Zimmer Biomet ORTHOsoft Knee 2.4 Universal User Manual Dec 2016

Table of Contents

System Overview...1 Indication for Use/Intended Use... 1 Training... 1 Implant Indications... 1 Contraindications... 1 Complications ... 1 Preoperative Guide...2 Application Launch... 2 OR Setup... 3 Intraoperative Guide... 3 Tracking System’s Volume... 3 Remote Control in the Sterile Field... 5 Assembling Markers... 5 Surgery Task Bar, Snapshot and Menu Buttons... 6 Surgeon Profile... 6 General Preferences... 7 Workflow... 8 Femur Preferences... 8 Tibia Preferences... 9 Targets... 9 Patient Information... 9 Calibration of the Navigated Instruments ... 9 Positioning of the Bone References ... 11 Digitization of the Bony Landmarks ... 11 Surgical Technique: Distal Cut First... 14 Surgical Technique: Anterior Cut First with Insall Gap Balancing Technique... 24 Postoperative Guide...29 Exiting the Application... 29 Case Data Manager... 29 Updating the System... 29 Update According to Regulatory Region... 29 Shut Down the Sesamoid Plasty Computer... 30 Ordering and Instrument Cleaning/Sterilization Information... 31 Instrument Inventory and Sterilization/Cleaning Methods... 31 Sterilization Parameters... 32 APPENDICES Appendix A - CAS Same Incision Trackers... 43 Appendix B - Posterior Referencing Instrumentation... 45 Appendix C - CAS Femoral Cut Alignment Guide used in Anterior Cut First... 48 Appendix D- CAS Independent Adjustment Mechanism Technique... 50 Appendix E - Universal Positioning Block Technique ... 53 Appendix F - Distal Cut Navigation with Natural-Knee II System... 57 Appendix G - Implant “Universal” - Anterior Cut First with Insall Gap Balancing Technique ... 58 General Information...Back Cover

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System Overview

Indication for Use/Intended Use

Contraindications

The ORTHOsoft Knee Universal System is indicated for use as a stereotaxic instrument to assist in the positioning of total knee replacement components intraoperatively.

Clinical

It is a computer controlled image-guidance system equipped with a three-dimensional tracking sub-system. It is intended to assist the surgeon in determining reference alignment axes in relation to anatomical landmarks, and in precisely positioning the alignment instruments relative to these axes by displaying their locations.

1. In the case of a hip pathology severely limiting its range of motion (e.g. arthrodesis, severe contractures, chronic severe dislocation);

Training Prior to use of the system, surgeons must follow a training given by Zimmer CAS or the application distributor. Warning: Zimmer CAS Surgical Navigation Systems should only be used by trained surgeons.

Implant Indications The knee implants installed with the system must be used in accordance with their package insert labeling. The operation should be performed in accordance with the corresponding surgical technique published by the manufacturer for the specific implant. The ORTHOsoft Knee Universal System is compatible with the femoral distal cut first and anterior cut first surgical techniques. Warning: The system should only be used with the instruments provided by Zimmer CAS or by the distributor for the given application.

Zimmer CAS Surgical Navigation System should not be used:

2. In the case of a hip joint pathology or knee pathology with significant bone loss (e.g. evascular necrosis of the femoral head with collapse, severe dysplasia of the femoral head or the acetabulum, femoral condyle collapse); and 3. For any other contraindicated case, as given by the implant manufacturer.

General Zimmer CAS Surgical Navigation System should not be used: 1. In the presence of strong infrared sources or infrared reflectors in the vicinity of the optical markers. This could cause interference with the Zimmer CAS Optical System and alter its performance; or 2. To perform surgery other than those specified in the surgical technique and the user guide.

Complications Possible complications associated with the use of the Zimmer CAS Surgical Navigation System may include, but are not limited to, the following: 1. Infection; and 2. Misplacement of the implants potentially leading to dislocation, impingement or leg length discrepancy. The occurrence of one of these complications may affect the patient’s mobility.

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Preoperative Guide

Application Launch Step 1: After turning on the Sesamoid Plasty Computer, press “ORTHOsoft TKA” and the Patient ID dialog box will launch. Step 2: To launch the application: a. Enter the desired information in the Patient ID dialog box and then click the “Continue” button; or b. Click on the “Skip” button. Warning: To comply with the US HIPAA regulation, this field should not contain any information that could identify the patient.

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Preoperative Guide (cont.)

Intraoperative Guide

OR Setup

Tracking System’s Volume

Given that the field of the optical tracking system is limited, appropriate positioning of the optical tracking equipment is crucial. A specific camera location must be selected to allow an unobstructed camera view of the operation field.

The ORTHOsoft Knee Universal Application supports three different types of the optical system volumes. An automatic detection is performed when the application is launched. The appropriate Volume viewer is selected according to the camera’s configuration, i.e. available tracking volumes and installed firmware.

