MINNEAPOLIS (WCCO) — A new medical robot is designed to make knee replacement surgery a less painful experience with a much quicker recovery.

Knee replacement is the most sought-after orthopedic procedure nationwide, and doctors the new technology could be a breakthrough for a lot of patients.

“This is truly game changing, from the standpoint of being able to achieve results that are accurate and precise within a millimeter or less,” Dr. Robert Hartman of Twin Cities Orthopedic said. “[It’s] something that’s been unattainable for orthopedic surgeons in the past.”

Kimala Walters was the first person in Minnesota to have the new procedure.

“Once I stop, then it sets in,” she said before the surgery. “And when I get up again I can feel the pain.”

Walters says she got sharp pain through the back of her knee, constantly distracting her from work and day-to-day activities.

The pain has made her cautious — she wouldn’t cross her legs, she gave up running, and she worried about keeping her home cleaning company afloat. That’s why she decided that surgery would be the best option.

“She just didn’t have enough load bearing cartilage,” Dr. Hartman said. “She developed what I would call moderate or mid-range arthritis on the inner half of her knee, or bone rubbing on bone.”

Dr. Hartman performed the first operation in Minnesota using a partial knee resurfacing technique called Makoplasty, using a $1.5 million robot. He believes the precision of the robot-assisted surgery will dramatically improve the patient’s recovery time.

“Really by two weeks she should be back doing 80 to 90 percent of what she likes to do, and by 4 weeks she should be fully recovered,” Dr. Hartman said.

The computer calculates position using 8 black discs — called arrays — in the patient’s leg that bounce an infrared signal to the machine. They allow the computer to map her leg and how it moves. A standard surgery would require an eight-inch incision, but the robot only needs about half of that.

Once the leg is open, the surgeon uses a hand-held array to verify points inside the knee, moving it around to mark special points.

“It’s a little bit like playing a video game,” Dr. Hartman said. “I’m sure my kids would be better at this than I am.”

The verification process confirms the actual structure of the patient’s knee to a CT scan, taken earlier. The robot then uses combines the two images, and formulates a plan.

Spinning at about 80,000 RPM, the robot arm grind away damaged cartilage in Walters’s knee. Using colored markers on a screen, the surgeon will carve out a space to make a near perfect fit for the implant. Thanks to software in the machine, the robot can specifically target the bad cartilage, and won’t let the surgeon go outside the lines.

“The computer will actually turn the robot off,” Dr. Hartman said. “It just will not let you penetrate the parameters you have set for yourself.”

Once it’s all removed, implants are put in place, creating a new bearing surface between the bones. Using the Makoplasty, accuracy can now be measured in millimeters, within the thickness of a piece of paper.

A robot can do that over and over, while a human may not be as consistent.

“The eye is not that accurate, the saw blade is not particularly accurate,” Dr. Hartman said. “This is eight times overall more accurate than doing it by sight, so that’s the real advantage of the robot.”

Three weeks after her surgery, Kimala Walters is doing therapy at home.

“I am feeling so much better now than then,” she said.

Walters stopped taking pain medication two days after the surgery, and she says she looking forward to getting back to work.

“I was cleaning the house, cleaning bathrooms five days after the surgery,” she said. “Five days and I was up and about.”

Makoplasty is covered by most insurance carriers as well as Medicare. Dr.Hartman says the cost of Makoplasty is approximately $600 to $1,000 more than a traditional knee surgery, due to the need for the preoperative CT scan. In the long run, however, it may cost less because a quicker recovery can mean a shorter hospital stay.

A similar robot is now in use in Minnesota called the Navio System.

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