Design Rationale

Next generation robotics and state-of-the-art planning software placed in the hands of skilled surgeons

Supporting healthcare professionals

1 NAVIO Design Rationale

Device descriptionThe Smith & Nephew NAVIO™ Surgical System is a surgical planning, navigation, and intra-operative visualization system combined with a hand-held, smart instrument for bone sculpting. The NAVIO Surgical System aids the surgeon in planning and executing a procedure involving bone preparation for unicondylar knee replacement (UKR), patellofemoral arthroplasty (PFA), and total knee arthroplasty (TKA) procedures.1,2

The system is comprised of computer-assisted surgical instrument control, a commercially available surgical drill, image-free navigation, and planning software with standard navigation technology. The NAVIO Surgical System software consists of a patient and user management module, a surgical planner, and an intraoperative cutting module. The NAVIO Surgical System uses the tracked position of the surgical bur to control its cutting engagement to the bone that is intended to be removed. This cutting control is based on the bur’s proximity to the planned target surface of the bone.3

The camera cart communicates the relative position of the handpiece (cutting tool), the femur, and the tibia (via rigid tracker arrays) to the computer cart, which runs algorithms that control the handpiece. The NAVIO foot pedal is offered as an alternate to the touchscreen monitor to progress through the procedure or when data points are collected, and the Anspach foot pedal controls the Anspach drill.

The NAVIO Surgical System incorporates a detailed user interface that provides procedure setup, tracking status, visual indicators, and real-time cutting progress during the procedure.1,2

The patient’s bone is prepared according to an intraoperative plan that combines soft-tissue and anatomic information with controlled bone removal and predictable long-leg alignment.1

The NAVIO Instrument set consists of a two-level tray that contains all of the required instrumentation for a NAVIO-assisted surgery, such as a robotic-controlled NAVIO handpiece, Anspach power drill, interchangeable guards, tracker arrays, tissue protector, bone tracker hardware and clamps, a Z-retractor and a rasp that has a flat and rounded rasping surface.1,2

The NAVIO TKA application requires one additional instrument set that contains NAVIO reusable cut guides, a Plan Visualization Tool, and JOURNEY™ II, LEGION™, and GENESIS™ II drill guides.

The NAVIO Surgical System devices contain no medicinal substances, tissues, or blood products.

NAVIO Design Rationale 2

Robotics-assisted technologiesBeyond CAS a robotic component was added approximately 20 years ago for use in knee arthroplasty procedures to perform more precise bone cuts and alignment with the goal to restore normal kinematics.13,14,15 Some early robotic systems were considered to be overly complex, especially when placing fiduciary markers. Systems came at a high cost, surgical times were extensive, and reported safety concerns of autonomous units resulted in some systems being removed from use.13 Haptic feedback and autonomous or semi-autonomous controllers allows the surgeon to make the ultimate decision but adds accuracy in implant positioning and soft tissue balancing of the knee, especially for more challenging unicompartmental knee replacement (UKR) procedures.13,16

For total and partial knee replacement, robotic systems help surgeons avoid errors, decrease variability, and establish more natural kinematics.15,17,18,19 Studies have reported robotics to restore ideal neutral mechanical axis in 97% of TKAs, to achieve better accuracy and increase efficiency of bone resections in all planes than what was achieved by conventional CAS.15 When used in UKA procedures robotics reported short learning curves, increased accuracy in posterior tibial slope and coronal tibial alignment in comparison to other alignment methods.15

Robotic systems include passive, semi-active, and active systems13 with a robotic arm, robotic guided cutting jigs, and robotic milling systems. Robotic-assisted technology requires only a small learning curve.

The NAVIO™ Surgical System combines key features of a CAS System, handheld robotics, and patient-specific planning.

