The Future of Outpatient Total Knees


Promising research and early use of high-tech devices provide a glimpse into what could someday be the norm in same-day joint replacements.

When a patient from Raleigh Orthopedic Clinic returned home from his knee replacement surgery in May, there was a base station on his nightstand awaiting his return. The station was there because the patient was the first person in North Carolina to receive a smart knee implant — essentially a Fitbit inside his body. The implant, the first of its kind approved for use by the FDA last year, features a small stem with a sensor on its base that allows the patient and his surgical team to know how fast the patient is walking, how far they’re walking each day and their new knee’s functional range of motion.

The sensor and the stem are effectively an extension of a normal knee implant. The stem has an accelerometer and goniometer in it and the sensor collects data as the patient walks for weeks and months postoperatively. Using Wi-Fi technology, the data that’s collected by the stem is linked to the base station, which uploads the data and transmits it to a HIPAA-compliant cloud-based platform that the patient and care team can access.


“The technology provides objective data for measuring how patients are progressing during their recoveries,” says Tyler Steven Watters, MD, the surgeon who placed the smart implant in the patient. “It also allows the patient to take a more active and personalized role in their rehabilitation and recovery following joint replacement surgery.”

Monitoring gait speed, step cadence, stride length, range of motion and step counts have twofold benefits. “It allows patients to see what their baseline levels are preoperatively and then track their progress through recovery,” says Dr. Watters, who practices in Raleigh, N.C.

Cumulative data collected from individual patients over time, once its aggregated and de-identified, should help the orthopedic community learn what should be expected from patients postoperatively, says Dr. Watters. Knee replacement outcomes vary widely — some patients are able to walk three miles a day six weeks post-op, while others are only able to walk a half-mile. The in vivo data captured by the smart implant will help surgeons come up with reasonable expectations about the progress patients in various demographics should be making over time as they continue to recover and normalize. Dr. Watters expects the use of smart implants to be standard in the future.

Herman G. Botero, DO, a fellowship-trained surgeon who specializes in knee and hip replacements at OrthoTennessee in Knoxville, agrees that the technology is good and its applications have promise. He doesn’t see it gaining widespread acceptance in ASCs, however, until the price of the implants come down and research shows that using it definitively improves clinical outcomes. 
In the meantime, surgeons are tapping into other high-tech solutions in addition to smart implants to enhance their skills and improve outcomes. 

Robotic assistance. Four major companies have robotic systems for orthopedic procedures, yet challenges remain for them to become standard operating equipment in the outpatient settings. One is the capital expense of the technology, as the systems can cost up to $1M. The disposable tools used on the systems are expensive as well. The platforms also take up a lot of space, which is always at a premium in ASCs.

Dr. Watters says that robotic procedures — even those performed by the most practiced hands — take a little longer to complete than traditional techniques, and time equals money in outpatient total joints. He adds that definitive data shows robotic assistance produces better outcomes than traditional laparoscopic abdominal hysterectomies and prostatectomies, but to date there is no randomized, controlled study showing a significant difference in clinical outcomes for orthopedics.

That said, Dr. Watters points out there are retrospective, non-blinded studies that show robotics helps to improve outliers in terms of joint alignment and component positioning, and that the accuracy (although not necessarily the precision) of bone cuts is improved in robotic cases over traditional surgical techniques. “Robotics is here to stay and there’s a very real chance that future studies will show it makes a clinically meaningful difference,” he says.

TBD on TKA Surgeons such as OrthoTennessee’s Herman Botero, DO, say studies showing improved outcomes from using new technologies are needed before their use becomes more widespread.  |  OrthoTennessee

Dr. Botero agrees and notes that a double-blinded randomized, controlled trial involving 1,000 robotic knee replacement surgeries and 1,000 knee replacements performed using traditional instrumentation found that each method produced the same clinical outcomes. Still, Dr. Botero thinks the current orthopedic robotic technology is “fantastic” and produces precise bone cuts.

When patients are actively engaged in their recovery, they tend to have better outcomes.
— Tyler Steven Watters, MD

The ASC in which Dr. Botero operates has an orthopedic robot and the surgeons love using the technology. They acquired it for free from the manufacturer in part of a larger business deal that has the center buying other products from the same company. To date, a robotic knee replacement costs $1,500 to $1,800 more per case than traditional total knee replacements, so acquiring the robotic console as part of a larger arrangement with the manufacturer might currently be the most practical option for many surgery centers.

Handheld navigation. This technology is a practical option for ASCs because it can be used on a case-by-case basis. The devices are a logical replacement for the computer navigation craze that existed in joint replacement surgery 15 years ago, according to Dr. Watters. They help surgeons improve the accuracy of implant alignment at a reasonable per-case cost without the bulky tower that comes with computer navigation systems. “Many handheld navigation systems are not cost-prohibitive and they don’t take up a lot of real estate, so they can be used very effectively in an ambulatory setting,” says Dr. Watters.

Dr. Botero thinks the devices can be good options when robotics systems aren’t in a facility’s budget and best used by surgeons who don’t routinely perform knee replacements. While robotic systems are more accurate, the handheld navigation devices allow for ease of use from a technical standpoint and increase overall surgical accuracy, especially for low-volume physicians. “Studies have shown that these technologies help surgeons who perform 30 to 50 knee replacements a year to reduce their outliers and performance errors,” says Dr. Botero.

Remote patient monitoring. Providers can use these platforms to deliver continuous information to patients who own smartwatches or smartphones, and patients can respond with direct feedback. The two-way communication facilitates better overall care from the patient’s pre-op preparation phase until their recovery is complete.

“This technology is all about patient engagement,” says Dr. Watters. “Patients like it, many have come to expect it, and when patients are actively engaged in their recovery, they tend to have better outcomes. The more connected and personal the patient experience is, the better.” Reimbursement levels to providers for these services can be relatively low, however, which could be a barrier for use of the platforms when ortho centers operating in a bundled payment system must closely watch the cost of each line item to remain profitable.

Dr. Botero says surgeons must guard against getting to the point at which they feel like they’re selling technology to the patient, as some insurance plans offer patients the ability to rent a smartwatch or smartphone and an opportunity to buy them when the rental period ends. It would be best if the technology that tracks outcomes data could be included on the front end in the cost of the bundle of care, says Dr. Botero.

These technological advancements will benefit patient care and their adoption will continue to increase when data shows they improve how knee replacements are performed. “The crux of the role providers play in orthopedics is about improving clinical outcomes at a lower cost,” says Dr. Botero. “This technology is exciting and is going to continue to improve. Its use will become more widespread when payers and patients see high value in it and prices continue to decrease.” OSM

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