P. F. C. Sigma RP Knee System surgical technique

Transcription

1 P. F. C. Sigma RP Knee System surgical technique

2 I N T E L L I G E N T O R T H O P A E D I C S

3 Contents Ci System Connections 2 Ci System Set-up 4 Start-up Procedure 5 Ci Menu Buttons 6 Ci Procedure Set-up 8 Incision & Exposure 10 Tibial & Femoral Array Positioning 12 Tibial & Femoral Array Fixation 14 Camera Alignment 15 Calculating the Femoral Head Center 16 Pointer Tips 17 Definition of the Malleoli 18 Definition of the Tibial Mechanical Axis 19 Tibial Sizing 20 Tibial A/P Direction 21 Tibial Modeling 22 Tibial Plateau Modeling 23 Tibial Model Calculation and Verification 24 Femoral Mechanical Axis 25 Registration of Epicondyles 26 Registration of the Anterior Cortex 27 Whiteside s Line 28 Femoral Condyle Modeling 29 Anterior Cortex Modeling 30 Femoral Model Calculation and Verification 31 Initial Leg Alignment 32 Definition of the Anatomic Axis 33 Tibial Resection Setting 34 Tibial Implant Planning 34 Tibial Resection (standard jig) 37 Tibial Resection Verification (standard jig) 39 Tibial Resection (optional jig) 40 Tibial Resection Verification (optional jig) 43 Alignment Settings 44 Ligament Balancing 44 Femoral Implant Planning 47 Femoral Preparation 50 Distal Femoral Resection Navigation 52 Distal Femoral Resection 54 Distal Femoral Resection Verification 54 A/P Femoral Resection Navigation 56 A/P Femoral Resection 58 A/P Femoral Resection Verification 58 Femoral Notch Cut 60 Patellar Resection 61 Tibial Plateau Preparation 63 Central Stem Preparation 64 MBT Tray Preparation 66 Trial Reduction 67 Final Component Implantation 70 Final Flexion & Extension Checks 72 TKR Manual Technique 73 Tibial Resection (standard jig) 73 Tibial Resection (optional jig) 77 Femoral Preparation 83 Conservative Distal Femoral Resection 87 Ligament Balancing 90 A / P Femoral Resection 91 Final Distal Femoral Resection 93 1

4 Ci System Connections Ci Unit Connections Connecting the Ci System 1. Power switch (on / off) 2. Power lead connection 3. Currency switch All cables are connected to a panel at the The power switch is positioned below the The standard 3-pin power lead connects The red H-shape switch adjusts the rear of the Ci unit. All power cables and power socket. A green light indicates when to the power socket. power supply between 110 volts and 220 connectors are supplied with the system. the unit is switched on. volts. Make sure that the correct voltage is selected before switching on the system. 2

5 Power lead Camera cable Camera unit cable 1 Camera unit cable 2 Earth / ground connection 4. Earth / ground lead connection 5. Camera unit connection Important: The camera must be switched Please refer to the System User Guide The earth / ground socket is identified by The orange colored camera cable plugs on at least 20 minutes prior to the start of (Art-No: EN) for detailed the standard yellow and green colors. into the camera unit socket (also marked the procedure. set-up instructions. The system must be earthed / grounded using the cable supplied before switching on the system. in orange). The cable pins are aligned before inserting the cable. The cable is removed by pulling smoothly and slowly to avoid damaging the pins. Connections on the camera unit should also be checked at this stage. Note: The Ci instrumentation (tibial jig assembly, femoral clamp and fine-tune mechanism) must be coated with a medical grade lubricant prior to surgery. 3

6 Ci System Set-up Ci Unit Surgeon Assistant Surgeon O.R. Nurse O.R. Nurse Ci Unit Assistant Camera Unit Camera Unit Option 1: Ci System opposite surgeon Option 2: Ci System next to surgeon Positioning the Ci System in the O.R. Ideally the infrared camera unit has an If the Ci unit is positioned within the Please refer to the System User Guide The Ci unit should be positioned so that uninterrupted view of the tibial and femoral sterile field it must be covered using the (Art-No: EN) for detailed the surgeon has a clear view of the screen. marker arrays throughout a full range of sterile drape supplied. set-up instructions. The touch-screen should be within easy reach of the surgeon or surgical assistant. motion (knee flexion, extension and pivoting of the hip joint). The camera unit should be positioned between 4 and 6 feet (1.5 and 2 meters) away from the surgical site. Unstable stands or tables should not be used for placement of the Ci unit (see ordering information for Ci unit cart). 4

7 Start-up Procedure Figure 1 Figure 2 Figure 3 All cables must be fully connected before Once the power supply has been switched If the camera unit is not properly The start-up screens allow the user to switching on the system. on, the Ci software will automatically connected, no beeps will be heard and configure network and video settings initialize (Figure 1). an error message will appear asking you if required (Figure 3). Two beeps indicate that the camera unit to restart the system (Figure 2). A blank CD-R (not CD-RW) should be is properly connected. inserted into the Ci unit to allow any patient data to be stored. 5

8 Ci Menu Buttons 1. Status Field red / orange / green Green: Normal tracking mode Yellow: Ci instrument not visible to camera Red: Ci instrument and / or navigation array not visible to camera for more than 3 seconds Pressing on this button brings up the camera field of view screen. This will show the position of all visible navigated instruments in the field of view. 2. Information Button Provides information on the application, version number, phone hotline numbers and website 3. Zoom In Zooms in on the morphed bone model 4. Zoom Out Zooms out of the morphed bone model 5. Ligament Balancing Can be used at any time after the registration procedure is complete 6

9 6. 3D Model Allows the user to switch between displaying or hiding the 3D model, leaving only the cloud of acquired points visible on screen. 7. Implant information Provides details on the implants and sizes. This may be used to confirm the selected implants after the implant planning stage. If this option is selected before the optimization process, the femoral implant displayed will usually be too small. 8. Verification Button If, at any time, the reference arrays are moved or knocked out of position, you can reverify the accuracy of the bone model using the pointer. If the bone model is no longer accurate, the registration process will need to be repeated. (If only one array has been moved, the registration will only need to be repeated for that array). Use the next / back buttons to return to the appropriate point in the procedure. 9. Screenshot Button This allows the user to take manual screenshots at any stage of the procedure. Screenshots are stored within the system and can be written to a CD. The system will also take automatic screenshots at key stages during the procedure. 10. Close Button This closes the application. All information can then be stored on disk before continuing with a new procedure. The patient s name and ID are stored as a HTML file with all information gathered during the procedure. 7

10 Ci Procedure Set-up On screen there are next and back buttons. In this surgical technique we use arrows to indicate movement to the next step. Arrow Key: Press next to continue Press back to return to the previous step Figure 4 Figure 5 Figure 6 The procedure is started by entering the patient s name and ID, using the touchscreen keyboard (Figure 4). This information will appear on the screen and on each screenshot taken during the operation. The appropriate knee system software is selected from the choices displayed - LCS Complete / P.F.C. Sigma / P.F.C. Sigma RP / Preservation Unicondylar Knee Systems (Figure 5). A choice of instrument set is selected. P.F.C. Sigma Specialist ll adapted conventional instruments or i-p.f.c. Sigma Ci instrumentation (Figure 6). 8

11 Figure 7 Figure 8 Figure 9 The appropriate workflow for P.F.C. Sigma is selected tibia first / femur first / P.F.C. Sigma RP (Figure 7). The appropriate product line is selected (Figure 8). Press change to alter the selections on screen. The appropriate treatment side for the surgery is selected (Figure 9). The femoral component is selected first, followed by the tibial component and the tibial insert. 9