An appropriate camera placement should allow for the calibration of instruments and the navigation to be carried out with a single rotation of the camera. This will facilitate handling during surgery.

The shape and dimensions of the three kinds of volumes, “Pyramid”, “Arc” and “Silo”, are shown in Figures 4.2 through 4.4.

The OR setup must be determined according to the side of the operated knee (left or right knee), the specifications of the optical system and the standard instrument setup. Special care should be taken to ensure that the femoral reference is seen during the entire kinematics process (for more details about the kinematics, refer to the Femoral Landmarks section (p. 12). Warning: Control of the line of sight is essential to the proper use of the optical tracking system. Refer to the Figure 4.1 for the correct camera placement. The exact camera position depends on the OR setup, the surgeon preferences and the position of the tracked instruments relative to the patient.

Figure 4.1 Environment and OR Setup

Figure 4.2 Tracking Area of the “Pyramid” Volume 1. Top View 2. Front View 3. Tracking Area

Figure 4.3 Tracking Area of the “Arc” Volume 1. Top View 2. Front View 3. Tracking Area

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1.

Figure 4.4 Tracking Area of the “Silo” Volume 1. Top View 2. Front View 3. Tracking Area

The optimal visibility of the optical markers can be controlled with the Volume viewer. Be careful not to have two instruments with the same marker in the camera’s field of view. All foreign objects should be removed from the path between the camera and the markers. The Volume viewer helps to aim the camera and to verify that all tracked instruments are inside the camera field before any calibration/navigation steps. The markers that are seen by the optical tracking system are displayed in the graphical representation of the camera field. The application displays an icon marked with the “No” symbol each time that an instrument needed to complete the task is outside of the camera volume. Two views of the Volume viewer are shown in Figure 4.5. The top view is used for the horizontal adjustment of the camera and the frontal view is used for the vertical adjustment. The grey area outlined in both views represents the optimal volume of the camera. It is recommended to position the markers within the grey area for the calibration of instruments. Warning: It is preferable to calibrate or navigate instruments in the central region of the volume (identified in grey in every Volume viewer), rather than on the outside edges of the volume.

2.

Figure 4.5 Volume Viewer 1. Pyramid Volume Viewer 2. Arc Volume Viewer 3. Silo Volume Viewer

3.

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Intraoperative Guide

Remote Control in the Sterile Field The system can be also controlled with the help of the CAS Registration Pointer, to activate the “Next” and “Previous” buttons. This feature allows navigation through the intraoperative procedure without user interaction with the screen or the mouse. The pointer tip placed on the femoral reference switches the “Next” button. The pointer tip placed on the tibial reference switches the “Previous” button. The implant size can be modified by touching the bone reference with the CAS Universal Offset Paddle. The tip of the CAS Universal Offset Paddle placed on the femoral reference switches the “Size Increment” button, whereas the CAS Universal Offset Paddle placed on the tibial reference switches the “Size Decrement” button. Through all navigation panels (except in Femoral and Tibial Landmarks panels), the snapshot can be triggered using the CAS Registration Pointer from the sterile field, by orienting the pointer’s tip upwards and respecting the stability criterion. In any landmarking task, orienting the pointer’s tip upwards and respecting the stability criterion will trigger activation of the Remote menu (Figure 4.7) for landmark reacquisition. This menu will provide the ability to choose any available landmark to reactivate. By tilting the pointer on one side or the other, as shown with the feedback needle in Figure 4.7, the focus of the selector will change accordingly. Once the focus is on the desired landmark to reactivate, holding the pointer upwards and stable, in the OK section, will trigger selection of the item.

Figure 4.7 Remote Menu

Assembling Markers The NavitrackER Markers must be installed on each instrument used for navigation. Push the marker onto the mounting studs until it is firmly seated (CAS NavitrackER Pliers can be used to facilitate the installation of the markers on the instruments). It is important to verify that the NavitrackER Markers remain clean throughout the surgery. Warning: Always minimize handling of the NavitrackER Markers, since errors may result from the non-uniform reflection of their surface. Warning: Always use unblemished markers. Warning: Always ensure that reflective NavitrackER Markers are firmly seated. Warning: The use of optical markers other than those provided by Zimmer CAS may lead to inaccuracies.

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Surgery Task Bar, Snapshot and Menu Buttons The Surgery Task bar shown in Figure 4.8 allows direct access to a specific panel. Icons featuring a thick white color frame and blue background color indicate the currently active panel. Icons featuring a thin blue color frame and black background color indicate that the surgery task is directly accessible. Greyed out icons indicate that the surgery task is inactive. Inactive surgery tasks become accessible once all preceeding surgery tasks have been completed. The number and order of the displayed surgery tasks depend on the chosen Surgeon Profile settings.

Figure 4.8 Surgery Task Bar

The “Snapshot” button allows to capture the screen display and save it to a file. The “Menu” button gives access to a menu which includes: a “Volume Viewer” button to verify the instruments tracked by the optical tracking system, a “Help” button that displays contextual help, an “Audio Volume” button to set the volume, a “Language” sub-menu to select the language of the user interface and a “Quit Application” button to exit the application.

