Bionic technology · Össur

Össur Power Knee: the active, motor-powered bionic knee

Össur’s Power Knee is a motor-powered microprocessor knee: it does not just control movement, it adds power when you rise from a chair, walk and climb stairs.

Motor adds power to flexion and extension
Assistance when rising from a chair
Help when climbing stairs
Less effort when walking
For unilateral or bilateral amputation

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Woman with an above-knee prosthesis and Össur Power Knee rising from a chair and walking

Össur’s Power Knee is the first motor-powered microprocessor knee, designed for people with an above-knee amputation. The difference from other bionic knees is fundamental: most of them control how easily the knee bends, but the user generates the movement. The Power Knee adds active power, replacing some of the missing muscle strength. At Hlamidis Orthopaedic Center in Thessaloniki we assess whether the Power Knee can help you and fit it with a socket made to measure.

How the Power Knee works

The Power Knee’s motor actively assists both flexion and extension of the knee, mimicking the function of the thigh muscles. Advanced algorithms recognise your movement patterns, learn and adapt to your speed and rhythm in real time, and detect whether you are on level ground, going uphill or downhill, sitting or standing.

Three key benefits

Symmetry

Assistance when rising from a chair, during the swing phase of the step and when climbing stairs helps you move more symmetrically. More natural movement means less strain on the rest of your body, such as your sound leg and your lower back.

Stability

When going down stairs and slopes, the knee provides controlled resistance, and when you shift your weight onto it, it locks automatically to support you while standing.

Endurance

Because the knee adds its own energy, walking takes less effort on your part. This can make a difference for people who tire quickly with a conventional knee.

Who the Power Knee is for

According to Össur, the Power Knee can be fitted for unilateral or bilateral amputation at above-knee level, knee disarticulation or hip disarticulation. It is often considered for people who find it hard to stand up from a seat or climb stairs, for those with amputations of both legs, or for those who want to conserve their energy throughout the day. Activity level, strength, weight and general health all play an important role, which is why the choice is always made after an assessment and together with your doctor.

Fitting and training

An active knee works differently from what you are used to, so training is important. After the assessment, we make a test socket and then a definitive socket tailored to you, and set up the Power Knee with Össur’s software. In the training area at our premises you practise rising from a chair, walking, stairs and a ramp, and, working with your physiotherapist, we gradually develop the settings. Regular check-ups follow so that you can make full use of what the knee can do.

What to expect in the first few weeks

The feeling of a knee that “pushes” with you is new, even for experienced prosthesis users. In the first few weeks you learn to work with the motor’s assistance rather than “fight” it. That is why we start with simple movements, such as rising from a chair and walking on the level, and move on to stairs and the ramp when you feel confident. At this stage, guidance from us and your physiotherapist matters most.

Cost and EOPYY

The price of the Power Knee depends on its configuration and the other components of the prosthesis. 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 provision for full cover of a bionic knee; the difference is paid by the patient. After the assessment we will tell you the exact amount. 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).

To find out whether the Power Knee is right for you, contact us. See also the Rheo Knee and all the systems in our bionic technology section.

FAQ

Frequently asked questions

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How much does a Power Knee cost?

The price depends on the knee’s configuration and on the other components of the prosthesis, such as the socket and prosthetic foot. 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.

What is the difference between an active and a passive bionic knee?

A passive microprocessor knee, such as the Rheo Knee or the C-Leg, adjusts resistance, but the user provides the energy for movement. The Power Knee has a motor, so it adds power, for example when you rise from a chair or climb stairs.

Is the Power Knee suitable for people with both legs amputated?

According to Össur, the Power Knee can be fitted for unilateral or bilateral amputation at above-knee level, knee disarticulation or hip disarticulation. Whether it suits your case is decided after an assessment, together with your doctor, taking into account your strength, balance and goals.

Does EOPYY cover the Power Knee?

EOPYY reimburses people insured in Greece for prosthetic 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 bionic knee. If you are not insured in Greece, EOPYY does not apply. Contact us and we will check what applies in your case. See our EOPYY page.

Does the Power Knee need charging?

Yes, the Power Knee’s motor and electronics run on a rechargeable battery. How long it lasts depends on how much and how you use the knee. When we hand it over, we explain charging and care in detail, so that you always have the battery life you need during the day.