Posted: 02 Nov. 2021 8 min. read

Smart Knee brings Future of Health one step closer: A conversation with Canary Medical

By Glenn Snyder, principal, MedTech Practice leader, Deloitte Consulting LLP

My background is in engineering, and I’ve always been fascinated by medical devices and remote sensors that can gather and transmit data. I also recently had a hip replacement, so I was intrigued when I heard about a knee-replacement sensor that recently received clearance from the US Food and Drug Administration (FDA). 

By the year 2030—as baby boomers and younger generations try to remain active into their older years—total-knee-replacement surgeries are expected to grow by nearly 700% to 3.5 million procedures a year, according to an estimate from the American Academy of Orthopedic Surgeons. Data generated by smart-knees and other medical devices could become invaluable for tracking the patient’s progress after a surgery and for preventing complications, as we noted in our report, Reshaping total hip replacements. Future breakthroughs in medical devices are likely to be less invasive, more precise, and more convenient than what we have today. When organizations deploy them optimally, these devices have the potential to increase consumer satisfaction, improve medication adherence, and help consumers track and monitor their health (including signs and symptoms that may alert them to the need for additional care).

People are growing more comfortable with sharing data generated by medical devices, according to our 2020 survey of US health care consumers. Along with helping individuals maintain or improve their own health, we know that sharing data can help improve population health, advance clinical research, and enhance the performance of the device itself.

7 questions for Canary Medical CEO, Bill Hunter

I recently spoke with Canary Medical’s founder and CEO, William Hunter, M.D., about CanturioTM, his company’s new smart-knee device and how it might take us one step closer to the Future of HealthTM that Deloitte envisions. The new technology also aligns to our Six winning roles for medtech to thrive in the future. Here is an excerpt from our conversation: 

Glenn: What was the impetus for your smart-knee device? What is Canary’s vision?

Bill: When I was in medical school, I began working on the idea of drug-eluting stents, and later started a company that expanded on that research. We eventually partnered with Boston Scientific and patented the process of coating coronary stents with paclitaxel to prevent the artery from narrowing. At one point, we had 70% of the world stent market. The idea there was to combine pharmaceuticals with a medical device. The idea behind Canary was to combine sensor technology with a medical device. Why is it that your refrigerator is connected to the internet, but your heart valve or your knee replacement isn’t? The vision for this company is straightforward…let's collect data from inside the body and connect that device to the internet.

Glenn: Why target the knee?

Bill: The knee is one of the largest joints in the body, so there is sufficient space to insert our device [about the size of a AAA battery] into a non-weightbearing part of the knee replacement. Orthopedics is all about movement, so we wanted sensors that would track various movements by using 3D gyroscopes and 3D accelerometers. It uses a pacemaker battery as a power source. The amount of power needed is so low that we will be able pull data from that knee for up to 20 years, which is typically the lifespan of a knee replacement. After a surgery, we will collect data every day as the patient is recovering. After the second year, we expect data-collection will be less frequent.

Glenn: This device recently received clearance from the FDA?

Bill: Yes. In late August 2021, we received approval to market and sell this device, and in October it was implanted in the first patient at the Hospital for Special Surgery in New York. We had previously received Breakthrough Status from FDA, which means this is the first such device that has been approved. We are partnered with Zimmer Biomet, the US market leader in knee replacements. The commercial device, called Persona IQ, combines Zimmer Biomet’s best-selling Persona Knee System with the Canturio tibial extension.

Glenn: Wearable devices keep getting better and smaller. What are the advantages of an implanted sensor?

Bill: The biggest barriers to adoption of wearable sensors are human nature and compliance. Studies have shown that while about 25% of patients will do absolutely everything the doctor tells them to do after a surgery, another 25% won’t comply at all. The rest of us fall somewhere in between. We made this device as patient-friendly as possible to minimize the need for patient compliance. The patient only has to set up a small base-station in their bedroom. If it’s plugged in and connected to WIFI, the data-collection system works all by itself. All of the data is transmitted to the cloud while the patient is asleep. The Canary Cloud does all the analytics and then the patient and doctor receive an update through a user interface the next morning.

Glenn: How does it work, and who is tracking the data?

Bill: This device sits inside the joint, which gives us a front-row seat to what is going on in the knee. We measure metrics of patient activity such as steps, walking speed, stride length, cadence, and distance walked. We also measure two physiologic metrics that are important after knee-replacement surgery—range of motion (ROM) and gait. Right now, ROM is typically measured in-person [by a clinician] three to four times in the year after surgery. The Canary device begins collecting data immediately and measures ROM three times per day, every day, for the first year. The high-fidelity sensor array we use is derived from the same technology used in drone guidance systems and collects 25 observations per second (similar to the human eye) to measure patient activity. Three times a day, it collects higher fidelity data at 800 observations per second, which allows us to create a three-dimensional view of joint movement, gait, and range of motion. Every time the heel hits the ground, it sends a vibration wave up through the leg and into the knee replacement that can be measured by Canturio in a manner analogous to pinging a tuning fork. Once we have enough information on normal versus abnormal vibration patterns, we believe we can identify potential problems with the joint—like loosening or even infection—using artificial intelligence to read and interpret the vibration pattern. It’s going to take data from about 1,000 patients before we can start doing that.

The patient might be interested in how they're progressing post-operatively or how they’re doing versus expectations. The clinician might be interested in patient activity, ROM, and gait. Positive changes in ROM might indicate that the joint is moving freely, while negative changes might suggest the presence of scar tissue hindering movement. With respect to gait, not all steps are equal. This device can count steps, but potentially also determine the quality of those steps. Is the patient walking normally? Or is she limping, shuffling, or moving painfully? Lastly, once we have enough patients, we hope to generate enough data to develop predictive outcomes for the early identification of potential complications in order to facilitate earlier, less invasive, and less expensive intervention.

Glenn: There is a lot of talk about value-based contracts in the medtech sector. Could reimbursement for this device be tied to its value?

Bill: Just like airplane pilots want to know when there are potential problems with engine parts, surgeons and patients want to know that their implants are working. Sensors embedded within these devices could transmit alerts about specific problems and preemptively notify the surgeon. Usually by the time a patient is having a problem with a joint replacement, such as infection, that patient needs to go back to the operating room. But if the surgeon knew there was a potential problem three or four weeks sooner, antibiotics might be able to treat the infection before surgery is needed. If we were able to do that, we will go from having a patient-management tool to a diagnostic or predictive tool. I think the value of that would be very high. In addition, follow-up visits can be done remotely with our technology, and the doctor can bill for virtual post-op visits. This makes it possible for the clinician to direct patient care in their home, which is a lot cheaper than managing the patient in a clinical or hospital setting.

Glenn: What’s next? Could a similar device be used in other joint replacements?

Bill: We expect that this device could be modified and inserted into other joint replacements, such as a shoulder or a hip. A sensor could even be implanted into a hollow screw for bone-fracture repair or spinal surgeries. A smart screw might be capable of signaling if it is bending, breaking, or backing out…and even measure how well the bone is healing around it. We are also looking into vascular applications, which is closer to my background. If a vascular surgeon could tell that a heart valve was leaking, or if a cardiologist knew whether a coronary stent was open or closed, I think that would be a game-changer. The only way to determine that now is with advanced diagnostic imaging. We see vascular as the next frontier for smart devices where sensor-enabled observations could have life and death implications. I believe the vascular value proposition would be tremendous.

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