Performing a knee replacement is a balancing act.
The term “knee replacement” is itself somewhat of a misnomer in that the knee is not taken out and replaced. Instead, cartilage is removed and the knee is resurfaced and fitted with an implant.
Each patient is different, so surgeons have to cut the bone to fit the implant while balancing the ligaments on both sides of the knee so it gets proper wear.
“The way I try to explain it to patients is if you’re trying to balance your car tires you want to balance them perfectly so that they wear perfectly and last longer. That’s what you’re trying to do with a (joint) replacement — is get that proper customized balance for each individual,” said Dr. Chris Browne, an orthopedic surgeon with Oklahoma Surgical Hospital who specializes in knee, hip and total joint replacement.
By getting the inside and outside to wear evenly, the knee feels more natural to the patient.
“I’ve been doing this for 17 years, and I’m good at what I do, but it’s still technically difficult to match every implant to every patient,” Browne said. “It’s like building a shelf. If you’re a really great shelf builder, it’s still hard to build shelves sometimes, depending on the house.”
New robotic technology from MAKOplasty that hit the market a couple of months ago allows doctors such as Browne to create a virtual model of a patient’s knee before surgery so the knee can be fitted to the implant down to the half-millimeter.
The knee can be put through range of motion during surgery to get an idea of the ligament balance and to adjust the virtual implant for fit and balance before even cutting the bone.
The surgeon directs a robotic arm, which removes the cartilage and bony tissue to get an exact replica of the virtual model.
“It’s unlike the standard saws and drills we use that can be off by a millimeter or more; the robotic arm doesn’t allow you to go outside that space,” Browne said. “As long as you create the model, it will only work within that little field that you create.”
The technology has been in place for partial knee replacements for years but was just recently approved for full knee replacements, said Rick Ferguson, CEO of Oklahoma Surgical Hospital in south Tulsa.
“We feel that it’s important as an organization to continue to offer new and cutting-edge technology to our community, and we have long embraced robotic technology,” Ferguson said.
“The addition of this technology is another step in continuing our singular focus on providing the best possible outcome for our patients.”
One of the biggest benefits for patients is that robotic surgery can be less invasive. The incision still has to be large enough to insert the implant, but with the technology doctors can limit much of the soft tissue damage.
Browne envisions the technology progressing to include shoulder replacements and fracture care, as well as other areas.
“Robots are hopefully not going to take over the world,” he said, “but they’re going to be used in different ways because we’re able to get greater precision with them.”