KneeAlign 2 System. Surgical Technique Manual Tibia and Distal Femur Navigation

Transcription

1 KneeAlign 2 System Surgical Technique Manual Tibia and Distal Femur Navigation

2 KneeAlign 2 System precise alignment simplified This technique guide describes the proper use of the KneeAlign 2 System. This system is not compatible with its previous generation, the KneeAlign System and the two systems should not be used in the same operating environment. Any reference below to the navigation unit or sensor refers to the KneeAlign 2 unit and Reference Sensor 2 system components. Table of Contents SETUP 1 Install Sensor Battery Confirm Sensor ID Attach Bracket Hold Horizontally Hold Vertically Verify Calibration Assemble Femoral Jig Assemble Tibial Jig Select Knee Select Bone... 6 FEMUR 1 Secure on Femur Input A/P Offset Attach Sensors Maneuver Leg Set Resection Plane Set Resection Depth Finished Femur...11 tibia 1 Attach Sensors Secure on Tibia Match Probe Offsets Register Lateral Malleolus Register Medial Malleolus Set Resection Plane Set Resection Depth Finished Tibia...17 disposal...17 troubleshooting Setup...18 Femur Maneuver...18 Tibia...19 System...19 technical bulletin 1. Placement of Femoral Jig Maneuver Too Slow Rejection Inconsisten Hip Point Error Distal Resection Depth Settings Distal Cut First...22 Specifications Ordering Information...23

3 Set up 1 Install Sensor Battery a b a Open navigation unit package and pass sterile inner blister package into operative field. b Remove navigation unit and sensor battery from blister pack. c Turn navigation unit on by pressing center button. d Insert battery into sensor and close cover. c d + TIP: Sensor LED will slowly flash yellow to indicate battery has been inserted correctly. LED will momentarily flash green and navigation unit will move to next screen when sensor is found. 2 Confirm Sensor ID Navigation unit screen displays serial number of sensor to which it is paired. If this number matches that marked on sensor being used, press center button.otherwise, press left button to let navigation unit find another sensor. Repeat until correct sensor serial number is displayed. TIP: Navigation unit will move to next screen when pairing is confirmed. 1

4 Set up 3 Attach Bracket Attach navigation unit to mounting bracket by sliding unit in the direction indicated by arrow on bracket. Attach sensor to coupler at other end of mounting bracket as shown. Press center button when completed. If navigation unit is dropped on floor, it must be discarded. If sensor is dropped on floor, it must be returned to manufacturer for verification of function and calibration. 4 Hold Horizontally Calibration 1: Rest navigation unit horizontally on level surface with screen facing upwards and hold steady with ball in circle. Navigation unit will beep twice and automatically proceed to next screen. TIP: During calibration steps: Navigation unit must be maintained in steady position, or calibration will not be accepted. A red hand will flash on screen to indicate that unit is not steady. Level must be green, but ball does not need to be in exact center of circle. 2

5 Set up 5 Hold Vertically Calibration 2: Rest navigation unit vertically on level surface and hold steady with ball in circle. Navigation unit will beep twice and automatically proceed to next screen. 6 Verify Calibration Calibration 3: Rest navigation unit in angled position on level surface and hold steady with ball in circle. Navigation unit will beep twice and automatically proceed to next screen. TIP: Displayed angles should be 2 or less. If navigation unit does not proceed to the next screen after several seconds, check that navigation unit and sensor are correctly attached to the bracket and press left button twice to repeat from step 4. 3

6 Set up Maximum Setting 7 a c b d Assemble Femoral Jig a Push guide rod in direction indicated by arrow labeled Lock until it stops. b Fully extend slider to its maximum setting in order to position guide rod against gold latch. Ensure gold latch is unlocked. c Lock guide rod by sliding gold latch into position. d Slide femoral cutting block onto guide rod in direction indicated by arrow on cutting block labeled Assemble until it locks into place. Lock Assemble Femoral Jig (cont.) Once assembled, ensure microblock is in neutral position by adjusting varus/valgus and flexion/extension screws with ball driver. Press center button when completed. TIP: Plate and bracket of microblock should be approximately parallel to each other when viewed from front and side. F/E V/V Neutral Position Plate Bracket 4

