- Email: [email protected]
NAVIO Surgical System—Handheld Robotics
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NAVIO Surgical System—Handheld Robotics Riddhit Mitra and Branislav Jaramaz Smith & Nephew, Pittsburgh, Pennsylvania, United States
ABSTRACT Robotics-assisted arthroplasty has gained increasing popularity as orthopedic surgeons aim to increase the accuracy and precision of implant positioning. With advances in computer-generated anatomy data through image-free data collection, surgeons have the ability to better predict and influence surgical outcomes. Based on planned implant position and soft-tissue considerations, robotics-assisted systems can provide surgeons with planning tools to make informed decisions for knee replacement specific to the needs of the patient and with intelligent tools to implement those decisions. This is achieved by customizing the surgical cuts rather than prosthesis designs, while staying within clinically acceptable boundaries. Postoperative alignment of knee implants has been shown to influence patient outcomes in terms of implant longevity and functionality. The use of robotics in orthopedic surgery has helped to minimize human error, and in turn reduce implant wear and theoretically lead to longer prosthesis survivorship. This chapter provides a framework for the surgical techniques for using the NAVIO surgical system to perform partial and total knee arthroplasty (TKA). The NAVIO system supports unicompartmental knee arthroplasty, patellofemoral knee arthroplasty, bicruciate retaining, cruciate-retaining or bicruciate sacrificing TKA. Handbook of Robotic and Image-Guided Surgery. DOI: https://doi.org/10.1016/B978-0-12-814245-5.00026-8 © 2020 Elsevier Inc. All rights reserved.
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Handbook of Robotic and Image-Guided Surgery
Introduction
Although conventional knee arthroplasty is considered a successful intervention for end-stage osteoarthritis, some patients still experience reduced functionality and require revision procedures, ranging from 4.9% to 19.6% over a 10-year period, for partial and total knee replacement [1,2]. Similarly, in the space of unicondylar or partial knee replacement, which is considered as a relevant option for younger, active patients with early stages of arthritis, successful results and durability of knee arthroplasty are affected by a variety of factors, including appropriate surgical indications, implant design, component alignment and fixation, and soft-tissue balance [3,4]. Accurate alignment of the tibial component using conventional techniques has been difficult to achieve [5 7]. Outliers beyond 2 degrees of the desired alignment may occur in as many as 40% 60% of cases using conventional methods, and the range of component alignment varies considerably, even in the hands of skilled knee surgeons [8]. Similarly, for total knee replacement outliers beyond 2 degrees of the desired alignment may occur in as many as 15% of cases in the coronal plane, going up to 40% of unsatisfactory alignment in the sagittal plane [9]. From the 1970s, designs of implants and instruments have evolved into two principal branches. Anatomic implant designs, which attempt to reconstruct the patient’s anatomy and preserve the cruciate ligaments, are limited by expensive manufacturing and challenging execution. On the other hand, functional designs, with a focus on measured resection and gap balancing techniques, attempt to restore joint function by optimizing the use of a serially produced implant design. While the implant designs are continually evolving, there is still room for improvement in achieving repeatable functional outcomes and natural proprioception. Modern implants tend to blend the two principles, where anatomic designs and a functional approach to resection are combined for improved functional outcomes. However, there still remains room for optimization by improving the precision of proper alignment and ligament balancing [10]. While navigation and patient-specific blocks have aimed to help in achievement of accuracy in alignment, studies have shown that 15% 20% of the cases may fall outside the range of 6 3 degrees of desired outcome [11]. Robotics-assisted systems have challenged traditional instruments as a method to decrease mechanical alignment outliers, optimize soft tissue balancing, and restore normal knee kinematics [12 15]. Robotics-assisted surgery has been available for nearly 25 years. Current robotics-assisted systems use various navigation principles augmented with the technology of robotic bone preparation, allowing the surgeon to conduct a UKA (unicompartmental knee arthroplasty) or TKA (total knee arthroplasty), based on preoperative 3D images or image-free intraoperative planning [16]. While most of the current robotics-assisted orthopedic cutting systems are autonomous robots or haptic arm-based instruments, NAVIO (Smith & Nephew, Pittsburgh, PA, United States), is a next-generation robotics-assisted system that uses handheld miniaturized robotics-assisted instrumentation that is freely moved by the surgeon but restricts the bone cutting within the confines of the designated resection area of the patient’s bone, and within the proper depth and orientation (Fig. 26.1).
26.2
The NAVIO surgical workflow
The following section provides an overview of the recommended techniques for using the NAVIO surgical system technology in clinical applications. The NAVIO surgical system is indicated for use in surgical knee procedures in which the use of stereotactic surgery may be appropriate, and where reference to rigid anatomical bony structures can be determined. The NAVIO technique description for knee replacement surgery is divided into the following steps: 1. Patient and system setup: This section covers the details of patient and system setup needed for a handheld roboticsassisted surgery. 2. Registration: The intraoperative registration steps to define anatomical and soft-tissue information for the system are explained in this section. 3. Prosthesis planning: This section captures the ability of the system to plan the implant on the defined patient’s anatomy based on registration. 4. Robotics-assisted bone cutting: The modes of robotic-assisted control and execution are defined in this section. 5. Trial reduction: Postbone preparation, implant trialing, and ligament balancing assessment are highlighted in this section. 6. Cement and close: This section defines the specifics of cementation and closing.
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26.2.1
Patient and system setup
The NAVIO computer system is positioned close to the operating table to allow the surgeon to easily interact with the system, while maintaining complete control of the procedure. In addition to the surgeon-controlled touch screen, the surgeon can navigate through the different stages of operation using foot-pedal controls. During setup, the NAVIO handheld robotic instrument is assembled and configured according to the surgeon’s preference with regard to the robotic mode of control. After incision, all peripheral osteophytes are removed, to reliably assess the patient’s anatomy as well as joint stability. For cruciate retaining (CR) or posterior stabilized designs, it is recommended to release the anterior and posterior cruciate ligament, respectively, depending on the design of the prosthesis component to be implanted, and the disease condition of the patient’s knee (Figs. 26.2 and 26.3).
26.2.1.1 Bone tracking hardware For attachment of tracking arrays to the femur and tibia, NAVIO utilizes a two-pin bicortical fixation system. To place the tibia tracker, the first bone screw is percutaneously placed inferior to the tibial tubercle on the medial side of the tibial crest, to avoid stress risers on the tibia bone. The bone screw should be drilled slowly into the tibia, perpendicular to the bony surface, stopping once the opposing cortex has been engaged. A tissue protector is used to mark the position of the second bone screw, inferior to the initial placement and the second screw is engaged with the bone. Similarly for the femur, the bone screws are percutaneously placed about four to five finger breadths superior to the patella. The femur and tibia tracker frames are clamped to these screws, and oriented with the reflective markers toward the camera,
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FIGURE 26.1 Handheld robotic-assisted tool and the NAVIO surgical system.
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FIGURE 26.2 Typical OR setups. OR, Operating room.
