Bone implant technology breaks new ground
April 05, 1996
RICHLAND, Wash. –
In 1992 baseball and football great Bo Jackson underwent hip-replacement surgery, but the rigors of baseball proved too much for the artificial hip after just two seasons.
Each year, almost 500,000 patients receive hip implants worldwide, about the same number need bone reconstruction due to injuries or congenital defects and 16 million Americans loose teeth and may require dental implants.
While available implants can alleviate excruciating pain and allow patients to live more active lives, there often are problems getting bone to attach to the metal devices. Small gaps between natural bone and the implant can increase over time, requiring the need for additional surgery to replace the implant.
Long-lasting implants that can attach permanently to bone could save many patients the pain, risk and expense of undergoing repeat surgeries. Now, scientists are researching new technologies and materials that, together, promise to make bone, joint and tooth implants almost as good as nature's own version. This research is based on a unique combination of four breakthrough technologies:
- a wear-resistant metal alloy
- a new method to create pores and channels in metal
- a new method to make bone-like mineral coatings on implants natural protein factors that cause bone regeneration
These technologies are being combined and developed under a cooperative research and development agreement between the Department of Energy's Pacific Northwest National Laboratory and a new medical device company called Applied Biological Coatings and Implants of Dallas, Texas.
Two of the technologies were developed by Pacific Northwest researchers. By observing how shells, bone and teeth are formed, scientists developed a process for depositing a bone-like mineral on the implant surface. The process "grows" the material onto the implant from a water-based solution, creating a biocompatible surface for the newly forming bone that can reduce patient recovery time by facilitating rapid bone formation around the implant. Studies show that this new coating bonds more tightly to bone than mineral-coated implants produced by conventional methods.
Pacific Northwest also has developed a method of creating pores and channels in metal implants and coating solid implants with this porous material. The process, called void metal composite forming, creates tiny channels or "voids" in the surfaces of the implants. New bone grows into these pores or voids to form a "lock and key" effect that attaches the implant firmly to the surrounding bone.
Both technologies were licensed by Pacific Northwest to Dr. Arup Sen, the founder of ABCI, which also owns the rights to a wear-resistant metal alloy. The alloy is expected to out-perform other materials currently used for replacement hips, teeth and other implants. When rubbed 5 million times against a pin of bone cement, the alloy showed absolutely no degradation, unlike titanium and other alloys currently used as implants.
Sen also has been researching bone-growth factors since 1983. A natural bone-growth factor can be used in these new implants to speed-up healing by signaling the body to produce bone-forming cells called osteoblasts. When the growth factors and alloy are packaged with the Pacific Northwest technologies, a line of extremely unique implants should be feasible which will interact better with the human body than available implants.
"The ideal device of the future will not crack, will have channels into which new bone can grow and anchor, will be coated with a bone-like material and will signal the body to regenerate bone," said Allison Campbell, one of the Pacific Northwest development team. "In the meantime, either the mineral coating, the new alloy or the method of making channels in metal fixation devices can be used to improve upon products that are already approved and are on the market," added Sen.
"The road to Food and Drug Administration approval for applying these technologies to improve implant devices and creating novel medical products is arduous," said Sen. The initial focus will be on facial implants and device improvements, followed by proving the viability of specialty implants for load-bearing joints. Researchers estimate that it may be another five years before patients begin receiving improved facial and dental implants and up to 10 years before a breakthrough device is on the market.
However, the combined improvements are expected to be so significant that the implants of the future will provide many years of pain-free movement to bone replacement recipients and eliminate the need for additional surgeries.
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