Re-inventing the Implant; UMaine Researchers Explore New Materials for Bone Repair
Contact: David Munson (207) 581-3777
Thanks to the pioneering efforts of surgeon and UMaine researcher Ian Dickey and Chemical and Biological Engineering Professor Darrell Donahue, UMaine is at the leading edge of research aimed at improving medical implants using a group of new materials collectively referred to as foam metals.
Composed of a variety of metal and metal-based hybrid materials, foam metals are recognized by their complex, pored structure, which is surprisingly compatible with living tissues.
Because of the body’s natural resistance to foreign materials, implants used for bone repair have been fraught with difficulties. Slow recovery times, costly and painful second surgeries, and imperfect results often leave patients less mobile and more prone to future complications. In most cases, the problems associated with medical implants like replacement hips and bone-strengthening pins have to do with compatibility — the body’s tissues recognize the implant as foreign and treat it like any other invader, walling the implant off from the living cells in an effort to protect themselves. Because no biological connection is established between the living and nonliving material, traditional implants are often weak and prone to infection.
Tests conducted by Dickey and Donahue during their initial research showed that foam metal washers used for repairs at the rotator cuff were stronger than other surgical repairs at four weeks, as strong as a normal joint by six weeks, and at 30 months the attachments not only stayed strong, they were 20 percent stronger than a healthy, uninjured joint.
The added strength of the foam metal implants comes from the new tissue that forms within the tiny spaces throughout the material. Living bone and soft tissue gradually merges with the porous structure of the foam metal, fed by tiny blood vessels that also form inside the implant. Where traditional implants caused the formation of scar tissue that weakened the repair, foam metal implants provide a kind of biological scaffolding for the growth of new tissue.
Dickey, a reconstructive surgeon, and Donahue, an expert in bone biomechanics, came together in 2004 while Dickey was still conducting research at the Mayo Clinic in Rochester, MN. As their research into foam metals continued, they began tapping into additional resources at UMaine, recruiting Scott Collins of UMaine’s Laboratory for Surface Science and Technology, Anja Nohe and Michael Mason of the Department of Chemical and Biological Engineering and Andre Khalil of the Department of Mathematics and Statistics for various projects. Their ultimate goal is not only to prove that foam metal implants work, but to find out why.
Together, Collins, Nohe, Mason and Khalil are developing a high-tech tool kit for the study of foam metals, allowing UMaine researchers to better understand what makes the material so effective as a medical implant. Their discoveries will help foam metal manufacturers to develop a new line of products that will improve the lives of patients around the world.
Thanks to the pioneering efforts of Dickey and his growing team of UMaine researchers, the university is already at the leading edge of foam metals research, and is poised to take the project even further. By drawing on the energy, experience, and equipment available through UMaine’s LASST lab, the Institute for Molecular Biophysics, and other resources, UMaine’s research team is pursuing funding from both public and private sources that could expand their research efforts considerably. Foam metal projects are also being considered for UMaine internal research and development funding as and area of new and emerging research.
Each year in the United States, more than 600,000 surgeries are performed to repair knee and hip injuries alone. Approximately one percent of those surgeries fail, leaving 6,000 patients with few options for recovery. Foam metal implants could change all that.