FIGURE 26.3 Bicortical engagement of bone screws for rigid fixation of tracking arrays.
to maximize the operative field of view. A camera orientation stage in the system guides the surgeon for best position of the camera and trackers, to allow manipulation of the patient’s leg through the range of motion (ROM), and ensure that the trackers stay visible throughout the surgical procedure. Small checkpoint pins are also placed in the femur and tibia. They are used throughout the procedure to determine if the bone tracking frames have moved, ensuring the system integrity throughout the procedure (Fig. 26.4).
26.2.2
Registration—image-free technology
The NAVIO surgical system does not require the use of any preoperative data, and the entire anatomy registration and planning workflow is performed intraoperatively (Fig. 26.5). NAVIO relies on image-free localization of anatomic landmarks and surface “painting” to construct a virtual representation of the patient’s anatomy. This step ensures that the true surface of the patient anatomy is captured, as the system registers the articulating surfaces and defects, for best assessment of prosthesis placement during planning. The first step in registration is to use the point probe to identify the most prominent points on the medial and lateral malleoli in order to register the ankle center. The next step, hip center calculation, follows the femoral tracker array through circular movements of the hip and calculates the center of rotation. The femur should be slowly pivoted at the hip until all sectors of the graphic on the screen have turned green. Then the leg is placed in full extension, applying a slight compressive force on the tibia, to calculate the patient’s varus/valgus deformity and capture any existing flexion contracture. This collection is followed by the preoperative knee motion collection step, which allows the user to record normal flexion motion. The leg is moved through a normal ROM to maximum flexion, while keeping the knee joint in contact, making sure to collect all possible sectors. Then, constant and consistent varus and/or valgus stress is applied
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FIGURE 26.4 Tibial tracker attachment on the patient’s bone, with the reflective markers facing the camera.
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FIGURE 26.5 Hip center collection of the patient’s anatomy to determine the center of the femoral head.
to the collateral ligaments to collect soft-tissue laxity data throughout the patient’s knee flexion. The system graphically depicts medial and/or lateral compartment space, depending on the surgery (uni or total). These data are used to identify how much laxity exists in the current soft-tissue structure. This information is unique to the patient and can be used during the planning stage. This allows the surgeon to plan for the best approach when it comes to bony resections and soft-tissue releases, with virtual implementation of anatomic or functional principles of bone preparation, before making any cuts (Figs. 26.6 and 26.7). With a focus on rigid anatomy next, the femoral condyle is registered using landmark points. Using the point probe, the surgeon collects the knee center that with the hip center determines the mechanical axis of the femur. Additional landmark points in the uni and TKA applications allow the surgeon to inform the NAVIO system of basic anatomy, with which the system can provide a starting selection of implant size and position. At this stage, the user further
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FIGURE 26.6 Patient ligament laxity collection, to assess medial and lateral joint space. This stage can be accessed before making cuts, as well as after bone cuts are made.
FIGURE 26.7 Image-free patient femur anatomy mapping.
digitizes the femoral condyle by moving the probe over the entire surface while holding down the foot pedal. In the total knee application the rotational reference of the femur or tibia can additionally be fine-tuned from the previously defined rotation axes (posterior condylar axis, or transepicondylar, or anterior posterior axis), in the free surface collection stage, giving the surgeons the flexibility to make the most informed decision, based on specific patient anatomy. Following successful femoral registration, tibial landmarks are collected, including the knee center which, in conjunction with the ankle center defines the mechanical axis. The last registration step, tibial condyle surface mapping, offers visualization of the mapped surface and previously collected tibial mechanical and landmark points. Similar to the femur, the rotational axis of the tibia can be fine-tuned by the surgeon at this stage, customizing it specific to the patient’s anatomy (Figs. 26.8 and 26.9).
26.2.3
Prosthesis planning
The implant planning stage provides the user a virtual reconstruction of the patient’s femoral and tibial anatomy, soft-tissue ligament tension, and joint balance. There are three stages during planning: (1) initial sizing and placement, (2) gap planning, and (3) cut guide placement. The surgeon has multiple options of visualizing the anatomy at this stage, with the choice of solid bone and implant graphics, or a “virtual” CT slice mode, called the cross-section view.
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FIGURE 26.8 Fine tuning of the rotational axis by taking into consideration transepicondylar axis, Whiteside’s line as well as posterior condylar axis, specific to the patient’s knee.
FIGURE 26.9 Image-free patient tibia anatomy mapping.
26. NAVIO Surgical System With coronal, transverse, and sagittal screens, the surgeon can assess the position of the implant components on the bone in all three dimensions. Using the cross-sections, the surgeon first confirms that the component size provides adequate coverage on the digitized femur bone surface. The transition of the implant component on the anatomy is verified and adjusted in the sagittal view screen, confirming good anterior posterior implant component fit and transition from bone to implant on the terminal edges. In order to assess size coverage, implant anterior transition, and the bone resection plan, the user can toggle on the virtual cut view mode to visualize the implant component on the bone surface. Rotation of the component on the anatomy is confirmed in the transverse view, while assessing diseased bone from the virtual reconstruction of the anatomy, compared to the build back due to the position of the implant. The coronal view is used to assess implant alignment and distal resection within the bounds of surgical principles when compared to the patient’s mechanical axis (Figs. 26.10 and 26.11).
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FIGURE 26.10 Initial femur implant planning with consideration of sizing and anatomical fit on the patient’s bone.
FIGURE 26.11 Initial tibia implant planning with consideration of sizing and anatomical fit on the patient’s bone. Image shows bicruciate retaining knee implant.
For the tibial component, the NAVIO software will attempt to provide a starting size and initial placement utilizing the landmarks and tibia “paint” collection. With similar view screens and options, the surgeon can assess the depth of resection and alignment, component rotation, and posterior slope with respect to the mechanical axis. The tibial component defaults to the thinnest poly insert, but thicker inserts can be selected by changing the poly component during the planning stages.
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The second stage of implant planning allows the user the ability to dial in soft-tissue laxity for the patient in extension and flexion based on the soft-tissue input from prior ligament balancing collection. There are four interactive views for translating and rotating the components with respect to the patient’s virtualized joint. The goal of this stage is to optimize extension and flexion laxity balance with no overlap (or tightness) in either medial or lateral condyle. The surgeon can choose to perform anterior cruciate ligament (ACL) release for a CR procedure, or ACL and posterior cruciate ligament release for a bicruciate sacrificing procedure, and collateral ligament release to recollect laxity information by clicking on the “Recollect Joint Laxity” button in order to augment what the joint space will actually look like after the bone cuts are made. The user can manipulate and fine tune the position and orientation of the implant components in this stage such that the resulting gaps are “balanced” in both extension and flexion. While the extension gaps are affected by changing distal femur resection, and varus/valgus cut adjustments within the bounds of acceptable surgical principles, balancing of the flexion gap in the medial and lateral compartments can be performed by rotating the femur component internally or externally. Adjustments to femoral component rotation should be carefully considered relative to prior parameters such as anterior notching for TKA, and implant fit on condyle, for a UKA. Adjustments to femoral flexion should also be considered against prior considerations regarding anterior fit and bone transition (Figs. 26.12 and 26.13).