12 Incision & Exposure Figure 10 Figure 11 With the knee flexed, make a straight mid- The subvastus ("Southern") approach may Should tension prevent adequate lateral Following a lateral parapatellar incision line incision from 6 to 10 cm above the be used. If significant valgus deformity displacement of the patella, detach the in the valgus knee, incise the anterior patella, passing over the patella, and exists, a lateral parapatellar deep incision medial one-quarter to one-third of the compartment fascia longitudinally one ending at the tibial tubercle (Figure 10). as part of a lateral release may be patellar tendon from the tibial tubercle. centimeter from the tibial tubercle. With neutral alignment or with varus preferred. Following a median parapatellar To further mobilize the extensor Osteotomy and subperiosteal excision of deformity, make a median parapatellar incision, reflect the patella laterally to mechanism, continue the sharp incision of the fibular head is occasionally necessary incision through the retinaculum, capsule expose the entire tibio-femoral joint the medial portion of the quadriceps in extreme valgus deformities. and synovium (Figure 11). (Figures 12 & 13). tendon proximally. 10

13 Figure 12 Figure 13 Elevate the tibial tubercle with an osteo- Excise hypertrophic synovium and a Excise redundant synovium to prevent Evaluate the condition of the posterior periosteal flap if necessary for exposure. portion of the infrapatellar fat pad to allow possible impingement or post-operative cruciate ligament to determine the Reflect the patella and periosteal access to the medial, lateral and overgrowth. It is recommended that at appropriate tibial component to use. attachments medially. intercondylar spaces. least two thirds of the fat pad is removed The choice of tibial implant can be when using a posterior cruciate retaining changed on the system at this stage. implant. Some surgeons may prefer a complete synovectomy. 11

14 Tibial & Femoral Array Positioning Schantz pin position Position of standard Ci tibial jig Schantz pin position Position of optional Ci tibial jig The tibial array and pin may need to be removed before final tibial tray preparation to avoid any contact with the instrumentation Intended tibial array position Intended tibial array position Figure 14 Ci Standard Jig Figure 15 Ci Optional Jig The arrays must be placed within the Note: The position of the reference arrays Positioning of the tibial jigs If the optional Ci tibial jig is selected, the incision and away from the intended must not be moved during the operation, First, the varus / valgus and proximal tibial fixation housing, the tibial jig, and the positions of both the femoral and tibial as this will lead to inaccurate information translation positions on the standard Ci saw capture should be loosely assembled instruments to avoid any contact during being displayed, and possible cancellation tibial jig or the optional Ci tibial jig are (see page 40 for assembly instruction). bone resection and drilling. To accurately of the procedure. Please refer to the set to neutral. This will ensure that the The selected jig is roughly aligned along the position the arrays it is important that the Clinical User Guide (Art-No: EN) devices have the ability to move superiorly anatomic axis of the tibia sufficiently distal femoral and tibial instruments are for further information on positioning and or inferiorly, and provide for proper varus to represent a 10 mm resection assembled prior to array fixation. fixation of the reference arrays. or valgus fine tuning during navigation. from the unaffected tibial plateau. 12

15 Left / right limb setting Position of optional Ci positioning gauge Schantz pin position Intended femoral clamp position Intended femoral array position Figure 16 This will ensure that the jig has enough Positioning of the femoral assembly It is essential that the P.F.C. Sigma The gauge should touch the most distal movement to accommodate both large The femoral clamp and positioning gauge locator on the gauge is correctly condyle and should be appropriately set and small proximal tibial resections. The are assembled and positioned on the positioned in the femoral clamp before for a left or right limb, in line with the tibial jig is held in position while a mark is made to identify the Schantz pin position. Care should be taken to position the array clear of the tibial jig and any subsequent anterior femur (see pages 50 and 51 for assembly instructions). positioning the array. anatomic axis of the femur (Figure 16). A mark is again made to identify the Schantz pin position. tibial tray keel (Figures 14 & 15). 13

16 Tibial & Femoral Array Fixation Screw connector Flexible joint Fixation knob Cortical bone spikes Figure 17 Figure 18 Reference array fixation The tibial array is lowered onto the pin until The screw connector is tightened by hand The same sequence is followed for fixing A Schantz pin is inserted into the drill and it touches the surface of the leg and the until the array is stable (Figure 17). A the femoral array. The camera unit should introduced bicortically to the tibia. spikes on the bottom of the array engage wrench is used to fully secure the final now be able to detect all six marker The reflective marker spheres should now be attached to the tibial (T-shape) array. with cortical bone. The array is angled as required (usually pointing down and in-line with the tibia). position and angle of the array (Figure 18). Care should be taken if the patient has osteoporotic bone, as over tightening of the array may loosen the Schantz pin. spheres on the reference arrays. The arrays should remain visible by the camera unit while performing flexion, extension and pivoting the hip joint. 14

17 Camera Alignment Red dots: Tibial array Yellow dots: Femoral array Purple dots: Ci pointer Blue dots: Additional Ci tools Grey dots: Unknown marker The status field lights indicate that all instruments are visible Green: Normal tracking mode Red circles: Tibial array Yellow circles: Femoral array Purple circles: Ci pointer Blue circles: Additional Ci tools Grey circles: Unknown marker The camera field of view is indicated by the blue cone Yellow: Red: Grey: Ci instrument not visible to camera Ci instrument and / or navigation array not visible to camera for more than 3 seconds Camera communication error during start-up Re-start the system Figure 19 The camera alignment window highlights Colored dots represent the positions The status field lights indicate the visibility movement of the reference arrays and instruments. These are displayed as different colored dots and circles on-screen (Figures 19). of the femoral and tibial reference arrays, and the Ci pointer. The circles show the position of the instruments in relation to the camera unit s field of view. of the arrays and instruments. The camera displays can be accessed at any time during the procedure by touching the status field lights. 15

18 Calculating the Femoral Head Center An assistant may hold the pelvis in position during this step to ensure that an accurate calculation is made. Figure 20 Figure 21 Registration defines the mechanical axis Calculating the rotational center of the motions (Figure 20). The system calculates The system calculates the center of the and important anatomic landmarks. This femoral head defines the proximal point of a series of points to determine the femoral head to within 3 mm. This relates allows accurate positioning and sizing of the mechanical axis. It is important to rotational center and will automatically to no more than a 0.5 deviation on the the intended implants. A customized 3D make sure that the patient s pelvis is not proceed when the rotational center has mechanical axis. If the center of the model of the patient s bone anatomy is moved excessively during registration as been calculated (Figure 21). femoral head is not calculated correctly, created. Each screen offers the option to this will lead to miscalculation by the a warning box will appear and the step repeat the step if required. system. The femur is pivoted using circular is repeated. 16

19 Pointer Tips The pointer is pivoted prior to a point being acquired Figure 22 Figure To acquire points accurately, it is helpful 2. To avoid acquiring unnecessary points 3. Make sure all three marker spheres on to refer to the screen as each point to hold the tip of the pointer with one before the pointer is positioned, it may the pointer are directed towards the is acquired. If the camera cannot see hand while pivoting the pointer with the be helpful to cover one of the marker camera unit when acquiring a point. the pointer, a deep sounding beep will other. This will ensure that all of the points are registered on the bone, not away from the patient (Figure 22). spheres with a hand. This will effectively eliminate the pointer from the camera s field of view (Figure 23). 4. When a point has been successfully acquired, the system will sound an audible beep. This removes the need be heard. 5. If at any stage during the procedure the marker spheres become contaminated with blood or tissue, they may be gently 17 cleaned using lint-free cloth.