Surgeon Profile The system uses the concept of profiles to store particular surgical preferences. Once a profile is created, it can be used to perform a surgery without specifying the preferences again. A list of the existing profiles is located on the left side of the Surgeon Profile panel. Three buttons are available to create (Create Profile), edit (Edit Profile) or permanently remove (Delete Profile) a selected profile. Each selected profile contains a list of preferences that are classified into the following categories: General, Workflow, Femur, Tibia and Targets.

Figure 4.9 Surgeon Profile

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Intraoperative Guide

General Preferences Implant This preference allows the surgeon to select the implant used in the total knee replacement surgery. The “Universal” choice can be selected to navigate only the distal femoral and proximal tibial cuts (orientation and resection levels) without navigating the femoral implant size selection, the axial rotation or the A/P position.

Pointer Type This preference allows the surgeon to select the type of the CAS Registration Pointer that will be used for navigation. The US pointer is the pointer manufactured by Zimmer CAS with part number 20-8000-070-01. The EU pointer is a pointer manufactured by Zimmer Biomet with part number 05.00017.310.

Show 30°–60° in ROM (Range of Motion) This option enables the 30 and 60 degrees of flexion indicators in the ROM panel in addition to the 0 and 90 Degrees of flexion indicators.

Positioning Instrument This preference allows the surgeon to select between two instruments for adjusting varus/valgus, flexion/ extension or tibial slope using femoral distal and tibial cutting guides. 1. CAS Universal Positioning Block (calibration is required) Warning: The spring of the CAS Universal Positioning Block should not be bent with pliers. Doing so could damage the instrument.

• If a 1.27 mm or thicker cutting block slot thickness (closed cutting block) is used to perform the cuts, the CAS Universal Offset Paddle 1.27 mm (P/N 108.116) should be used to navigate the cutting planes. In the Surgeon Profile settings, the selection for the Cutting Slot Thickness preference must be equal to the thickness of the saw slot used to perform the cuts even if thicker than 1.27 mm. • If the cutting blocks have no integrated cutting slots (open cutting block), the CAS Universal Magnetic Offset Paddle (P/N 108.117) could be used to navigate the cutting planes. In the Surgeon Profile settings, “No Cutting Slot” must be selected as the Cutting Slot Thickness. Warning: Make sure the appropriate Cutting Slot Thickness is selected for the saw slot of the cutting block. Warning: The CAS Universal Magnetic Offset Paddle must not be used with cutting guide having a saw capture (closed cutting block). Warning: Whenever using a CAS Universal Offset Paddle or the CAS Universal Positioning Block, ensure the blade is fully inserted in the slot to be navigated.

Cutting Slot Thickness

Warning: The MIS Innex A/P Cutting Guide* should be used with the CAS Universal Magnetic Offset Paddle placed against the lower portion of the cutting saw slot. The 1.00 or 1.27 mm CAS Universal Offset Paddles should not be used with the MIS Innex A/P Cutting Guide* and its saw capture which presents offsets.

This preference allows the surgeon to select the appropriate slot thickness. If the cutting blocks have saw guide slots, the surgeon must choose between the 1.00, 1.27, 1.35 or 1.45 mm thickness in accordance with the thickness of the slot used for the tibial and femoral cuts.

Warning: The standard Innex A/P Cutting Guide* should be used only with the 1.00 or 1.27 mm CAS Universal Offset Paddles because the shoulder is too narrow for it to provide stable support for the CAS Universal Magnetic Offset Paddle.

• If a 1.00 mm cutting block slot thickness (closed cutting block) is used to perform the cuts, the CAS Universal Offset Paddle 1.00 mm (P/N 108.115) should be used to navigate the cutting planes. In the Surgeon Profile settings, 1.00 mm must be selected as the Cutting Slot Thickness.

Warning: For the insertion of the CAS Universal Offset Paddle (1.00 mm or 1.27 mm) in the slot of the cutting block, avoid recessed holes since the instrument could remain trapped.

2. CAS Universal Offset Paddle (calibration is not required)

*Innex Implant not available in the US

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Workflow

Femur Preferences

First Cut

Compute Distal Resection Level

This preference allows the surgeon to select the preferred surgical technique starting with the anterior cut first (AC 1st) or distal cut first (DC 1st).

This preference enables navigation of the distal resection level that requires digitization of the femoral distal condyles.

Surgical Flow

Compute Posterior Resection Level

This preference allows the surgeon to select the surgical flow for the surgery. The femur can be navigated first or the tibia.

This preference enables navigation of the posterior resection level on the Femur Rotation Navigation panel or the Anterior Cut Navigation panel.

Perform Initial ROM

Distal Condyles Acquisition Method

This option enables the preoperative Range of Motion (ROM) panel. It can be used to help evaluate the flexion contracture and the varus/valgus deformity at different flexion angles.

