More than the bare bones for implant patients

Children may sing about how "the hip bone is connected to the leg bone," but for patients with hip replacements, this connection could cause implants to fail in less than 10 years.

At Pacific Northwest National Laboratory, researchers developed a unique bone-like coating process that addresses the problem of poor bonds between artificial joints and real bone. It could potentially increase the useful life of hip, knee and other joint replacements as well as dental implants.

In recent tests, a promising antimicrobial compound was added to the coating to help fight infection. This addition would be especially beneficial for patients with external fixator pins that go through the skin to temporarily hold a mending bone in place.

"To put it simply, our Biomimetic Coating Process makes the body believe that the implant is actually bone," said Allison Campbell who developed the process. As a result, the body creates a strong bond between the implant and the bone during the natural process of breaking down old bone and building new bone.

The Laboratory's process begins with pretreating the implant with a tether molecule. Then, the implant is soaked in a solution of calcium phosphate. "The tether acts as a template for the calcium phosphate crystals that grow on the implant surface," Campbell said. "The resulting coating mimics that of natural bone."

The water-based soaking process takes place at room temperature and can fully coat the surfaces of crevices and cavities—advantages over vapor-based techniques that require high temperatures and do not cover intricate implant features as well.

The Laboratory would like to license the patented technology to a company to support further testing and Food and Drug Administration approval.