Welcome to the C-Leg 4 online training course. My name is Ariel Cabana and I am a member of the Professional & Clinical Services team at Ottobock.
1 Ottobock’s mission is to help people maintain and regain their freedom of movement
2 The first C-Leg came to market in 1999. With its evolution, the C-Leg, now on the 4th version, has continually improved to provide more safety and improved dynamics. The C-Leg 4 offers additional safety with enhanced stumble recovery to minimize the risk of falling. Stance release is much easier and a standing function which allows standing on a flexed knee under load can help improve the user’s flexibility and freedom of movement.
3 The detected parameters are directly measured via sensors inside the joint. • The knee angle sensor measures the flexion angle of the knee joint as well as the speed of flexion. • The Knee moment sensor detects a certain knee extension moment • The inertial motion unit measures linear acceleration of the joint in 3 axes, shank inclination (+ velocity) via a gyro measures inclination of the prosthesis in space + speed of inclination change.
With this new technology and the inertial motion unit, there is no need for an ankle sensor allowing a standard 34 mm pylon to be used that will be supplied with the knee.
4 With the C-Leg 4 there is no danger of stance release while walking backwards (walking backwards safely is possible). The movement monitoring feature is active during the whole gait cycle and ensures that there is no stance release during instable static and dynamic situations. In addition, different surfaces or a different body weight (i.e. when carrying a heavy backpack) does not change stance release behavior.
5 The C-Leg 4 is easier for the patient and the CPO. There are few parameters to program making the knee easy to adjust. There is a new protective cover and guard to protect the knee. Bluetooth is integrated into the knee and by default it is always active, the user can turn it off if desired. The knee comes with a standard 34 mm pylon that can be cut to the needed length; this increases build height and offers options for more dynamic feet. In addition, there is now an app for Android and Apple devices that offer easier mode switching among other features.
6 The knee joint is weather-proof with an IP67 rating, but it is not resistant to corrosion. There are many corrosive elements in soaps as well as chlorinated and salt water. Should the knee come in contact with any of these elements rinse it with fresh water. Send the knee to service if there is any malfunction.
7 The stumble recovery has been improved further with the C-Leg 4 to provide additional safety and hopefully fall prevention. The flexion resistance ramps up higher than the adjusted setting if swing is interrupted to provide enhanced stability on the prosthetic side and allow more time to shift the body weight to the contralateral side.
8 One of the goals in the development of the C-Leg 4 was to provide a broader range of ADLs.
One of best new features is the intuitive stance function. The user can stand still with the knee bent and the knee will block flexion in that position. This is especially useful when standing on a slope such as in an auditorium with a slight pitch or waiting in line to board an airplane while walking down a jetbridge. This allows the user to shift their wieght fully onto the prosthesis and it will immediately block flexion to relieve the contralateral limb.
There is a manual function that can be activated as well, but this requires a more specific motion pattern. This may be preferable for a bilateral user to set on one side or a long time user who has utilized this function in the past. The following video (on the next slide) demonstrates both options.
9 VIDEO LINK: https://youtu.be/PQ8p2YCZiiw
VIDEO NARRATION: The knee joint is always locked in the flexion direction when the prosthetic leg is not fully extended and is at rest. The patient can fully load the prosthesis because it is locked in flexion direction. Upon forward or backward rollover the level of resistance is immediately reduced to stance phase resistance again. Intuitive stance can also be exited by full extension of the knee joint. For safety reasons, the blockade of the joint is only possible when the thigh is not inclined forward and not inclined backward more than 60 °.
To activate the manual stance function, the patient has to flex the joint between 5° and 65° and keep it still for one second. After that the patient slowly extends the joint up to the desired flexion angle. The patient holds the knee joint in this position for one second until it vibrates. Now the blocked joint can be loaded in the flexion direction. The patient can change this position by slowly extending the knee joint. An exit of the manual stance function is only possible by rapid or complete extension of the joint. For safety reasons, the blockade of the joint is only possible when the thigh is not inclined forwardly and not inclined backwardly more than 60 °.
10 A Sitting Function provides a free knee for sitting and an additional energy saving feature. The Sitting Function can only be activated if the thigh is inclined >60° to level ground. It would be activated when someone is lying in bed for instance. This is ideal when a user is sitting in a confined area such as at a desk or in a movie theater where the knee will tuck back under them easily.
The C-Leg 4 is weatherproof with an IP rating of 67, and there are 2 additional modes for specific activities that can be programmed based on individual preference.
