face a plurality of directions.

14. The method of claim 13, wherein the connector includes one or more of: a ball-and-socket connector; an adjustable fastener; magnetic ball connectors; a magnetic swivel connector; a hinged connector with a locking mechanism; or a threaded pivot connector.

15. The method of claim 14, wherein the connector includes the ball-and-socket connector, wherein the method further comprises adjusting a fastener of the ball-and- socket connector to face tracking array in a specified direction.

16. The method of claim 13, wherein attaching the baseplate to the bone of the patient includes attaching the baseplate to at least a portion of a greater trochanter of the patient.

17. The method of claim 13, wherein a top surface of the baseplate includes a set of grooves or divots arranged thereon;Attorney Docket No.: 8178.6136WO wherein the set of grooves or divots is configured to receive contacts of the kinematic coupling device for attaching the tracker arm to the baseplate; and wherein the kinematic coupling device comprises a magnet and a set of ball bearings positioned between the magnet and the top surface of the baseplate, wherein the set of ball bearings are the contacts and are configured to be seated in the set of grooves or divots on the top surface of the baseplate.

18. The method of claim 17, wherein the kinematic coupling device incudes a tray arranged between the magnet and the baseplate; and wherein the tray includes a set of holes configured such that the set of ball bearing sits within a corresponding one of the set of holes and touches a groove or divot through the corresponding hole.

19. The method of claim 18, wherein the kinematic coupling device includes a housing configured to enclose the magnet and at least a portion of the tray on the top surface of the baseplate; wherein one or more tabs, flanges, posts or protrusions extend from an upper surface of the magnet to be received by first slots of an internal area of the housing; wherein one or more tabs, flanges, posts, or protrusions extend from an upper surface of the tray to be received by second slots of the internal area of the housing; and wherein the tracker arm extends from a top surface of the housing of the kinematic coupling device.Attorney Docket No.: 8178.6136WO20. The method of claim 13, further comprising: enclosing the baseplate with a housing, the tracker arm extending from a top surface of the housing; attaching the housing onto the baseplate using at least a clamp, the clamp comprising a pair of arms having handles, wherein applying a force on the handles actuates a spring pivot configured to move a bottom portion of the arms apart; wherein removing the force on the handles causes the spring pivot to force the bottom portion of the arms together; wherein the bottom portion of the arms includes a flange configured to be received by a corresponding slot on the baseplate; and wherein a biasing tension provided by the spring pivot facilitates holding the tracker arm to the baseplate.

Images