Orthopedic surgeon Joshua Johnston uses three arms when he performs knee and hip replacement surgeries at St. Clare Hospital in Lakewood.
One of them is robotic.
“I feel like I’m a better surgeon with the robot than without the robot,” Johnston said recently, on a break between his fifth and sixth robot-assisted surgery of the day.
Johnston has been using the robot for the past 14 months to make precise cuts that allow a better fit of the artificial knees and hips.
“It’s a tool that helps us put these parts in more precisely,” he said.
He’s quick to point out that the robot serves him and isn’t performing surgery on its own.
“Some people get freaked out,” Johnston said. He assures them a human is in charge of the procedure.
The $1.2 million robotic arm looks like something you’d find in a dental office, not on “Star Wars.”
The technology has been around for eight years, said Johnston, who has been practicing for a decade.
“Just in the past two years has it become available for total hip and total knee (joint replacement),” he said.
Johnston used them for partial knee replacements at first. Now, he uses the Mako robot, made by Stryker, for full knee and hip replacements.
A GROWING NEED
The market for joint replacements is rising, and the medical industry is keen to meet the challenge.
Across the United States, 500,000 knee and 300,000 hip replacements are performed each year.
“Those are expected to go up five times and three times respectively, over the next 10 years, as the boomer population ages,” Johnston said.
In 2018, Johnston completed 500 surgeries. Of those, 300 were joint replacements, with hip surgeries slightly tipping the scale over knees.
Johnston is in the top five nationally for the number of robotic arm-assisted hip surgeries, according to Stryker.
Before Johnston and his robotic assistant begin any surgery, a CT (computerized tomography) scan is made of the patient’s joint. The series of slice-like scans are assembled into a 3D image.
Much like the way live action is translated into animation for Hollywood, the 3D image is synchronized with the bones in the patient’s body, using a camera on the robot’s arm.
“The robot camera knows where the joint is in space, then puts it together with the (3D) model you have (on the computer),” Johnston said.
In order to install an artificial joint in a knee, six cuts must be made on a patient’s bones: Five on the femur and one on the tibia.
“You’re taking away bone and replacing it with the implant,” Johnston said of the surgery’s goal. “The robot knows where the knee is in space. It won’t let you cut outside of the boundaries.”
The surgeon, not the robot, controls the saw.
“The surgeon has his finger on the trigger,” Johnston said. “The surgeon is moving the saw. The robot doesn’t let you color outside the lines.”
THE PATIENT PERSPECTIVE
One of Johnston’s first patients to benefit from the robot arm was Margaret Santoyo. She received a partial knee replacement.
Like many of Johnston’s patients, she has arthritis. She had already had both hip joints replaced.
“I thought I was done with joint replacements, and then my knee started hurting,” Santoyo said.
The pain and swelling made it hard for her to work. She’s been a registered nurse since 1976. More than 40 years of cement floors, running and squatting had taken their toll.
“I was having to wrap it every day,” she said. “When I went home, I had to ice it and put it up.”
In November 2017, she went under the robotic knife. She’s happy with the results. The pain is gone.
“It’s a little stiff sometimes,” she said. “I have to stay active, keep moving.”
Santoyo took six weeks off work but could have been back in four weeks, she said.
Physical therapy is key to a full recovery, she said.
Santoyo’s results are not uncommon, Johnston said.
Since using the robot, he’s seen quicker rehabilitation, less pain in his patients and lower costs.
Knee replacements are a notoriously fickle procedure with up to 35 percent of patients reporting some level of dissatisfaction with the results, according to various studies.
Pre-robotics, Johnston said, 15 to 20 percent of his patients did not like their new knees after replacement because of stiffness and pain.
“Some of those are explainable, the part is the wrong size, the part is malaligned, it doesn’t move,” Johnston said. “All of those (problems) are fixed with the robot.”
With the old way, Johnston had to return about 5 percent of his patients to the OR to fix problems.
“Since we’ve had the robot, we’ve done zero,” Johnston said.
OLD VS. NEW
Without the robotic arm, traditional knee joint replacements require a rod to be temporarily placed inside the patient’s femur. The rod ensures the joint will align properly.
The robot eliminates that need, which reduces pain and speeds recovery.
With hip replacements, the same cuts need to be made in soft tissue with or without robotic assistance.
On the knee, however, the robotic surgery is less invasive than the traditional methods.
The two surgeries use different tools which are attached to the robot’s arm.
Knees use a saw. Hips use a reamer to precisely carve out the socket and prepare it for the replacement.
“We trust the robot now, from all the data that goes into it,” Johnston said.
Johnston thinks all joint replacements will be assisted by robotics within the next five years. Future versions will allow surgeons to customize replacements of hip joints based on how the patient uses their hips.
“The next generation of software will have that 3D model move so you can model what happens to the hip and pelvis when the patient sits down, what happens when the hip turns in a golf swing,” he said.
The only extra cost associated with robotic surgery is the CT scan which, so far, insurance companies have not denied, Johnston said.
As with the rest of society, medicine seems to be on the cusp of a robot revolution.
Other robotic assistants help with cardiac, colorectal, gynecologic, thoracic, urologic and other types of surgery.
At Mary Bridge Children’s Hospital, doctors are using robotic surgical assistance technology to correct scoliosis in children.
Robots now routinely sterilize hospital rooms using intense UV light.
Johnston recently had kids from a Clover Park high school’s robotic club operate the St. Clare robot after surgery was completed for the day.
“We had them wash their hands and took them back to the OR,” Johnston said. “They got to really get hands on with the robot.”
“I took off the saw,” he added.