11 VIDEO LINK: https://youtu.be/pdyMJEDYZaw
VIDEO NARRATION: To increase the freedom of movement, the C-Leg 4 reduces the resistance in the flexion and in the extension direction after sitting down. When standing up the knee will automatically reengage stance resistance.
Enable the function by selecting the corresponding checkbox via the adjustment software. When the function is activated, it can be turned on or off subsequently using the Cockpit App or Remote Control.
12 The CPO adjusts the desired flexion angle in the adjustment software C-Soft Plus in degrees (e.g. 65°). The joint automatically controls the resistances during swing flexion so that the desired angle is reached.
If the user is walking so slowly that the desired angle cannot be reached, no additional resistance is set. 65° is biomechanical for maximum swing angle during walking speed.
13 In comparison to older C-Leg versions, there is different extension behavior for swing phase. For walking with slow speeds a basic extension resistance can be set. For fast walking, ramps, and stairs a minimal extension resistance is auto-adaptive to get the knee back into full extension reliably.
The automatic real-time control provides a smooth extension stop.
14 The C-Leg 4 can be connected to an osseointegrated system. Assure the manufacturer of the implant system allows exoprosthetic components and reference the Instructions for Use specific to that system.
15 Looking at the gait cycle helps us determine how the knee is functioning in real time during every step of gait. • At Intial Contact, the knee provides high stance resistance offering safety at heel strike. • In Loading Response, anatomically the knee bends approximately 15 degrees. The C-Leg 4 offers support for this stance flexion movement. • In Mid Stance, the forward movement of the body leads to a knee extension moment → the real-time controlled stance phase extension resistance provides a smooth extension stop. • In Terminal Stance, the knee joint switches off stance phase safety for easy initiation of swing phase. • In Preswing, the joint sets the lowest flexion resistance possible to make swing initiation as easy as possible requiring minimal hip flexion to initiate swing. Due to that, a moderate hip flexion moment is enough to initiate knee flexion. • Initial Swing is when the knee reaches its maximum flexion angle. The adaptive swing phase control ensures that the maximum flexion angle (normally 65°) is reached. The necessary flexion resistance is set automatically and adaptively by the C-Leg 4. • In Midswing a great safety aspect of the C-Leg 4 is apparent. During swing extension, a high flexion resistance is readily available for stumble
16 recovery. Should the user stub their toe in this phase, the user can additionally rely on the enhanced stumble recovery feature. • In Terminal Swing, the real-time controlled swing phase extension takes care of a smooth extension stop independently of the chosen walking speed. The necessary resistance is adjusted by the joint and stops the extension movement at 0°.
16 The continuous monitoring of the gait cycle ensures that stance is always released at the optimum point of time. Because of that, a harmonic gait pattern is reached and the safety for the user is increased.
17 As mentioned the C-Leg 4 monitors the gait cycle in real time. There is no longer an ankle moment sensor requiring a toe load. The knee uses an inertial motion unit thus the criteria for stance release are different than older versions.
The knee needs to be extended and there needs to be forward inclination and forward movement of the shank. The user must keep the knee moving forward over the entire foot. The release is independent of body weight changes and ground condition. Due to the forward movement detection, backwards walking with a fully extended knee is safe.
18 Due to the adaptive swing phase flexion control, a harmonic gait pattern is reached independently of the chosen walking speed of the user. If the flexion angle is too small, the toes may scuff the floor; if the flexion angle is too large, the user will be waiting for the knee to come into extension.
Because of the automatic adaptation, a different shoe weight is automatically compensated after a few steps. The following video (on the next slide) demonstrates swing flexion resistance settings.
19 The C-Leg 4 offers 49 mm or almost 2” of increased clearance over older versions allowing taller feet to be used and accommodating longer limbs or shorter stature users.
The smallest distance of knee axis to ground which can be fit with C-Leg 4 is 307 mm with a LoRider foot (289 mm distal system height + 18 mm system height LoRider).
The proximal system height is 5 mm with a pyramid connector or 23 mm with a screw top connector.
The C-Leg 4 with screw top connector (3C88-3) has a 3 mm increased proximal system height compared previous C-Leg versions.
21 The tube adapter can be cut to a minimum length. The tube adapter comes with or without torsion. The additional build height of the torsion unit is 40 mm.
22 To determine the necessary knee axis to ground distance for different feet, the tube adapter configuration tool in C-Soft Plus can be used. This tool can also be used without being connected to a knee.
23 There are a number of adapters that can be helpful during your fitting. The 4R170 offers A-P slide adjustment as well as flexion and rotation. For each recommended adapter the maximum permitted body weight should be taken into account as well as the positioning to assure no collision with the knee.