20 Definition of the Malleoli Figure 24 Figure 25 The medial and lateral malleoli are defined Place the tip of the pointer to the medial Acquiring the malleoli defines the distal It is important that these points are using the Ci pointer. malleolus and pivot the pointer (Figure 24). point of the mechanical axis. acquired as accurately as possible. The malleoli can usually be located by hand before acquiring the points. It is important that draping or bandaging is reduced to a minimum to enable the malleoli to be located. It is important not to move the tip of the pointer from the bone. Once the system has registered the medial malleolus, the lateral malleolus can be registered in the same way (Figure 25). All single registration points for anatomic landmarks are acquired in the same way. 18

21 Definition of the Tibial Mechanical Axis Figure 26 Figure 27 The mechanical axis is defined by acquiring the posterior aspect of the ACL tibial attachment point (Figure 26). This is indicated by the arrow on screen (Figure 27). It is important that the point acquired defines the mechanical axis, and not the tibial eminence. The definition of the mechanical axis is the basis for all further calculations and should be acquired as accurately as possible. Final implant position will be referenced to the mechanical axis. 19

22 Tibial Sizing Figure 28 Figure 29 After removal of any osteophytes, the most medial and lateral points of the proximal tibia are acquired using the pointer. These are followed by the most anterior and posterior points (Figures 28 & 29). The points should be registered at the expected resection level. This will help to avoid oversizing the tibial component. Note: Failure to remove osteophytes at this stage may lead to oversizing the implant (during implant planning). 20

23 Tibial A/P Direction Figure 30 Figure 31 The pointer is placed on the tibia to acquire the A/P direction only (Figure 30). If access to the center of the The pointer is held in place for 2 seconds to allow the system to calculate the direction (Figure 31). tibia is limited, the pointer can be placed to one side. 21

24 Tibial Modeling Points should be acquired around the rim, and as posteriorly as possible Figure 32 Figure 33 A fixed number of points along the anterior The pointer is placed on the tibia and The tip of the pointer should paint the less important, but will add shape to the and medial / lateral tibia are acquired pivoted to begin the procedure. A beep exposed surface of the tibia making sure it model. The system will indicate when using the Ci pointer. These points are will indicate when to begin moving the does not leave the surface of the bone. enough points have been acquired. used to further define the bone model pointer (Figure 33). Points should be acquired mainly around (Figure 32). the rim and extend as posteriorly as possible. Points further down the tibia are 22

25 Tibial Plateau Modeling Place the tip of the pointer in the center of the plateau Figure 34 Figure 35 The Ci pointer should be placed in the center of the medial tibial plateau. The tip of the pointer is moved in a circular motion across the surface of the plateau (Figure 34). It may be helpful to apply varus or valgus stress to the knee joint to allow greater access to the tibial plateau. The system will automatically proceed to the lateral plateau, which is registered in an identical manner to that of the medial plateau (Figure 35). 23

26 Tibial Model Calculation and Verification The white areas represent acquired points The deviation from the tip of the pointer to the bone is represented in mm Figure 36 Figure 37 Following registration, the system adapts Brown areas are parts of the model The maximum acceptable deviation is less Note: Implant sizing is based on acquired the tibial model (Figure 36). where no points have been acquired. than 2 mm. Acquired points will normally points only. The accuracy of the model White areas are parts of the model with deviations no greater than 2 mm from the actual bone structure. The accuracy of the model is checked by holding the Ci pointer to the tibia. The exact deviation from the tip of the pointer to the model is displayed on the screen. show a deviation of less than 1 mm. Verification of the model will only be accurate in white areas where points have been acquired (Figure 37). should be checked on the areas responsible for implant sizing and position (medial and lateral boundary, medial and lateral plateau). 24

27 Femoral Mechanical Axis Figure 38 Figure 39 The registration of the femur is The pointer should be placed at the Do not use the femoral canal entry point It is important that the mechanical axis automatically activated once the tibial anterior aspect of the femoral notch point as a guide for acquiring the point. point is acquired as accurately as possible. registration has been completed. as indicated on screen (Figures 38 & 39). 25

28 Registration of Epicondyles Figure 40 Figure 41 Acquisition of the most medial and lateral epicondylar points are used to define the epicondylar axis (Figures 40 & 41). 26

29 Registration of the Anterior Cortex Figure 42 Figure 43 The anterior cortex is acquired using the pointer. Ideally, the pointer should be placed on the deepest point on the anterior femoral cortex just above the superior border of the femoro-patellar articular surface (Figures 42 & 43). This will enable the system to determine the size of the femoral implant required. It is important to acquire this accurately to avoid the intended cutting plane notching the femur. 27

30 Whiteside s Line Figure 44 Figure 45 Whiteside s line is marked using electrocautery. This line marks the deepest part of the trochlear groove. It is easiest to draw by looking along the horizon of the trochlear groove. Once the line is drawn the pointer can be held along this line. The pointer must be held perfectly still while the system acquires this reference (Figures 44 & 45). In the event of a system failure the marked line will be used as an alignment reference point for the back-up instrument set. 28

31 Femoral Condyle Modeling Points should be acquired as posteriorly as possible on the femoral condyles Figure 46 Figure 47 A fixed number of points along the surface of the medial and lateral condyles are acquired using the Ci pointer (Figures 46 & 47). The tip of the pointer should paint the surface of the condyles. Points should be acquired as posteriorly as possible and along the distal part of the affected condyles. This allows the system to accurately calculate both the size and position of the intended implant. If insufficient posterior points are acquired the system will ask for the step to be repeated. 29

32 Anterior Cortex Modeling Figure 48 Figure 49 Multiple points along the anterior cortex are acquired using the Ci pointer. These points will define the anterior position of the implant to avoid notching of the femur (Figures 48 & 49). 30

33 Femoral Model Calculation and Verification The white areas represent acquired points The deviation from the tip of the pointer to the bone is represented in mm Figure 50 Figure 51 Following registration, the system adapts Brown areas are parts of the model The maximum acceptable deviation is less Note: Femoral implant sizing is based on the femoral model (Figure 50). where no points have been acquired. than 2 mm. Acquired points will normally acquired points only. The accuracy of the White areas are parts of the model with deviations no greater than 2 mm from the actual bone structure. The accuracy of the model is checked by holding the Ci pointer to the tibia. The exact deviation from the tip of the pointer to the model is displayed on the screen. show a deviation of less than 1 mm Verification of the model will only be accurate in white areas where points have been acquired (Figure 51). model should be checked on the areas responsible for implant sizing and position. 31

34 Initial Leg Alignment Femoral mechanical axis HKA line Tibial mechanical axis Figure 52 Figure 53 It is important to register the knee joint in extension. The leg is held in clinical extension for 2 seconds to register the patient s pre-operative condition prior to the procedure (Figure 52). The orange lines on screen represent the tibial and femoral mechanical axes. The green line represents the hip / knee / ankle (HKA) line. This step allows a comparison to be made between the initial and final alignments at the end of the procedure (Figure 53). 32