7 Set up 8 Assemble Tibial Jig Assemble tibial jig as follows: Set fixation arm on proximal end of tibial jig to Left or Right for leg being operated on. Ensure that varus/valgus and posterior slope levers of tibial jig are locked. Attach midline probe (a) to proximal end of tibial jig. Attach shin spacer (b) to tibial jig. Attach ankle tube (c) to distal end of tibial jig and lock in place. Attach malleolar probe (d) to ankle tube. Press center button on navigation unit when completed. TIP: Fixation arm is spring-loaded and may be adjusted by pulling arm away from jig, then rotating. TIP: Shin spacer may already be attached. TIP: Squeeze button on ankle tube and insert malleolar probe through slot until it reaches limit of its travel. Use curved malleolar probe to extend range for extremely long or short tibias. c a b d Tibial Jig Assembly Order Assembled Tibial Jig 5

8 Set up 9 Select Knee Press button to select L (Left) or R (Right) for leg being operated on. 10 Select Bone Press button to select tibia or femur. TIP: If TIB is selected, proceed to Tibia resection steps on page 12. If FEM is selected, proceed to Femur resection steps on page 7. 6

9 Femur 1 Whiteside s Line Epicondylar Axis Secure on Femur Expose knee. Place knee in flexion and seat microblock on femur in approximately neutral varus/valgus and flexion/ extension position. Insert headed pin in center hole of microblock slider and drive it into most distal point of sulcus of trochlea, directing it toward center of femoral head. TIP: A typical IM drill placement approximates this point. Do not bias medially or laterally. Rotate microblock to approximately line up with Whiteside s line. Slide microblock in anterior/posterior direction as necessary to achieve three-point contact to femur. Pin medial and lateral feet of instrument against condyles, using headed pins provided in instrument tray. Press center button when completed. Hardened, stainless steel headed pins provided in instrument tray should be used. Do not impact or hammer system components. TIP: Verify that there is approximately 10 mm of clearance between femoral cutting block and anterior condyles. 2 Input A/P Offset Read anterior/posterior offset position of center pin on microblock slider scale. Enter offset value into navigation unit by pressing right button until correct number is displayed on bottom right corner of screen. Press center button when completed. TIP: If displayed value exceeds desired offset, continue to press right button to cycle back to desired value. Read A/P Offset 7

10 Femur 3 Attach Sensors Attach navigation unit and sensor to microblock. Align ball in center of rectangular box on side of screen by changing angle of femur until box turns green. TIP: Navigation unit on mounting bracket should be attached to coupler adjacent to white dot on microblock. Sensor should be attached to coupler adjacent to black dot on microblock. TIP: If sensor is not attached correctly, box on the side of screen will not appear and screen will read Mount Sensor Here. Once navigation unit and sensor are attached, do not adjust varus/valgus or flexion/extension screws of microblock until after completing hip point registration (Femur 4). 4 Maneuver Leg Hold Still in Start Position Move Knee Medial/Lateral 8

11 Femur 4 Maneuver Leg Hold femur stationary until green light appears on navigation unit screen and unit starts to beep continuously. As soon as navigation unit starts beeping, maneuver femur rapidly as follows while keeping the pelvis stationary: First, move knee in medial-lateral arc by internally and/or externally rotating hip while keeping heel on table, and maintaining knee in flexion. Next, move knee in sagittal plane by flexing and extending hip. TIPs for Maneuver: Maneuver must be completed before beeping stops and as rapidly as possible. TIP: Maneuver leg using two hands, grasping behind knee and ankle. Do not hold navigation unit or femoral jig. Rotate knee between 10 and 45 subtended during registration maneuver. For accurate results, it is important that hip is kept stationary during registration. Knee must be returned to start position (within ± 2 cm and ± 5 rotation). TIP: Following maneuver completion, during hip point calculation, navigation unit screen will provide user with feedback on speed of maneuver in medial-lateral (M/L) and anterior-posterior (A/P) planes. Green bars displayed for a given plane indicate that speed of the maneuver is sufficient in that plane. Red bars displayed for a given plane indicate that speed in that plane is insufficient. TIP: In the event maneuver is too slow in a given plane, or otherwise insufficient, navigation unit screen will provide instructions to repeat maneuver. Flex/Extend Hip Return Gently to Start Position, Hold Still 9

