FDA approves the first implantable, above-the-knee prosthesis

The U.S. Food and Drug Administration has approved an option for patients who have trouble with the standard socket leg prosthetics that are typically used for those with above-the-knee amputation. The implantable prosthetic requires two surgeries, but it's intended to encourage prosthetic usage and to improve patient outcomes.

OPRA Implant System connected to an external prosthesis through the OPRA Axor™ II.--Courtesy Integrum AB

The OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) Implant System, as the newly approved prosthetic is known, is from Swedish bone-anchored prosthetic specialist Integrum AB. It was approved under a Humanitarian Use Device (HUD) designation, which is comparable to Orphan Disease designation for drugs in that it can be used for devices "to treat or diagnose a disease or condition that affects or is manifested in fewer than 4,000 individuals in the U.S. per year," according to the agency.

"Prostheses can help people who have lost a leg due to trauma or cancer to regain mobility and to more easily participate in everyday activities," Dr. William Maisel, acting director of the Office of Device Evaluation in the FDA's Center for Devices and Radiological Health said in a statement. "The OPRA device may help those with above-the-knee amputations who have had problems with rehabilitation and have not been able to benefit from available socket prostheses."

The newly approved prosthetic is intended to reduce scarring, pain, recurrent skin infections, or help adjust to fluctuations in the shape of the residual limb that may limit use of traditional socket-based prosthetics.

The OPRA device requires to surgical procedures to install. First, a cylinder-shaped fixture is implanted into the central canal of the remaining thigh bone. Then about 6 months later, another surgery is needed to attach a rod to the previously implanted fixture. After another 6-month period of training and rehabilitation with a training prosthesis, patients are then fitted with their own customized one.

The FDA said that clinical data on OPRA from a 51-patient trial found that "subjects reported increased prosthetic use, and improved mobility, comfort, function, and quality of life compared to the subjects' own outcomes prior to the surgeries," with the most common adverse event being infection.

- here is the FDA statement