Visualization of real-time bone sculpting with minimal bone loss due to inaccuracies and dynamic ligament balancing, improved radiographic outcomes, and reduced mechanical axis malalignment.13,20

Studies have demonstrated that the minimal learning curve of robotic technology quickly enables less experienced surgeons to achieve reproducible and accurate alignment and successful clinical outcomes equivalent to those obtained by surgeons with vast experience.21 Operative times using robotic assistance after a few initial cases are expected to decrease without impact on surgical efficiency.18

Conventional instrumentsRestoration of the neutral mechanical axis to the lower limb via arthroplasty has traditionally used manual instruments to guide placement of the implant and determine where to resect bone in reference to anatomical landmarks.4 Manual instruments include alignment rods that are intra- or extra-medullary that centralize and align the components according to the surgical plan.4

Intramedullary and extramedullary alignment guides lack precision, are not tailored to each patient’s individual morphology, and can result in inadvertent deviations from the surgical plan. Inaccurate alignment has been reported to occur in cases where convention manual instrumentation was used in approximately 30% of TKAs5,6,7 and 40% to 60% of compartment arthroplasties.8

Mechanical malalignment >3° has been reported in more than 10% of TKAs equating to higher risk of increased wear, poor function, early loosening, and decreased survivorship.9

Computer-assisted navigationComputer-assisted navigation systems (CAS) are intended to intraoperatively improve alignment, component positioning, and ligament balancing to enhance patient satisfaction, implant survival, and functional outcomes.9,10,7

In addition to more precise alignment and implant positioning, CAS can improve surgical outcomes including ligament gap measuring throughout range of motion with more accurate balancing of the flexion space which can reduce component rotation errors.11,12

Cons of intraoperative computer assistance include increased operative time, a higher associated cost for navigation equipment, exposure to radiation for imaging (e.g. CT, fluoroscopy), and the system can be difficult to learn.

The history of robotics

3 NAVIO Design Rationale

Summary• Based on meta-analysis computer navigation has been

shown to obtain more accurate mechanical alignment with few outliers, better short term functional outcomes, and fewer complaints than conventional instruments in TKA and UKA.22,23

• Robotic navigation systems have also demonstrated similar ability to consistently restore mechanical alignment more precisely than conventional instruments but with the added benefit of providing perioperative feedback to the surgeon. Meta-analysis has reported computer navigation including robotic systems to provide more accurate alignment (i.e. mechanical axis, coronal femoral, femoral flexion, tibial slope, and femoral component rotation)over CONV6,23,24

The next generation of robotics: NAVIO Surgical SystemConfidence of handheld robotics

The NAVIO handpiece accurately removes bone identified by the surgeon approved, patient-specific plan25

The surgical plan is enforced with two types of robotic control modes, Exposure Control and Speed Control. The surgeon can alternate between these two cutting control modes or can disable both control modes and operate the NAVIO Surgical System as a standard navigated drill.

2

4

56

3

1

1 Handpiece

2 Tracking array

3 Infrared reflective disks

4 High speed internal drill

5 Interchangeable guard

6 Cutting bur

The history of robotics (continued)

Exposure ControlExposure Control adjusts the bur’s exposure with respect to a guard. If the surgeon encroaches on a portion of bone that is not to be cut, the NAVIO Surgical System retracts the spinning bur behind the guard, disabling cutting. The NAVIO Surgical System software adjusts the depth of the cut by adjusting the exposure of the bur outside of the guard.

During Exposure Control, the bur spins at full power (80,000 rpm), regardless of exposure level.

Speed ControlSpeed Control regulates the speed of the bur, from 0 to 80,000 rpm, depending on its position. The control mode limits the speed of the spinning bur or disables bur motion entirely if the target surface has been reached. Bur motion is also disabled if the bur is moved outside of planned cutting boundaries.

NAVIO Design Rationale 4

The NAVIO TKA application also has a Bur All feature. • Bur All allows the surgeon to forgo the use of cut guides

and prepares the bone surface using the robotic-assisted bur. Bur All is the same method of bone removal as the UKR and PFA applications.