12 Femur 5 F/E V/V Set Resection Plane Set desired varus/valgus and flexion/extension angles using ball driver to adjust microblock s navigation screws. Press center button when completed. TIP: Navigation unit must be oriented within its operating range in order for unit to display resection angles. TIP: Varus/valgus and flexion/extension angles are measured relative to mechanical axis of femur. Do not attempt to adjust cutting block orientation by applying force to jig. Angles must be adjusted using ball driver to adjust screws prior to pinning the cutting block. Applying excessive torque to adjustment screws at limit of travel will cause damage to microblock. If bone interferes with cutting block while setting resection angle, microblock has been pinned in too much flexion. Two alternatives may be considered: 1. Use sagittal saw to trim interfering bone to provide additional travel for cutting block. Care should be taken not to remove too much bone, which could cause notching or interfere with subsequent sizing. 2. Unpin microblock and re-pin closer to neutral flexion angle, repeating Femur s Set Resection Depth Remove navigation unit/bracket assembly, and sensor from microblock. a Attach distal guide to microblock guide rod by squeezing pushbutton (b), and slide distal guide to desired resection depth (c). d Press gold latch on side of microblock to unlock guide rod/cutting block assembly from its maximum anterior position. Position distal guide paddles flush against condyles, and slide cutting block posteriorly to contact femur. e Pin distal femoral cutting block to anterior femur using most proximal holes using headless pins provided in instrument tray. f Remove pins from microblock by pulling in distal direction, while securely holding cutting block in place. Fix cutting block with oblique pin if desired. g Resect distal femur. Press center button when completed. Resection Scale a c b d Unlock 10

13 Femur 6 Set Resection Depth (cont.) TIP: Resection depth is indicated by scale on anterior face of guide rod, viewed at top of distal guide. Shoulder on guide rod stops distal guide at 9 mm resection depth. Resection depth can be increased in 1 mm increments by squeezing pushbutton and pulling distal guide up. Resection depth measurement should be set according to implant manufacturer s recommendations. Resection depth scale is relative to position of distal guide. Ensure that distal guide paddles remain flush on highest point of condyle being referenced. TIP: When pinning the cutting block, take care to avoid applying excessive force that could alter intended varus/ valgus and flexion/extension angles. To prevent potential interference of oblique pin with microblock pins, do not insert oblique pin until microblock has been removed. Use angel wing stylus to verify resection level prior to resection. TIP: If more bone needs to be resected, move cutting block proximally on parallel pins (+2mm, +4mm). Required saw blade thickness is 1.27 mm (or in). e f g If distal guide contacts condyle before the desired depth setting is reached, microblock has been pinned in too much extension. Unpin microblock and re-pin closer to neutral flexion angle, repeating Femur s Finished Femur Use of navigation unit for distal femoral resection is finished. TIP: Press center button to continue if additional use is appropriate in this procedure. Removal of navigation unit from bracket 11

14 Tibia 1 Attach Sensors Remove navigation unit and sensor from mounting bracket and attach to tibial jig. Press center button when completed. TIP: Attach sensor so that it is on lateral side of tibial jig (opposite fixation arm) during procedure. 2 Secure on Tibia a Pull malleolar probe to maximum anterior position in order to avoid interference during placement of jig. b Place tibial jig on anterior tibia, aligning etched line on fixation arm of jig with medial third of tibial tubercle. c Position tip of midline probe just posterior to insertion of Anterior Cruciate Ligament (ACL). d Secure fixation arm to tibia with at least two headed pins provided in instrument tray. e Secure mid-tibia v-rest of tibial jig with calf strap. Press center button when completed. a c b d 12

