With its 36.5 degrees range of motion, 4-axis kinematics, and automatically adjusted hydraulic resistance, the Meridium Foot is Ottobock’s most lifelike bionic foot/ankle.
What’s On This Page?
- A Quick Look at the Meridium
- Ankle Range of Motion (ROM)
- Ankle Accommodation
- Electric Propulsion
- Sensor and Microprocessor Capabilities
- Meridium’s 4-axis Kinematics
- Water and Dust Resistance
- Device Weight & User Weight Limit
- K-Level Rating
- User Software
- Compatibility with Bionic Knees
- Clinical Insights
- User Feedback Survey & Results
- Considerations Before Buying a Meridium Foot
- Related Information
A Quick Look at the Meridium Foot
Although this video is from Ottobock and therefore somewhat promotional, it provides a good look at the Meridium Foot in action:
This is not as smooth as Ottobock’s Empower Ankle in similar tasks but neither is any other bionic foot/ankle. It also doesn’t have the Empower’s $40K to $50K US price tag.
The key to appreciating the Meridium is focusing on how it makes lives easier for amputees. It achieves this by automatically adapting to many different types of terrain, accommodating shoes of varying heel heights, and allowing users to control key settings through a mobile application.
Meridium’s Key Features
Ankle Range of Motion (ROM)
The reported ankle ROM for the Meridium Foot is 36.5 degrees. This is the highest of all bionic feet/ankles.
However, one does need to be careful with this number because the true net ROM consists of the foot ROM as well as the ankle ROM, which is sometimes reported differently by each manufacturer. But we like to include this figure as a reminder to prospective users to discuss ROM (and its implications) with their prosthetist.
The Meridium Foot uses a within-step ankle accommodation strategy. This means that the ankle adjusts to the terrain during the Stance Phase of each step instead of the Swing Phase. This is important because within-step systems generally respond to changing terrain faster than between-step systems.
The Meridium Foot does not augment push-off with electric power but it does optimize energy storage and reuse through its carbon fiber foot.
The only bionic foot/ankle currently on the market that enhances push-off with electric power is Ottobock’s Empower model.
Sensor and Microprocessor Capabilities
We don’t have a lot of information on Meridium’s sensor and microprocessor systems except for the following:
- Sensor data is updated and processed 100 times a second.
- The device has an Inertial Motion Unit (IMU) that uses gyroscopes and acceleration sensors to determine rotational speeds and position, movements, and the distances covered by the foot in space. This helps differentiate between standing and walking on level ground, as well as on stairs and ramps. It also triggers the activation of energy-saving functions when sitting.
- Meridium can accommodate different shoe heel heights up to 5 cm (2 inches). These adjustments occur automatically within the first 20 steps after a shoe change or can be set immediately through a smartphone application.
For controlling the foot on varied terrain or for different walking gaits, Meridium appears to actively manage hydraulic resistance alone. The only mention of actively managing the foot angle is to prevent the front of the foot from dipping during the Swing Phase.
Meridium’s 4-axis Kinematics
One of the interesting features of the Meridium is that it offers 4 axes for foot adjustment: the heel, ankle, toe, and mid-foot. This suggests that it should more easily conform to varied terrain, as explained in this video:
The Meridium’s battery life is 24 hours.
The battery requires 8 hours of charging to go from a low-power state to fully charged.
Water and Dust Resistance
The Meridium Foot is listed as having an IP rating of 54, meaning it is dust resistant and can tolerate water splashes but not submersion.
Device Weight & User Weight Limit
According to our independent data from August 2018, the Meridium Foot weighs 1500 grams.
The Meridium Foot is rated for K2 and K3 use. It is not intended for high-impact sports, such as running, basketball, etc.
Ottobock provides a software application for users to manage some of Meridium’s key settings. The app is called Cockpit:
Cockpit allows users to do the following:
- Set the heel height for a new pair of shoes (i.e. when switching shoes).
- Switch modes for different activities, such as golf, biking, skiing, etc. Note, the prosthetist must first set up these modes, which mainly consists of setting the appropriate resistance levels for each activity.
- Turn Bluetooth on and off.
- View the percentage of remaining battery charge as well as the daily and total step counts (total step counts are tied to service checks).
This warranty includes one free service and a free loaner foot during maintenance and repairs.
Users have the option of purchasing a warranty extension of an additional three years, providing six years of total warranty coverage.
According to our information from individual users, the Meridium Foot sells for between $20,000 to $25,000 US inclusive of all prosthetist fees.
To see how the price of the Meridium compares to its competitors, please see our Bionic Foot Price List.
Compatibility With Bionic Knees
The following comments are from clinicians with extensive experience with the Meridium Foot:
User Feedback Survey & Results
Are you or have you previously been a Meridium Foot user? If so, please share your insights with others looking at the Meridium as a possible prosthesis.
We do not yet have a sufficient number of survey participants to publish fair and accurate results for the Meridium.
As soon as we do, we’ll update this section.
Considerations Before Buying a Meridium Foot
We do not yet have sufficient user feedback to offer consumer guidance on the Meridium.
What we can say is that, if you are in the market for a bionic foot/ankle, do yourself a favor and take them all for a test walk. The ankle accommodation and microprocessor strategies differ so significantly from one device to another that compatibility with the end user may be the most important factor.
For a list of competitor devices, see All Bionic Feet.
For a complete description of all current lower-limb technologies, devices, and research, see our comprehensive guide.
Click here for more information on Ottobock.