FIGURE 26.13 Full range of motion ligament balance planning with the virtual components in place, before the bone cuts are performed for a UKA surgery. UKA, Unicompartmental knee arthroplasty.
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FIGURE 26.12 Ligament balance planning with the virtual components in place, before the bone cuts are performed. This stage can also be accessed after ligament releases or bone cuts for fine-tuning implant placement plan. Image shows bicruciate sacrificing implant.
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FIGURE 26.14 Full range of motion ligament balance planning with the virtual components in place, before the bone cuts are performed. This stage can also be accessed after ligament releases or bone cuts for fine-tuning implant placement plan. The image shows bicruciate retaining implant.
The NAVIO system also shows the full ROM laxity, based on the planned implant positions to assess mid-flexion stability and joint space. The above stage therefore gives the surgeon the ability to augment and virtually construct the patient’s final ligament balance based on bone resections, as well as soft-tissue laxity definitions. This ability allows the bone cuts to be customized for the patient, based on the prosthesis design, the soft-tissue balance, and the amount of bony resections for an informed surgical output as desired for the patient. Lastly, during the cut guide placement stage, the surgeon can fine tune the position of cut guides optimally on the specific patient anatomy. The femur cut guide is placed to ensure that all locking features on the femur cut guide assembly have purchase into the bone surface. Similarly locking features on the tibia cut guide assembly are confirmed to have purchase into the bone surface (Fig. 26.14).
26.2.4
Robotic-assisted bone cutting
In the area of orthopedic robotics, the robotic systems can be distinguished as active, semiactive, or passive. Active systems, such as TSolution One (THINK Surgical, Fremont, CA), are completely autonomous, where the cutting tool is free from human control and the robot completes the required bone cuts according to the plan. In the semiactive segment, the surgeon and the robotic tool share control over the operation, where the robotics is utilized for active action assistance and guidance during fine manipulations, while the surgeon is still in general control over the procedure. Examples of such systems are NAVIO (Smith and Nephew, Pittsburgh, PA) and Mako (Stryker, Kalamazoo, MI). Passive systems guide the surgeons with assistive information during the procedure (navigation systems) or may provide robotically controlled positioning tools (such as OMNIBotics, OMNIlife science, Inc., Raynham, MA), but do not perform any action. Semiactive robotics prevents the surgeon from cutting the bone outside the areas designated by the surgical plan. Haptic systems attach the cutting tool to the end of the robotic arm, which then prevents the surgeon from moving outside the designated space. NAVIO employs a different principle, where the tool can be moved freely in space, but the cutting action is disabled when the tool is outside designated space (Figs. 26.15 and 26.16).
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FIGURE 26.16 NAVIO surgical screen depicting the locking features to be created on the patient’s bone with a color map.
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FIGURE 26.15 NAVIO handheld robotics using exposure control that retracts the bur in a safe guard once the depth and orientation of cut as per implant plan is reached on the anatomy.
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NAVIO supports two modes of robotic control. With spatial boundaries of bone preparation defined during planning, the handheld robotics disables the bone cutting when the cutting end moves outside the planned boundaries of bone preparation. In exposure control, the system prevents cutting by retracting an operational bur within a safe-physical guard, to prevent bone from being overcut. Alternatively, the bur can be used in a speed control mode, where once the bur is approaching the perimeters of cutting limits, the speed of the bur slows down to ultimately stop as the final required depth and orientation of cut planes are reached. For total knee replacement, the NAVIO system alternatively supports a hybrid approach, with the use of burs and saws for complete bone preparation. For unicompartmental knee replacement, the system uses the handheld roboticassisted bur for the entire bone preparation. The NAVIO system also supports bicruciate retaining TKA implants, where the femur can be prepared using a hybrid approach, while the tibia is completed using the robotics-assisted handpiece. In the case of total knee replacement, the robotic speed control mode is used to prepare locking features on the patient’s bone, to secure femur and tibia guides in positions consistent with the surgical plan. The use of robotics in total knee replacement is to allow for implementation of the implant placement plan, by precise placement of rigid, fixed cutting guides on the bone. When preparing the locking features on the bone, the handheld instrument ensures that the alignment and depth of feature preparation are controlled with the bur. This only allows a single accurate positional fixation of the cut guide on the bone, which then controls the position of the final cuts for the prosthesis (Fig. 26.17). In accordance with the implant placement plan, the robotic-assisted handpiece creates features on the patient’s bones that lock the cutting guides in place. The recommended saw blade thickness for the implant system is 1.35 mm. Utilizing crosshair visualization and tool’s eye view modes, the handpiece tool is aligned to the cut target and the bone preparation is executed under speed control. As the bur works to remove bone, the system provides live feedback visually by removing all of the colors on the virtual bone model until the target surface is reached. The bur automatically shuts off once the depth of preparation has been reached, or if the bur goes out of alignment. Once the locking features are prepared, the femoral distal cut guide is placed on the anterior features that have been prepared on the bone and its position is “locked” using the stabilized block. The distal cut guide assembly at this point is secured on the bone surface using 1/8v speed pins. Before engaging the saw, a virtual confirmation tool is used to assess the position of the cut guide, compared to the NAVIO plan. Using a recommended saw, the distal cut is executed on the patient’s bone. Based on the implant size plan, a NAVIO drill guide adapter is attached to the distal cut guide. This adapter ensures that the rotation of the anteroposterior (AP) cut block is set according to the implant plan made in NAVIO. Based on the femur implant size chosen in the plan, holes are drilled through the drill guide adapter. The appropriate AP cut guide is inserted in the drilled holes as per the planned implant size and pinned into position. The virtual confirmation tool can be used to ensure that the AP cut guide is placed in its intended position (Figs. 26.18 and 26.19). Similarly for the tibia, the robotics-assisted cutting tool is used to prepare features in order to lock the tibia cut guide onto the bone surface. Under speed control on the cut zone, the handpiece is aligned utilizing the crosshair and tool’s eye view. While engaging the drill foot pedal, the bur is slowly plunged into the bone surface until the system has removed all colors and the target surface is reached. Once the burred fixation feature depths are reached, the bur automatically shuts off, similar to the femur preparation. The tibia cut guide is placed on the prepared bone features and the position is confirmed with the virtual confirmation tool against the planned prosthesis position. The tibia cut guide is secured on the bone surface using 1/8v diameter headless speed pins. The saw is then engaged to complete the final tibial preparation. Once the cut is completed, the virtual confirmation tool can once again be used to gage the accuracy of the saw preparation. This tool can also be used before, as well as after sawing, to visualize the actual cut prepared. Handheld robotics can be used in case of any errors during saw cut execution, where there is bone left behind. Using exposure or speed control mode with the bur, cuts can be fine-tuned to achieve accurate execution to the prosthesis placement plan. For unicompartmental resections, the handheld robotics-assisted tool is used to completely prepare both the femur and tibia resections. For bicruciate-retaining tibia implants, similarly, the handheld tool is used to prepare bone in accordance with the plan (Fig. 26.20).
