The future of remote orthopedic monitoring.

The Smart Knee is a low power wearable for up to three months of continuous monitoring of knee use and recovery .

Purchase Smart Knee kits are now available

Acquire - Track - Research - Rehab

Development kits are available now for research applications and product integration

Magnetic attachment to skin pads
Low Energy Bluetooth, 3-axis accelerometer and 3 month battery life.
Bend labs patented two axis elastomeric bend sensor.
Skin pads attach via medical adhesive strips.
Cutting Edge Hardware

The core of the Smart Knee is the Bend Labs ultra durable, low power 2-axis bending sensor. This sensor measures angular displacement, which means that as long as the ends are registered with the bony anatomy, an accurate joint angle will be acquired. Additional hardware includes a triaxial accelerometer, onboard memory and processor, and a long range low energy bluetooth radio. The Smart Knee is ultra low power and runs continuously for an impressive three months on a single CR2477 coin cell battery, which can be easily replaced.

Advanced Motion Analysis and Tracking Algorithms

Our advanced algorithms record every knee bend event and body position update which are saved to onboard memory. Upon connecting to the Smart Knee with our Android app, all events and positions are automatically transferred to the phone or tablet. Researchers, clinicians, and health care providers can see a complete picture of how an individual is using their knee and track important parameters such as range of motion and activity level over time during healing and recovery. Because two Smart Knees can be connected to our app at once, you can even compare right to left metrics to monitor symmetry during normal activities.

Fully Featured App and API

Our easy to use Android app gives you full access to the functionality of the Smart Knee, including live data streaming and recording, summary and export of tracking data, device calibration, firmware update, battery level, and much more. Our API makes creating your own Android based app or integration easy, opening the door to a limitless number of applications for remote orthopedic monitoring, athletic training, physical therapy, and research using the Smart Knee.

Convenient, Accurate and Easy to Use

Adhesive skin pads ( 3M®) securely and comfortably hold the Smart Knee to the knee for up to two weeks and make application easy and convenient. The Smart Knee attaches and detaches using a magnetic coupling mechanism which automatically turns the device on and off for increased battery life. Because the Smart Knee Is low profile and lightweight, users often forget that they are wearing it. Since no charging is required, it seamlessly integrates into even the most demanding lifestyle.

datasheet coming soon

Smart Knee Demo Video

Product Photos

Have a look at some of our Smart Knee product photos


We've got answers!

When can I get a Smart Knee Development Kit, and who can buy one?

We have development kits in stock now and can fulfill orders within a few days. The kits can be purchased by anyone with an interest in building on our exciting platform!

Why choose the Smart Knee over other knee monitoring products?

The Smart Knee is the only knee tracking technology that can continuously monitor knee angle and body position for months at a time without being charged. Since there is nothing to charge, user compliance in wearing the device remains extremely high. This opens the door to a whole new class of patient monitoring products and research studies that were formerly not possible.

Why continuously track and monitor knee use and body position?

When a patient leaves the clinic or research lab, their lives turn into a black box. The Smart Knee tracks the ROM and count of every knee bend, so not a single knee motion goes unnoticed. By tracking body position (via the onboard triaxial accelerometer), a very clear picture of how an individual is using their knee is obtained. The Smart Knee will take the mystery out of research, patient compliance during recovery and empower future patients and healthcare providers with the information they need to make the right decisions.

What comes with the Smart Knee Development Kit?

Every Smart Knee development kit comes with at least one Smart Knee, a set of reusable skin pads (2 sets total), enough medical adhesive tape for 10 applications, and access to the Smart Knee app and API. We also include a Nexus 6p smartphone to ensure you have the best experience. Kits with one, two and ten Smart Knees can be purchased here

How much email/phone support comes with the development kit?

We will warranty the device to be free of manufacturing defects and normal use for two months after purchase, and will provide limited customer support in the event a unit malfunctions. We do not have the bandwidth to provide extensive support for customers in all their applications, but will provide support via email and our knowledge base depending on the package you choose.

What Makes the Bend Angular Displacement Sensor in the Smart Knee so Special?

The Smart Knee is based on an entirely new sensing technology (soft capacitive angular displacement sensors). Unlike IMU based products, there is no drift or large power consumption, which means you get an accurate and reliable knee angle in a unit that never has to be charged by the user. Since the sensors are based on angular displacement, erroneous kinking or bending won’t introduce an error, which is something that conventional sensors based on resistance are prone too.

Why a 2-axis sensor for the knee?

By using a 2-axis sensor, we have created the most versatile device possible. Using a single axis of this sensor has proven sufficient for most applications that need to measure flexion/extension of the knee. However, the two axes can be fused,providing a more accurate knee angle measurement in the event of large skin motion or placement into a fabric sleeve for applications where medical adhesive tape is not appropriate. Furthermore, having a 2-axis sensor opens the door to using the device on other joints such as the wrist, ankle, back and other joints that have multiple degrees of freedom.

What smartphones do you support?

Currently we’re supporting Android only. The phones we support are Nexus 5 & 6, Samsung Galaxy S4, S5 & S6. We support Android 4.4 or newer but recommend Android 5.0 or newer for the best experience. If you don’t have one of the phones listed you can purchase one of our kits that come with an unlocked version of the Nexus 5.

Can the Smart Knee be used on other joints?

Although our initial application of this technology is aimed at the knee, other joints could be monitored, including the ankle, wrist, elbow, back, neck and others. Purchase a development kit and try it out!

How accurate is the joint angle data and what is the sample rate?

The precision of the joint angle data is three degrees, with virtually no noise seen on the signal. The device can sense +/- 360 degrees of bending. In order to save power, the device samples at 20 Hz, which is sufficient for most normal daily activities. Higher performance units with higher sample rates are available for high speed athletics and research studies upon request.

I’m a researcher, why would I be interested in the Smart Knee?

The Smart Knee is the first device of it’s kind and will enable a new class of long term studies focused on knee recovery that were previously not possible. Because subjects can comfortably wear the device over long periods of time, researchers can now get access to accurate movement data that were previously inaccessible. It’s also feasible to remotely check in on patient data without the subject needing to be physically present.

I’m developing a remote orthopedic monitoring product, why would I be interested in the Smart Knee?

The Smart Knee is the perfect device for at home use by knee patients. It’s comfortable, accurate and connected allowing patients and clinicians to discover in real time how a patient is progressing. Bend Labs has focused on developing the hardware platform(hardware and API), but we don’t have plans to develop consumer facing software and services for medical use. The Smart Knee offers a truly unique solution in a space where all other options require the user to periodically charge their device or make inaccurate measurements and assumptions. We have found this combination to be the primary cause of poor long term compliance.

Is this FDA approved?

Currently, this is classified as a research device and is not registered with the FDA. For most research applications, this shouldn’t pose a problem. If your end use application requires regulatory filings, we will work with you to ensure that your product complies with all regulations and standards.

Stay updated!

We're working tirelessly to ship Smart Knees to a growing list of companies and research institutions for remote orthopedic monitoring and research applications. Click here to purchase your Smart Knee kit. Add your email below for company updates.