The FDA has decided that a knee replacement surgical guide system using only X-rays is not substantially equivalent (NSE) to systems that use MRI or CT.
On December 22, 2015, Belgian-based Materialise NV announced receipt of an FDA NSE letter after the company submitted a 510(k) application to market its product in the U.S. After announcing the first total knee surgery using the Materialise X-ray knee guide in October 2014 and performed at Holy Family General Hospital in Reet, Belgium, it looks like it will take a while longer for U.S. patients to have access to the technology.
Materialise’s guide system allows for the preplanning and 3D printing of the surgical guides using only 2D X-ray imaging and is intended to be used as a surgical instrument to assist in the positioning of total knee replacement components, without MRI or CT.
Wilfried Vancraen, the founder and CEO of Materialise said he is “disappointed that the FDA concluded that, based on the information submitted, our X-ray knee guide system cannot be considered as substantially equivalent to our solutions based on CT or MRI images. While this decision will impact the timing of the marketing of our innovative solution in the U.S., we will continue to pursue the regulatory clearance process, taking into account the feedback from the FDA.”
According to the company, until now, the technology that combines the surgical planning of total knee replacements in a virtual 3D software environment with the 3D printing of corresponding patient-specific surgical guides required the availability of CT or MRI scans of the patient’s knee. The company’s technology actually turns 2D X-ray images into 3D information and solutions.
The company didn’t divulge the contents of the FDA letter, but no safety or effectiveness issues were noted in the announcement.