26.2.5
Trial reduction
After completing all bone cuts and adjustments to the final surfaces, the incision is cleaned and dried thoroughly. With appropriate-sized trial components, the leg is taken through its ROM, which displays the achieved balance of the knee,
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FIGURE 26.17 Hybrid total knee execution where handheld robotics prepares “locking” features on the patient anatomy, as per the surgical plan, and utilizes “locking” reusable cut guides for saw preparation of bone cuts.
26. NAVIO Surgical System FIGURE 26.18 Confirmation of saw cut before execution, in accordance to prosthesis plan.
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FIGURE 26.19 Hybrid total knee tibia execution where handheld robotics prepares “locking” features on patient anatomy, as per surgical plan, and utilizes “locking” reusable cut guides for saw preparation of bone cuts.
FIGURE 26.20 Robotic-assisted burring to fine tune saw cuts, in order to achieve cut accuracy for final implant placement.
against the virtual plan created by the system, before bone resections are made. Holding the leg in extension allows the surgeon to confirm the achieved long-leg mechanical alignment. A postop stressed gap assessment screen allows the user to assess the postop gap throughout flexion in both the medial and lateral compartments. After the dynamic ROM test, final preparation of the fixation features for the implantation of the final components is done by using appropriate instruments and tools. The NAVIO planning and bone removal stage can be easily accessed from this step, in the case of any needs for adjustment. The robotics-assisted bur can be utilized in the exposure or speed mode for recutting. The plan for the component can also be flexibly adjusted based on the trial postop evaluation, and the new bone cuts can be prepared robotically using the handheld bur, to get the desired balance in the joint. When the final results are acceptable per the dynamic ROM test, the NAVIO system is shut down and cleaned for use in the next surgical case.
26.2.6
Cement and close
To better anchor the cement, it is recommended to prepare additional anchor holes on both the tibia and femur. First, the bone should be prepared with pulse lavage and dried. Then, a thin layer of cement is applied to the inner surfaces of the components, and to the prepared bone surfaces. With the knee flexed, the tibial and femoral components are inserted and seated using appropriate tools. Excess cement is carefully removed after implant placement. Finally the bearing component is inserted, and the joint incision is closed.
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Conclusion
The NAVIO surgical system represents the next generation of robotics-assisted technology in orthopedics. It combines the benefits of CT-free anatomic localization and planning with the flexibility of handheld robotics. This approach optimizes the use of the surgeon’s skills, while maintaining the precision and accuracy required for knee orthopedics. For optimal outcome, the knee arthroplasty procedures require that soft-tissue considerations are taken into account during planning. The systems that rely on preoperative CT imaging often ignore this information in the interest of easier preoperative planning, or allow the plan to be modified based on the intraoperatively collected soft-tissue information. In addition, as CT scans do not image cartilage, the articulating surface cannot be accurately assessed from the CT image. NAVIO collects the bone landmarks and articulating surface information, as well as the ligament laxity and ROM information at the time of surgery, thus creating a reliable framework for planning. When compared to haptic technologies or active robotics, the concepts of minimizing the footprint with handheld smart instruments, combined with intraoperative CT-free planning and dynamic gap balancing, establish the NAVIO system as an ergonomic and efficient robotics-assisted solutions for orthopedic reconstruction.
References
Further reading Park SE, Lee CT. Comparison of robotic-assisted and conventional manual implantation of a primary total knee arthroplasty. J Arthroplasty 2007;22:1054 9. Lording T, Lustig S, Neyret P. Coronal alignment after total knee arthroplasty. EFORT Open Rev 2016;1:12 17. Available from: https://doi.org/ 10.1302/2058-5241.1.000002.
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[1] Kim YH, Kim JS, Kim DY. Clinical outcome and rate of complications after primary total knee replacement performed with quadricepssparing or standard arthrotomy. J Bone Joint Surg Br 2007;89:467 70. [2] Jackson G, Waldman BJ, Schaftel EA. Complications following quadriceps-sparing total knee arthroplasty. Orthopedics 2008;31:547. [3] Collier MB, Eickmann TH, Sukezaki F, et al. Patient, implant, and alignment factors associated with revision of medial compartment unicondylar arthroplasty. J Arthroplasty 2006;21(6 suppl 2):108 15. [4] Hernigou P, Deschamps G. Alignment influences wear in the knee after medial unicompartmental arthroplasty. Clin Orthop Relat Res 2004;423:161 5. [5] Fisher DA, Watts M, Davis KE. Implant position in knee surgery: a comparison of minimally invasive, open unicompartmental, and total knee arthroplasty. J Arthroplasty 2003;18(7 suppl 1):2 8. [6] Hamilton WG, Collier MB, Tarabee E, et al. Incidence and reasons for reoperation after minimally invasive unicompartmental knee arthroplasty. J Arthroplasty 2006;21(6 suppl 2):98 107. [7] Keene G, Simpson D, Kalairajah Y. Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br 2006;88:44 8. [8] Cobb J, Henckel J, Gomes P, et al. Hands-on robotic unicompartmental knee replacement: a prospective, randomized controlled study of the acrobot system. J Bone Joint Surg Br 2006;88:188 97. [9] Iorio R, Bolle G, Conteduca F, Valeo L. Accuracy of manual instrumentation of tibial cutting guide in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2013;21(10):2296 300. [10] Hamelynck KJ. History of TKR. 2012. ,https://www.scribd.com/document/200390981/01-Hamelynck-1.. [11] Lustig S. Unsatisfactory accuracy as determined by computer navigation of VISIONAIRE patient-specific instrumentation for total knee arthroplasty, 2012. J Arthroplasty 2013;28(3):469 73. [12] Bellemans J, Vandenneucker H, Vanlauwe J. Robot-assisted total knee arthroplasty. Clin Orthop Relat Res 2007;464:111 16. [13] Song EK, Seon JK, Yim JH, Netravali NA, Bargar WL. Robotic-assisted TKA reduces postoperative alignment outliers and improves gap balance compared to conventional TKA. Clin Orthop Relat Res 2013;471:118 26. [14] Borner M, Wiesel U, Ditzen W. Clinical experiences with robodoc and the duracon total knee. In: Stiehl JB, Konermann WH, Haaker RG, editors. Navigation and robotics in total joint and spine surgery. Berlin: Springer; 2004. p. 362 6. [15] Mai S, Lorke C, Siebert W. Clinical results with the robot-assisted Caspar system and the Search-Evolution Prosthesis. In: Stiehl JB, Konermann WH, Haaker RG, editors. Navigation and robotics in total joint and spine surgery. Berlin: Springer; 2004. p. 355 61. [16] Decking J, Theis C, Achenbach T, et al. Robotic total knee arthroplasty: the accuracy of CT-based component placement. Acta Orthop Scand 2004;75:573 9.