4R104: Moveable double adapter to optimize alignment in one dimension (only suitable for test fittings) 4R57: Rotation adapter to rotate the (flexed) knee around the socket 4R41 / 4R43 / 4R89 / 4R111 / 4R116 / 4R119: Different lamination anchors (three-pronged or four-pronged) with thread, pyramid adapter or pyramid receiver 4R170=1/2: Spherical siding adapter to compensate a flexion position of stump/socket (5°-12°) 4R118: Adapter plate to optimize alignment in a/p direction (also suitable for permanently fittings) 4R84: Double adapter as connection piece between prosthetic foot and tube adapter -> additional system height of 32 mm!
24 There are different mechanical feet permitted for use with the C-Leg 4. Due to the FDA approval of the C-Leg, the prosthetic components were required to be tested as a system, including the knee, pylon and foot.
Different mechanical and mechatronic feet are permitted for use with the C- Leg 4:
• Dynamic Foot: 1D10 • Dynamic Foot (Women): 1D11 • Adjust: 1M10 • Terion: 1C10 • Terion K2: 1C11 • Greissinger plus: 1A30 • Trias: 1C30 • Dynamic Motion: 1D35 • C-Walk: 1C40 • Triton: 1C60 • Triton Vertical Shock: 1C61 • Triton Harmony: 1C62 • Triton Low Profile: 1C63
25 • Triton Heavy Duty: 1C64 • Axtion: 1E56 • Lo Rider: 1E57 • Meridium: 1B1 • Triton smart ankle: 1C66 • Triton side flex: 1C68
The suitable prosthetic foot has to be chosen based on various criteria (e.g. mobility grade, body weight).
25 The Triton smart ankle, Meridium and now Empower, Ottobock‘s mechatronic feet, are permitted for use as well. There is a recommended sequence of fitting this combination. Please reference the respective online trainings for further information or contact a member of the Professional & Clinical Services team for additional support.
26 There is new software required for programming the C-Leg 4 called C-Soft Plus. Upon completion of this course, you will receive an email to download C-Soft Plus and you will have a specific username and unlock-pin. The Bluetooth is now internal so you only need the BionicLink PC 60X5 for programming.
Minimum system requirements for C-Soft Plus 4X440=*: PC with Pentium III/ 1 GHz 32-bit (x86) or faster 512 MB RAM / 1 GB free disk space Graphics accelerator with Open GL Resolution of 1024 x 768 at 96 DPI, 32 Bit color depth (16.7 million colors) CD-ROM drive / Mouse and keyboard / 1 free USB connection
The following 32 Bit operating systems are supported: Microsoft Windows 7 Microsoft Windows 8 Microsoft Windows 10
The following 64 Bit operating system is supported: Microsoft Windows 7 Microsoft Windows 8 Microsoft Windows 10
27 Only PC compatibility is guaranteed for C-Soft Plus 4X440=V1.0 (no support of Apple, iPads, smartphones). Most common net-books do not fulfill system requirements because of a too low vertical resolution.
Because of the automatic configuration, which is done during establishing a Bluetooth connection, no manual pairing has to be done anymore. It isn‘t possible to use the old Bluetooth dongle ANYCOM 250.
27 This slide indicates the required components on the left versus the optional components on the right available with the C-Leg 4. • Together the battery charger (4E50-2) and the AC adapter (757L16-2) make up the charging unit of the C-Leg 4. • Please reference the information for use manual for the CPO and the user as needed. • The knee extender (4H105) is a required component for establishing optimal bench alignment. • Flexion stops come pre-mounted at 8 degrees. If additional flexion stops are needed to prevent the socket hitting the posterior aspect, an optional 16 degree flexion stop (4H106) is available. • There is a new C-Leg Protective Cover with ankle cuff (4X860 =*) or C-Leg Guard (4P862=*) with exchangeable shield inserts (4P863=*) that can be used. • The remote control is no longer compatible as the user can use the Cockpit App with either an Apple or Android device. • Please see the Resources tab in the upper right for additional components that may be useful, including cosmesis and quick change adapters to change prosthetic feet.
28 Additonal optional components include a charger extension cable if a one piece cosmesis will be used. You can view the YouTube video for additional installation information.