15 Tibia 2 e e Secure on Tibia (cont.) Midline probe should not be impacted into tibial plateau. During pinning, ensure that midline probe is not pulling away from main tibial jig body. If it has, push probe down to reseat. After pinning, fixation arm should be inspected to verify it has not pulled away from main tibial jig body and that it is seated fully within notch in jig body. If fixation arm has disengaged from jig body, push jig towards tibia to fully reseat fixation arm in jig body. TIP: Hardened, stainless steel pins provided in instrument tray should be used for pinning KneeAlign 2 instrumentation. TIP: If jig appears in extension relative to tibia, remove shin spacer. This may be the case for very obese legs. 3 Match Probe Offsets Confirm tip of midline probe is placed just posterior to insertion of ACL. Read number on midline probe where arrow indicates. Release PS and V/V levers to allow jig to move freely. Set matching number on malleolar probe by pushing button on ankle tube and sliding malleolar probe to desired position. Press center button when completed. Release Levers Release Levers 13

16 Tibia 4 Register Lateral Malleolus Palpate lateral malleolus and place cup of malleolar probe on its apex. Press center button to register lateral malleolus. TIP: Extend jig distally if necessary, by releasing ankle tube latch. In event that leg is positioned at orientation outside of range of KneeAlign 2 system, box at top center of screen will turn orange. Change position of leg until black ball is within square box and box has turned green. TIP: A double beep will sound on registration. Navigation unit must be maintained in steady position or red hand will flash on screen. Ankle tube should be locked during registration. 5 Register Medial Malleolus Palpate medial malleolus and place cup of malleolar probe on its apex. Press center button on navigation unit to register medial malleolus. TIP: A double beep will sound upon registration. After registration, do not move base of jig relative to tibia. Keep fixation arm and v-rest in their attached positions. Pushing or pulling fixed base of jig may introduce errors in navigation accuracy. 14

17 Tibia 6 Set Resection Plane V/V V/V Lock P/S Lock Retract malleolar probe to maximum anterior position. Move distal end of tibial jig to obtain desired varus/ valgus and posterior slope angles and lock in place with side levers. TIP: Malleolar probe may be adjusted to assist in setting posterior slope angle. Do not use malleolar probe to set posterior slope angle if posterior slope lever is locked. After locking levers, do not move jig relative to the tibia. Pushing or pulling locked bars of the jig may introduce errors in navigation accuracy. KneeAlign 2 System does not display measurement values when oriented outside of its operating range. Change position of leg until black ball is within rectangular box and box has turned green. Posterior Slope Press center button on KneeAlign 2 when this step is completed and remove midline probe by pulling straight up. 15

18 Tibia 7 Adjust Resection Depth Release Cutting Block Set Resection Depth Insert tibial cutting block and rotate it into position against tibia. Attach resection stylus to tibial cutting block. Push release plate of tibial jig up to adjust height of the tibial cutting block (locking mechanism on cutting block is in 1 mm increments.) Once tibial cutting block is at desired position, pin in place with headless pins provided in instrument tray using distal pin holes. Resect tibia. Press center button when completed. Prior to resecting tibia, confirm that posterior slope and varus/valgus angles still match desired values. Use angel wing stylus to confirm resection level and perform a visual confirmation of alignment. TIP: While setting resection depth, stylus end should not be pressed into tibial plateau. TIP: Resection depth measurement should be set according to implant manufacturer s recommendations. TIP: If additional support is required, place oblique pin through tibial cutting block. TIP: If additional resection is required, move cutting block down on pins (2 mm). Tibial jig will need to be removed to facilitate this. TIP: Required saw blade thickness is 1.27 mm (or in). Verify resected tibia with drop rod. 16

19 Tibia 8 Finished Tibia Use of navigation unit for tibial resection is finished. TIP: Press the center button to continue if additional use is appropriate in this procedure. Prior to disposal, power off navigation unit by pressing left and right buttons for 2 seconds. DIsposal a To power off navigation unit, press and hold down left and right buttons simultaneously. Navigation unit must be powered off and discarded. b Battery must be removed from sensor and discarded Sensor, calf strap, and pins must NOT be discarded. These items should be returned to their designated locations in the instrument tray. a b 17