35 Definition of the Anatomic Axis Ci cutting block adaptor Figure 54 Figure 55A Figure 55B The flexion / extension and rotation femur and held still for 2-3 seconds to The software will display the angular If a negative angle is recorded the implant position of the femoral implant can be register the anatomic axis (Figure 54). difference between the mechanical and will be positioned according to the positioned according to the anatomic or A blue plane is displayed on the screen anatomic axes in the coronal plane mechanical axis to avoid femoral notching. mechanical axis. If the mechanical axis is indicating the position of the Ci Cutting (Figure 55B). The femoral component required, continue to the next step. If the Block Adaptor (Figure 55A). position will be rotated by the same angle anatomic axis is required the Ci cutting to ensure accurate anterior alignment. block adaptor is placed on the anterior 33

36 Tibial Resection Setting Tibial Implant Planning Figure 56 Figure 57 The option to align the tibial cut to the The system has already calculated the Initial planning and alignment of the Fine tune functions allow the user to higher or lower tibial plateau is selected on height of the plateau from the information implant position is automatically calculated reposition the implant as required. Tibial screen (i.e. 2 mm below the lower plateau acquired during registration. during the registration procedure. slope, varus / valgus, internal / external or 8 mm below the higher plateau) rotation, medial / lateral, inferior / superior (Figure 56). and anterior / posterior movement can be adjusted on screen at this stage (Figures 57-61). 34

37 Frontal view (top left) Lateral view (top right) The A/P position of the implant is aligned to the most anterior point as determined during registration. Tibial resection level Varus / valgus adjustment is referenced to rotate around the higher tibial plateau Tibial resection level and slope. The P.F.C. standard slope is 3. This can be manually adjusted using the blue arrows. Varus / valgus rotation Superior / inferior translation Varus / valgus rotation Slope adjustment A/P translation Slope adjustment Figure 58 Figure 59 When using the fine tune functions, the acquired points are the main reference for planning and implant placement. The 3D model only provides additional information and 3D orientation. Button Functions Blue arrows allow repositioning of the tibial component. Yellow line tibial resection level. The image can be enlarged on screen using the zoom function on the menu bar. 35

38 Axial view (bottom left) Planning information (bottom right) M/L position the implant is positioned between the most medial and lateral points as determined during registration The implant size button changes the size of the tibial component. The tibial cut is recalculated and the gaps adjusted accordingly. The system only allows compatible sized implants to be selected. Internal / external rotation the implant is aligned to the A/P direction determined during registration Acquired points The freesize option can be used to change this manually. However, the system will only allow you to change the tibial component and insert size if a compatible femoral implant is also selected at the same time. Internal / external rotation M/L translation Internal / external rotation Resets all adjustments Returns to the previous step Accepts all adjustments Figure 60 Figure 61 During fine-tuning, all images are shown The following information is displayed in Resection high - indicates the distance to Lateral shift (in millimeters). with a group of points. These groups indicate the actual bone, as defined during the registration procedure, and should be used as a guide during all alignment and the bottom right hand side of the screen (Figure 61): Posterior slope (in degrees). the higher plateau from the resection level. Resection low - indicates the distance to the lower plateau from the resection level. Posterior shift (in millimeters). Reset resets everything back to initial planning values. fine-tuning procedures (Figure 60). Varus / valgus (in degrees). Internal / external rotation (in degrees). 36

39 Tibial Resection (Standard Jig) Figure 62 Figure 63 Before placing the Ci tibial jig on the tibia its varus / valgus, M/L and proximal translation positions should be set as close to neutral as possible to allow for fine-tune adjustment in all directions. The insertion plate on the navigated Ci cutting block adaptor is placed into the saw capture on the tibial alignment jig. The screen data is used to guide the jig into an approximate position (in line with the anatomic axis of the tibia and close to the desired tibial resection level). (Figure 62). The jig is pinned in place on the tibia using the most distal pin hole on the instrument (Figure 63). 37

40 The tibial resection must always be made through the saw capture slot. Third pin position in any of these 6 holes Second pin position Proximal translation adjustment screw Varus / valgus adjustment screw Tibial slope adjustment screw Figure 64 Figure 65 The medial / lateral position of the The tibial slope, varus / valgus and proximal Once accurately positioned, the jig is The navigated Ci cutting block adaptor is instrument should be checked and translation adjustments can now be made secured using a third pin. The pin can be removed and the tibial resection completed. adjusted if necessary. When this is complete, a second pin is positioned in the jig slot to support the instrument in this using the three adjustment screws, with reference to the on screen data. positioned in any of the 6 holes below the cutting block (Figure 65). A small amount of rotational navigation can still be The tibial resection must always be made through the saw capture slot. position (Figure 64). performed at this stage if required. 38

41 Tibial Resection Verification (Standard Jig) Varus / valgus screen Posterior slope screen Resection level screen Figure 66 Figure 67 Figure 68 The insertion plate of the Ci cutting block The difference between planned and The yellow plane represents the planned The tibia resection numeric data is adaptor is placed flat on the resected actual resection planes can be seen on plane and the blue plane represents the displayed by pressing next. The tibial plane (Figure 66). screen (Figure 67). actual plane. resection can be repeated if necessary (Figure 68). 39

42 Tibial Resection (Optional Jig) The top of the tibial jig can be angled more anteriorly by adjusting the lower screw hole The array adaptor block is secured to the jig The notch on the tripod is placed perpendicular to the anatomic axis The tibial jig is secured using either the hex head screwdriver or the array fixation wrench Figure 69 Figure 70 Figure 71 Position of tibial tripod Fixation of tibial tripod inserted in positions which offer maximum The jig is attached by tightening the lower The optional jig, tripod and navigated Ci The tibial tripod is secured to the tibia tripod stability (Figure 69). screw using the hex head screwdriver or cutting block adaptor are assembled and aligned along the anatomic axis of the tibia sufficiently distal to represent a 10 mm resection from the unaffected tibial plateau. This will ensure that the device has enough movement to accommodate both large using fixation screws. The screw holes can be pre-drilled using a 2 mm drill bit. The first screw should be placed in the most proximal hole of the tripod. Two to three screws are required to fully secure the tripod. The remaining screws should be Care should be taken not to over tighten the screws. The tibial alignment jig is secured to the tibial tripod in line with the A/P axis of the proximal tibia (Figure 70). by using the array fixation wrench. The navigated Ci cutting block adaptor is placed into the array adaptor block and secured in position on the tibial alignment jig (Figure 71). and small proximal tibial resections. 40

43 Varus / valgus adjustment A/P slope adjustment Resection level adjustment Figure 72 Figure 73 Fine tuning of the resection level is achieved by adjusting the A/P slope, resection level and varus / valgus angle with reference to the on screen data (Figures 72 & 73). The adjustments can be made from either the top or the bottom of the tibial jig. 41

44 The top of the cutting block can be removed by loosening the side screws to provide an open cutting surface if required Figure 74 Figure 75 Once the correct alignment has been The saw guide / saw capture is attached The cutting block can be pinned in place The proximal tibia is resected taking care achieved, the cutting block adaptor to the top of the tibial jig. For maximum using the 2 pin holes on the block face for not to overstress the fixation by bending is removed. stability, the guide should be positioned as additional stability. Before resecting the the sawblade on to or into the saw guide / close to the bone surface as possible. tibia, the cutting block array can be placed capture (Figure 75). The device is locked into the fine tune on to the saw guide to check that the assembly using the hex head screwdriver. alignment has remained in the correct position (Figure 74). 42