• The Bur All feature also provides a way to refine the bone model and make additional fine cuts if adjustments need to be made

− Modification of bone cuts for varus/valgus, slope, and resection level can be made in 0.5mm and 0.5° increments

Total kneesThe NAVIO™ Surgical System uses a hybrid approach for complete bone preparation, with the combined use of burs and saws. The robotic-assisted bur is used to prepare the femur and tibia bone surfaces to receive NAVIO specific cut guides which guide a surgical saw in bone removal.

Workflow for tibia bone preparation (Left: tibia cut guide; Right: twin peg tibia cut guide)

Workflow for femur bone preparation using cut guides

Refine tibia

Bur All for the tibia

Partial kneesBone removal is completed exclusively using the cutting modes of the robotics-assisted handheld bur.

5 NAVIO Design Rationale

Image-free navigation

Flat markers• Single-use, sterile disposable infrared reflective disks

used as part of the NAVIO™ system to provide optical tracking performance

• The NAVIO system’s infrared tracking camera is used to determine the position of the point probe and the surgical bur tip, and track their movement by scanning the position of reflective trackers relative to the position of trackers mounted on the patient’s femur and tibia.

Tracking arrayNAVIO uses a two-pin bicortical fixation system to fix tracking arrays to the femur and tibia. Flat Markers are secured to the tracking arrays to relay position information to the computer cart with the assistance of the infrared camera.

Infrared cameraThe mobile infrared tracking camera is used to determine the position of the point probe and the surgical bur tip and track their movement by scanning the position of reflective trackers relative to the position of trackers mounted on the patient’s femur and tibia.

NAVIO Design Rationale 6

NAVIO™ Cart

The mobile cart contains the touchscreen monitor, electronic control system, electrical system integration unit, computer, and uninterruptible power supply (UPS). The cart provides storage for the power cord, Anspach® drill foot control, and the NAVIO system foot control.

Surgeon controlled with with foot pedal or through the touch screen• Touch screen monitor

− The touchscreen monitor is the primary user interface for the NAVIO system

• Foot control pedals

− Anspach® Drill Foot Control The Anspach drill foot control is used to control the Anspach drill during surgery, however the speed of the drill is controlled by the NAVIO Surgical System

− NAVIO System Foot Control The NAVIO system foot control is used as an alternative to the touchscreen monitor when data points are being collected to define landmarks, shape bone, and position the implant prior to surgery

Portability• Easily move the cart from OR to OR or facility to facility, providing

flexibility and efficiencies

• Featuring simple calibration and a footprint designed for use in the surgery center or hospital, NAVIO can easily support the demand for efficiency needed by orthopaedic programs

Small footprint

Camera Cart

Camera Cart

Computer Cart

Computer Cart

Monitor

Monitor

Left knee OR setup

Right knee OR setup

7 NAVIO Design Rationale

Trays

NAVIO™ Instrument KitThe NAVIO instrument kit consists of a two-level tray that contains required instrumentation for total knee, unicondylar knee, and patellofemoral joint replacement surgery using the NAVIO Surgical System.

NAVIO Total Knee Instrument KitThe NAVIO total knee instrument kit is a single-level tray that contains required instrumentation for total knee replacement using the NAVIO Surgical System. NAVIO-specific drill guides pair with existing AP cut blocks from the JOURNEY™ II, GENESIS™ II, and LEGION™ manual instrument sets.