VIDEO LINK: https://youtu.be/fhOk5afYfT4
29 Let’s take a look at the programming process: • The combination of username and Unlock-PIN enables every CPO to use any PC with C-Soft Plus installed to connect to the C-Leg 4 and make adjustments. • After successfully completing this certification course, a certificate and the Unlock-PIN are provided by the education department. • Open the Data Station, select or enter the patient name and new job, click on C-soft Plus, and then enter your username and unlock pin. • It will ask you to change your password to something you can remember. It is recommended to make all of your Ottobock software passwords the same for ease of use. You can always contact customer service to get your original unlock-pin and reset your password if needed.
30 The tube adapter configuration tool in C-Soft Plus helps you determine the pylon cut length and can be resourced without an active Bluetooth connection.
After entering the necessary data (foot type, foot size, system height of the foot, tube adapter type, preliminary distance knee center-to-ground), the correct cut length and insertion length of the tube adapter is calculated.
31 For a user with knee disarticulation or a very long residual limb, this measurement scheme cannot be used or may need to be modified. In this case, the knee rotation center of the joint may be set lower than on the contralateral side.
One possible procedure for determining the distance from knee axis to the ground is to measure the distance between the end of the socket and the ground without a shoe on the contralateral side. The build height of the lamination anchor must then be deducted from this distance.
32 Cut the tube adapter accordingly. Use caution when clamping in a vise and use protection. If clamped too tightly, the tube adapter can be deformed. Smooth the cut area inside and out for ease when inserting the tube adapter.
33 Insert the tube adapter a minimum of 40 mm to assure both screws can be securely tightened to no more than 7 Nm. It is recommended that the user sit during length adjustments because a forceful insertion of the tube over 55 mm can damage the joint.
If length adjustments are made, remember to change these values in the job specifications tab in C-Soft Plus as well.
34 Fully insert the charging cable and assure the knee is charging. After removing the charger, the knee joint performs a self test. The knee joint will beep and vibrate once indicating it is ready for operation. Charging is only possible at a temperature greater than 32° Fahrenheit.
VIDEO LINK: https://youtu.be/LmKEmQJgRyY
35 A new feature is available to indicate charge level and re-activate Bluetooth only if it has been turned off or at inital programming. In addition, a series of beeps will be heard indicating charging status.
• 5 beeps = Full charge • 3 beeps = about 50% • 1 beep = less than 35%
36 The knee can also be turned off for shipping or long journeys. Connect and remove the charger 3 to 4 times quickly until you heard a downard tone indicating the knee has been turned off. The charger will be needed to turn the knee back on.
VIDEO LINK: https://youtu.be/8Dqu7xPSEKo
37 The bluetooth module of the Cleg4 is always active now by default, however when first pairing the knee to the computer or the app the bluetooth must be made visible. To make the bluetooth visible it is necessary to turn the prosthesis upside down 180 degrees or attach and remove the charger. In both instances a 2 minute window is available to connect. If this time frame is exceeded the process must be repeated. After the initial pairing with the app or the computer this procedure is no longer necessary. If desired, Bluetooth can be deactivated in the app by the user or in the software by the CPO.
38 Connect the 60X5 to the PC, then select the connect button. When established, the connection icon is displayed in green and confirmed by a flashing LED on the knee joint and a feedback signal.
39 The following data has to entered into C-Soft Plus: • Body weight with prosthesis • Distance from knee axis to ground • Amputation level • Bilateral above-knee amputation • Foot type • Foot size
40 Under the Alignment tab, enter the degree of hip flexion contracture you measured when taking a Thomas-test during your initial evaluation. This defines the flexion contracture of the user in degrees and will help determine the proper flexion angle to set in bench alignment.
The effective heel height of the shoe can be calculated by subtracting the toe and heel difference. The heel height influences the individual alignment recommendation. A typical 3/8 inch heel height is equivalent to 10 mm. Select the amputation level and bilateral accordingly.
41 The Thomas-test is the best method to define a given hip flexion contracture of a patient.
If a flexion contracture is present, it has to be considered in the bench alignment to obtain an optimal result for the user. If the prosthesis is aligned too straight, it leads to poor gait biomechanics, such as insufficient step length, and can lead to potential low back problems for the user (hyper lordosis). If the contracture is unaccommodated, the knee will tend to bend immediately leading to potential safety concerns.
42 The correct socket rotation is crucial for the determination of the socket reference point (SRP). To get the correct socket rotation, it can help if the user dons the socket. Use a 50/50 gauge to find the proximal bisection of the socket at ischial tuberosity (IT) level. The SRP is 30 mm proximal to this point for a general hip rotation axis.
43 Select plumb line/lasar line in the software to obtain the individual bench alignment recommendation unless you have a PROSA assembly. Do not forget to use the knee extender during bench alignment.
