An interesting headline was doing the rounds of the financial newspapers this month. “Smart Implants Market Size to Reach $22.5 Billion by 2032,” read one.
If the experts are right, the global demand for such devices is set to rise by over 18% a year, from six billion dollars now to more than $22bn in 10 years’ time. In case you were wondering what on earth they meant by all this, however, the article also provided a helpful definition of the new technology:
“Smart implants are modern medical devices with built-in sensors capable of monitoring, diagnosing and treating various medical conditions,” it explained.
So what is this technology? And, from a knee replacement perspective, should we be getting interested – even excited – about it?
How would a smart knee implant work?
A knee replacement implant contains three main components: a top part that attaches to the thigh bone, a central “spacer”, and a bottom section that fixes to the shin bone. That final component is secured in place with a special stem. And it’s this stem, in particular, that has the potential to house a range of sensors that would monitor the new joint once it has been implanted.
What “smart” features would it contain?
In theory, a smart implant could contain all kinds of data-collecting sensors. They could monitor the balance and alignment of the new joint, its range of motion, the patient’s step count, and potentially much more. “Temperature sensors could give early warning of an infection,” explains a recent piece in the Guardian, (Power tools at the ready! The life-changing science behind hip and knee replacements). “Movement sensors could give patients confidence to exercise and feel safe in the knowledge that any problems would be quickly detected.”
Do any smart knees exist yet?
One of the best-known smart knees to date is the Persona IQ implant, which launched in 2021. The manufacturer, Zimmer Biomet, calls it “the world’s first smart knee implant.” Its “smart stem extension” collects data on everything from range of motion to stride length, cadence, distance, walking speed and step count. The stem connects to a home hub device, which transfers the data to a “mymobility” app on your smartphone.
Why could this be useful?
One advantage of an implant like this is that it gives patients direct access to – and potential reassurance about – how their new knee is faring. The data also goes to their doctor (“You’ll have confidence that you’re connected to your healthcare team, every step of the way,” says the company.) From a doctor’s point of view, future smart knees may be able to give us all kinds of other useful information about a patient’s biomechanics. The implant’s alignment and balance within the leg, for example. The force and load it absorbs during different activities. Perhaps even an early warning if it starts to experience problems, such as loosening of the components.
What are the caveats?
The main caveat with any new medical technology is that… it’s new. Which means it takes time to collect data on their safety and effectiveness as patients use them. The standard implants we use today, for example, often have decades of data behind them. This gives us confidence about how long-lasting and secure they are for the majority of patients. That said, every advance in implant technology has to start somewhere. So we’ll be keeping a close eye on the research, studies and data that emerges around smart knees in the coming months. It may be a while before they become the go-to technology for knee joint replacement. But, as those financial headlines imply, they’re a development that many doctors will be cautiously excited about.
Interested in reading more about smart implants? You may find these articles useful
“Smart Knee Implants: An Overview of Current Technologies and Future Possibilities” (2023 medical paper)
What can the National Joint Registry tell you about knee replacements? (blog)