This preference allows the surgeon to select the preferred method for digitization of the distal femoral condyles. The product supports two methods: acquisition of multiple points or digitization with the CAS Universal Validation Tool.

Enable Femur Rotation Panel (DC 1st) This option enables the Femoral Rotation panel in the distal cut first sequence. This panel allows selecting the implant size, set the Anterior/Posterior position and the axial rotation of the implant.

Gap Balancing Technique This option allows the selection of the preferred ligament balancing technique. The supported techniques are Insall Gap Balancing and Soft Tissue Balancing. Insall Gap Balancing is only available when the Femoral Rotation panel is enabled.

Navigate CAS Tensor This preference allows the surgeon to use the CAS Tensor for ligament balancing and placement of the femoral component. The CAS Tensor is only available when performing Insall Gap Balancing.

Enable Varus/Valgus Panel (AC 1st) This option enables the Varus/Valgus Adjustment panel that is used to set the desired varus/valgus of the cutting block.

Compute A/P Axis of Rotation This preference triggers the application to display the femoral rotation angle with respect to Whiteside’s line on the distal femur, as digitized by the user. If enabled, the A/P axis and rotation angle based on the Whiteside’s line will be displayed in the Femur Rotation Navigation panel or the Anterior Cut Navigation panel.

Compute Epicondylar Axis Rotation This preference triggers the acquisition of two landmarks on the medial and lateral femoral epicondyles. If enabled, the femoral rotation angle, based on the line between the two epicondyles, will be displayed in the Femur Rotation Navigation panel or the Anterior Cut Navigation panel.

Compute M/L Size This option enables computation of the M/L sizing. The suggested M/L size of the implant will be displayed in the Femur Rotation Navigation panel and Anterior Cut Navigation panel. For Gender Solutions® Implant families, the M/L sizing suggestion will provide information on the appropriate implant type (male or female) among the selected implant size. An M/L sizing suggestion displayed in red means that the smallest implant size is too wide in comparison to the digitized femur.

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Intraoperative Guide

Tibia Preferences

Patient Information

Compute Resection Level

The Patient Information panel allows selection of the operative side. Click the “L” icon for a left knee or the “R” icon for a right knee (Figure 4.11). The selected operative side is highlighted in blue.

This preference enables the navigation of the resection level that requires the acquisition of two points on the tibial condyles.

Axial Acquisition Method This preference allows the surgeon to select the preferred method for axial acquisition. The product supports two methods: acquisition of PCL-tubercle or acquisition of the relative position of the femur and tibia when the knee is flexed at 90 degrees (refer to the Tibial Landmarks section (p.13) for more details).

Warning: Make sure that the correct patient side is selected before starting the navigation.

Show Natural Varus/Valgus This preference triggers the calculation of the natural varus/valgus angle. If enabled, the natural varus/valgus angle will be displayed in the Tibia Navigation panel. The natural varus/valgus angle is the varus/valgus orientation of the intact tibial plateau as defined by the medial and lateral points digitized on the tibia.

Show Rotational Angles This preference enables the display of the axial rotation angles in the Tibia Navigation panel.

Compute Post. Plateau Rotation This preference triggers the calculation of the rotation angle with respect to the points acquired on the medial and lateral posterior plateau of the tibia. If enabled, the posterior plateau rotation angle will be displayed in the Tibia Navigation panel.

Targets Distal Resection Level This preference sets the targeted resection level of the distal cut in the Femur Navigation panel.

Implant Distal Cut Angle This preference is available only when the “Universal” implant is navigated in the Anterior Cut First sequence. This option is required to pre-set the targeted implant distal cut angle (flexion/extension).

Tibia Posterior Slope This preference sets the targeted posterior slope of the tibial cut in the Tibia Navigation panel.

Tibia Resection Level This preference sets the targeted resection level of the tibia cut in the Tibia Navigation panel.

Figure 4.11 Patient Information

Calibration of the Navigated Instruments Note: The following instruments can be calibrated while the patient is being prepared in order to minimize the time of the surgery: Warning: Verify that the tools are in good condition to perform the operation. If you notice any signs of bending, fatigue or deterioration, do not use the application and contact technical support. Warning: Avoid placement of markers on both sides of the CAS Universal Validation Tool Body.

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US and EU CAS Registration Pointer

CAS Universal Positioning Block

The instructions related to the pointer calibration procedure are illustrated in Figure 4.12.

The instructions related to the CAS Universal Positioning Block Calibration procedure are illustrated in Figure 4.13.

Figure 4.12 CAS Registration Pointer Calibration

Figure 4.13 CAS Universal Positioning Block Calibration

1. Attach the size 4 NavitrackER Marker on the side of the CAS Universal Validation Tool Body that will face the camera.

1. Attach NavitrackER Markers, sizes 2 and 9, to the CAS Universal Positioning Block.

2. Attach the CAS Short Posterior Condyles Digitizer (with the applicable drill guide) or the CAS Posterior/Distal Condyles Digitizer to the CAS Universal Validation Tool Body and secure the locking mechanism.