44 The schematic on the left shows a proper bench alignment starting point. The image on the right shows an improper bench alignment. What do you see that is wrong with this picture?
An anterior tilt to the pylon is essential for stance release. If a hip flexion contracture (HFCx) is not accommodated, most often the foot will be plantarflexed initially when the socket should really be slid forward. Often we see the socket too posterior with the result being a plum line falling behind the knee. The knee is no longer over the ankle reference point (often at the anterior aspect of the pylon) and there is not a heel wedge being used for a built in safety factor.
45 The knee extender is a critical tool in assuring a proper bench alignment and encouraging a knee extension moment in Terminal Stance. You can see the knee extender changes the angle of the pyramid when used, allowing a more anterior placement of the socket during bench alignment. This is especially important when fitting a user with a large hip flexion contracture, a knee disarticulation, or using a 3 prong lamination anchor.
46 Insert the knee extender to the posterior aspect of the knee and turn the screw clockwise until the extender touches the flexion stops. Turn the knob 10 degrees full turns further. You can visibily see the knee pushed into extension.
VIDEO LINK: https://youtu.be/OwHi5p7kGKw
47 The photo on the left shows the effect of an alignment achieved using the knee extender. The photo on the right shows the effect of an alignment that was done without the knee extender. The slide notes the negative effects of not using the knee extender in bench alignment.
Getting the center of the socket positioned over the knee with the correct flexion accomodation is important for optimal dynamic alignment. If you do not use the knee extender, the foot will be more anterior and you will lose 2 degrees of the socket flexion you put in without using the knee extender as soon as the patient loads the prosthesis. The ground reaction force will be more anterior to the knee axis generating a higher knee extension moment. This will require the user to generate more hip muscle effort to initiate swing.
48 The criteria for stance release includes forward inclincation and movement of the shank as well as a defined knee extension moment.
If a new user is having a hard time releasing stance, some good cues are to: • Keep rolling over the entire foot, look up, and keep your momentum moving forward. • The release is independent of body weight and ground conditions.
49 The given alignment recommendation by C-Soft Plus should be followed precisely for an optimal starting point.
Assure you have clicked the plumb line unless you have a PROSA assembly and assure you have installed the knee extender. The first step is to find the Socket Reference Point (SRP) as discussed. Assure you have taken a Thomas-test and put in the correct flexion angle to accommodate any contracture. The plumb line should drop from the SRP 5 mm posterior to Knee Center and 30 mm posterior to the middle of the foot with the shoe on and a 5mm wedge placed under the heel of the shoe. This wedge is a built in safety factor.
The more accurate the individual alignment recommendation is followed, the better is the basis for the following static alignment optimization.
50 It is important to assure clearance between the socket and the knee in full extension and full flexion. Assure additional clearance when using a protective cover. It is recommended to place any 3 or 4 prong adapters with the screw medially, as well as the 4R57 rotation adapter button, to prevent contact with the knees main electronics.
(YouTube video link included in the next slide.)
51 VIDEO LINK: https://youtu.be/VTUPadqqzK0
VIDEO NARRATION: Following bench alignment of the prosthesis, it is necessary to check that there is no potential for contact between the socket and main electronics at maximum extension of the knee joint.
Even when there is still space when the knee is extended, collision and therefore damage to the main electronics of the knee joint may still result when weight is placed on the prosthesis. If, as in this case, the specified minimum distance is not maintained, readjustment of the distal socket area is required at a minimum.
The knee extender must be applied during bench alignment of the C-Leg 4 to simulate a loaded prosthesis. There must be at least 5 mm of space between the socket and main electronics even when the knee extender is applied. This is the case here.
Finally, the constructed prosthesis is checked once more on the user for sufficient distance under a load in a static situation. If a C-Leg 4 protective cover needs to be installed later, the required safe distance between the prosthetic socket and main electronics increases from 5 mm to 10 mm. This is necessary as an installed
52 protective cover later reduces the available space by 5 mm.
Particular caution is required when a C-Leg from a previous generation is replaced with a C-Leg 4. Due to the additional extension potential of the C-Leg 4, switching the knee joints could result in contact between the socket and main electronics even when there was sufficient distance with the previous fitting. This is particularly important during trial fittings.
In conclusion, the distance between the socket and main electronics must always be checked when the knee extender is being used. If the specified minimum distance is not maintained, readjustment of the distal socket area is required at a minimum.
52 Here are the recommended torque values for different components. Once everything is torqued, have the user don the prosthesis and evaluate overall height as well as static alignment.