45 Tibial Resection Verification (Optional Jig) Varus / valgus screen Posterior slope screen Resection level screen Figure 76 Figure 77 Figure 78 The insertion plate of the Ci cutting block The difference between planned and The yellow plane represents the planned The tibial resection numeric data is adaptor is placed flat on the resected actual resection planes can be seen on plane and the blue plane represents the displayed by pressing next. The tibial plane (Figure 76). screen (Figure 77). actual plane. resection can be repeated if necessary (Figure 78). 43

46 Alignment Settings Ligament Balancing (Optional) Spacer blocks are included with the standard Ci instrumentation Figure 79 Figure 80 A choice of anterior or posterior alignment Ligament balancing allows the ligament To achieve equal and balanced ligaments options are available for positioning the femoral implant. Rotation can be referenced to either the epicondylar line, posterior line, or Whiteside s line (Figure 79). tension on the medial and lateral collateral ligaments to be controlled. The Ci System displays current and maximum values for reconstruction of the ligaments. a tensioning device or spacer blocks may be used (Figure 80). 44

47 Figure 81 Figure 82 Ligament balancing in extension The leg is placed in extension and distracted. Varus and valgus stresses are applied to the knee joint. The system displays current and maximum values for reconstruction of the joint. Spacer blocks or tensioning devices can be used to achieve this (Figure 81). The values for the extension gap, varus / valgus angle and knee joint angle are stored on the system by pressing the Store button (Figure 82). 45

48 Note: If the extension / flexion gap is too small for the thinnest available insert, the measurements will be displayed in red. The minimum amount of extra bone resection will be displayed in mm. Figure 83 Figure 84 Ligament balancing in flexion The leg is placed in flexion. Independent but equal pressure is applied to the medial and lateral compartments of the knee (Figure 83). The values for the flexion gap, varus / valgus angle and knee joint angle are stored on the system by pressing the Store button (Figure 84). This data will be used to rotate the implant with respect to the proximal tibial resection in order to also achieve a parallel gap space in flexion. 46

49 Femoral Implant Planning Lateral and frontal views The joint line and flexion / extension gaps can be adjusted by repositioning the femoral implant Implant rotation Superior / inferior translation Implant rotation Superior / inferior translation Figure 85 Figure 86 The data gathered during the registration Button functions and screen information and verification procedures is used to calculate the femoral implant size and the position and levels for the femoral Blue arrows - allow repositioning of the femoral component. Orange line - mechanical axis line. Yellow line - tibial resection level. The image can be zoomed in or out for better viewing using the Zoom function on the menu bar. resections. The recommendations should Dark blue lines - proposed cutting planes be thoroughly checked and adjusted as of the femur. necessary (Figures 85-90). 47

50 Planning Information (bottom right) Second screen axial view (top right) Note: If the extension gap is too small for the thinnest available insert, the measurements will be displayed in red. The minimum amount of extra bone resection will be displayed in mm. The Implant Size function is used to change the size of the femoral component. After changing the size, the distal cut will be re-calculated, and the flexion gap adjusted. The system will only allow compatible sized components to be selected. The medial / lateral shift of the femoral implant is based around the epicondylar points selected earlier (shown by red dots on the epicondylar alignment line) Resets all adjustments Returns to the previous step Accepts all adjustments Internal / external rotation M/L translation Internal / external rotation Figure 87 Figure 88 The freesize option is available to The proceed option will be removed at If all femoral planning adjustments are Light blue lines - All three rotational manually change the implant size. this stage to force the user to select acceptable, a second implant planning alignment lines (epicondylar line, However, if inappropriate implants are compatible implants. screen allows adjustment of varus / posterior line, Whiteside s line). selected, the system will display a warning message relating to implant compatibility. Reset resets everything back to initial starting screen. valgus, internal / external rotation and medial / lateral position. The yellow lettering shows the rotational alignment deviations. 48

51 Second screen frontal view (top left) Second screen planning Information (bottom right) Varus / valgus adjustment rotates around the most distal part of the condyle Varus / valgus rotation Varus / valgus rotation Figure 89 Figure 90 M/L position this can be adjusted on screen with the blue arrows (a neutral position is recommended by the system central to the mechanical axis). Varus / valgus can be adjusted with the blue arrows (rotates around the most distal part of the condyle). Internal / external rotation is adjusted in relation to the chosen alignment (epicondylar / posterior / Whiteside s line). Reset resets everything back to initial starting screen. When using the fine tune functions, the acquired points are the main reference for planning and implant placement. The 3D model only provides additional information and 3D orientation. 49

52 Femoral Preparation P.F.C. Sigma locator LCS locator Guide is positioned in-line with the anatomic axis of the femur Top locking screw Positioning gauge guide adjuster Femoral clamp attachment bar Positioning gauge slot Positioning gauge guide Clamp legs Figure 91 Figure 92 Figure 93 The femoral clamp is prepared by A gap of 1 mm to 2 mm between the top The positioning gauge is then attached It is essential that the P.F.C. Sigma loosening the top locking screw until the locking screw and the top plate should be to the femoral clamp with the positioning locator on the gauge is correctly clamp legs can be moved easily by hand sufficient to allow correct manipulation of gauge guide adjusted to match the positioned in the femoral clamp. (Figure 91). If the legs are over released the instrument. anatomic axis of the femur (Figures 92 this will affect the ratchet. If they are too & 93). tight it may become difficult later to close the legs onto the bone surface. 50

53 Secure the clamp legs using the hex head screwdriver Face plate rests flush against the most distal femoral condyle Legs may also be secured with pins Clamp legs are manually pushed into place on the femur to initially secure the instrument in place Figure 94 Figure 95 The assembly is placed on the anterior (Figure 94). Care should therefore be With the positioning gauge held in place, Final locking is completed using the hex part of the distal femur, with the positioning taken to ensure that the varus / valgus push the legs of the femoral clamp until head screwdriver. This can be done from gauge guide pointing along the anatomic alignment of the device is driven by the they contact the surface of the bone. The either side of the clamp (Figure 95). If soft axis of the femur. The face plate should positioning gauge guide being placed legs can then be locked in place using the or osteoporotic bone is encountered, the rest flush against the most distal condyle along the anatomic axis of the femur. top locking screw. legs of the clamp may be secured with pins. 51

54 Distal Femoral Resection Navigation Ci cutting block adaptor Central locking screw Outer locking screw Figure 96 Figure 97 The positioning gauge is removed from It is essential that the instrument is correctly The Ci cutting block adaptor is The mechanism is adjusted using the the clamp and the femoral fine tune locked to the clamp. The undercut in the positioned on the fine tune mechanism navigation array as a supporting handle. mechanism is attached (Figure 96). The distal translation screw should click into (Figure 97). The two large outer locking Varus / valgus, flexion / extension, varus / valgus, flexion / extension and place at the rear of the clamp. screws on the fine tune mechanism are and internal / external rotation are adjusted internal / external rotation positions should be set as close to neutral as possible. The central locking screw on the fine tune device should be semi-tightened loosened by hand. until approximately correct on screen. prior to fine tune navigation. 52

55 Flexion / extension adjustment Internal / external rotation adjustment Varus / valgus Flexion / extension Varus / valgus adjustment Resection level Figure Figure 99 With the two outer screws securely locked, the final fine tuning of varus / valgus, flexion / extension and distal femoral resection level can be performed using the When all final adjustments have been made, the resection plane on the fine tune mechanism is locked in place with the central locking screw. hex head screwdriver (Figures 98 & 99). 53

56 Distal Femoral Resection Distal Femoral Resection Verification Figure 100 Figure 101 The distal femur is resected. Care should be taken not to over stress the device during resection (Figure 100). The insertion plate of the Ci cutting block adaptor is placed flat on the resected plane (Figure 101). 54