2. Insert the CAS Universal Positioning Block into the CAS Universal Validation Tool Body. Make sure it is fully entered into the slot to the shoulder limit.

3. Place the assembly on the CAS Calibration Star Holder.

3. Orient optical markers towards the camera and secure the rotational tracker (if applicable).

4. Insert the CAS Registration Pointer in the CAS Universal Validation Tool Body and tighten the wing screw.

4. Position the assembly in the optimal part of the camera volume (grey zone).

5. Make sure that the tip of CAS Registration Pointer is in contact with the base of the pointer hole.

5. Successful calibration will be confirmed by a check mark and a sound.

Warning: Make sure that the tip of the CAS Registration Pointer is in contact with the base of the pointer hole. If not, calibration of the pointer may be inaccurate and lead to inaccurate positioning of the implant. 6. Position the assembly in the optimal part of the camera volume (grey zone). 7. Successful calibration will be confirmed by a check mark and a sound.

Warning: Whenever using the CAS Universal Offset Paddle or the CAS Universal Positioning Block, ensure the blade is fully inserted in the slot to be navigated with the blade’s shoulder against the edge of the slot.

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Intraoperative Guide

Positioning of the Bone References

Digitization of the Bony Landmarks

The bone references are used to track the patient’s femur and tibia and show the navigated instruments in relation to their respective positions.

Digitization of the bony landmarks is required to display the relevant information in the navigation panels. This system allows automatic registration of points using a stability criterion with the pointer. An initial movement of the instrument is first required to initialize the registration of the points. Confirmation sounds are played to advise the user that a point has been acquired successfully or unsuccessfully.

Warning: Bone references MUST be firmly attached to the bone and MUST NOT move at any moment during surgery. In the case of a bone reference has moved, the landmarks digitized on that bone must be digitized again. Warning: Beware that muscle fibers may apply bending forces on the pins. Warning: Make sure that the pins are not positioned close to the bone cuts. Placing the pins close to the bone cuts location will increase the risk of breaking the pins with the cutting tools.

Femoral Reference In order to install the femoral reference, use two CAS Fix Pin Fluted or pins of equivalent type (Steinmann). The pins can be inserted percutaneously through the vastus medialis in the femur, as proximal as possible, to stay clear of the working area. The pins should be set bicortically in the bone to ensure maximum stability. However, when an intramedullary rod is used, place the pins in the distal part of the femur to avoid interference between the pins and the rod. Warning: Be alert to the risk of causing damage to the saphenous artery and vein, femoral artery and vein, or the popliteal artery and vein while installing the bone reference.

Tibial Reference Two CAS Fix Pin Fluted are used to install the tibial reference. To obtain a non-obstructed working area, the pins are inserted percutaneously into the medial surface of the tibial diaphysis at approximately mid-tibia. They should be set bi-cortically to ensure maximal stability in the bone. In cases where an intramedullary rod is used, place the pins in the proximal part of the tibia to avoid interference between the pins and the rod. If a keeled implant is used and the pins are placed more proximally, ensure that the pins are not placed in an area of interference with the keel. Impact with the keel or its broaching instruments can cause breakage of the pins as well as movement of the reference, which could result in inaccuracies.

Furthermore, two points may not be digitized at the same location. Therefore a minimal displacement of 5 mm is required between two points.

Exceptions 1. The posterior tibia and healthy plateau points on the same M/L side can be digitized at the same position, as well as the distal femoral condylar points and the M/L landmarks. Also, no proximity criterion is applied between the mechanical tibial entry point and the PCL entry point. 2. The minimum distance between the femur mechanical entry point and the A/P trochlear groove points is 3 mm. 3. A minimal distance of 20 mm must be observed between two points used to create an axis (e.g. epicondylar axis, tibial tubercle-PCL axis, etc.).

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Femoral Landmarks Successful digitization of the femoral landmarks enables the Femur Navigation panels.

Femoral Head Detection of the femoral head center is performed by recording 14 static positions of the leg. For each acquired point, the leg should be stabilized until a confirmation sound is played. The points should be taken in a large conical pattern with respect to the femoral reference. If a non-recommended pattern such as two unique positions in flexion/extension or a small cone is performed, the center of rotation algorithm will reject the result. As a result, a pop-up will appear asking the user to redo the acquisition (Figure 4.14). If a center was already acquired and accepted, the user will be asked to retry or keep the previous accepted center of the femoral head.

Warning: To ensure an accurate detection of the center of the femoral head, cover a wide circle with the leg when completing the process.