Small PartsSterilization Case

Point Probe

T-Handle Wrench

Anspach® eMAX® 2 Plus Handpiece

Z Knee Retractor

Tissue Protector

Bone Screw Driver

Long Attachment

Tracker Array Clamps (2)

Guards

Handpiece Tracker Array

Fomon Rasp Tibia Tracker Array

Handpiece

Femur Tracker Array

Femur Distal Cut Guides (Small, Medium, Large)

JOURNEY™ II Femur Drill Guide

LEGION™/GENESIS™ IIFemur Drill Guide

Femur CutAdapter

Plane Vizualization Tool

Twin Peg Tibia Cut Guides, Left and Right

Femur Stabilizers (Small, Medium, Large)

Tibia Cut Guides, Left and Right (Small, Medium)

NAVIO Design Rationale 8

CT-free registration

A 3D model of the patient’s cartilage and bone is captured through direct surface mappingThe NAVIO™ Surgical System does this without requiring a CT scan and allows surgeons, staff and patients the experience of a patient-specific plan without the extra steps associated preoperative imaging that can increase cost or delay surgery

Total and unicompartmental knees• Limb alignment and soft tissue laxity are collected to assist

the surgeon during implant component placement

Surgeon controlled, patient-specific planning

Component placement is planned virtually using cross-section and three dimensional surface views

Total and unicompartmental knees:• Registration information allows the surgeon to virtually

place implant components and predict postoperative joint laxity at the time of surgery without being locked into a plan before verifying the severity of the disease

State-of-the-art planning software

• Planned implant position is combined with ligament laxity information under varus/valgus stress through full range of motion to calculate postoperative joint balance

9 NAVIO Design Rationale

Bone preparationPatented NAVIO™ handheld burring technology removes only the bone determined by the surgeon plan.

• Bone removal is seen on the NAVIO screen in real-time allowing the surgeon to continually assess patient anatomy against the plan.

ConfirmationTotal knee replacement and unicompartmental knee replacement

• Postoperative range of motion is evaluated by collecting alignment data while moving the leg through flexion/extension

• Varus/valgus balance is assessed to confirm the achieved long-leg alignment

In total knee replacement, a Plane Visualization Tool confirms the plane of the cut, depth of the bone resection, and rotation of the components are consistent with the surgeon’s plan

Multiple implant supportNAVIO™ provides the accuracy from robotics-assistance as well as the flexibility of multiple pioneering implant designs for partial and total knees to accommodate surgeon and patient needs.

Surgeons must assess patients as they are and utilize the best tools at their disposal to treat them.

STRIDE ZUK UNIJOURNEY UNI JOURNEY PFJ JOURNEY II CR GENESIS II PS/CR LEGION PRIMARY BCS/CR

JOURNEY II XR*JOURNEY II BCS JOURNEY II CR

NAVIO supports the JOURNEY™ II Total Knee System. The anatomical shape of JOURNEY II TKA is designed to reproduce normal knee kinematics and thereby delivers improved functional outcomes and high patient satisfaction26–31.

Components made with OXINIUM™ alloy, an advanced material shown to be 4,900 times more resistant to abrasion32, more than twice as hard33, and has a coefficient of friction that is up to half that of CoCr34

Supports STRIDE UNI, designed to be optimized for robotics

Offers a selection of implant options with a strong clinical heritage including ZUK UNI35, GENESIS™ II36 and LEGION™ Primary37-39

*NAVIO with JOURNEY II XR not available for commercial use until 2018

www.smith-nephew.comSmith & Nephew, Inc.2905 Northwest Blvd., Suite 40Plymouth, MN 55441 USA

™Trademark of Smith & Nephew.

©2018 Smith & Nephew, Inc.All rights reserved.10229 V1 04/18

Supporting healthcare professionals for over 150 years

The information presented herein is solely for informational and educational purposes. Smith & Nephew does not provide medical advice. This information is not intended to serve as medical advice. For detailed device information, including indications for use, contraindications, effects, precautions and warnings, please consult the product’s Instructions for Use prior to use. Promotion and advertising of Smith & Nephew products is to be on-label and consistent with authorized indications and intended uses as stated in the product’s Instructions for Use.