NAVIO Surgical System—Handheld Robotics Riddhit Mitra and Branislav Jaramaz Smith & Nephew, Pittsburgh, Pennsylvania, United States
ABSTRACT Robotics-assisted arthroplasty has gained increasing popularity as orthopedic surgeons aim to increase the accuracy and precision of implant positioning. With advances in computer-generated anatomy data through image-free data collection, surgeons have the ability to better predict and influence surgical outcomes. Based on planned implant position and soft-tissue considerations, robotics-assisted systems can provide surgeons with planning tools to make informed decisions for knee replacement specific to the needs of the patient and with intelligent tools to implement those decisions. This is achieved by customizing the surgical cuts rather than prosthesis designs, while staying within clinically acceptable boundaries. Postoperative alignment of knee implants has been shown to influence patient outcomes in terms of implant longevity and functionality. The use of robotics in orthopedic surgery has helped to minimize human error, and in turn reduce implant wear and theoretically lead to longer prosthesis survivorship. This chapter provides a framework for the surgical techniques for using the NAVIO surgical system to perform partial and total knee arthroplasty (TKA). The NAVIO system supports unicompartmental knee arthroplasty, patellofemoral knee arthroplasty, bicruciate retaining, cruciate-retaining or bicruciate sacrificing TKA. Handbook of Robotic and Image-Guided Surgery. DOI: https://doi.org/10.1016/B978-0-12-814245-5.00026-8 © 2020 Elsevier Inc. All rights reserved.
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26.1
Handbook of Robotic and Image-Guided Surgery
Introduction
Although conventional knee arthroplasty is considered a successful intervention for end-stage osteoarthritis, some patients still experience reduced functionality and require revision procedures, ranging from 4.9% to 19.6% over a 10-year period, for partial and total knee replacement [1,2]. Similarly, in the space of unicondylar or partial knee replacement, which is considered as a relevant option for younger, active patients with early stages of arthritis, successful results and durability of knee arthroplasty are affected by a variety of factors, including appropriate surgical indications, implant design, component alignment and fixation, and soft-tissue balance [3,4]. Accurate alignment of the tibial component using conventional techniques has been difficult to achieve [5 7]. Outliers beyond 2 degrees of the desired alignment may occur in as many as 40% 60% of cases using conventional methods, and the range of component alignment varies considerably, even in the hands of skilled knee surgeons [8]. Similarly, for total knee replacement outliers beyond 2 degrees of the desired alignment may occur in as many as 15% of cases in the coronal plane, going up to 40% of unsatisfactory alignment in the sagittal plane [9]. From the 1970s, designs of implants and instruments have evolved into two principal branches. Anatomic implant designs, which attempt to reconstruct the patient’s anatomy and preserve the cruciate ligaments, are limited by expensive manufacturing and challenging execution. On the other hand, functional designs, with a focus on measured resection and gap balancing techniques, attempt to restore joint function by optimizing the use of a serially produced implant design. While the implant designs are continually evolving, there is still room for improvement in achieving repeatable functional outcomes and natural proprioception. Modern implants tend to blend the two principles, where anatomic designs and a functional approach to resection are combined for improved functional outcomes. However, there still remains room for optimization by improving the precision of proper alignment and ligament balancing [10]. While navigation and patient-specific blocks have aimed to help in achievement of accuracy in alignment, studies have shown that 15% 20% of the cases may fall outside the range of 6 3 degrees of desired outcome [11]. Robotics-assisted systems have challenged traditional instruments as a method to decrease mechanical alignment outliers, optimize soft tissue balancing, and restore normal knee kinematics [12 15]. Robotics-assisted surgery has been available for nearly 25 years. Current robotics-assisted systems use various navigation principles augmented with the technology of robotic bone preparation, allowing the surgeon to conduct a UKA (unicompartmental knee arthroplasty) or TKA (total knee arthroplasty), based on preoperative 3D images or image-free intraoperative planning [16]. While most of the current robotics-assisted orthopedic cutting systems are autonomous robots or haptic arm-based instruments, NAVIO (Smith & Nephew, Pittsburgh, PA, United States), is a next-generation robotics-assisted system that uses handheld miniaturized robotics-assisted instrumentation that is freely moved by the surgeon but restricts the bone cutting within the confines of the designated resection area of the patient’s bone, and within the proper depth and orientation (Fig. 26.1).
26.2
The NAVIO surgical workflow
The following section provides an overview of the recommended techniques for using the NAVIO surgical system technology in clinical applications. The NAVIO surgical system is indicated for use in surgical knee procedures in which the use of stereotactic surgery may be appropriate, and where reference to rigid anatomical bony structures can be determined. The NAVIO technique description for knee replacement surgery is divided into the following steps: 1. Patient and system setup: This section covers the details of patient and system setup needed for a handheld roboticsassisted surgery. 2. Registration: The intraoperative registration steps to define anatomical and soft-tissue information for the system are explained in this section. 3. Prosthesis planning: This section captures the ability of the system to plan the implant on the defined patient’s anatomy based on registration. 4. Robotics-assisted bone cutting: The modes of robotic-assisted control and execution are defined in this section. 5. Trial reduction: Postbone preparation, implant trialing, and ligament balancing assessment are highlighted in this section. 6. Cement and close: This section defines the specifics of cementation and closing.
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26.2.1
Patient and system setup
The NAVIO computer system is positioned close to the operating table to allow the surgeon to easily interact with the system, while maintaining complete control of the procedure. In addition to the surgeon-controlled touch screen, the surgeon can navigate through the different stages of operation using foot-pedal controls. During setup, the NAVIO handheld robotic instrument is assembled and configured according to the surgeon’s preference with regard to the robotic mode of control. After incision, all peripheral osteophytes are removed, to reliably assess the patient’s anatomy as well as joint stability. For cruciate retaining (CR) or posterior stabilized designs, it is recommended to release the anterior and posterior cruciate ligament, respectively, depending on the design of the prosthesis component to be implanted, and the disease condition of the patient’s knee (Figs. 26.2 and 26.3).
26.2.1.1 Bone tracking hardware For attachment of tracking arrays to the femur and tibia, NAVIO utilizes a two-pin bicortical fixation system. To place the tibia tracker, the first bone screw is percutaneously placed inferior to the tibial tubercle on the medial side of the tibial crest, to avoid stress risers on the tibia bone. The bone screw should be drilled slowly into the tibia, perpendicular to the bony surface, stopping once the opposing cortex has been engaged. A tissue protector is used to mark the position of the second bone screw, inferior to the initial placement and the second screw is engaged with the bone. Similarly for the femur, the bone screws are percutaneously placed about four to five finger breadths superior to the patella. The femur and tibia tracker frames are clamped to these screws, and oriented with the reflective markers toward the camera,
26. NAVIO Surgical System
FIGURE 26.1 Handheld robotic-assisted tool and the NAVIO surgical system.
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FIGURE 26.2 Typical OR setups. OR, Operating room.
