Knee surgeries get assist from robot arms

There’s a new surgical assistant at Central Peninsula Hospital.

Robotic Surgical Assistant, called ROSA, is a new addition to CPH and the first in Alaska. Made by Zimmer Biomet, ROSA is being used exclusively at CPH for knee replacement surgeries.

Dr. Michael Reyes has been performing knee replacement surgeries for 22 years and has worked at Central Peninsula Hospital for the last six. He’s one of four surgeons who performs knee replacements at the hospital and is the only one certified to use ROSA in surgery.

Using ROSA, Reyes said, the procedure can be customized to each patient such that the stability of the knee throughout its range of motion is optimized. That’s as opposed to applying a standard replacement procedure to all patients.

Reyes said ROSA directly addresses what he calls a “concerning statistic”: Of the nearly 800,000 knee replacement surgeries performed each year, roughly 20% of patients — about one in five — are not satisfied with their results. That, Reyes said, is as compared to hip replacement surgeries, where nearly all patients — about 95% — are satisfied with their results.

“That’s the gap that we’re trying to solve with the robot,” Reyes said.

During a knee replacement surgery, Reyes said, a patient’s cartilage surface — the cap at the end of a bone — is replaced with a metal cap. Reyes said the majority of knee replacement candidates suffer from arthritis, a condition in which the cartilage layer that lubricates joints wears down, causing pain.

There are two components to ROSA: a camera that communicates with trackers placed on a patient’s leg and a robotic arm that positions the cutting block. Since ROSA arrived at Central Peninsula Hospital about five weeks ago, she’s already participated in 21 surgeries, Reyes said.

During a traditional knee replacement surgery, Reyes said, focus is placed on anatomic alignment. Anatomic alignment, in which the goal is to get the position of someone’s knee aligned with the rest of the bones in their leg, is meant to distribute weight put on the knee evenly. The even distribution is meant to prevent too much wear on one side of a knee replacement.

Though anatomic alignment has been the status quo when it comes to knee replacement surgery for decades, Reyes noted it still produces patients who are unhappy with their results. That’s where a new focus — on range of motion — comes in.

People spend most of their lives with their knees bent between 30 and 90 degrees, Reyes said, not fully extended. When a knee replacement surgery focuses on stability when fully extended, the final product can sometimes feel mechanical or like it’s not functioning property.

“We think a big chunk of what’s causing this unhappiness is the instability of the knee, that it doesn’t feel balanced in different portions of the range of motion in the knee,” Reyes said. “While it’s nice that a knee looks perfect in full extension when you do an x-ray, nobody lives their lives with their knee fully straight.”

He said surgeons have been using computer navigation for decades, but that ROSA “goes a step further” by optimizing for stability throughout the range of motion — or a knee that is kinematic. That allows the final knee replacement to feel more balanced and natural.

The ability to personalize knee replacement to each patient means that surgeons are also not trying to force anatomical alignment onto someone whose legs weren’t straight to begin with, such as people who are bow-legged or have knock knees. Kinematic alignment also keeps a patient’s ligaments and tendons happy, Reyes said.

There’s nothing new about the actual implant, he said, but rather the way that implant is aligned.

ROSA differs from other robotic surgical assistants in that a human still performs the surgery. Other robotic assistants, Reyes said, such as the da Vinci surgical system, require a surgeon to manipulate the technology using a remote controller. ROSA, Reyes said, provides him with more real-time information.

“Before we make a single cut, and during every step of the procedure (there are) checks and balances to make sure that the cuts are pretty accurate,” Reyes said. “It allows me to have a pretty solid game plan of the cuts and then it executes the cuts perfectly.”

In his pool of 21 patients so far, Reyes said he’s already seeing better results.

“We are seeing that patients are recovering quicker, they have less swelling, they’re getting to their physical therapy goals quicker and they’re walking more naturally,” Reyes said.

More precise knee replacements aren’t just about comfort, though. The Australian Orthopaedic Association National Joint Replacement Registry, which Reyes said has done thousands of robotic knee surgeries, has seen the number of people who have had their replacement surgery redone due to dissatisfaction has fallen by more than one-third.

Dr. Herbert Boté is also an orthopedic surgeon at Central Peninsula Hospital. He specializes in sports medicine and said Wednesday that most of the surgeries he performs are arthroscopic, or address shoulders, hips, knees and ankles. The use of robotics in joint surgery, he said, is something he supports and expects to become more standardized over the next five years.

“I stand with continuing to push the envelope and make robotics work for orthopedics,” Boté said.

Boté said that he and Reyes are always keeping an eye on advances in their field that could benefit patients. Though there’s a learning curve for doctors who may have to re-learn what they were taught in residency in order to incorporate robotics into surgery, robotics is something newer graduates should be familiar with.

“It’s going to be commonplace,” Boté said of robotics. “Surgeons not using it now will gravitate towards ROSA because they’ll hear more and more about it as the public demand goes up.”

While Boté is capable of performing knee replacement surgeries, he said it makes more sense for Reyes to handle those procedures given the patient volume seen at Central Peninsula Hospital and the precision of ROSA. Over time, he only expects ROSA’s applications to surgery to grow.

“Rosa for knee replacement is just the beginning,” he said.

More information about ROSA can be found on Zimmer Biomet’s website at zimmerbiomet.com.

Reach reporter Ashlyn O’Hara at ashlyn.ohara@peninsulaclarion.com.