The C-Leg 4 Microprocessor Knee

Reclaim your determination.

The best C-Leg of all time.

The C-Leg’s greatest strength is helping people achieve independence. No other microprocessor leg prosthesis is trusted by as many users worldwide. More than 60,000 fittings for people with transfemoral amputations have been carried out since 1997.

With its numerous innovative features, the new C-Leg marks the start of a new era: It’s the best C-Leg of all time – safer, more dynamic, more modern, easier. From stairs and ramps to varying surfaces and walking backwards – the C-Leg leg prosthesis adjusts itself dynamically to various everyday situations. A relaxed standing position with a slightly flexed knee is intuitive now. Also new is the design and also the option of controlling the knee joint via an app.

Finally, we’ve taken the stumble recovery function to an even higher level.

The C-Leg is now available on the NHS. Learn more on our dedicated MPK NHS Funding page.

Electronic control unit

The integrated microprocessor receives and processes sensor signals. It controls the movement of the knee joint in real time.

Inertial motion unit (IMU)

The gyroscope and acceleration sensors allow the position and acceleration of the C-Leg in space to be measured.

Prosthetic Control is based on motion analysis and additional force determination.

Bluetooth®

Integrated Bluetooth® technology permits straightforward communication with the joint. An existing connection is displayed with an LED. Bluetooth® can be deactivated if necessary.

Hydraulic unit

The hydraulic unit controls the C-Leg. It generates movement resistance for flexion and extension during the stance and swing phase.

Lithium-ion battery

A lithium-ion battery provides energy for controlling the knee joint. It is located right in the rotation axis of the C-Leg. If you use the C-Leg on a daily basis, we recommend that you always charge the battery overnight.

New carbon frame design

In order to withstand the varied demands of everyday life, the frame is made of carbon – an especially strong, high-grade and lightweight material. The frame houses and protects the electronics, the hydraulic unit and the battery.

Thanks to its new design, the C-Leg has a lower system height and therefore a larger fitting spectrum.

Knee angle sensor

The knee angle sensor provides important data: It measures the flexion angle and angular velocity of the joint.



Benefits at a glance

More freedom of movement

Thanks to a new, patented method for the C-Leg microprocessor leg prosthesis system, the user’s sequence of movement has become significantly easier – for example on challenging surfaces such as sand, grass or gravel. The flow of smaller step sequences and the user’s gait pattern when changing walking speeds are controlled more smoothly. Even if you’ve never worn a C-Leg before, this technology typically makes the adjustment period quite short.

Greater mobility

Fluid movements occur first and foremost when the prosthesis responds quickly to different everyday situations. The resistance of the C-Leg microprocessor knee adapts to all walking situations in real time, whether on level ground, stairs, ramps or varying surfaces. This gives you a noticeably smoother and more reliable movement pattern – and more energy for the better things in life.

Select the stance function yourself

The C-Leg microprocessor knee supports you when standing. Using a discreet movement pattern, you can assume a relaxed position with a slightly flexed knee. You might already be familiar with this function. It is especially comfortable on slopes and uneven surfaces. A new feature of the C-Leg microprocessor knee is that your prosthetist can alternatively set the intuitive stance function at your request. With this function, the joint detects from your movement when you’d like to stand in a relaxed position and when you need support for your next step.

Stumble recovery for enhanced safety

The C-Leg microprocessor leg prosthesis system has always put the user’s safety in numerous everyday situations first. A large number of studies have proven that the frequency of falls in people with a transfemoral amputation is significantly lower with the C-Leg in comparison to conventional prostheses. This makes the C-Leg one of the most reliable leg prosthesis systems out there. Scientific research shows that this increases confidence in the prosthesis and that users pay greater attention to their surroundings. We’ve taken the stumble recovery of the C-Leg to a new level: It is now even more precise and offers greater stability.

Comfortable sitting

Another new feature is the automatic sitting function. This function helps you assume a relaxed position after sitting down, as the joint swings freely.

Smart control via app

For the first time, the Cockpit app lets you control the C-Leg microprocessor knee directly using your smartphone (Android) and access information regarding the joint, such as the battery level. The C-Leg communicates with the app via integrated Bluetooth.

Wet or dry

The weatherproof C-Leg microprocessor knee is rated to IP67. This rating means C-Leg 4 is protected from damage due to incidental contact such as a downpour or temporary submersion in fresh water up to 1 metre for 30 minutes. Now everyday activities such as washing the car or watering your garden are no longer a concern.

Protection and attractive design

The C-Leg microprocessor knee Protective Cover safeguards the prosthesis system against jolts, the environment and normal wear and tear. It consists of a robust main protector component, a shield insert for the front side as well as a foot cuff. The Protective Cover also gives the leg a natural volume under long clothing.

Functionality

Intelligent System

The C-Leg technology provides intelligent control of the prosthesis system for people with a transfemoral amputation and adapts it to their gait pattern in real time. Behind this is a complex sensor system that captures data in real time and recognises which phase of walking you are in, whether on level ground, going down stairs step-over-step, or on slopes – and now on difficult surfaces such as forest floor, sand and gravel as well. This makes the C-Leg one of the most reliable leg prosthesis systems out there. Thanks to the prosthesis’ capacity to adjust itself, the user can also master small obstacles, unclear terrain or large crowds.

Technical Info

C-Leg 4 specifications

Highly stable yet lightweight carbon fiber frame

Patient weight: Max. 300 lbs/136 kg

Weight of the knee joint only: about 2.8 lbs / 1,235 g

Height of the knee joint with adapter: between 11.2 inches / 28 cm and 21 inches / 53 cm (with torsion adapter)

Adjustable activity modes: 2

Operating time with fully charged battery: 40 to 45 hours

Maximum possible knee flexion angle without flexion stop: 130°

*All components of your prosthesis must be appropriately rated to reach this weight limit. See your prosthetist for specifics.

Downloads

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C-Leg 4: User brochure

Download out latest C-Leg 4 brochure for end-users.

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C-Leg 4: Lifestyle image

Download a lifestyle image of the new C-Leg 4

C-Leg 4 - Product image

C-Leg 4 is available in 2 colours: Desert Pearl and Volcano Shadow

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C-Leg 4 -Limb build image

Download an image of the full C-Leg 4 limb build

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