57 Figure 102 Figure 103 Figure 104 The difference between the planned and actual resection planes can be seen on screen (Figure 102). The yellow plane represents the planned cut. The blue plane represents the actual cut. The resection numeric data is displayed by pressing next (Figures 103 & 104). The resection can be repeated if necessary. 55

58 A/P Femoral Resection Navigation A/P carrier locks A/P carrier Capture slot A/P cutting block lock A/P cutting block Figure 105 Figure 106 Figure 107 The appropriate sized A/P block is slotted into the A/P carrier and locked into place (Figure 105). The assembly is slotted into the distal saw capture on the fine tune device (Figure 106). The A/P block should rest accurately against the resected surface of the distal femur (Figure 107). 56

59 A/P translation screw Central locking screw Locking screws Figure 108 Figure 109 The Ci cutting block adaptor is placed into the anterior slot of the A/P block (Figure 108). The hex head screwdriver is used to adjust the A/P translation and internal / external rotation of the cutting block. The A/P position is monitored on screen (Figure 109). When navigation is complete the central locking screw, A/P carrier and the A/P block are locked in place. The cental locking screw must be loosened prior to making any adjustments. 57

60 A/P Femoral Resection A/P Femoral Resection Verification Anterior femoral resection Chamfer cut Steinmann pin Posterior femoral resection Chamfer cut Figure 110 Figure 111 Two Steinmann pins should be positioned The anterior, posterior and chamfer cuts The A/P block, carrier and fine-tune The Ci cutting block adaptor is placed in the holes at the side of the cutting are made through the cutting block mechanism can be removed as one unit onto the anterior cut with its insertion plate block. These will provide additional stability (Figure 110). prior to verifying the resections. This will flat on the resection (Figure 111). during the following resections. allow the block to be replaced if further resection is required. 58

61 Figure 112 Figure 113 The difference between the planes can be seen on screen (Figure 112). The yellow plane represents the planned plane and the blue plane represents the The resection numeric data is displayed by pressing next (Figure 113). The resection can be repeated if necessary. actual plane. 59

62 Femoral Notch Cut (cruciate-substituting only) Pin 3 Pin 1 Pin 2 Pin 4 Figure 114 Figure 115 Figure 116 The trial component is positioned on the The appropriate femoral notch guide is The guide is seated flush on the resected The notch cut is made using an oscillating femur. The M/L position of the notch cut is positioned on the distal femur in line with anterior and distal surfaces and pinned in saw and an osteotome. marked using electrocautery (Figure 114). the electrocautery marks (Figure 115). place in the order shown (Figure 116). 60

63 Patellar Resection 9 mm 16 mm 25 mm Figure 117 Figure 118 The synovial tissue and retinaculum are released from the periphery of the patella down to the plane of the quadriceps Patellar size Implant thickness 32 mm 8.0 mm Example (for a 38 mm size dome or oval/dome patella): From a patella 25 mm thick, 9 mm of articular surface is A template is selected that most adequately covers the articular surface without overhang. The handle is positioned on the medial side of tendon and patellar tendon reflection. 35 mm 8.5 mm resected, leaving 16 mm of residual bone the everted patella. Where bone is deficient on The patella is measured using the calipers 38 mm 9.0 mm to accommodate the 9 mm thick implant the lateral side, the next smaller size is and the resection level determined (see 41 mm 11.5 mm (Figure 117). selected and positioned slightly medially to table). enhance patellar tracking (Figure 118). 61

64 Resection adjustment Note: The resection can be made either through the cutting guide on the gauge or with the saw flush to the surface. Locking switch Figure 120 Figure 119 Figure 121 The patellar cutting guide is adjusted to The leg is placed in extension with the The resection is performed using either the everted patella. The template is firmly the predetermined dimension of residual guide firmly attached to the patella. The slotted guide or non-slotted option engaged to the resected surface and the patella as indicated on the calibrated switch is placed to the LOCK position and (Figure 120). holes made with the appropriate drill bit column (Figure 119). the jaws are closed to firmly engage the patella (Figure 119) The previously selected template is positioned onto the cut surface with the (Figure 121). handle placed on the medial side of the 62

65 Tibial Plateau Preparation Rotational alignment can be marked with electrocautery. Figure 122 Figure 123 Figure 124 With the knee in full flexion and the tibia subluxed anteriorly, the alignment handle is attached to the MBT tray trial by retracting the lever (Figure 122). The tray trial is positioned on the resected tibial surface, taking care to properly rotate and maximize the coverage of the MBT tray trial on the proximal tibia (Figure 123). The tray is secured with two fixation pins inserted through the recessed holes. Rotational alignment of the MBT tray trial can be marked with electrocautery on the anterior tibial cortex to aid in the permanent tibial tray implantation (Figure 124). 63

66 Central Stem Preparation Drill stop Figure 125 Figure 126 Figure 127 The MBT drill bushing is seated in the tibial tray trial by lightly tapping the top of the drill bushing (Figure 125). Stem Preparation - Punch The MBT stem punch is advanced into the drill bushing and impacted into the cancellous bone until the appropriate tray size marking is reached (Figure 126). Stem Preparation - Drill The drill stop is assembled onto the MBT drill and positioned at the selected tray size (Figure 127). 64

67 Table A: Creating Central Stem Cement Mantle Tray Size Drill Stop Setting Cement Mantle None (line-to-line fit) mm per side / 4 mm distal None (line-to-line fit) mm per side / 4 mm distal None (line-to-line fit) Drill bottoms out on tray trial 0.5 mm per side / 4 mm distal Note: If over-reaming is desired, remove the tray trial to avoid impingement of the reamer on the tray trial. To compact cancellous bone, advance the drill in reverse. Figure 128 Figure 129 The MBT drill is advanced through the Cement will interdigitate as the tray is Insert the MBT keel punch bushing Remove the punch bushing impactor / MBT drill bushing and into the cancellous implanted. For a larger cement mantle into the MBT tray trial, utilizing the MBT extractor and fixation pins (Figure 129). bone, until it hits the drill stop (Figure 128). refer to Table A. The porous tray will create punch bushing impactor / extractor. When Note: The MBT drill creates a cavity that is line-to-line with the punch bushing and final implant. an interference fit of mm around the entire central stem when fully impacted complete, the superior surface of the punch bushing should be flush with the superior surface of the tibial tray trial. 65

68 MBT Tray Preparation Figure 130 Figure 131 Figure 132 Keeled Tray Option The universal handle is assembled to the The assembly is impacted into the Non-Keeled Tray Option If a keeled MBT tray is to be employed, appropriately sized MBT keel punch and cancellous bone until the shoulder of the The RP adaptor is inserted into the punch and the bone of the medial or lateral inserted into the MBT punch bushing, punch is in even contact with the MBT bushing (Figure 132). plateau is sclerotic, it is helpful to initially taking care to avoid malrotation. punch bushing (Figures 130 & 131). prepare the keel slot with an oscillating saw or high speed burr. 66

69 Trial Reduction Figure 133 Figure 134 Figure 135 Figure 136 (cruciate retaining) (cruciate substituting) (cruciate retaining) (cruciate substituting) The trial bearing thickness determined The knee is placed in deep flexion. The during implant planning (matching the femoral trial is inserted and impacted in femoral size) is selected and inserted onto place (Figures 135 & 136). the MBT tray trial (Figures 133 & 134). 67

