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It is a cruel irony for some amputees that the very artificial limbs that should increase their mobility limit it instead. Complications such as chronic pain, excessive sweating into the socket and recurring wounds of the residual limb often prevent amputees from fully enjoying the freedom afforded by their prostheses. 

Froedtert & the Medical College of Wisconsin orthopaedic specialists are leading the way in offering amputees a new, advanced alternative. The Osseointegrated Prostheses for the Rehabilitation of Amputees system, called OPRA™, is unique in that it provides an attachment point for the amputee’s prosthesis anchored in their bone. 

“We’re one of only a dozen places in the United States to do this procedure and we’re excited to share it with other providers,” said John Neilson, MD, an orthopaedic oncologist and MCW faculty member whose practice has branched out to include treating the complications of amputation.

Froedtert Hospital’s involvement with the OPRA system dates to the 1990s, when the developer of the technology performed some of the first surgeries there.

The latest version of OPRA implant system is currently approved by the FDA. It offers significant advantages to the right candidates that fall into the eligibility criteria and guidelines.

“Most of our patients are either nonsocketable because their residual limb is too short, or those who can and do wear a prosthesis but struggle with the problems,” Dr. Neilson said. “Some of the patients have been in sockets for years, others have had traumatic amputations and others have never had prosthetic legs. They’re now up and walking on new legs they would not have had otherwise. A number of patients are fairly high functioning in sockets but want to do better.”

A Bond With Bone

The OPRA system consists of seven titanium or titanium alloy components, implanted during two separate surgeries.

“First, we implant the fixture, which is like a large screw, into the femur and close the wound,” Dr. Neilson said. “The bone bonds to that and between six weeks and three months later, we add to the ingrown fixture the abutment, a piece that extends outside the skin to attach to the prosthesis.”

The extended wait between surgeries serves a twofold purpose: time for the bone and device to bond and for the bone to build up strength. 

“Long-term amputees develop relative osteoporosis because they don’t normally bear weight through the femur,” Dr. Neilson said. “They have to spend a couple of months building up strength in the femur or it might break because it hasn’t seen body weight for a number of years.” 

Between the two surgeries, patients will essentially be out of their leg for three to nine months.

OPRA Axor Prosthetic

Once the patient has healed, the OPRA Axor is attached to the abutment. It is a connection device that acts like a fail-safe. If the implant is overloaded, the Axor twists the prosthesis to protect the implant from damage. Patients can attach standard prosthetic components to the Axor connector. Many, in fact, mount the same prosthesis they were previously using with a socket. 

“With everything that happens outside of the body, the possibilities are endless,” Dr. Neilson said. “This is simply a different way to mount a prosthetic limb to the leg.”

Recipients of the OPRA system report more natural sensations in the residual limb, a phenomenon called osseoperception. 

“When metal is implanted in bone, it’s a direct connection,” Dr. Neilson said. “Amputees can actually feel vibration through the bone, and they learn how to use that vibration to feel the heel strike. They’ve didn’t have that sensation with a socket, and many patients improve because of it.”

Following the implants, patients go through rehabilitation directed by David Del Toro, MD, physiatrist and MCW faculty member. They can do virtually any activity except for running, which might place too much stress on the implant. Perhaps not surprisingly, double amputees experience some of the most positive outcomes.

“Many of them are wheelchair dependent most of the day because of the difficulty of putting on two limbs or their residual limbs are too short. They have the most potential for improvement,” Dr. Neilson said.

Referring Patients for OPRA Implant Evaluation

Physicians can refer patients to either Dr. Neilson or Dr. Del Toro. An initial assessment will evaluate the patient’s present level of function, goals and risks for complications and then determine the best solution. Some patients might be better suited to another approach, such as limb lengthening, for example, to optimize their use of an existing prosthesis.

 “The Froedtert & MCW health network was willing to invest in the system because we saw the value to patients and we are committed to making it accessible,” Dr. Neilson said. “We’ve honed the plan and have the experience and the team. We want to make sure providers know about OPRA because we’ve seen such great results from the amputees we’ve worked with so far.”

For Our Referring Physicians:

Academic Advantage of the OPRA Implant System

The Froedtert & MCW health network gives patients and their referring physicians a distinct advantage.

Contact our physician liaison team for more information about the OPRA Implant System or if you would be interested in meeting with any of the orthopaedic team members.

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