Bionic technology · Ottobock

Ottobock C-Leg 4: microprocessor knee for safe, confident walking

Ottobock’s C-Leg is one of the most widely used microprocessor knees. It adapts to the way you walk in real time and supports you if you stumble.

Adapts to every step in real time
Stumble recovery to help reduce falls
Step-over-step stairs, ramps and uneven ground
Waterproof in fresh water (IP68)
Cockpit app with MyModes

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Above-knee prosthesis user with a C-Leg knee on a motorbike in front of the White Tower, Thessaloniki

Ottobock’s C-Leg is a microprocessor knee for people with an above-knee amputation. Since its first version in 1997, it has been described as an “intelligent system”, because it adapts how it works to the user’s gait in real time. The current generation, the C-Leg 4, combines this technology with features aimed at one thing: helping you walk with confidence, without having to think about every step. At Hlamidis Orthopaedic Center in Thessaloniki we fit the C-Leg as part of a complete above-knee (transfemoral) prosthesis, with a socket made to measure for you.

How the C-Leg works

Sensors continuously measure the position, speed and load of the prosthesis. The microprocessor uses this information to adjust the knee’s hydraulic resistance in every phase of the step: when the knee needs to stay stable to support you, and when it needs to bend freely so the leg can swing through. This way the knee follows your rhythm, whether you walk slowly or quickly, and responds to sudden changes in speed or in the slope of the ground.

Key features of the C-Leg 4

Stumble recovery

When the system detects a movement that looks like a stumble, it immediately increases the knee’s resistance so that you can put your weight on the prosthesis and regain your balance. The aim is to reduce the risk of falling.

Stairs, slopes and ramps

Controlled knee flexion under load, mimicking the quadriceps muscle, absorbs shock and lets you go down stairs step over step and walk safely down slopes, ramps and uneven ground.

Walking backwards and stable standing

The C-Leg’s inertial measurement unit provides stability when you step backwards, for example in tight spaces. When you stand, the Intuitive Stance function locks the knee automatically, so you can distribute your weight evenly on both legs, even on sloping ground.

Weather-resistant

The current C-Leg 4 has an IP68 protection rating: it is safe for occasional submersion in fresh water (up to 3 metres for 1 hour). There is no need to worry if you get caught in the rain.

Cockpit app

From your phone (iOS or Android) you can check the battery, see your daily step count and select preset MyModes for activities such as cycling.

Who the C-Leg is for

The C-Leg is designed for people with an above-knee amputation or knee disarticulation, and, combined with the Helix 3D joint, it is also fitted for hip disarticulation. According to Ottobock it suits users with activity levels (mobility grades) K2 to K4 — from people who move about outside the home over limited distances to those who walk every day at different speeds, at work and around town. According to the manufacturer, the maximum user weight is 136 kg. If your main goal is safety in everyday life, the C-Leg is often the first option we consider. For more demanding activities, we also compare it with the Genium together with you.

Fitting and training at Hlamidis

Assessment: we examine your residual limb, strength, balance and goals, working with your doctor.
Socket: we make a test socket and then a definitive socket tailored to you, because a good fit is the foundation for the knee to perform.
Set-up: we adjust the C-Leg’s parameters to your own gait using Ottobock’s software.
Training: in the training area at our premises you practise on the level, on stairs and on a ramp.
Follow-up: with regular check-ups we make any adjustments needed as you get used to the knee.

Cost and EOPYY

The price of the C-Leg depends on its configuration and the other components of the prosthesis (socket, silicone liner, prosthetic foot). EOPYY (ΕΟΠΥΥ), Greece’s national health insurance organisation, reimburses people insured in Greece for prosthetic components according to the categories and maximum prices in its price list, with a co-payment by the insured person of, as a rule, 25%. There is no full cover for a microprocessor knee: the difference above the reimbursement category is paid by the patient. After the assessment we will tell you the exact amount in your case. See our pages on EOPYY reimbursement and our bionic knee comparison. If you are not insured in Greece, EOPYY reimbursement does not apply; you can pay privately, and any cover depends on your own insurer’s rules — contact us and we will give you the information you need for your case. The EOPYY information is correct as of the date this page was last updated (October 2026).

Would you like to know whether the C-Leg is right for you? Contact us to book an assessment, or see all the systems in our bionic technology section.

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Walking with a C-Leg knee

FAQ

Frequently asked questions

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How much does a C-Leg cost?

The price depends on the knee’s configuration and on the other components of the prosthesis, such as the socket, silicone liner and prosthetic foot. That is why we give a price after an assessment, with a detailed proposal. For people insured in Greece, EOPYY covers up to the amount of the relevant category in its price list and the patient pays the difference. Call us on +30 2310 282 894.

Does EOPYY cover the C-Leg?

EOPYY reimburses people insured in Greece for above-knee prosthesis components according to the categories and maximum prices in its price list, with a co-payment of, as a rule, 25%. There is no provision for full cover of a microprocessor knee. We tell you from the start exactly how much is covered and how much you will pay. If you are not insured in Greece, EOPYY does not apply. See our EOPYY page.

Can the C-Leg 4 get wet?

The current C-Leg 4 has an IP68 protection rating: it withstands rain, splashes and occasional submersion in fresh water up to 3 metres for 1 hour (not salt or chlorinated water). However, it is not designed for swimming or for salt water. If you want to take part in water activities, talk to us about alternatives, such as a dedicated water-activity prosthesis.

What is the difference between the C-Leg and the Genium?

Both are Ottobock microprocessor knees. The C-Leg focuses on safety and stability when walking day to day. The Genium has more sensors and functions for a more natural gait, such as step-over-step stair climbing, for users with greater demands. We decide together which one suits you after the assessment.

How long does the C-Leg battery last?

Battery life depends on how you use the knee. For most users, charging overnight is enough. With the Cockpit app you can check the charge level on your phone at any time, and when we hand over the knee we show you how to charge it correctly.