FIGURE 26.3 Bicortical engagement of bone screws for rigid fixation of tracking arrays.
to maximize the operative field of view. A camera orientation stage in the system guides the surgeon for best position of the camera and trackers, to allow manipulation of the patient’s leg through the range of motion (ROM), and ensure that the trackers stay visible throughout the surgical procedure. Small checkpoint pins are also placed in the femur and tibia. They are used throughout the procedure to determine if the bone tracking frames have moved, ensuring the system integrity throughout the procedure (Fig. 26.4).
26.2.2
Registration—image-free technology
The NAVIO surgical system does not require the use of any preoperative data, and the entire anatomy registration and planning workflow is performed intraoperatively (Fig. 26.5). NAVIO relies on image-free localization of anatomic landmarks and surface “painting” to construct a virtual representation of the patient’s anatomy. This step ensures that the true surface of the patient anatomy is captured, as the system registers the articulating surfaces and defects, for best assessment of prosthesis placement during planning. The first step in registration is to use the point probe to identify the most prominent points on the medial and lateral malleoli in order to register the ankle center. The next step, hip center calculation, follows the femoral tracker array through circular movements of the hip and calculates the center of rotation. The femur should be slowly pivoted at the hip until all sectors of the graphic on the screen have turned green. Then the leg is placed in full extension, applying a slight compressive force on the tibia, to calculate the patient’s varus/valgus deformity and capture any existing flexion contracture. This collection is followed by the preoperative knee motion collection step, which allows the user to record normal flexion motion. The leg is moved through a normal ROM to maximum flexion, while keeping the knee joint in contact, making sure to collect all possible sectors. Then, constant and consistent varus and/or valgus stress is applied
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FIGURE 26.4 Tibial tracker attachment on the patient’s bone, with the reflective markers facing the camera.
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FIGURE 26.5 Hip center collection of the patient’s anatomy to determine the center of the femoral head.
to the collateral ligaments to collect soft-tissue laxity data throughout the patient’s knee flexion. The system graphically depicts medial and/or lateral compartment space, depending on the surgery (uni or total). These data are used to identify how much laxity exists in the current soft-tissue structure. This information is unique to the patient and can be used during the planning stage. This allows the surgeon to plan for the best approach when it comes to bony resections and soft-tissue releases, with virtual implementation of anatomic or functional principles of bone preparation, before making any cuts (Figs. 26.6 and 26.7). With a focus on rigid anatomy next, the femoral condyle is registered using landmark points. Using the point probe, the surgeon collects the knee center that with the hip center determines the mechanical axis of the femur. Additional landmark points in the uni and TKA applications allow the surgeon to inform the NAVIO system of basic anatomy, with which the system can provide a starting selection of implant size and position. At this stage, the user further
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FIGURE 26.6 Patient ligament laxity collection, to assess medial and lateral joint space. This stage can be accessed before making cuts, as well as after bone cuts are made.
FIGURE 26.7 Image-free patient femur anatomy mapping.
digitizes the femoral condyle by moving the probe over the entire surface while holding down the foot pedal. In the total knee application the rotational reference of the femur or tibia can additionally be fine-tuned from the previously defined rotation axes (posterior condylar axis, or transepicondylar, or anterior posterior axis), in the free surface collection stage, giving the surgeons the flexibility to make the most informed decision, based on specific patient anatomy. Following successful femoral registration, tibial landmarks are collected, including the knee center which, in conjunction with the ankle center defines the mechanical axis. The last registration step, tibial condyle surface mapping, offers visualization of the mapped surface and previously collected tibial mechanical and landmark points. Similar to the femur, the rotational axis of the tibia can be fine-tuned by the surgeon at this stage, customizing it specific to the patient’s anatomy (Figs. 26.8 and 26.9).
26.2.3
Prosthesis planning
The implant planning stage provides the user a virtual reconstruction of the patient’s femoral and tibial anatomy, soft-tissue ligament tension, and joint balance. There are three stages during planning: (1) initial sizing and placement, (2) gap planning, and (3) cut guide placement. The surgeon has multiple options of visualizing the anatomy at this stage, with the choice of solid bone and implant graphics, or a “virtual” CT slice mode, called the cross-section view.
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FIGURE 26.8 Fine tuning of the rotational axis by taking into consideration transepicondylar axis, Whiteside’s line as well as posterior condylar axis, specific to the patient’s knee.
FIGURE 26.9 Image-free patient tibia anatomy mapping.
26. NAVIO Surgical System With coronal, transverse, and sagittal screens, the surgeon can assess the position of the implant components on the bone in all three dimensions. Using the cross-sections, the surgeon first confirms that the component size provides adequate coverage on the digitized femur bone surface. The transition of the implant component on the anatomy is verified and adjusted in the sagittal view screen, confirming good anterior posterior implant component fit and transition from bone to implant on the terminal edges. In order to assess size coverage, implant anterior transition, and the bone resection plan, the user can toggle on the virtual cut view mode to visualize the implant component on the bone surface. Rotation of the component on the anatomy is confirmed in the transverse view, while assessing diseased bone from the virtual reconstruction of the anatomy, compared to the build back due to the position of the implant. The coronal view is used to assess implant alignment and distal resection within the bounds of surgical principles when compared to the patient’s mechanical axis (Figs. 26.10 and 26.11).
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FIGURE 26.10 Initial femur implant planning with consideration of sizing and anatomical fit on the patient’s bone.
FIGURE 26.11 Initial tibia implant planning with consideration of sizing and anatomical fit on the patient’s bone. Image shows bicruciate retaining knee implant.
For the tibial component, the NAVIO software will attempt to provide a starting size and initial placement utilizing the landmarks and tibia “paint” collection. With similar view screens and options, the surgeon can assess the depth of resection and alignment, component rotation, and posterior slope with respect to the mechanical axis. The tibial component defaults to the thinnest poly insert, but thicker inserts can be selected by changing the poly component during the planning stages.
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The second stage of implant planning allows the user the ability to dial in soft-tissue laxity for the patient in extension and flexion based on the soft-tissue input from prior ligament balancing collection. There are four interactive views for translating and rotating the components with respect to the patient’s virtualized joint. The goal of this stage is to optimize extension and flexion laxity balance with no overlap (or tightness) in either medial or lateral condyle. The surgeon can choose to perform anterior cruciate ligament (ACL) release for a CR procedure, or ACL and posterior cruciate ligament release for a bicruciate sacrificing procedure, and collateral ligament release to recollect laxity information by clicking on the “Recollect Joint Laxity” button in order to augment what the joint space will actually look like after the bone cuts are made. The user can manipulate and fine tune the position and orientation of the implant components in this stage such that the resulting gaps are “balanced” in both extension and flexion. While the extension gaps are affected by changing distal femur resection, and varus/valgus cut adjustments within the bounds of acceptable surgical principles, balancing of the flexion gap in the medial and lateral compartments can be performed by rotating the femur component internally or externally. Adjustments to femoral component rotation should be carefully considered relative to prior parameters such as anterior notching for TKA, and implant fit on condyle, for a UKA. Adjustments to femoral flexion should also be considered against prior considerations regarding anterior fit and bone transition (Figs. 26.12 and 26.13).