53 The next step in the programming process is to calibrate the knee in static standing. The user has to stand on a hard, level surface in an upright position. Remember to recalibrate after every alignment change. The software now provides quick start videos via YouTube links to assist with the programming process.
VIDEO LINK: https://youtu.be/jQGIhuOrXH8
54 The calibration sets the standing angle representing the degrees from vertical. We don’t want to see a posterior leaning pylon as the knee uses the forward tilt beyond the shank calibration angle for stance release. It is important that the shank has a slight anterior tilt; the knee is not flexing or moving.
Remember to recalibrate after any alignment changes or after torqueing the set screws. In addition C-Soft Plus will remind the CP to recalibrate at the end of programming.
55 The calibration screen provides error descriptions, rather than numbers, indicating if the static alignment is out of the range.
Assure the knee is extended, the user is standing with equal weight on both feet, and the feet are in alignment prior to calibration. Recheck bench alignment if one of these errors is present. The most common alignment issue tends to be a socket placed too far posterior.
The following video (next slide) demonstrates proper calibration.
56 VIDEO LINK: https://youtu.be/jQGIhuOrXH8
VIDEO NARRATION: The knee joint has to be calibrated in the standing position before the user walks with the prosthesis for the first time. This ensures that the knee joint works in a safe manner from the very start.
Calibration must be performed after both the static and the dynamic alignment optimization are carried out. An incorrect calibration can lead to the swing phase being triggered either too soon or too late. Tighten the tube adapter screws with 15 Newton meters after each change. For a correct calibration, ensure that the user is standing in his or her natural, upright position and that the user’s body weight is distributed evenly on both sides. The toes should be at the same height if the alignment is correct.
Three criteria are required for a successful calibration: • The user must stand still, • with the knee joint extended, • and the angle of inclination of the knee joint must fall within the calibration range.
57 Now perform the calibration in the adjustment software. If all of the criteria for a successful calibration are met, you can click the “Calibration” button. Successful calibration is confirmed with the message “Calibration complete” and the knee joint simultaneously emits a beep signal.
If one of the three listed criteria is not met, for example, because the user moves during the calibration, a message appears in the adjustment software. Make sure that the user stands still and with his or her leg extended. If the knee joint is not fully extended during the calibration, a message appears in the software as well. If the knee joint is not extended while standing, this could indicate that the alignment is less than optimal.
Take into account any hip flexion contracture which may be present during the prosthetic alignment by ensuring the correct flexion position of the socket, and check the foot position. If the lower leg is tilted too far to the front or rear, you will receive a message that the lower leg angle is outside the calibration range. Check whether the user is in his or her natural, upright position. A less than optimal prosthetic alignment may be the cause in this case as well.
The calibration can only be successfully completed once all of the deviations have been corrected. If calibration is not performed, or is deliberately performed incorrectly, this may result in undesired behavior of the knee joint and restrict its function or even endanger the user’s safety.
57 For stance phase control, only the stance phase flexion resistance has to be set. The stance extension resistance is controlled automatically in real-time.
Have the user sit initially to try out the recommended value and adjust the slider accordingly. Cue the user to sit with intention in a fluid motion so they don’t activate the intuitive stance function by hesitating. Fine tune this setting when descending ramps, curbs or stairs step over step.
(YouTube video link is included on the next slide.)
58 VIDEO LINK: https://youtu.be/6P1uQUoBjas
VIDEO NARRATION: The stance flexion resistance can be set up in the adjustment software for the patient individually. Based on body weight and lower leg length, a recommendation for the value is shown in the software in the field “Recommendation.”
First, the adjusted stance flexion resistance is checked while performing a sitting down movement. The patient should be able to load the prosthesis while sitting down. The flexion velocity should meet the patient’s need. The value can be adjusted via the adjustment software.
In the next step, the stance flexion resistance has to be checked while going downstairs. The value should meet the patient’s need. If the patient has the feeling that he is sinking down too fast, for example, the value can be adjusted in small increments via the software.
Finally, the value has to be checked while walking down a ramp. Here, too, the value can be adjusted, if necessary.
59 The final adjusted stance flexion resistance must offer the patient a satisfactory level of support in all three situations.
59 The swing phase flexion angle default is 65 degrees, which is biomechanically consistent with normal human locomotion.
The swing phase extension basic resistance can be set in the expert mode and only affects slow walking speed extension. The swing flexion adjustment is no longer accessible in the app. The only reason to change the value would be if the user had insufficient toe clearance or sometimes a user with a long residual limb might want a higher angle.
