A Kirkland-based surgeon is among the first in the country to utilize new technology allowing them to mold custom knees for patients.

For Dr. Vincent Santoro, a surgeon at the Evergreen Health Orthopedics and Sports Care, the 3D imaging technology provides a wide range of benefits to patients requiring knee replacement surgery, while so far having little to no downsides.

Santoro said he first became aware of the technology during a symposium in Las Vegas.

“Like any new innovation you read about these things, you hear about it from colleagues, and it’s a matter of testing it out,” he said. “The way it was instructed, and the way it anatomically fits, just kind of made sense.”

Santoro recently used the imaging on a patient who had already had their original knee replaced six years ago using a regular prothesis but found it very painful. Following the latest surgery, his recovery time was much faster and since then has reported being able to resume his regular activities such as horseback riding.

The 3D printing technology enables Santoro to have a wax mold created within a few weeks after the initial scan which forms the metal sections of the entire knee.

“I felt this was something that made sense, especially when 15-20 percent of patients end up having pain post-operatively,” he said. “Some of the reasons are mismatch of the implant to the person, maybe too small, maybe too big.”

One of the major improvements the precision of the imaging technology provides is that it makes it possible for surgeons to preserve sections of the patient’s knee unaffected by arthritis. This can prevent misalignments with the new knee or other complications.

“Sometimes pain comes from reasons that there’s no clear cut answer,” he said. “Sometimes an x-ray looks absolutely perfect, but there’s maybe some element of soft tissue impingement. That’s a very common problem. It doesn’t feel right.”

Another advantage is that it prevents post-surgery issues with the replacement knee. The imaging makes for a more precise replacement knee than traditional methods in which the replacement can either be too small, too big, or not perfectly fitted to the patient. Most knee implants come in only a limited range of sizes and can prove problematic for patients whose knee fits in-between two sizes.

“I think the key is that with the CT scan, you are putting this prothesis in the absolutely correct position as long as you align everything,” he said. “You are recreating the normal mechanical access and bringing it back to the joint. That can’t be said for stock protheses. There are always changes in the joint line because again the prothesis doesn’t always fit perfectly.”

Whereas in the past surgeons often had to get the patient to fit the mold, the 3D imaging flips this around so that the conformist creating the knee designs it to fit the patient.

“In a stock protheses often the cuts may be excessive in trying to fit the implant,” Santoro said. “Sometimes it takes configurations because they’re trying to fit the patient to the prothesis. You wind up taking way too much bone. In the ConforMIS protheses, because it is anatomically designed, the amount we remove is remarkably less.”

Santoro said he hopes the new replacement knees will also last longer due to a better fitting.

“No prothesis will last a lifetime, but the idea is to try to increase the 12-15 years that we’re seeing now, and trying to get them into the 20-25 years.”

Although surgeons can improve their methods when using a traditional mold, Santoro said it will still not provide the same precision or accuracy that the imaging does.

“You can only do so much to vary it, because it still needs to fit the patient,” he said. “Some fit beautifully and it was absolutely designed for the patient. If you’re number five and it’s a number 5, perfect, but if you’re 5.5 that causes troubles. That’s the biggest issue.”

The new imaging also reduces the time spent on the operating table, Santoro said, in which putting the new knee in can take as little as 30 minutes.

So far, he said, he hasn’t found any negative aspects to using the new imaging.

“I think as we get older, if there’s going to be areas with deformity when we’re in our 70 or 80s, I’m not sure we need to use it,” he said. “But if you really think about it with high functioning people…it’s definitely the way to go.”