Ottobock’s Kenevo knee is the first bionic knee designed for users with lower mobility grades, meaning persons who walk at no more than half-speed, have difficulty overcoming obstacles, and are at a higher risk of stumbling or falling. This knee is exciting because it demonstrates the ability of bionic limbs to adapt to specific needs.
What’s On This Page?
- A Quick Look at the Kenevo Knee
- Sensor & Microprocessor Capabilities
- Behavior Common to All Kenevo Modes
- Benefits of the Kenevo’s Design
- Compatibility with Prosthetic Feet
- Water & Dust Resistance
- Device Weight & User Weight Limit
- K-Level Rating
- User Software
- Clinical Insights
- User Feedback Survey & Results
- Considerations Before Buying a Kenevo Knee
- Related Information
A Quick Look at the Kenevo Knee
It is not possible to provide a quick general overview of the Kenevo because it can operate in multiple modes and is functionally more like three different knees depending on the mode. Instead, we offer you a glimpse of the type of patient best suited for the knee and its impact on her life:
As explained in the video, this is a patient who had fallen several times with a mechanical knee. Her use of the Kenevo is primarily to ensure greater safety.
Another use case might be a patient who is recovering from amputation and is undergoing rehabilitation. The Kenevo knee is uniquely suited to this task because users can progress through its different modes. To understand those modes, you first need to understand the knee’s basic capabilities.
Kenevo Key Features
Sensor & Microprocessor Capabilities
To understand how bionic knees work in general, please see A Complete Guide to Bionic Legs & Feet.
The short story is that the microprocessors in bionic knees have three main tasks:
- automatically adjusting the resistance in the knee to ensure the proper level of support through each stage of the Stance Phase regardless of terrain;
- ensuring the optimal release point for the knee to begin the Swing Phase and also the proper foot clearance during this phase, especially when ascending stairs, ramps, etc.;
- assisting in stumble recovery.
The Kenevo offers varying levels of knee resistance depending on the selected mode. It does not attempt to actively control the Swing Phase flexion in any mode but it does actively manage the Swing Phase release point in two of its modes.
To better understand what we mean by this, it is best to examine the knee’s behavior in each mode.
Behavior Common to All Kenevo Modes
The Ottobock Kenevo supports a basic set of functions including:
- supported sitting down;
- supported standing up;
- wheelchair function.
These functions are described in the following video:
In Kenevo’s May 2021 update, Ottobock then added the following basic functions:
- intuitive support for an indoor exercise bike:
- a new donning function that allows users to put the Kenevo on in a sitting position even when using modes that restrict the knee from flexing:
- enhanced stumble recovery, which Ottobock calls Stumble Recovery Plus; note, this does not apply to Mode A, since the knee is already locked.
Mode A: Locked Mode
In this mode, the Kenevo essentially acts like a fixed prosthesis except during the basic functions described in the preceding section.
The purpose of this mode is to ensure maximum safety with no surprises. It is intended for users with less control of their residual limbs who mainly walk short distances indoors and sit.
Mode B/B+: Semi-Locked Mode With and Without Stance Phase Flexion
Both the B and B+ modes release the knee late in the Stance Phase to begin the Swing Phase. They also control the damping of the knee at the end of the Swing Phase. Users require average control over their residual limb to use this mode.
Mode B+ also introduces up to 10 degrees of flexion during heel strike and actively adjusts damping for the Stance Phase extension in real-time.
Mode C: Yielding Mode
In this mode, the knee is no longer locked during the Stance Phase but instead exhibits a high level of damping. Also, the knee is released earlier to start the Swing Phase.
This mode more closely resembles natural walking. It is intended for users who have better control over their residual limb, the ability to handle obstacles like curbs, and the potential to walk step-over-step up and down stairs, ramps, and slopes.
Benefits of the Kenevo’s Design
Quite frankly, this knee has one of the most thoughtful designs that we’ve encountered in bionic limbs. It targets a specific group of users. It is the lightest of the bionic knees, which makes it easier for users to control. And its multi-mode approach makes it ideal for a broader range of use-cases.
The ability to change modes ranging from maximum safety to more dynamic walking is especially useful to:
- accommodate users from a low level of mobility to moderate levels;
- support the incremental stages of rehabilitation for new amputees.
In its May 2021 update, Ottobock further enhanced the Kenevo by adding its indoor exercise bike function, a new donning feature for Modes A & B, and improved stumble recovery.
Compatibility with Prosthetic Feet
The Kenevo can be paired with numerous Ottobock feet rated for K1/K2 use, as well the Trias, which is rated for K3/K4 use.
The Kenevo’s battery can last for up to 24 hours. Ottobock recommends charging the battery each night.
Despite searching extensively for this information, we do not yet know how long it takes to fully charge the battery if it is completely drained. We do know that in its May 2021 update, Ottobock added the ability to charge the knee even when wearing its cosmetic cover.
Water & Dust Resistance
The Kenevo has an IP rating of 22, meaning it is protected from dripping water but otherwise has little protection against water or dust.
It is best used indoors or in clean, dry environments.
Device Weight & User Weight Limit
The Kenevo is the lightest bionic knee at .92 kilograms. The maximum allowable user weight for the knee is 125 kilograms.
The Kenevo is technically rated for K1/K2 use, though it would be more commonly selected by K2 users. For a thorough understanding of K-levels, please see the Amputee Coalition’s web page on this topic.
In particular, the Kenevo was designed for those with lower-to-moderate mobility, i.e. the ability to walk up to 3 kilometers per hour versus the average walking speed of 6 km per hour.
With the latest update to the Kenevo in May 2021, users can now adjust some settings using Ottobock’s Cockpit App:
The settings that we know for certain apply to the Kenevo are:
- turning the exercise bike mode on or off;
- turning Bluetooth on and off;
- viewing the percentage of remaining battery charge, the daily and total step counts, and the next service date.
Ottobock offers a full three-year warranty on the Kenevo including any repair costs due to defects. They also offer a free service inspection in month 24 and a free service unit during repair and service inspections.
The warranty can be extended to six years at the user’s option.
According to our information, the Ottobock Kenevo typically sells for between $25,000 and $35,000 US including the socket, prosthetic foot, and all prosthetist fees.
For a complete list of prices for other microprocessor knees, please see our Microprocessor Knee Price List.
The following comments are from clinicians with extensive experience with the Kenevo knee:
User Feedback Survey & Results
Are you or have you previously been a Kenevo Knee customer? If so, please share your insights with others looking at the Kenevo as a possible prosthesis.
We do not yet have a sufficient number of survey participants to publish fair and accurate results for the Kenevo.
As soon as we do, we’ll update this section.
Considerations Before Buying a Kenevo Knee
If you are a K2 amputee with low-to-moderate mobility, we think you should definitely put the Kenevo on your shortlist of bionic knees. It is designed specifically for you and Ottobock seems to have done a good job executing that design.
For a list of competitive devices, see Current Options for Microprocessor Knees.
For a comprehensive description of all current lower-limb technologies, devices, and research, see our complete guide.
Click here for more information on Ottobock.