References:1. 500075 Rev. B - NAVIO Surgical System for Total Knee Arthroplasty User’s Manual. 2. 500084, Rev B - NAVIO Surgical System for Unicondylar Knee Replacement and Patellofemoral Arthroplasty User’s Manual. 3. NAVIO TKA Risk Analysis - RF0011, Rev. M. 4. Pastides P, Nathwani D. The role of newer technologies in knee arthroplasty. Orthopaedics and Trauma. 2// 2017;31(1):47-52. 5. Fu H, Wang J, Zhou S, et al. No difference in mechanical alignment and femoral component placement between patient-specific instrumentation and conventional instrumentation in TKA. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA. Jun 11 2014. 6. Cheng T, Zhao S, Peng X, Zhang X. Does computer-assisted surgery improve postoperative leg alignment and implant positioning following total knee arthroplasty? A meta-analysis of randomized controlled trials? Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA. Jul 2012;20(7):1307-1322. 7. Goradia VK. Computer-assisted and robotic surgery in orthopedics: Where we are in 2014. Sports Medicine and Arthroscopy Review. 2014;22(4):202-205. 8. Nair R, Tripathy G, Deysine GR. Computer navigation systems in unicompartmental knee arthroplasty: a systematic review. Am J Orthop (Belle Mead NJ). Jun 2014;43(6):256-261. 9. Clayton AW, Cherian JJ, Banerjee S, et al. Does the use of navigation in total knee arthroplasty affect outcomes? The journal of knee surgery. Jun 2014;27(3):171-175. 10. Venkatesan M, Mahadevan D, Ashford RU. Computer-assisted navigation in knee arthroplasty: a critical appraisal. The journal of knee surgery. Oct 2013;26(5):357-361. 11. Stiehl JB, Heck DA. How precise is computer-navigated gap assessment in TKA? Clinical orthopaedics and related research. Jan 2015;473(1):115-118. 12. Stiehl JB. Femoral and tibial malrotation in total knee arthroplasty: Causes and cures. Seminars inArthroplasty. 6// 2015;26(2):73-79. 13. Banerjee S, Cherian JJ, Elmallah RK, Jauregui JJ, Pierce TP, Mont MA. Robotic-assisted knee arthroplasty. Expert review of medical devices. 2015;12(6):727-735. 14. Hill C, El-Bash R, Johnson L, Coustasse A. Robotic joint replacement surgery: does technology improve outcomes? The health care manager. Apr-Jun 2015;34(2):128-136. 15. Jacofsky DJ, Allen M. Robotics in Arthroplasty: A Comprehensive Review. The Journal of arthroplasty. Oct 2016;31(10):2353-2363. 16. Shaner J, Ko LM, Lonner J. Handheld Robotics for Unicompartmental Knee Arthroplasty. 2016. 17. Lonner JH. Robotically Assisted Unicompartmental Knee Arthroplasty with a Handheld Image-Free Sculpting Tool. Orthopedic Clinics of North America. 2016;47(1):29-40. 18. Roche M. Robotic-assisted Unicompartmental Knee Arthroplasty. The MAKO Experience. Orthopedic Clinics of North America. 2015;46(1):125-131. 19. Lonner JH, Moretti VM. The Evolution of Image-Free Robotic Assistance in Unicompartmental Knee Arthroplasty. American journal of orthopedics (Belle Mead, N.J.). May-Jun 2016;45(4):249-254. 20. Tamam C, Poehling GG. Robotic-assisted unicompartmental knee arthroplasty. Sports Medicine and Arthroscopy Review. 2014;22(4):219-222. 21. Augart MA, Plate JF, Bracey DN, Jinnah A, Poehling GG, Jinnah RH. Robotic Lateral and Medial Unicompartmental Knee Arthroplasty. Operative Techniques in Orthopaedics. 6// 2015;25(2):95-103. 22. Shi J, Wei Y, Wang S, et al. Computer navigation and total knee arthroplasty. Orthopedics. 