Researchers have developed a biocompatible and biodegradable screw used for the stabilization of ligament ruptures that will not require patients to undergo further surgery for screw removal, according to a Fraunhofer-Gesellschaft press release.
“We have modified biomaterials in such a way that they can be formed into robust bioactive and resorbable screws by means of a special injection molding process,” Philipp Imgrund, head of the biomaterial technology department at Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research (IFAM), stated in the release. “Depending on the composition, they biodegrade in 24 months.”
Improved material
The release noted that biodegradable screws made of polylactic acid are currently available to physicians, but these screws can leave holes in bone when they degrade. To address this problem, the IFAM researchers sought to improve the material and developed a moldable composite of polylactic acid and hydroxylapatite — a ceramic which is the main constituent of the bone material.“This composite possesses a higher proportion of hydroxylapatite and promotes the growth of bone into the implant,” Imgrund said in the release.
Similar to bone
The engineers at IFAM have developed a granulate from the biomaterials with similar properties to real bone. Its compressive strength of more than 130 N/mm2 is comparable to that of bone, which is between 130 N/mm2 and 180 N/mm2, according to the release.Additional improvements were also made in the injection molding process, which normally requires compression at temperatures of up to 1400°C. Imgrund noted in the release, “We only need 140° for our composite materials.”
Posted on the ORTHO SuperSite April 5, 2010
