Osseointegration Feasibility Trials Receive Approval

A new implantable prosthetic device is being developed by researchers at the University of Utah and George E. Wahlen Department of Veterans Affairs Medical Center.

A team of researchers and surgeons from the University of Utah (U of U), Salt Lake City, and the George E. Wahlen Department of Veterans Affairs (VA) Medical Center, Salt Lake City, hope to provide an alternative solution to prostheses with socket-type attachments via osseointegrated prosthetic limbs. They have announced that feasibility trials have been approved and are set to begin in two years.

For the last six years, this team has been developing a device that can be implanted directly into a person's residual bone, passing through the skin, so they can securely attach a prosthetic limb without the need for a socket. Their research recently hit two milestones. One was a partnership with DJO Surgical, the surgical business unit of DJO Global, Vista, California, which has licensed the implant technology and is assisting with the remaining research and development. The other milestone was being accepted into a new U.S. Food and Drug Administration (FDA) program that allows them to design a human early feasibility study. DJO Surgical applied for the FDA study and is responsible for managing its implementation.

Thousands of wounded warriors suffer with limb amputations, and standard prostheses are not always an option. Skin issues or short residual-limb length can cause individuals with amputations to forgo socket-type attachment systems.

"We are trying desperately to provide relief to the many veterans who have lost a limb," said Roy Bloebaum, PhD, a U of U Department of Orthopaedics research professor and the director of the VA Bone and Joint Research Lab. "Most of these people are very young and have many years to live. Our goal is to give them back all of the abilities they had before they were injured."

Osseointegration of an amputated limb in humans has never been done at a U.S. hospital, and the procedure has only been attempted an estimated 250 times worldwide in Europe and Australia, with mixed results, according to a U of U press release. Researchers studying these implants have faced three problems-getting the bone to grow into the device, preventing infection, and determining how to address the skin interface. However, they believe most of these problems have been addressed, as the solutions lie in the design of their device and the materials used. Specifically, the titanium device is integral to its success because it is coated with a porous titanium material called P(2) (P-squared), which is a proprietary coating that is owned by DJO. P(2) acts as both the bone in-growth as well as the seal material on the implant that provides a "soft tissue seal" around the device to prevent bacteria from entering the body. Its use is backed by an animal study.

The U of U research team, from left, Bachus, Bloebaum, and Beck. Photographs courtesy of Technology Venture Development.

The early feasibility study will last up to three years. The initial trial sites are expected to be within the VA system and most of the patients are expected to be war veterans with amputations. During that time, the clinical research team will implant their device into ten patients. A unique element will be the ability to develop and refine their device between operations, which should accelerate the overall refinement process by compressing the development cycle.

Bloebaum is working with two other U of U professors-Kent Bachus, PhD, an engineer and a U of U Department of Orthopaedics research associate professor and co-director of the Harold K. Dunn Orthopaedic Laboratory at the U of U; and J. Peter Beck, MD, an orthopedic surgeon and a U of U adjunct assistant professor, orthopedic surgery operations. They still have a long way to go before U.S. hospitals will be offering their implant prosthesis. They are currently working to secure $5 million in grants and partnerships like the one with DJO.

"We are excited to sign this partnership agreement with the University of Utah and Dr. Bloebaum," said Bryan Monroe, DJO's senior vice president and general manager of DJO Surgical. "With the combination of our proprietary titanium P2 porous coating and Dr. Bloebaum's unique approach for percutaneous osseointegrated prosthesis, we believe that we have developed a winning solution that will have a monumental impact on the lives of amputees."

Editor's note: This story has been adapted from materials provided by the University of Utah.