C-Leg 4 above knee prosthetic leg

C-Leg 4: Reclaim your determination

Dependability you can count on

The C-Leg 4 continues the industry-leading tradition of improving outcomes for more than 60,000 fittings worldwide. With studies citing increased stability and reduced falls*, the C-Leg 4 is weatherproof, can be controlled with the Android Cockpit app, and makes walking backward easier. Whether on sidewalk steps or dodging subway crowds, the C-Leg 4 helps transform the way you walk.

Go to the Advantages for you tab below to learn how the C-Leg can transform the way you walk.

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Hydraulic unit

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

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.

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.

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.


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

Knee angle sensor

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

What you need to know

Advantages for you

Stop worrying about falls

No matter the terrain or your speed, the C-Leg 4 is always thinking about security—so you don’t have to. Its sensors recognize when you’re in an insecure position, and during a trip or stumble, increases resistance to provide the support you need to recover your balance. You can speed up, slow down, and go down stairs step over step with the assurance that the C-Leg 4 is there for you.

Real-time adjustments driven by 3D motion analysis

Since your motion occurs in three dimensions, the C-Leg 4 uses sophisticated sensors to determine where it is in space at all times and to make precise adjustments at every moment of every step. As a result, C-Leg 4 lets you easily navigate ramps, stairs, and nearly every type of challenging surface – even when walking backwards.


C-Leg 4 helps people master everyday life more confidently. With two additional MyModes, your Prosthetist can set up the knee to help make activities like biking, dancing, or golfing easier. Switching modes is simple, you can use the the Cockpit app for Android, remote control, and motion pattern to quickly change your settings using Bluetooth® technology.

Stance support when you need it

C-Leg 4 offers you the choice of Intuitive Stance, which recognizes you have stopped moving and dampens the knee in a slightly flexed position. This makes standing more comfortable and less tiring even on uneven surfaces, ramps, and slopes. This feature is sophisticated, adjusting and readjusting with every step in real time.

Easy going

Getting your prosthetic leg into motion is easy with the support from a C-Leg microprocessor. The smooth, natural start to your “swing phase” gives you the freedom and control you need to meet the challenges of your everyday life.

Every step is smooth and secure

Ottobock offers multiple feet options compatible with C-Leg 4 including the Triton family. Go to the Components tab on this page to view the list of feet.

How the C-Leg works

How the C-Leg Works

The innovative C-Leg was designed to reproduce the functions of a biological leg. Click here to see a video about how the C-Leg's microprocessor-controlled hydraulic system performs throughout your walking pattern ("gait cycle") to give you stability and control.


C-Leg 4 system components

Please go to the Downloads tab on this page to download a list of C-Leg 4 components and their product numbers.

Feet options

Ottobock offers multiple feet options compatible with C-Leg 4 including the Triton family as seen below:

The Triton Harmony with integrated vacuum technology

The Triton Vertical Shock (VS) with great shock absorption in a compact design

The Triton Low Profile, with especially low structural height for those who need the extra room

The Triton Heavy Duty, robust and waterproof, for particularly challenging conditions

The lightweight Triton carbon fiber foot with exceptionally smooth control

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.


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C-Leg 4 Brochure

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C-Leg 4 Instructions for use

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C-Leg Patient Information

More information about the C-Leg microprocessor knee

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Advanced prosthetic knee technology brochure

Advanced prosthetic knee technology brochure

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Triton Family of Feet brochure

Triton Family of Feet brochure

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Clinical Studies comparison list – C-Leg and other MPKs

Clinical Studies comparison list – C-Leg and other MPKs

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C-Leg clinical studies bibliography

C-Leg clinical studies bibliography

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C-Leg components list

C-Leg components list


Take a look at our Frequently Asked Questions for more information.

Not finding what you are looking for? Please contact us!


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