Power Knee by Össur (Embla Medical): status and timeline

Power Knee

Give above-knee amputees a leg that adds power like real thigh muscles, so stairs, slopes and standing up stop demanding extra effort from the hip and the other leg.

DeployStage 4 of 5

On sale since the 2022 generation; own Medicare code L5827 since April 2025

Updated 16 Apr 2025Checked 11 Oct0 updates this week

Milestones

No announced next step

First motor-powered prosthetic knee introduced2006Complete.
New-generation Power Knee launched9 Feb 2022Complete.
Össur renamed Embla Medical (parent)Apr 2024Complete.
Medicare code L5827 for electromechanical knees1 Apr 2025Complete.

Most important updates

Current obstacles

Weight versus powerAt 2.6 kg it is heavier than passive microprocessor knees; the motor and battery that add power also add mass the hip must swing.
Getting users to use the powerEarlier versions needed effortful triggering and many users rarely used stair and sit-to-stand modes; the 2022 model simplified activation.

Physics limits

Batteries cap the work a leg can doA real knee is powered by food-fuelled muscle; a motorised one must carry every joule in a battery, so more assistance means more weight or more charging.
Guessing intent from motionWithout a link to the user's nerves, the knee infers what the user wants from posture and load, so unusual moves can be misread.

How it works

3 parts

Sensing

Reads speed, slope and posture

Sensors tell the knee's processor whether the wearer is walking, on an incline, on stairs, sitting or standing, and at what cadence.

Motor

Electromechanical actuator

An electric actuator controls both the swing and stance phases and can drive the knee straight, doing work the missing thigh muscles once did.

Assist and brake

Push going up, resist going down

Going up stairs, ramps or out of a chair the motor assists; going down or sitting it provides controlled resistance instead.

Spec sheet

Spec	Power Knee
Weight incl. battery	2.6 kg^R (reported)
Battery life	25 h normal use^R (reported)
Recharge time	5 h 30 min^R (reported)
Max user weight	116 kg^R (reported)
Knee flexion	120°^R (reported)
Medicare base code fee (avg)	$7,242 (L5827)^R (reported)

^R reported by the company

Update log

2 updates

Wed 16 Apr 2025

Minor: Medicare's new code L5827 for electromechanical knees takes effect for the Power KneePressRegulatory

Wed 9 Feb 2022

Major: Össur launches new Power Knee, which it calls the world's first actively powered microprocessor kneePressHardware

About Össur (Embla Medical)

The team behind Power Knee

Össur (Embla Medical)

Prosthetic knees and feet, Power Knee, bracing

Össur is an Icelandic maker of prosthetic legs, feet and braces, founded in Reykjavik in 1971. Since 2024 its listed parent is Embla Medical. It makes the Power Knee, the first motor-powered prosthetic knee.

Össur became Embla Medical in April 2024 (ticker EMBLA, Nasdaq Copenhagen); Össur stays the product brand.
Power Knee first appeared in 2006; a lighter generation with a 25-hour battery launched in February 2022.
In April 2025 Medicare created code L5827 for electromechanical knees like the Power Knee.

ossur.com (opens ossur.com)Company profile →

Founded: 197155 yrs
Headquarters: Iceland
Status: Public
Listed: EMBLANasdaq CPH
Valuation: public
Works in: NeurotechBionic limbs & muscle control
Coverage: 1 program · 3 updateslatest 16 Apr 2025checked 11 Oct
Investors: William Demant Invest
People: Sveinn Sölvason (opens ossur.com)President and CEO

Spec

Power Knee

Weight incl. battery

2.6 kg^R (reported)

Battery life

25 h normal use^R (reported)

Recharge time

5 h 30 min^R (reported)

Max user weight

116 kg^R (reported)

Knee flexion

120°^R (reported)

Medicare base code fee (avg)

$7,242 (L5827)^R (reported)