Bone Implant Research May Suggest Better Materials, Textures

Originally Published MDDI November 2003

R&D DIGEST

Maureen Kingsley

Makers of bone implants may soon have reason to rethink traditional implant shapes and textures. Researchers at three institutions are studying bone implants to determine how weight loads on the devices influence blood supply, cell differentiation, and bone healing around the implant site. They received a $1.9 million, four-year grant from the National Institutes of Health to fund the research.

“Initially, we're focusing more on the biomechanics of the [implant-tissue] interface, and how loading affects early healing around implants,” says one of the researchers, John Brunski of Rensselaer Polytechnic Institute (RPI; Troy, NY). “But surrounding all of that is also the materials question—the materials that are actually used to make the implants.” Bone implants and the related surgeries aren't particularly new to healthcare, Brunski says. But the exact role the implant itself plays in the healing process remains a mystery. 

Science also can't quite explain—yet—how implants are or are not accepted by bone. “Certainly over the years there have been many, many claims that the implant itself is doing something special to the bone,” Brunski says. Often it is the implant makers or the researchers they fund who make these declarations. “Some of these claims have been around for a long time, but they were never really tested at the molecular level.” Bone implants generally work well, he says, especially orthopedic and oral implants. “But it's only now that we're trying to unravel the ‘why' underlying the way they work.”

As this research progresses, implant size, shape, and texture will come under scrutiny. “We think the shape and size of the implant govern the way loading is distributed into the bone,” Brunski says. “And we think that's a very important design parameter.” 

Surface texture offers particularly intriguing implications for implant makers. According to Brunski, some cell-culture work suggests that texturing can make a difference in what cells do. “Materials and shapes and sizes: those are all fair game for designers,” he says.

Joining Brunski in the project are Jill Helms and Celine Colnot of the University of California at San Francisco and Antonio Nanci at the University of Montreal.

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