Three months after his second knee surgery, Ralph Dreitzler was back in the saddle again. The semi-retired horse trainer didnt’ think it was possible, given that it had taken him a year to get to this point after his first knee replacement six years ago.
“I’m amazed at how fast I came back,” said Dreitzler, 62. “There’s been a lot less pain, right from the get go. It’s been a piece of cake compared to my other knee.”
Dreitzler is one of the patients to receive the only specialized knee replacement prosthesis on the market. Dr. Vincent Santoro at Evergreen Health Orthopedics & Sports Care in Bellevue is among the first surgeons in the U.S. to use this technology for total knee replacements. While he said there are patients who will do very well with a stock prosthesis, it has benefitted active patients like Dreitzler.
“I’ve been using it for people who want to maintain an active lifestyle,” said Santoro. “It’s the BMW of prosthesis.”
The device, called the iTotal CR, is designed specifically for each patient based on 3-D scans of the person’s knee. Surgeons take CT scan images of the knee of the patient receiving an iTotal knee replacement, which are converted into 3-D images by ConforMIS that are used to create the prosthesis.
People’s knee bones are generally not completely the same size, especially in the back, so 3-D images are especially applicable in knee replacements because they can show the intricacies in each patient’s knee bone, said Santoro.
The stock total knee replacement prosthesis used in most surgeries comes in pre-set sizes, sometimes extending too far or not covering enough of the bone, potentially leading to pain, bone bleeding and scar tissue.
According to ConforMIS, a study in the The Journal of Bone and Joint Surgery found that bone overhang affected 40 percent of male and 68 percent of female knee replacements.
More bone is also taken away during the insertion of the standard knee replacement prosthesis, leading to a greater potential for the prosthesis to loosen faster and possibly making installing a second knee replacement more complicated.
“It’s made out of the same materials, but this prosthesis conserves bone,” said Santoro, who has been using the specialized knee replacements for about a year and a half. “I know there are more doctors who want to use them.”
In the last 18 months, Santoro has used the individualized prosthesis for about 75 patients, and says that demand is growing.
It does take around six to seven weeks to get the prosthesis made, and the cost varies for patients. But, Dreitzler said the difference in cost between the stock prosthesis and the iTotal CR was about $150.
The prosthesis emerged from other, smaller individualized knee replacement parts created by the Burlington, Mass.- based company.
ConforMIS also manufactures a handful of products used in partial knee replacements. Altogether, the company has sold over 30,000 implants from their product range.
The first surgeries were performed in Boston, Indio, CA, and Houston in May 2011, according to a ConforMIS press release. At the time, John Slamin, senior vice president of engineering at ConforMIS, said “these first iTotal cases reinforce my belief that patient-specific knee replacement will redefine the category.”
The prothesis has not been without complaints. In October 2014, a Texas woman filed a lawsuit alleging that the iTotal G2 knee replacements (the previous generation of iTotal product) she received were defective, and is suing for liability, negligence, breach of warranty and damages. A ConforMIS representative declined to comment on the claims, citing the ongoing legal case.
Despite this lawsuit, the company closed its initial public offerings on July 7, selling 10,350,000 shares of common stock at $15 per share. The custom-made prosthesis technology is also being considered for other surgeries, including hip replacements.
And Dreitzler has returned to doing what he loves — training horses, with a lot less pain and a lot more mobility.
