Robot arm lends new precision to knee surgery

Orthopedic surgeon Dr. Timothy Lane uses a probe and a system of arrays to digitally map a partial knee surgery using the MAKO robotic arm interactive orthopedic system at North Florida Regional Medical Center on Wednesday, April 23.

Doug Finger/The Gainesville Sun
Published: Wednesday, April 30, 2014 at 6:01 a.m.
Last Modified: Wednesday, April 30, 2014 at 3:57 p.m.

Dr. Timothy Lane, a surgeon with the Orthopedic Institute, has performed thousands of knee replacement procedures, including both total knee replacements and partial knee replacements. An article published Wednesday in The Sun misstated how many partial knee replacements Lane had performed and did not differentiate that the Orthopedic Institute is an entity independent of area hospitals.

Gwen Parrish of Gainesville grew up bow-legged. Over time, that caused damage to the inside of Parrish's knee cap, so for about a decade, the 56-year-old's knee caps have been wearing down to the point of bone-on-bone pain.

“I couldn't stand for any length of time or walk any distance,” Parrish said.

That was before. The “after” happened last week at North Florida Regional Medical Center, where Parrish had a long-awaited partial knee replacement of her right knee.

Partial knee replacements have been around at least two decades, but the novelty of Parrish's procedure is that it was guided by a robot. Or rather, a robotic arm called the RIO, which is made by the Fort Lauderdale-based company MAKO Surgical Corporation, which orthopedic giant Stryker acquired in December.

The procedure itself is called MAKOplasty partial knee resurfacing, and Parrish's procedure marked the sixth one performed in Gainesville -- all of them at NFRMC, the first medical center in the area to acquire the robotic arm. The first MAKOplasty procedure was performed at North Florida Regional in January.

Dr. Timothy Lane, a surgeon with the Orthopedic Institute, has performed thousands of knee replacement procedures, including both total knee replacements and partial knee replacements, with traditional equipment and said that using the robotic arm has improved his accuracy.

“The very first one I did was perfect,” Lane said. “It's a dramatically more powerful tool. Traditionally you use your eye, but a lot of times that's too crude.”

The robotic arm gets its precision in part from an attached probe with a high-speed burr that chips away at the damaged bone within the lines, so to speak. A computer screen shows 3D anatomical images of the patient's knee from a preoperative CT scan. The computer also displays real time what the surgeon is doing.

“If you move outside (the lines, the probe) turns off automatically,” explained Dr. Hari Parvataneni, an orthopedic surgeon at UF Health Shands Hospital, who also performed MAKOplasty before joining Shands (which does not yet own a robotic arm).

Parvataneni explained that the robotic arm uses haptics feedback, in which the probe vibrates when moved outside the designated area, which is also displayed on the computer screen.

“It's a more precise operation,” Lane said. The bone cuts are made within one millimeter of accuracy -- or 6 sheets of paper thick.


The robotic arm is the latest technology in an evolution of computer-guided surgery, Parvataneni said. Such navigation systems have been around for two decades, and like cell phones -- which have been around roughly the same amount of time -- the technology has evolved.

Several companies have navigation systems, including Gainesville-based Exactech's GPS (guided personalized surgery), which also uses a probe and 3D images to chart the course of surgery. Parvataneni called Exactech's GPS “the easiest system” to use.

“GPS is an excellent navigation system and one of best on market … if you are better off getting the total knee (procedure),” he added.

MAKOplasty is currently only used for partial knee replacements, and the robotic arm distinguishes it from other navigation systems. Orthopedic surgery, Parvataneni said, is analogous to driving a car where the surgeon is in the driver's seat.

“A good driver goes from point A to B quickly. A driver who is not as efficient uses the GPS,” Parvataneni said. “The MAKO actually helps you drive the car.”

“I think it is the future,” Parvataneni said, referring to robotics surgery. Stryker is developing the technology for hip replacements as well, said Rob Greene, Stryker Mako's territory sales manager for Southeast Georgia and North Central Florida.

More than 100,000 MAKOplasty procedures have been performed worldwide, he added.

“The robot allows doctors to take a difficult procedure and make it more mainstream.”

Some 324 institutions actually have the robotic arm, which costs at least $750,000. Parrish said that she was told by NFRMC that the procedure's price tag fell between $80,000, and $130,000. Her insurance covered most of it, and Greene said that insurance generally covers the procedures.

For Parrish, the cost was well worth it.

“It was a very delightful experience, if you can say that about major surgery,” Parrish said on Monday, five days after her surgery. “I am practically without a walker today.”

Parrish added that she is not in pain and is planning to do a partial knee replacement on her left knee in a couple of months.

Lane explained that the surgery involves a smaller incision and involves replacing less parts (ligaments and tendons) of the original knee, and so is generally a less painful procedure.


But partial knee replacements are not for everyone.

“It is for a unique set of patients,” Parvataneni said, adding that partial knee replacements currently comprise less than 10 percent of knee replacement procedures. To qualify, patients must have isolated arthritis in just one part of the knee, which has three compartments potentially affected by the disease -- the patella, or kneecap; the medial, or inside of the knee; and the lateral, or outside of the knee.

“Very few people are truly candidates,” said Dr. Claudette Lajam, assistant professor of orthopedic surgery and chief safety officer at NYU Hospital for Joint Diseases.

“The physical exam before surgery is very important,” she continued, for assessing bone pain. It is also likely that people with isolated arthritis may develop bone pain in the other areas of the knee, necessitating a total knee replacement, she added.

“Is it (partial knee replacement) that much better than a total knee? Which is a very good, predictable, reliable operation,” she asked.

“Don't push your surgeon to do the surgery because it's new and fancy and then six months later be miserable because it's the wrong operation for you,” she continued.

But for middle-aged patients -- those in their 40s and 50s -- who have experienced injuries such as a partial meniscal tear and have active lifestyles, the operation is ideal, Parvataneni said.

Lajam added that the navigation system “is useful because unicompartmental knees are tricky. If you don't get it right, you're going to fail,” leading to do-over procedures that would invariably be total knee replacements, she said.

However, no technology replaces a surgeon's skill, she continued.

“The bottom line is, 'Who is drawing the lines?'” Lajam said. “Yes, it's great technology, but it doesn't replace a surgeon's experience and judgment.”

Contact Kristine Crane at 338-3119, or

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