Mechanical Axis Entry Point The entry point of the mechanical axis is defined as the deepest point of the intercondylar notch.1 It is recommended to determine the desired entry point on a preoperative radiograph and compare it with the intraoperative location in situ. Together with the femoral head, the entry point forms the femoral mechanical axis that is used as the main axis of the femoral coordinate system. The varus/valgus, flexion/extension and rotation values are computed relative to the mechanical axis.

Anterior Cortex Points These points are digitized on the anterior cortex and are then used for the sizing of the femur and to gage notching. Three points have to be acquired along the femoral mechanical axis. The length between each of the three points should be 2–2.5 cm, totaling approximately 4–5 cm between the first and last point. Warning: If the digitization of the anterior cortex is done on the extension of the lateral condyle, the implant sizing suggestion will be over-estimated.

Epicondylar Axis (Optional) The epicondylar axis is used for the femoral rotational alignment. It is determined according to the digitization of the medial and lateral epicondyles. Figure 4.14 Failure of the Center of Rotation Algorithm

The pelvis and the optical camera must remain stable during the whole process to obtain a good level of accuracy. The minimum distance between each position is 20 mm. The algorithm automatically validates the kinematics. Femoral head detection is a crucial process that will influence the end result of the surgery. The contraindications for the femoral head detection are hip pathologies severely limiting its range of motion (e.g. arthritis and hip dysplasia). In order to verify the contraindications, place the femur in internal rotation and verify that the hip does not move during the kinematics procedure. Warning: The pelvis and the optical camera must remain immobile during the whole femoral head digitization process to ensure system accuracy.

M/L (Optional) The two points are digitized on the medial and lateral edges of the femoral distal condyles. Then the M/L sizing of the femoral component is suggested based on the digitized points.

A/P Axis (Optional) The A/P axis is also used for the femoral rotational alignment. It is determined according to the digitization of a point right above the femoral notch and a second one in the deepest section of the trochlea. References 1. Oswald MH et al. (1993). Radiological analysis of normal axial alignment of femur and tibia in view of total knee arthroplasty. J Arthroplasty. Aug;8(4): 419-26.

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Intraoperative Guide

Femoral Landmarks (cont.) Distal Condyles

Posterior Condyles

These points are digitized on the distal femoral condyles. They are used to compute the distal resection level that is displayed in the Distal Cut Navigation panel.

The most posterior points of the femoral condyles are digitized using the CAS Universal Validation Tool Body with the CAS Posterior Condyles Digitizer. Depending on the curvature of the distal femur in sagittal view, a slight flexion should be set before digitization of the points. During acquisition, verify that the CAS Posterior Condyles Digitizer is in contact with both posterior condyles. If proper contact is not achieved, sizing problems and rotational misalignment might occur.

Multiple Points Method One of the methods to digitize the distal femoral condyles is to acquire multiple points (six points) with the CAS Registration Pointer. Warning: Care must be taken not to penetrate through the cartilage with the pointer tip. Warning: Final results depend on the accurate acquisition of landmarks. For accurate depth results, ensure that distal condyles are digitized most distally with respect to the distal cut, taking into account the flexion of the cut.

CAS Universal Validation Tool Body Method The distal femoral condyles can also be acquired with the CAS Universal Validation Tool Body. Refer to Figure 4.15 for the detailed instruction.

Tibial Landmarks Successful digitization of the tibial landmarks enables the Tibia Navigation panel.

Mechanical Axis Entry Point The entry point is identified as the entrance point of the intramedullary canal. This point should be centered along medial/lateral axis. A/P positioning should fall between the middle and one-third of the anterior edge of the tibial plateau.

Healthy Plateau Points (Optional) The resection level displayed in the Tibia Cut Navigation panel is computed with two points digitized on healthy areas of the medial and lateral plateau of the tibia. Warning: Care must be taken not to penetrate through the cartilage with the pointer tip. Avoid damaged areas. Warning: Whenever the digitization of a healthy plateau is not possible, either due to spatial limitation in the incision or due to specific anatomical issues, register the inaccessible plateau on the anterior distal tibia. The resection level from that side will not be displayed, which will prevent confusion in the tibial resection levels.

Figure 4.15 Acquisition of the Distal Femoral Condyles with CAS Universal Validation Tool Body

1. Position the CAS Universal Validation Tool Body such that the edge of the instrument is in contact with the referenced (e.g. healthy) distal condyle. 2. Adjust flexion/extension and varus/valgus angles of the instrument to the target angles of the distal femoral cut. 3. Stabilize the instrument.

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Tibial Landmarks (cont.)

Surgical Technique: Distal Cut First

Axial Acquisition Method Tubercle - PCL

This technique can be applied to NexGen Complete Knee Solution, Persona® Knee Implants, Vanguard® Complete Knee System* or Natural-Knee System Implants. The workflow for cutting the distal femur first is as follows:

The neutral rotation is defined by a point in the middle of the PCL insertion area on the tibial plateau and one on the medial third of the tibial tuberosity. This axis should lie perpendicular to the posterior edges of the proximal tibia.

