THE SPORTS DOCTOR

Wise Up

‘Smart’ Knee Implant Could Be The Future of Joint Replacements

By dr. yair d. Kissin

We are surrounded by smart phones, smart watches, smart cars and even smart refrigerators. Now our knees can be smart too. Knee replacement surgery has undergone yet another major advancement with the recent FDA approval of a novel sensor that gives a conventional knee replacement the ability for surgeons to know exactly how well or how poorly their patient is doing.

Knee replacement is one of the most successful operations known to man. In the United States, this operation is performed approximately 800,000 times a year and that number is rising exponentially. With success rates exceeding 90 percent, patients’ lives are dramatically changed for the better when their severely arthritic knee is replaced with metal and plastic implants. While complications – such as infections, loosening of the implants, blood clots and re-operations – do exist, the complication rates are relatively low compared to the successes. However, one of the challenges is the ability to measure success in an objective way. New technologies, such as navigation and robotics, have been very exciting additions in the field of knee replacement, but scientifically, it will take years to prove superiority to conventional knee replacement, which has been around and successful for 35 to 40 years.

Or will it? With the introduction of a new device that is implanted with the prosthesis itself into the knee, surgeons will be able to track a patient’s progress during their recovery, perhaps giving us more rapid insight into which way or ways to perform a replacement best. It is akin to having a fitness tracker implanted into your knee at the time of the knee replacement, but don’t worry, it is not a GPS and no one can find you with this device. Instead of tracking your location, it can track your steps, stride length, cadence and how fast you walk. These are all true measures of how well someone is recovering after their surgery, and it is the kind of data that we have never had before. There was an attempt to monitor postoperative patients via smart watches, but 30-50 percent of patients did not wear them, which makes the data incomplete at best. With this device, since you can’t leave home without it, the

readings will be accurate for every patient. In addition, patients will have access to an online dashboard showing them the same data that their surgeon will monitor and use to gauge their personal recovery.

Who is it for? The device is currently only available for total knee replacement using a specific company’s implant. Ask your surgeon what implant they use and if this is available.

Who is this not for? First and foremost, be sure that you are a candidate for knee replacement. There are often successful nonsurgical treatments for knee osteoarthritis and should be considered prior to proceeding with surgery. Second, since this is part of the prosthesis being implanted into the tibia, some peoples’ anatomy may not be able to accommodate the device, such as patients with smaller bony anatomy or if they have prior hardware in the vicinity of the knee.

As a parting thought, while many technologies have come and gone, this new device may open a window that can help us understand why 10- 20 percent of knee replacement patients are not always happy with their outcome. Data is king, but only if the data is meaningful. A device like this can let us know, objectively, that a patient is doing well and meeting benchmarks for similar patients at similar time frames in the postoperative period. Likewise, the device can alert the surgeon if the patient’s activity level, even years later, suddenly drops off and may be a sign that they need to be evaluated. In other words, it can tell us if a patient is doing well and it can let us know, possibly before the patient knows, that something may be wrong.

It is very exciting to imagine what this data will show and how it will hopefully allow us to improve an already successful surgery even further.

Editor’s Note: If you are interested in learning more, search Zimmer-Biomet Persona IQ; the author does not receive any financial compensation from the company.

Yair D. Kissin, MD FAAOS is board-certified in orthopedic surgery and in sports medicine, with a specific interest in conditions of the knee. He serves as vice chairman of the department of orthopedic surgery at Hackensack University Medical Center. Dr. Kissin’s clinical research interests include robotic knee replacement, and he was one of only six surgeons selected to participate in the trial and development of the TSolution One robotic knee replacement system. The TSolution One system received FDA approval in October 2019, and Dr. Kissin performed the first case in New Jersey with the latest generation of this technology in 2020. Additionally, last month, Dr. Kissin became the first to implant this device in a New Jersey hospital, Hackensack University Medical Center. Dr. Kissin treats patients of all ages and with a wide variety of conditions, from acute injuries to chronic degenerative conditions. Additionally, he is an associate clinical professor at Rutgers University and Hackensack-Meridian Health School of Medicine at Seton Hall University. To learn more, visit his website at orthodoc.aaos.org/drykissin.