FIGURE 26.13 Full range of motion ligament balance planning with the virtual components in place, before the bone cuts are performed for a UKA surgery. UKA, Unicompartmental knee arthroplasty.
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FIGURE 26.12 Ligament balance planning with the virtual components in place, before the bone cuts are performed. This stage can also be accessed after ligament releases or bone cuts for fine-tuning implant placement plan. Image shows bicruciate sacrificing implant.
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FIGURE 26.14 Full range of motion ligament balance planning with the virtual components in place, before the bone cuts are performed. This stage can also be accessed after ligament releases or bone cuts for fine-tuning implant placement plan. The image shows bicruciate retaining implant.
The NAVIO system also shows the full ROM laxity, based on the planned implant positions to assess mid-flexion stability and joint space. The above stage therefore gives the surgeon the ability to augment and virtually construct the patient’s final ligament balance based on bone resections, as well as soft-tissue laxity definitions. This ability allows the bone cuts to be customized for the patient, based on the prosthesis design, the soft-tissue balance, and the amount of bony resections for an informed surgical output as desired for the patient. Lastly, during the cut guide placement stage, the surgeon can fine tune the position of cut guides optimally on the specific patient anatomy. The femur cut guide is placed to ensure that all locking features on the femur cut guide assembly have purchase into the bone surface. Similarly locking features on the tibia cut guide assembly are confirmed to have purchase into the bone surface (Fig. 26.14).
26.2.4
Robotic-assisted bone cutting
In the area of orthopedic robotics, the robotic systems can be distinguished as active, semiactive, or passive. Active systems, such as TSolution One (THINK Surgical, Fremont, CA), are completely autonomous, where the cutting tool is free from human control and the robot completes the required bone cuts according to the plan. In the semiactive segment, the surgeon and the robotic tool share control over the operation, where the robotics is utilized for active action assistance and guidance during fine manipulations, while the surgeon is still in general control over the procedure. Examples of such systems are NAVIO (Smith and Nephew, Pittsburgh, PA) and Mako (Stryker, Kalamazoo, MI). Passive systems guide the surgeons with assistive information during the procedure (navigation systems) or may provide robotically controlled positioning tools (such as OMNIBotics, OMNIlife science, Inc., Raynham, MA), but do not perform any action. Semiactive robotics prevents the surgeon from cutting the bone outside the areas designated by the surgical plan. Haptic systems attach the cutting tool to the end of the robotic arm, which then prevents the surgeon from moving outside the designated space. NAVIO employs a different principle, where the tool can be moved freely in space, but the cutting action is disabled when the tool is outside designated space (Figs. 26.15 and 26.16).
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FIGURE 26.16 NAVIO surgical screen depicting the locking features to be created on the patient’s bone with a color map.
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FIGURE 26.15 NAVIO handheld robotics using exposure control that retracts the bur in a safe guard once the depth and orientation of cut as per implant plan is reached on the anatomy.
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NAVIO supports two modes of robotic control. With spatial boundaries of bone preparation defined during planning, the handheld robotics disables the bone cutting when the cutting end moves outside the planned boundaries of bone preparation. In exposure control, the system prevents cutting by retracting an operational bur within a safe-physical guard, to prevent bone from being overcut. Alternatively, the bur can be used in a speed control mode, where once the bur is approaching the perimeters of cutting limits, the speed of the bur slows down to ultimately stop as the final required depth and orientation of cut planes are reached. For total knee replacement, the NAVIO system alternatively supports a hybrid approach, with the use of burs and saws for complete bone preparation. For unicompartmental knee replacement, the system uses the handheld roboticassisted bur for the entire bone preparation. The NAVIO system also supports bicruciate retaining TKA implants, where the femur can be prepared using a hybrid approach, while the tibia is completed using the robotics-assisted handpiece. In the case of total knee replacement, the robotic speed control mode is used to prepare locking features on the patient’s bone, to secure femur and tibia guides in positions consistent with the surgical plan. The use of robotics in total knee replacement is to allow for implementation of the implant placement plan, by precise placement of rigid, fixed cutting guides on the bone. When preparing the locking features on the bone, the handheld instrument ensures that the alignment and depth of feature preparation are controlled with the bur. This only allows a single accurate positional fixation of the cut guide on the bone, which then controls the position of the final cuts for the prosthesis (Fig. 26.17). In accordance with the implant placement plan, the robotic-assisted handpiece creates features on the patient’s bones that lock the cutting guides in place. The recommended saw blade thickness for the implant system is 1.35 mm. Utilizing crosshair visualization and tool’s eye view modes, the handpiece tool is aligned to the cut target and the bone preparation is executed under speed control. As the bur works to remove bone, the system provides live feedback visually by removing all of the colors on the virtual bone model until the target surface is reached. The bur automatically shuts off once the depth of preparation has been reached, or if the bur goes out of alignment. Once the locking features are prepared, the femoral distal cut guide is placed on the anterior features that have been prepared on the bone and its position is “locked” using the stabilized block. The distal cut guide assembly at this point is secured on the bone surface using 1/8v speed pins. Before engaging the saw, a virtual confirmation tool is used to assess the position of the cut guide, compared to the NAVIO plan. Using a recommended saw, the distal cut is executed on the patient’s bone. Based on the implant size plan, a NAVIO drill guide adapter is attached to the distal cut guide. This adapter ensures that the rotation of the anteroposterior (AP) cut block is set according to the implant plan made in NAVIO. Based on the femur implant size chosen in the plan, holes are drilled through the drill guide adapter. The appropriate AP cut guide is inserted in the drilled holes as per the planned implant size and pinned into position. The virtual confirmation tool can be used to ensure that the AP cut guide is placed in its intended position (Figs. 26.18 and 26.19). Similarly for the tibia, the robotics-assisted cutting tool is used to prepare features in order to lock the tibia cut guide onto the bone surface. Under speed control on the cut zone, the handpiece is aligned utilizing the crosshair and tool’s eye view. While engaging the drill foot pedal, the bur is slowly plunged into the bone surface until the system has removed all colors and the target surface is reached. Once the burred fixation feature depths are reached, the bur automatically shuts off, similar to the femur preparation. The tibia cut guide is placed on the prepared bone features and the position is confirmed with the virtual confirmation tool against the planned prosthesis position. The tibia cut guide is secured on the bone surface using 1/8v diameter headless speed pins. The saw is then engaged to complete the final tibial preparation. Once the cut is completed, the virtual confirmation tool can once again be used to gage the accuracy of the saw preparation. This tool can also be used before, as well as after sawing, to visualize the actual cut prepared. Handheld robotics can be used in case of any errors during saw cut execution, where there is bone left behind. Using exposure or speed control mode with the bur, cuts can be fine-tuned to achieve accurate execution to the prosthesis placement plan. For unicompartmental resections, the handheld robotics-assisted tool is used to completely prepare both the femur and tibia resections. For bicruciate-retaining tibia implants, similarly, the handheld tool is used to prepare bone in accordance with the plan (Fig. 26.20).