60 You can access the Swing Extension Basic Resistance, if needed, in the Data Overview tab. Click on expert mode to adjust this setting, which only affects slow level walking. Calibration can be performed directly in the Data Overview tab as well.
The following two slides show videos of the swing flexion angle and swing extension resistance.
61 VIDEO LINK: https://youtu.be/BOqAt4qj0rw
VIDEO NARRATION: The swing flexion angle describes the angle at which the knee starts to extend again. For a physiological gait it is approximately 65°, regardless of the walking speed. 65° is the standard value in the software. It can be adjusted individually for the patient.
While walking on level ground, this value is checked looking at how far the prosthesis swings backwards.
• If the value is significantly set too low for the patient, the prosthetic leg is coming forward too fast into knee extension. In addition the ground clearance can be reduced during swing phase. This could lead to a higher risk of stumbling.
• If the value is significantly set too high for the patient, the prosthetic leg is coming too late into knee extension. The patient has to wait for the prosthesis to come forward and is limited in walking speed. The gait is strongly asymmetric.
• If the value is appropriate for the patient, a symmetric pendulum behavior is
62 visible with adequate ground clearance.
62 VIDEO LINK: https://youtu.be/y0kTyXaTIXc
VIDEO NARRATION: The swing phase extension basic resistance is acting during slow walking on level ground. This parameter describes the resistance acting during the beginning of swing phase extension. It determines the extension speed and therefore also the duration of the extension movement.
The standard value in the adjustment software is preset to 20 and can be adjusted individually for each patient. The orthopedic technician checks the swing phase extension basic resistance steering slow walking on level ground.
• If the basic resistance is set significantly too low, the prosthesis is swinging forward too fast. The patient can get the feeling that the thigh is pulled forward by the prosthesis. The gait appears asymmetric.
• If the basic resistance is set significantly too high, the prosthesis is swinging forward too slowly. The prosthesis does not come forward in time or fully into extension. The patient must exert additional force to bring the knee joint into extension. This could be unpleasant for the patient.
63 • If the basic resistance is set optimally for the patient, the thigh is swinging forward in a harmonic way.
63 Under the Functions tab, the standing and sitting functions can be accessed to turn them on or off or change the standing function from automatic to manual. This would likely only be done for a long term wearer who used the manual function previously or if someone is having trouble sitting with intention and is engaging the lock too easily.
64 If the joint is at rest in flexion, it is instantaneously locked. If the user rolls forward or backward or unweights, the resistance is reduced smoothly.
For many users, the importance of the Intuitive Stance Function is not apparent at first. Activities of daily living reveal the benefits (for example, when standing on a slight slope).
VIDEO LINK: https://youtu.be/uIHK7U1oi2g
65 If the manual activation is selected, the user must flex the knee between 5 - 65 degrees and keep it at rest for one second. The user must then extend the joint to the desired angle and keep it at rest for one second until it vibrates. It will then be locked in that position. To exit the manual function extend the knee fully. There is a YouTube video that can be shown to the user to provide a visual reference.
VIDEO LINK: https://youtu.be/tkPj_ieizzI
66 The Sitting Function can only be activated if the thigh is inclined >60° to level ground. Either seated or in a supine position, the Sitting Function is activated. The knee switches into an energy saving mode when seated as well.
VIDEO LINK: https://youtu.be/yQfHdltw7BE
67 In this tab, the MyModes can be selected for the user in the order desired. The two MyModes can be activated via bouncing on the forefoot by checking the boxes accordingly. You can access the quick start video to demonstrate this bouncing motion for visual instruction, which may be useful for your patient.
VIDEO LINK: https://youtu.be/8spTUBQD0dc
68 “Basis” sets the starting resistance for the extended knee joint. “Gain” sets how fast the resistance increases with knee flexion. Depending on the set values for “Basis” and “Gain” the joint locks at a defined angle (this value is displayed in C-Soft Plus). The chosen name for the MyMode is also displayed on the Cockpit App or the remote control.
69 The software displays which devices are supported for use with the remote and/or the Cockpit App for Android, iOS, or both.
70 If you need the Bluetooth PIN, you can access this in the software without being connected to the knee. You can only be connected to one device at a time. Assure you have finished programming the knee, disconnect from the software and then connect via the App.
71 After the MyModes selection, the configuration data for the app or remote control has to be saved to the knee.
To connect the app or remote control, you must close C-Soft Plus as there is only one Bluetooth connection possible.