Flexion Acquisition In digitizing the A/P axis of the tibia, an acquisition in flexion can be used to transfer the alignment of the femoral mechanical axis to the tibial coordinate system. It must be noted that an initial movement of the leg is first required to initialize the acquisition in flexion. On average, this rotational axis option is aligned with the posterior aspect of the tibial plateau, which could differ from the tubercule-PCL alignment.

1. Initial Range of Motion 2. Tibial Cut Navigation 3. Distal Cut Navigation 4. Femoral Rotation Navigation (anterior cut) 5. Postoperative Range of Motion The sequence of tibia or femur first is user selectable in the Surgeon Profile panel settings. Warning: During ligament balancing procedure do not apply excessive stress to the knee joint compartments in order to avoid permanent damage to the ligaments.

Initial Range of Motion (ROM) The initial Range of Motion panel can be used to evaluate the preoperative flexion contracture and the varus/ valgus (V/V) deformity. The panel is shown in Figure 4.17. Figure 4.16 Flexion Acquisition

Warning: Care should be taken to avoid any torsion of the tibia during acquisition with the leg in flexion, i.e. aligning the unstressed foot forward (neutral rotation).

Posterior Plateau (Optional) The posterior plane rotation angle displayed in the Tibia Navigation panel is based on these two points. They must be digitized on the posterior limit of both the medial and lateral plateaus.

Figure 4.17 ROM Panel

Ankle points In order to recreate the mechanical axis of the tibia, two points are digitized on the medial and the lateral malleolus. The varus/valgus, flexion/extension and rotation values are computed relative to the mechanical axis.

*Vanguard XP not supported

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Intraoperative Guide

Initial Range of Motion (cont.) The varus/valgus (HKA) angle is displayed under the Left viewer that displays the lower limb alignment in an A/P view. The flexion angle is displayed under the Right viewer, which displays a sagittal view of the lower limb alignment. An initial movement of the leg is required first to initialize the procedure. Then, evaluate the varus/valgus stability in full extension (0 degrees of flexion) by applying medial and lateral stresses to the knee joint to assess the amount of passive correction obtainable. The amount of varus/valgus can be also assessed at 30 degrees, 60 degrees and 90 degrees of flexion. The maximum varus/valgus angle values are recorded in the indicators for each of the four angles of flexion (0 degrees, 30 degrees, 60 degrees and 90 degrees). During the ROM procedure, the application will switch automatically from one indicator to another as the user goes to each flexion angle. In addition, the “Clear All” button is available to reset the indicators and restart the ROM procedure.

Figure 4.18 Installation and use of the CAS Universal Offset Paddle

1. Place the standard extramedullary jig on the tibia. 2. Fix the jig on the tibial plateau. 3. Slide the CAS Universal Offset Paddle and navigate the tibial cut. 4. Insert pins through the cutting guide to the bone.

Tibial Cut Navigation The purpose of the Tibia Navigation panel is to assist the surgeon to perform the desired tibial proximal resection. This panel allows the positioning of the tibial cutting guide with respect to the tibial mechanical axis and adjustment of the resection level. The panel consists of three subtasks: Navigate Bone Fixation (only for CAS Universal Positioning Block Instrumentation, refer to Appendix E on page 53 for more details), Navigate Cutting Block, and Tibial Cut Validation. Warning: Make sure to use the appropriate CAS Universal Offset Paddle for the Cutting Block Navigation. The paddle used should be the selected from one of the preferences. Use of the wrong CAS Universal Offset Paddle could lead to resection level inaccuracies. Warning: The CAS Universal Offset Paddle is compatible with standard cutting blocks that have cutting slots or planar surfaces for cut alignment. The use of a CAS Universal Offset Paddle with any incompatible cutting block could lead to inaccuracies.

5. Remove the extramedullary jig to perform the tibial cut.

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Tibial Cut Navigation (cont.) Navigate Cutting Block

Tibial Cut Validation

The intent of the Navigate Cutting Block subtask is to set the appropriate orientation of the standard tibial cutting guide with respect to the mechanical tibial axis. In the panel, the medial and lateral Resection Level indicators are displayed under the Frontal viewer. Note that if a plateau was inaccessible and registered on the recommended anterior distal tibia, the resection level from that side will not be shown. The Posterior Slope indicator is displayed under the Lateral viewer. In addition, the varus/valgus and axial rotation angles of the navigated cutting guide are located in between the two viewers. In order to navigate and position the tibial cutting guide, refer to Figure 4.19 for the detailed instructions.

The purpose of the tibial cut validation is to verify if the tibial resection was achieved as desired. It is mainly used to inspect the orientation and, if needed, introduce the necessary corrections to the tibial cut. In order to validate the tibial resection, refer to Figure 4.20 for the detailed instructions.