2014;37(1):e39-e43. 23. Rebal BA, Babatunde OM, Lee JH, Geller JA, Patrick DA, Jr., Macaulay W. Imageless computer navigation in total knee arthroplasty provides superior short term functional outcomes: a meta-analysis. The Journal of arthroplasty. May 2014;29(5):938-944. 24. Hetaimish BM, Khan MM, Simunovic N, Al-Harbi HH, Bhandari M, Zalzal PK. Meta-analysis of navigation vs conventional total knee arthroplasty. The Journal of arthroplasty. Jun 2012;27(6):1177-1182. 25. Lonner J., Smith J., et al., High Degree of Accuracy of a Novel Image-free Handheld Robot for Unicondylar Knee Arthroplasty in a Cadaveric Study. Clin Orthop Relat Res 2014 Jul 8. Epub 2014 Jul 8. 26. Phil Noble et al; Does total knee replacement restore normal knee function? 2005; CORR. (431): 157-65. 27. Scott CE, Howie CR, MacDonald D, Biant LC; Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br. 2010 Sep;92(9). 28. Short-term Range of Motion is Increased after TKA with an asymmetric bicruciate stabilized implant. Accepted Poster Presentation, AAOS 2018 New Orleans. Kaitlin M. Carroll, Peter K. Sculco, Brian Michaels,Richard L. Murphy, Seth A, Jerabek, David J. Mayman. 29. J Orthop. 2017 Jan 7;14(1):201-206. doi: 10.1016/j.jor.2016.12.005. eCollection 2017. Bi-cruciate substituting total knee arthroplasty improved medio-lateral instability in mid-flexion range. 30. In Vivo Kinematic Comparison of a Bicruciate Stabilized Total Knee Arthroplasty and the Normal Knee Using Fluoroscopy Trevor F. Grieco, MS a, *, Adrija Sharma, PhD a, Garett M. Dessinger, BS a, Harold E. Cates, MD b, Richard D. Komistek, PhD. The Journal of Arthroplasty, September 2017 https://doi.org/10.1016/j.arth.2017.09.035. 31. A comparison of Rolback Ratio between Bicruciate Substituting Total Knee Arthroplasty and Oxford Unicompartmental Knee Arthroplasty. DOI: 10.1055/s-0037-1604445. ISSN 1538-8506. The Journal of Knee Surgery. Takanori Iriuchishima, Keinosuke Ryu. 32. Hunter, G., and Long, M. Abrasive Wear of Oxidized Zr-2.5Nb, CoCrMo, and Ti-6Al-4V Against Bone Cement. 6th World Biomaterials Cong. Trans., Society for Biomaterials, Minneapolis, MN, 2000, p. 835. 33. Long, M., Riester, L., and Hunter, G. Nano-Hardness Measurements of Oxidized Zr-2.5Nb and Various Orthopaedic Materials. Trans. Soc. Biomaterials, 21, 1998, p. 528. 34. Poggie RA, Wert J, Mishra A, et al (1992). Friction and wear characterization of UHMWPE in reciprocating sliding contact with Co-Cr, Ti-6Al-4V, and zirconia implant bearing surfaces. Wear and Friction of Elastomers, Denton R and Keshavan MK, Eds., West Conshohocken, PA: ASTM International. 35. Australian Orthopaedic Association National Joint Replacement Registry. Annual Report. Adelaide:AOA; 2015 36. McCalden RW, Hart GP, MacDonald SJ, Naudie DD, Howard JH, Bourne RB, Clinical Results and Survivorship of the Genesis II Total Knee Arthroplasty at a Minimum of 15 Years, The Journal of Arthroplasty (2017), doi: 10.1016/j.arth.2017.02.006. 37. LEGION™ Primary Knee System: A Prospective, Multi-Center, Non-Randomized, Safety and Efficacy Clinical Study of the LEGION Primary Knee System for Primary Total Knee Replacement in Subjects with Degenerative Knee Disease. 10-K300-95301, 29 April 2014. Version 1.0. 38. 2016 UK National Joint Registry. Figure 3.16 (a). Page 100. 39. Smith & Nephew Literature: 02961 V2 LEGION Clinical Heritage Brochure 03/17.