72 To manually switch without the app or remote control, the user initiates a bouncing mechanism according to the checked boxes set in C-Soft Plus by the CP.
The user always has to differentiate exactly between 3x or 4x bouncing. Even if bouncing was deactivated, it is always possible to go back from a MyMode to basic mode via bouncing (safety aspect).
The following video (next slide) demonstrates this motion pattern.
73 VIDEO LINK: https://youtu.be/8spTUBQD0dc
VIDEO NARRATION: With the help of the adjustment software, up to 2 modes can be configured. These MyModes can be selected by the patient using a special motion pattern, the Cockpit app, or the remote control.
The switching via motion pattern has to be activated by the orthopedic technician in the adjustment software.
To switch from the basic mode into the first MyMode, the patient stretches the prosthetic leg out to the back. With the prosthesis extended, the patient bounces exactly 3 times on the forefoot and waits for 1 second while containing contact with the floor. If the motion pattern was correct, you can hear a short beep and a vibration signal.
To confirm the motion pattern, the patient has to move the prosthetic leg immediately next to the contralateral leg, set it down and keep it still for approximately 1 second. The knee joint will emit a beep and a vibration signal 2 times and will switch into the first MyMode.
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If this confirmation signal does not sound, the motion pattern was not recognized and the joint does not switch into the first MyMode. Repeat the process to correctly switch to the desired mode.
To switch back into the basic mode, the same motion pattern is necessary. The patient has to bounce on the forefoot 3 or 4 times.
Switching from the basic mode into the second MyMode can be done in the same way, like switching in the first MyMode. However the patient has to bounce exactly 4 times on the forefoot.
For confirmation of the correct switching, the patient can hear a beep signal and a vibration signal 3 times.
Switching back from the second MyMode into the basic mode can be done by bouncing 3 or 4 times on the forefoot.
Direct switching between the MyModes is not possible.
74 In the Acoustic Signals tab, the volume of the acoustic signals can be adjusted. Warning signals are not affected by the adjustments.
75 In the case of a drained battery, the C-Leg 4 switches into safety mode.
This safety mode flexion resistance can be set in C-Soft Plus by the CP(O), and the user can feel what the safety mode would be like. In this tab, the knee joint simulates the special behavior of the safety mode.
If the user is not able to secure the heel strike actively via hip extension movement, a higher resistance is recommended to be set by the CP(O).
76 In the Data Overview, the values which are stored in the database can be transferred to the knee joint or vice versa. In expert function, every parameter can be adjusted directly.
77 The Maintenance tab provides information about the firmware, date of first use, and most recent maintenance. Information is provided when the knee joint requires maintenance or has to be sent in for service.
78 Under the Activites tab, measured activities can be calculated. The prosthetist first has to activate the data storage. The activity measurement can be reset and deactivated at any time.
79 You can see the activity distribution in a graph format as well. This is another way to view: • The Avg. number of steps/day • The Avg. walking speed • Number of steps on slopes, ramps and stairs • Time totals for walking, sitting, standing and use of MyModes.
This is a nice way to generate reports to monitor patient progress. You can print this for the patients chart periodically as desired. The ideal range to record activities is approximately 2 weeks and the maximum period for data collection is
80 limited to 6 months.
80 The C-Leg can be used in basic mode or in 1 of the 2 MyModes. Certain parameters can be adapted with the Cockpit app or remote control once these parameters are programmed by the CP.
81 The MyModes can now be activated with the Cockpit app on Android or Apple devices.
You will see DUAL labeled on the knee if it has DUAL compatibility. The remote control can not be used with an iOS compatible C-Leg 4.
82 It is possible to connect to 2 devices at once if you have two 60X5 BionicLink PCs. If not, you can open 2 Data Stations and program the first knee. Once complete, do not close the whole job, but disconnect and then connect to the second device to program. Save the 2 jobs at the end. You may consider saving them under Left and Right as an example.
83 Thank you for taking the time to learn about the C-Leg 4!
Please contact Ottobock’s Professional Clinical and technical Services (PCS) department for additional support you may need. We can easily assist you via phone or Facetime. In the Resources section on the upper right of this presentation, you can find additional training material, including PDFs of alignment, user training and the Cockpit app.
Thank you for your support of Ottobock! We wish you success in all you do.
84 Please click on the quiz link to take the mandatory quiz. A passing score of 80% provides verification that you have completed this course. Once our Education Team receives your quiz results, they will follow-up via email regarding the C-Leg 4 software, username and unlock-pin. If you would like CEUs, you can select that option as well and pay the fee.
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