70 Figure 137 Figure 138 (cruciate retaining) Figure 139 (cruciate substituting) With the cruciate retaining trial component in place, the femoral peg holes are initiated through the holes in the trial using a drill (Figure 137). Impact the femoral trial into position (Figures 138 & 139). 68

71 Figure 140 Figure 141 Component function and stability are evaluated on screen (Figures 140 &141). The following points should be assessed: Adequate range of motion Equal flexion and extension gaps Proper ligamentous tension in extension and in flexion Correct mechanical alignment of the extremity Correct rotation of the tibial component Natural motion without restrictions 69

72 Final Component Implantation Figure 142 (cruciate retaining) Figure 143 (cruciate substituting) The components are implanted in the penetration into the trabecular bone. The the rotating platform insert of the correct femur. The femur is hyperflexed and the following order (Figures 142 & 143). universal handle is attached to the MBT size and thickness is inserted into the tibia is subluxed forward. The implant is Tibial Implantation tray impactor. The tibial tray is carefully tray. attached to the femoral inserter and The entire site should be thoroughly inserted avoiding malrotation. When fully Femoral Implantation inserted onto the femur. The knee is cleansed using pulsatile lavage. Bone inserted, several mallet blows may be The entire site should be thoroughly extended to approximately 90 for final cement is prepared and applied by delivered to the top of the universal handle. cleansed using pulsatile lavage. Bone impaction. The inserter is released and any syringe or with digital pressure in its low Once the cement is cleared from the tibia cement is prepared and applied to the extruded cement is cleared using a curette. viscous state to assure maximal 70

73 Locking switch Figure 144 Figure 145 The patellar implant may be cemented last. The patellar clamp is designed to fully seat handles are closed and held by the ratchet The clamp is released by unlocking the The cut surface is thoroughly cleansed and stabilize the implant as the cement until polymerization is complete. All LOCK switch and squeezing the handles with pulsatile lavage. Cement is applied to polymerizes. It is positioned with the extruded cement is removed with a curette. together (Figure 144). The patella is the surface and the component inserted. silicon O-ring centered over the articular reduced and the patella implant is surface of the implant and the metal evaluated. An unrestricted range of motion, backing plate against the anterior cortex, free bearing movement and proper patellar avoiding skin entrapment. When snug, the tracking should be evident (Figure 145). 71

74 Final Extension & Flexion Checks Figure 146 Figure 147 Figure 148 Trial components are used to perform final checks in both extension and flexion to assess joint kinematics (Figures 146 & 147). A CD-ROM is inserted to allow all planning information, screenshots and therapy reports to be recorded. This information can be saved prior to shut-down. The system shut-down begins after pressing the close button on the final screen. On the close application screen, press finish to exit the Ci software (Figure 148). 72

75 TKR Manual Technique Tibial Resection (standard jig) The steps on pages 73 to 94 should be followed if manual instruments are Tibial stylus required prior to tibial resection. Figure 1 TKR Manual Instrument Set Figure 2 In the event of the manual instruments The manual instrument case contains all The tibial jig is roughly positioned on The tibial stylus is placed in the slot of the being required, the patient s pre-operative the necessary instruments to accurately the tibia with the height adjustment on cutting block and adjusted to the desired x-ray should be used to template the complete the procedure (Figure 1). the tibial jig set in the middle of the resection height (Figure 2). appropriate sizes of femoral and tibial adjustment limits. components for implantation. 73

76 Alignment rod Alignment guide Figure 3 Figure 4 The M / L position of the jig is adjusted to locate the ideal position for the initial pin fixation. When the correct position has been determined the initial pin is inserted The tibial stylus is removed and the alignment guide is positioned in the slot of the cutting block and the alignment rod is placed in the appropriate hole (Figure 4). (Figure 3). 74

77 Tibial slope adjustment screw Figure 5 (rod parallel to tibial mechanical axis) Figure 6 The angle of the tibial slope is adjusted using the slope adjustment screw with the alignment rod as a reference (Figures 5 & 6). 75

78 Figure 7 Figure 8 Varus / valgus adjustment is made by rotating the jig around the initial pin using the alignment rod as a guide (Figure 7). When all final adjustments are complete the block can be pinned in place and the tibial resection performed (Figure 8). 76

79 Tibial Resection (optional jig) The top of the tibial jig can be angled more anteriorly by adjusting the lower screw hole The notch on the tripod is placed perpendicular to the anatomical axis Figure 9 Figure 10 The tripod, tibial jig and saw capture are This will ensure that the device has The tibial jig and saw capture are removed Two to three screws are required to fully positioned by hand on the anterior surface enough movement to accommodate both and the tripod is secured to the tibia using secure the tripod. The remaining screws of the exposed tibia and aligned along the large and small proximal tibial resections fixation screws. The screw holes can be should be inserted in positions which offer anatomical axis of the tibia sufficiently (Figure 9). pre-drilled using a 2 mm drill bit. The first maximum tripod stability (Figure 10). distal to represent a 10 mm resection from screw should be placed in the most Care should be taken not to over tighten the unaffected tibial plateau. proximal hole of the tripod. the screws. 77

80 Tibial alignment block Tibial alignment rod The tibial jig is secured using either the hex head screwdriver or the array fixation wrench Figure 11 Figure 12 The tibial jig and cutting block are secured to the tibial tripod in line with the A/P axis of the proximal tibia. The jig is attached by tightening the lower screw using the hex head screwdriver or by using the array fixation wrench. The saw capture is removed from the jig (Figure 11). The angle of the posterior slope is selected using the tibial alignment block and the tibial alignment rod (Figure 12). 78

81 Tibial alignment rod Tibial alignment block Rod pin Alignment holes Figure 13 Figure 14 The tibial alignment rod is inserted into the appropriate sized hole of the tibial alignment block for the desired posterior slope (0, 3, 5, 7, or 10 degrees) (Figure 13). The pin on the tibial alignment rod should fully engage with the tibial alignment block. The assembly is placed on the tibial jig with the desired slope angle facing anteriorly (Figure 14). 79

82 Varus / valgus adjustment Tibial slope adjustment Figure 15 Figure 16 Figure 17 Correct alignment is achieved by adjusting This should represent a varus / valgus The tibial slope is fine tuned by adjusting Correct alignment is achieved when the the varus / valgus angle on the tibial jig angle of 0. the A/P setting on the tibial jig (Figure 15). tibial alignment rod is parallel to the tibial until the rod is aligned to the patient s mechanical axis (Figure 17). second metatarsal (Figures 15 & 16). 80

83 Incremental scale Resection level adjustment Figure 18 Figure 19 Figure 20 When all adjustments are complete the The resection level is adjusted on the tibial The resection level may be adjusted using measured using a caliper. The stylus is alignment block and rod are removed from jig until the stylus contacts the lowest the 1 mm incremental scale marked on the adjusted to sit on the superior surface of the tibial jig. The saw capture is placed on point on the unaffected tibial condyle. anterior face of the tibial jig. the resected tibia. Any additional the jig and positioned as close to the tibia as possible. The saw capture is locked in place and the tibial stylus is placed in the cutting slot (Figures 18 & 19). This will allow a 10 mm resection to be made from the unaffected condyle of the tibia (Figure 20). Note: If the tibial stylus does not connect with the tibia due to low positioning of the tripod, a conservative tibial cut can be made. The resected bone is then resection required is measured using the incremental scale on the tibial jig. 81

