FDA approves first implant system for adults who have above-the-knee amputations

The U.S. Food and Drug Administration today approved the Osseoanchored Prostheses for the Rehabilitation of Amputees (OPRA) Implant System, the first implant system marketed in the U.S. for adults who have transfemoral—or above-the-knee—amputations and who have or are anticipated to have rehabilitation problems with, or cannot use, a conventional socket prosthesis.

Today's approval of the OPRA Implant System expands options for prostheses for individuals who have had above-the-knee amputations and can help those who have had or may have problems with rehabilitation and have not been able to benefit from available socket prostheses. 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."

Capt. Raquel Peat, Ph.D., MP.H., USPHS, Director, FDA's Center for Devices and Radiological Health's Office of Orthopedic Devices

A conventional leg prosthesis uses a specially-fitted, cup-like shell called a socket that fits over the remaining portion of the patient's leg (the residual limb remaining after amputation) to secure the device to the leg. Some patients may not have a long enough residual limb to properly fit a socket prosthesis or may have other conditions, such as scarring, pain, recurrent skin infections or fluctuations in the shape of the residual limb that prevent them from being able to use a prosthesis with a socket. The OPRA Implant System is surgically anchored and integrated into the patient's remaining thigh bone to allow connection to an external prosthetic limb.

The OPRA Implant System has been on the market under a humanitarian device exemption since 2015. Humanitarian use devices are intended to benefit patients in the treatment or diagnosis of a disease or condition that affects or is manifested in not more than 8,000 individuals in the U.S. per year. Today's approval expands the patient population eligible for this device.

The OPRA Implant System is installed with two surgical procedures. In the first procedure, a cylinder-shaped fixture is implanted into the central canal of the remaining thigh bone. Approximately six months later, after tissue has grown to anchor the fixture and the skin tissue has healed, a second surgery is performed to attach additional device components of the OPRA Implant System to the fixture from the previous surgery. The OPRA Implant System extends through the skin at the bottom of the patient's residual limb and connects to the prosthesis.

After the second surgery, the patient works with a trained physical therapist to gradually place weight on the OPRA Implant System using a training prosthesis. Patients require about six months of training and rehabilitation after the second surgery, before being fitted with their own customized prosthesis by a trained prosthetist.

The FDA evaluated the safety and effectiveness in a clinical study of 65 participants who received the OPRA Implant System. Effectiveness was assessed using the Questionnaire for Persons with a Transfemoral Amputation, a patient reported outcome measure that reflects frequency of use, patient's mobility, problems with the device and patient's overall health. The average improvement in the prosthetic use score on a 100-point scale, was 35.1 points at two years and 39.6 points at five years as compared to their reported scores with a conventional socket prosthesis. Adverse events reported during the study included: infection, mechanical complications, pain, injury and loosening of the fixture.

Patients should discuss with their health care providers the benefits and risks of all prosthetic options.

The FDA reviewed the OPRA Implant System under the Premarket Approval (PMA) pathway. PMA is the most stringent type of device marketing application required by the FDA and is based on a determination by the FDA that the PMA application contains sufficient valid scientific evidence to provide reasonable assurance that the device is safe and effective for its intended use(s).

The OPRA Implant System is manufactured by Integrum AB in Mölndal, Sweden.

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