26.2.5
Trial reduction
After completing all bone cuts and adjustments to the final surfaces, the incision is cleaned and dried thoroughly. With appropriate-sized trial components, the leg is taken through its ROM, which displays the achieved balance of the knee,
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FIGURE 26.17 Hybrid total knee execution where handheld robotics prepares “locking” features on the patient anatomy, as per the surgical plan, and utilizes “locking” reusable cut guides for saw preparation of bone cuts.
26. NAVIO Surgical System FIGURE 26.18 Confirmation of saw cut before execution, in accordance to prosthesis plan.
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FIGURE 26.19 Hybrid total knee tibia execution where handheld robotics prepares “locking” features on patient anatomy, as per surgical plan, and utilizes “locking” reusable cut guides for saw preparation of bone cuts.
FIGURE 26.20 Robotic-assisted burring to fine tune saw cuts, in order to achieve cut accuracy for final implant placement.
against the virtual plan created by the system, before bone resections are made. Holding the leg in extension allows the surgeon to confirm the achieved long-leg mechanical alignment. A postop stressed gap assessment screen allows the user to assess the postop gap throughout flexion in both the medial and lateral compartments. After the dynamic ROM test, final preparation of the fixation features for the implantation of the final components is done by using appropriate instruments and tools. The NAVIO planning and bone removal stage can be easily accessed from this step, in the case of any needs for adjustment. The robotics-assisted bur can be utilized in the exposure or speed mode for recutting. The plan for the component can also be flexibly adjusted based on the trial postop evaluation, and the new bone cuts can be prepared robotically using the handheld bur, to get the desired balance in the joint. When the final results are acceptable per the dynamic ROM test, the NAVIO system is shut down and cleaned for use in the next surgical case.
26.2.6
Cement and close
To better anchor the cement, it is recommended to prepare additional anchor holes on both the tibia and femur. First, the bone should be prepared with pulse lavage and dried. Then, a thin layer of cement is applied to the inner surfaces of the components, and to the prepared bone surfaces. With the knee flexed, the tibial and femoral components are inserted and seated using appropriate tools. Excess cement is carefully removed after implant placement. Finally the bearing component is inserted, and the joint incision is closed.
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Conclusion
The NAVIO surgical system represents the next generation of robotics-assisted technology in orthopedics. It combines the benefits of CT-free anatomic localization and planning with the flexibility of handheld robotics. This approach optimizes the use of the surgeon’s skills, while maintaining the precision and accuracy required for knee orthopedics. For optimal outcome, the knee arthroplasty procedures require that soft-tissue considerations are taken into account during planning. The systems that rely on preoperative CT imaging often ignore this information in the interest of easier preoperative planning, or allow the plan to be modified based on the intraoperatively collected soft-tissue information. In addition, as CT scans do not image cartilage, the articulating surface cannot be accurately assessed from the CT image. NAVIO collects the bone landmarks and articulating surface information, as well as the ligament laxity and ROM information at the time of surgery, thus creating a reliable framework for planning. When compared to haptic technologies or active robotics, the concepts of minimizing the footprint with handheld smart instruments, combined with intraoperative CT-free planning and dynamic gap balancing, establish the NAVIO system as an ergonomic and efficient robotics-assisted solutions for orthopedic reconstruction.
References
Further reading Park SE, Lee CT. Comparison of robotic-assisted and conventional manual implantation of a primary total knee arthroplasty. J Arthroplasty 2007;22:1054 9. Lording T, Lustig S, Neyret P. Coronal alignment after total knee arthroplasty. EFORT Open Rev 2016;1:12 17. Available from: https://doi.org/ 10.1302/2058-5241.1.000002.
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[1] Kim YH, Kim JS, Kim DY. Clinical outcome and rate of complications after primary total knee replacement performed with quadricepssparing or standard arthrotomy. J Bone Joint Surg Br 2007;89:467 70. [2] Jackson G, Waldman BJ, Schaftel EA. Complications following quadriceps-sparing total knee arthroplasty. Orthopedics 2008;31:547. [3] Collier MB, Eickmann TH, Sukezaki F, et al. Patient, implant, and alignment factors associated with revision of medial compartment unicondylar arthroplasty. J Arthroplasty 2006;21(6 suppl 2):108 15. [4] Hernigou P, Deschamps G. Alignment influences wear in the knee after medial unicompartmental arthroplasty. Clin Orthop Relat Res 2004;423:161 5. [5] Fisher DA, Watts M, Davis KE. Implant position in knee surgery: a comparison of minimally invasive, open unicompartmental, and total knee arthroplasty. J Arthroplasty 2003;18(7 suppl 1):2 8. [6] Hamilton WG, Collier MB, Tarabee E, et al. Incidence and reasons for reoperation after minimally invasive unicompartmental knee arthroplasty. J Arthroplasty 2006;21(6 suppl 2):98 107. [7] Keene G, Simpson D, Kalairajah Y. Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br 2006;88:44 8. [8] Cobb J, Henckel J, Gomes P, et al. Hands-on robotic unicompartmental knee replacement: a prospective, randomized controlled study of the acrobot system. J Bone Joint Surg Br 2006;88:188 97. [9] Iorio R, Bolle G, Conteduca F, Valeo L. Accuracy of manual instrumentation of tibial cutting guide in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2013;21(10):2296 300. [10] Hamelynck KJ. History of TKR. 2012. ,https://www.scribd.com/document/200390981/01-Hamelynck-1.. [11] Lustig S. Unsatisfactory accuracy as determined by computer navigation of VISIONAIRE patient-specific instrumentation for total knee arthroplasty, 2012. J Arthroplasty 2013;28(3):469 73. [12] Bellemans J, Vandenneucker H, Vanlauwe J. Robot-assisted total knee arthroplasty. Clin Orthop Relat Res 2007;464:111 16. [13] Song EK, Seon JK, Yim JH, Netravali NA, Bargar WL. Robotic-assisted TKA reduces postoperative alignment outliers and improves gap balance compared to conventional TKA. Clin Orthop Relat Res 2013;471:118 26. [14] Borner M, Wiesel U, Ditzen W. Clinical experiences with robodoc and the duracon total knee. In: Stiehl JB, Konermann WH, Haaker RG, editors. Navigation and robotics in total joint and spine surgery. Berlin: Springer; 2004. p. 362 6. [15] Mai S, Lorke C, Siebert W. Clinical results with the robot-assisted Caspar system and the Search-Evolution Prosthesis. In: Stiehl JB, Konermann WH, Haaker RG, editors. Navigation and robotics in total joint and spine surgery. Berlin: Springer; 2004. p. 355 61. [16] Decking J, Theis C, Achenbach T, et al. Robotic total knee arthroplasty: the accuracy of CT-based component placement. Acta Orthop Scand 2004;75:573 9.