84 Figure 21 Figure 22 Figure 23 The tibial stylus is removed from the saw capture slot and the tibia is resected, taking care not to overstress the fixation by bending the sawblade onto or into the saw capture (Figure 21). The resected tibia is sized using existing MBT or P.F.C. Sigma tibial tray trials, aligned on the superior surface of the tibia (Figure 22). Alternatively, the caliper may be used in conjunction with the table of dimensions displayed in the instrument tray (Figure 23). 82

85 Femoral Preparation The steps on pages 83 to 94 should be followed if manual instruments are Top locking screw required after tibial resection. Positioning gauge slot Clamp legs Figure 24 Figure 25 The A/P dimension of the femoral component The femoral clamp is prepared by If the legs are over released this will affect A gap of 1 mm to 2 mm between the top is sized using the P.F.C. Sigma caliper loosening the top locking screw until the the ratchet. If they are too tight it may locking screw and the top plate should be (Figure 24). clamp legs can be moved easily by hand become difficult later to close the legs sufficient to allow correct manipulation of (Figure 25). onto the bone surface. the instrument. 83

86 Positioning gauge guide Figure 26 Figure 27 Whiteside's line is marked using electrocautery. This line marks the deepest part of the trochlear groove. It is easiest to draw by looking along the horizon of the trochlear groove (Figure 26). The positioning gauge is attached to the femoral clamp with the positioning gauge guide adjusted to match the anatomical axis of the femur (Figure 27). Please refer to the assembly instructions on page 50 for more information. 84

87 Positioning gauge guide adjuster P.F.C. Sigma locator LCS Complete locator Femoral clamp attachment bar Positioning gauge guide Figure 28 Figure 29 Figure 30 It is essential that the P.F.C. Sigma or The assembly is placed on the anterior The face plate should rest flush against The lateral edge of the slot in the LCS Complete locator on the gauge is part of the distal femur, with the positioning the most distal condyle (Figure 29). positioning gauge is aligned parallel to correctly positioned in the femoral clamp gauge guide pointing along the anatomical Whiteside s line (Figure 30). (Figure 28). axis of the femur. 85

88 Secure the clamp legs using the hex head screwdriver Legs may also be secured with pins Figure 31 Figure 32 The gauge may be pinned in position on Note: At this stage the surgeon s assistant With the positioning gauge in place, push Final locking is completed using the hex the femur using two of the pin holes should hold the positioning gauge while the legs of the femoral clamp until they head screwdriver. This can be done from (Figure 31). the surgeon aligns the face plate with contact the surface of the bone. The legs either side of the clamp (Figure 32). If soft Whiteside s line. can then be locked in place using the top or osteoporotic bone is encountered, the locking screw. legs of the clamp may be secured with pins. 86

89 Conservative Distal Femoral Resection Figure 33 Figure 34 The IM hole is drilled through the The femoral fine tune mechanism is It is essential that the instrument is An IM rod is inserted into the femoral canal positioning gauge slot using a 5 /16 attached to the clamp (Figure 34). The correctly locked to the clamp. The using the Specialist 2 IM Rod Handle. Specialist 2 drill. The entry point for the IM varus / valgus, flexion / extension and undercut in the distal translation screw The IM rod slot is positioned upward to hole should be medial to Whiteside s line internal / external rotation positions should should click into place at the rear of the provide the most appropriate surface to (Figure 33). The positioning gauge is be set as close to neutral as possible. clamp. The resection plane is locked in tighten the distal plane screw onto. removed from the femoral clamp. place with the centre lock screw. 87

90 Figure 35 Figure 36 The IM rod handle is removed and the The pin on the distal plane finder should The arm of the plane finder should be The distal plane screw is used to tighten P.F.C. Sigma distal plane finder is contact the intercondylar notch (Figure 35). parallel to Whiteside s line to maintain the distal plane finder onto the slot of the attached to the IM rod. The plane finder is femoral rotation (Figure 36). IM rod. positioned with LT facing distally for a left knee or RT facing distally for a right knee. 88

91 Figure 37 Figure 38 The distal plane finder extender is placed extender and the distal plane finder The outer locking screws are tightened The plane finder, IM rod and plane in the most proximal distal plane finder extender. The distal plane finder extender and locked once the plane extenders are extenders are removed and a 5 mm slot. The saw capture extender is should run parallel to Whiteside s line and aligned. The distal resection level is conservative distal resection is made positioned in the fine tune saw capture. remain in contact with the intercondylar adjusted on the fine tune mechanism until through the saw capture (Figure 38). The outer locking screws on the fine tune notch. the planes are in contact with each other mechanism are loosened to allow (Figure 37). alignment of the saw capture plane 89

92 Ligament Balancing When measuring extension gaps for P.F.C. Sigma fixed bearing or Rotating Platform components, 1 mm should be added to the absolute thickness of the spacer block required when measuring the extension gap. Figure 39 Figure 40 The spacer blocks supplied with the back up system can be used to perform ligament balancing in flexion and extension (Figure 39). Ligament releases may be made as required. Spacer block instruction tables are printed on the inside of the instrument tray lids. These tables should be used as a guide to selecting the appropriate block sizes (Figure 40). 1. Select the knee system and the size of femoral component to be implanted. 2. Read down the column to locate the bearing size required. 3. Read across the row to find the Absolute Thickness to determine the flexion gap spacer block size. 4. Select the appropriate sizes indicated in the Base and Shim columns. 5. Attach the P.F.C. Sigma tray alignment handle to the anterior face of the spacer base and position it on the resected tibial surface. The spacer blocks are used to assess the flexion and extension gaps. Note: Resize the bearing component by assembling thicker or thinner spacers based on the absolute thickness recommended for the desired bearing size. 90

93 A/P Femoral Resection A/P carrier locks A/P carrier Saw capture slot A/P cutting block lock A/P cutting block Figure 41 Figure 42 Figure 43 The surface of the anterior cortex of the femur is exposed using an osteotome or small chisel (Figure 41). The appropriate sized A/P block is slotted into the A/P carrier and locked into place (Figure 42). The assembly is slotted into the distal saw capture on the fine tune device (Figure 43). Note: A thin osteotome can be used to create the notch through the anterior slot of the A/P block. 91

94 Resection scale Figure 44 Figure 45 The A/P gauge is positioned in the anterior The A/P carrier is locked in place and the Alternatively, a conservative anterior If the A/P gauge is unable to contact the slot of the A/P block. The A/P block is A/P block is pinned to the femur. The resection can be performed using the anterior cortex the anterior cut can be adjusted to align the A/P gauge with the anterior and posterior femoral resections incremental scale on the A/P carrier. checked using the A/P gauge and the resected notch on the anterior cortex are made and the A/P assembly removed resection level adjusted in 1 mm (Figure 44). (Figure 45). increments until correct. 92

95 Final Distal Femoral Resection Figure 46 Figure 47 The spacer blocks are used to measure the extension and flexion gaps. Both the Any additional distal femoral resection is calculated by subtracting the extension The position of the distal femoral resection is verified by inserting the saw capture flexion and extension gap should be equal and rectangular (Figure 46). gap from the flexion gap. plane extender inferiorly into saw capture (Figure 47). 93

96 Translation scale Figure 48 Figure 49 The distal saw capture is adjusted using the axial translation scale. The 1 mm increments indicate the resection depth for the final distal femoral resection (Figure 48). The resection is made (Figure 49) and verified in both flexion and extension using the spacer blocks. The A/P block is replaced on the femur to allow the chamfer cuts to be made. Final femoral and tibial preparation and implantation are completed as shown on pages 60 to