20 Troubleshooting Setup Calibration step during set-up invalid due to incorrect attachment of sensor. Reattach sensor correctly and repeat validation steps. Sensor not attached correctly to femoral jig. Reattach sensor as shown in Screen F3. femur maneuver Hold knee steady before beginning maneuver. Hip point registration maneuver performed too slowly in either, or both anterior/posterior (A/P) or medial-lateral (M/L) planes. Press center button to repeat maneuver at higher speed sufficient to obtain green color bars for both A/P and M/L speeds. Hip point registration maneuver not finished prior to end of navigation unit beeping stream. Press center button to repeat maneuver, finishing maneuver and returning knee to starting position prior to end of unit beeping stream. Knee was not returned to starting position at end of maneuver. Press center button to repeat maneuver, returning knee to within ± 2 cm and ± 5 rotation of starting position prior to end of unit beeping stream. During hip point registration, software conducts a check for consistency of data throughout the maneuver. Inconsistent data triggers a rejection of registration. This can be caused by movement of pelvis, inadequate fixation of microblock to femur or excessive deceleration when heel is repositioned at the end of maneuver. If maneuver was conducted without these errors, press right button to proceed. Press center button to repeat maneuver if desired, ensuring the following: Use three headed pins (provided with KneeAlign 2 System) to mount the microblock to femur. Ensure microblock is secured with firm, three-point contact to femur. At end of hip point maneuver, place heel down gently. Stabilize pelvis during maneuver and ensure femur is free to move through full range of motion. 18

21 Troubleshooting femur maneuver (cont.) Press center button to repeat maneuver, increasing femoral rotation to at least 10. Jig pinned out of range of valid varus/valgus and/or flexion/extension values. Adjust or re-pin jig into neutral position and press center button to repeat maneuver. If jig re-pinned, back up to Femur 1. Generic hip point failure. Press center button to repeat maneuver. No maneuver detected. Press center button to repeat. Tibia Sensor medial-lateral position on tibial jig was changed during registration process. Attach sensor to lateral side of tibial jig and restart tibial navigation 3 (Register Lateral Malleolus). Sensor signal is lost. Remove and reattach sensor battery to re-establish connection. system There is a major system fault and navigation unit must be turned off and replaced. Please recover faulty unit and return to manufacturer for analysis. 19

22 TECHNICAL BULLETIN 1. Placement of Femoral Jig Description Appropriate placement and fixation of the femoral jig is necessary for system function. Placing the jig either in too much flexion or in too much extension can result in subsequent interference between the instruments and the femur. Instructions Prior to pinning the microblock, adjust it to be in a neutral position as shown in set-up step 7 of the technique. When pinning the microblock, orient the middle pin so that it is pointing toward the head of the femur. Prior to inserting the medial and lateral fixation pins, ensure A/P offset scale is at least 3, unless the A/P size of the distal femur is exceptionally small. Verify that there is approximately 10mm clearance between the femoral Figure 1. Neutral placement of the cutting block and the anterior aspect of the femur (Figure 1). microblock. Note clearance between If the femur interferes with the cutting block while setting the resection the femur and the cutting block. angle (Figure 2), a sagittal saw may be used to trim the interfering bone to provide additional travel for the cutting block. Care should be taken not to remove too much bone, which could cause notching or interfere with subsequent sizing. Alternatively, the microblock may be re-pinned in a more favorable position. In this case registration and resection angle adjustment steps must be repeated. If the distal guide contacts the condyles or other instrumentation before reaching the desired resection depth (Figure 3), the guide may be set at a depth 2 mm or 4 mm greater than the target depth. Pin the cutting block using the +2 mm or +4 mm holes, and shift the cutting block distally after removing the Microblock. Alternatively, the microblock may be re-pinned in a more favorable position. In this case registration and resection angle adjustment steps must be repeated. Clearance Cutting block interfers with femur when adjusted toward neutral flexion. Distal guide contacts condyles before desired depth is reached Microblock Angle Mechanical Axis Microblock Angle Mechanical Axis Pin Axis Figure 2. Mounting the microblock in excessive flexion results in interference between the cutting block and femur. Pin Axis Figure 3. Mounting the microblock in excessive extension results in interference between the distal guide and femoral condyles before reaching desired resection depth. 20