Figure 4.20 Tibial Cut Validation

1. Attach the CAS Short Posterior Condyles Digitizer (with the applicable drill guide) or the CAS Posterior and Distal Condyles Digitizer to the CAS Universal Validation Tool Body. Figure 4.19 Navigate Cutting Block

1. Use the extramedullary instruments (from the standard instrumentation system) to adjust varus/ valgus, posterior slope and the resection level. 2. Secure the position of the tibial cutting guide with the drive pins. 3. Remove the extramedullary assembly. 4. Perform the tibial resection with the help of the positioned tibial cutting guide. Warning: The CAS Universal Offset Paddle should not be used as a lever arm to correct the cutting block orientation. Doing so could bend the tip of the instrument and result in inaccurate measurements

for all subsequent navigated surgeries.

2. Place the CAS Universal Validation Tool Body on the tibial cut. 3. Stabilize the instrument to acquire the varus/valgus, posterior slope and resection level of the cut. 4. Verify the values and introduce the corrections if needed. 5. To restart the Tibial Cut Validation subtask move the CAS Universal Validation Tool Body in the camera volume.

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Intraoperative Guide

Distal Cut Navigation The intent of the Distal Cut Navigation panel is to assist the surgeon to perform the desired femoral distal resection. This panel is designed to allow accurate positioning of the distal cutting guide with respect to the femoral mechanical axis, adjustment the resection level of the cut, and estimation of the implant size. The panel consists of three subtasks: Navigate Bone Fixation (only for CAS Universal Positioning Block Instrumentation; refer to page 53 of Appendix E for more details), Navigate Cutting Block, and Distal Cut Validation.

2. It is recommended to add some extension during insertion of the spike to counter the common tendency of inserting with excess flexion. Only gross spike alignment is necessary since the adjustment mechanism allows for a fine adjustment of 30 degrees in extension and 15 degrees in flexion.

Instrument Setup In distal cut first, follow these steps to align the cutting guide as desired. 1. Assemble the CAS Distal First Spike with the CAS Extractor Adaptor, making sure the rotation limiting pin is properly aligned, as shown in Figure 4.21. Pierce the cortex at the mechanical axis entry point with a cortex breaker or a 3.2 mm drill bit (only a few millimeters in depth). Align the CAS Extractor Adaptor Arm in the anterior direction (along the Whiteside’s line). Impact the spike into the distal femur, as shown in Figure 4.21. Do not impact deeper than the end of the four blades on the spike.

Figure 4.22 Insertion of the Spike in Proper Flexion

Warning: Make sure the spike is stable before performing manipulations relative to the next steps. 3. In order to save time and ease intraoperative manipulations, the scrub nurse should align the varus/valgus (green screw) and the flexion/extension (AO fitting) at zero degrees as a starting point. Loosening the rotation locking lever (yellow) prior to installation will ease manipulations. See Figure 4.23.

Figure 4.21 Installation of the CAS Distal First Spike

Figure 4.23 Adjust the CAS Femoral Cut Alignment Guide.

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Distal Cut Navigation (cont.) 4. Assemble the CAS Mini Cutting Block 1.27 mm to the CAS Distal Cutting Block Platform using the CAS Cutting Block Screw and slide the assembly in the main alignment guide, as shown in Figure 4.24. The cutting guide can be positioned in three locations (medial, lateral, or centered). It is suggested to use the center position, but particular circumstances and patient conditions may require using another position per surgeon preference.

Navigate Cutting Block The intent of the Navigate Cutting Block subtask is to set the appropriate orientation of the cutting guide with respect to the femoral mechanical axis. In the panel, the angles of varus/valgus and flexion/extension of the navigated cutting block are displayed under the Frontal and Lateral viewers. In addition, the resection level and the suggested size of the implant are displayed in the indicators that are located between the two viewers. In order to navigate and position the distal femoral cutting guide, refer to Figures 4.26, 4.27 and 4.28 for the detailed instructions. 6. After releasing the T-handle, adjust the flexion/ extension angle and lock it in desired position by tightening that same T-handle.

Figure 4.24 Assembly of the CAS Mini Cutting Block 1.27 mm with the CAS Distal Cutting Block Platform.

5. Slide the complete assembly on the inserted spike.

Figure 4.26 Locking the Flexion/Extension Adjustment

7. Adjust varus/valgus angle by pressing on the “V-V” fork and releasing it in the desired position, as shown in Figure 4.28. Using the green screws, on both medial and lateral sides, finely adjust the varus/ valgus angle either by hand or using a screwdriver. 8. Adjust distal resection to the desired value by rotating the blue wheel on the distal platform, as shown in Figure 4.28. Figure 4.25 Assembly Fixed on the Femur

Warning: Using the CAS Universal Offset Paddle 1.0 mm in the CAS Mini Cutting Block 1.27 mm can be permitted if the thumb screw is tightened slightly more than usually to remove the free-play in the cutting slot. Warning: The CAS Mini Cutting Block 1.27 mm can be disassembled from the CAS Distal Cutting Block Platform if the user unscrews the CAS Cutting Block Screw (108.089.06) too much.