Meet the ‘Smart Knee’: Real-time Data for Customized Knee Replacement Recovery.

We live in a world of smart devices. Phones track our sleep, watches remind us to move, and our coffee makers start brewing before we’re out of bed. So why shouldn’t one of the most important medical devices in your life—your knee replacement—also help guide your recovery?

The new “smart knee” looks and functions just like a normal knee implant. But it has a tiny built-in sensor that gives your care team real-time information about how your knee is doing, such as your mobility, range of motion, and walking pattern. 

That means we can monitor your recovery day-to-day rather than waiting for follow-up visits spaced weeks apart. Outside of the controlled environment of physical therapy, these metrics track how your knee performs in everyday life—walking the dog, climbing stairs, running errands.

It also means you can get a more precise answer to a common question: “Is my rehabilitation on track?” We can look at your data and see exactly where you are compared to others of your age and sex who’ve had the same operation. If you’re progressing faster or slower than expected, we can adjust your rehab plan to help you get on track.

This level of data-driven, real-time guidance hasn’t been possible before. MedStar Health is among the first orthopedic surgery programs in the region to offer the PersonaIQ for knee replacement—our patients can now get this smarter, more personalized approach to recovery.

How does the ‘smart knee’ work?

The device includes a sensor built into a small tibial “stem extension”—a piece we routinely use in knee replacement for added stability. The surgical procedure and implant function are the same as in a typical knee replacement, with the addition of a tiny sensor that tracks recovery data. 

Each night, the sensor securely transmits that data to a bedside base station about the size of a wireless internet router. From there, information uploads to a secure platform that only you and your care team can access.

Most patients who get a cemented knee replacement (which uses fast-drying cement for the prosthetic to adhere to the bone) are potential candidates for a smart knee system.

Can’t my smartwatch data show how I walk?

Wearables are helpful, but they have limitations. Typically, they only give step counts and not knee-specific data. They can’t tell us how you’re walking or measure your exact range of motion.

Smart knees provide specific, performance-based data about your joint that used to be measurable only in the clinic. Now we can get real-world recovery data from the device, including:

• Step count 

• Distance traveled

• Walking speed

• Step length

• Cadence

• Range of motion

 What about patient privacy?

A smart knee reports only motion information, not location data:
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• It does not use GPS. It cannot track where you go. There is no way for us — or anyone else — to see if you are at the grocery store or gym or sitting on your couch.

• It only communicates with your personal base station. Even if you visit someone who also has a smart knee, your implant will not pair with their hub. 

• You can stop data transmission at any time. Simply unplug the base station and no further information is sent. The knee will still work perfectly and the implant will stay exactly where it belongs.

• The platform is secure and HIPAA-compliant. Only you, your surgeon, and designated care team can see your information.

Related: Read “How Long Will My Hip or Knee Replacement Last?"

 How do doctors use my smart knee data?

Instead of waiting four to six weeks between visits, smart knee data shows the care team how you’re doing every day—and allows us to step in sooner if you need help.

We also can set up alerts for when certain measurements fall below what we expect. When that happens, we can check in with you, saving you a phone call and time spent worrying whether there’s a problem.  

Here are a few more situations when smart knee data empowers the care team to better support your recovery:
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• Activity level suddenly drops: If we see your step count or walking speed dip several days in a row, we can check in to see if you have new pain or swelling.

• You’re too active: Some patients feel great after surgery … maybe a little too great. If the data shows you’re in the 110th percentile for walking, we might suggest you scale back for a couple days to avoid overuse setbacks.

• Range of motion stalls: If your knee isn’t bending as much as expected, we can adjust your therapy to help you regain flexibility.

• You report limping: We can look back through your data to see what might have triggered the limp and tailor your plan to get you back on track.

• Something might be brewing: Sometimes, subtle shifts in gait or motion changes can signal a problem behind the scenes. These can appear long before other symptoms, and we can potentially intervene before issues worsen.

Generally, we will set up your smart knee to collect data every day for the first six months, which is the most crucial time of recovery. After that, it will go to weekly, and then monthly to conserve the battery. The estimated battery life is 10 years. However, once the battery stops working, your knee replacement will continue to function normally; we just won’t be collecting data anymore. 

Related: Read “Considering Knee Replacement Surgery: Thoughts From a Surgeon-Turned Patient."

The future of knee replacement recovery.

The smart knee is the next step in personalized orthopedic care. The more data we collect across thousands of patients nationwide, the more insights we gain to advance knee replacement care.

One day, this type of technology could expand into hips, shoulders, and other joint replacements as the field evolves. Today, these new systems are helping orthopedic surgeons who perform knee replacements:
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• Identify early changes that may signal complications, often before patients notice a symptom. 

• Understand normal versus concerning recovery patterns, making it easier to reassure patients or intervene sooner.

• Examine trends in progress to refine the physical therapy plan. 

• Build more personalized, predictive recovery models.\

We often tell patients that knee replacement surgery is just the beginning. The real work comes in recovery, and a smart knee provides detailed information to steer that process. 

Many people find motivation in seeing their own data. You may think, “I’m almost at the average for my age, so I’m going to take a few more steps today.” Others appreciate being able to monitor their progress without waiting weeks between appointments.

This transparency also can help ease anxiety. Recovery from knee replacement is full of ups and downs. Some days feel great, and some days are just plain hard. It can be reassuring to see that your experience is normal and shared by thousands of others. 

With this smart knee technology, we can celebrate your milestones, catch concerns early, and help you feel more confident every step of the way.