23 TECHNICAL BULLETIN 2. Maneuver Too Slow Rejection during Hip Point Registration Description During hip point registration the software requires that the user maintain a minimum average angular speed in both the A/P and M/L directions. If either speed falls below the allowed limit the registration will be rejected. The display on the navigation unit will indicate the maneuver speeds for each direction (A/P and M/L). More bars indicate higher speed. Green bars indicate sufficient maneuver speed, while red bars indicate insufficient speed. Instructions Prior to surgery, practice maneuver on sawbones to develop a feel for a suitable maneuver speed. If a Maneuver Too Slow message is received, increase the speed of the maneuver in the direction indicated by red bars on the navigation unit display. A common tendency is to exaggerate the A/P motion when increasing maneuver speed. If only the M/L direction needs to be accelerated, do not unnecessarily exaggerate the A/P motion. Take care not to move the pelvis by exaggerating the size of the maneuver when increasing maneuver speed. 3. Inconsistent Hip Point Error during Hip Point Registration Description During hip point registration, the software conducts a check for consistency of the data throughout the maneuver. Inconsistent data triggers a rejection of the registration. This can be caused by movement of the pelvis, inadequate fixation of the microblock to the femur or excessive deceleration when the heel is repositioned at the end of the maneuver. Instructions Use at least three headed pins to mount the Microblock to the femur. Ensure the Microblock is secured with firm, three-point contact to the femur. At the end of the hip point maneuver, place the heel down gently. Stabilize the pelvis during the maneuver and ensure that the femur is free to move through the full range of motion. Remove any retractors or other instruments that could hit the sensor during the hip point maneuver. 21

24 TECHNICAL BULLETIN 4. Distal Resection Depth Settings Description The Distal Guide and Microblock provide five depth settings: 9 mm-13 mm in 1 mm increments. The Distal Guide stops on the Microblock Guide Rod at the default value of 9 mm. Instructions Read the depth setting at the top surface of the Distal Guide. At the 9 mm and 11 mm settings, the markings on the rod and Distal Guide align, as shown in Figure 4. The entire number should be visible at these positions. These marks line up These marks don t line up Bottomed out on shoulder These marks line up Figure 4. Aligned depth marks at 9 mm and 11 mm settings Figure 5. The marks do not align at the 10 mm depth setting. 5. Distal Cut First The KneeAlign 2 System can only be used with Distal Cut First surgical techniques and instrumentation. Most contemporary implant systems offer a DCF option. 22

25 instrument specifications Ordering Information Product Description C catalog Number KneeAlign 2 Navigation Unit KneeAlign 2 Instrument Set Replacement Parts KneeAlign 2 Tibial Jig Body KneeAlign 2 Mounting Bracket Ankle Tube Ball Driver (2.5 mm) Calf Strap Distal Guide Assembly Femoral Cutting Block Assembly Malleolar Probe, Curved Malleolar Probe, Straight Microblock Midline Probe Assembly Pin Driver, Tri-Flat Reference Sensor Resection Stylus, Adjustable, Captured Shin Spacer Threaded Pin, Headed (46 mm, 2-Pack) Threaded Pin, Headless (65 mm 2-Pack) Tibial Cutting Block, Left Tibial Cutting Block, Right Note: For cleaning and sterilization instructions, please refer to the Instructions for Use. 23

26 Straight Malleolar Probe Curved Malleolar Probe Calf Strap Sensor Ankle Tube Shin Spacer KneeAlign 2 Tibial Jig Body Tibial Cutting Blocks (left and right) Adjustable Stylus Midline Probe Threaded Pin Headless (65 mm) Threaded Pin Headed (46 mm) Pin Driver Ball Driver Distal Guide Microblock Mounting Bracket Distal Femoral Cutting Block 24

27 Notes KneeAlign 2 System Surgical Technique Manual

28 About OrthAlign, Inc. OrthAlign is committed to providing surgeons with user-friendly, cost-effective, surgical navigation products for precise alignment. For more information about the KneeAlign 2 System, please contact us at or info@orthalign.com. 120 Columbia, Suite 500 Aliso Viejo, CA / Rev P