Traditional titanium metal screws used in orthopedic procedures have a number of disadvantages, not the least of which is triggering metal detectors at airports. Now a group of German researchers have developed screws that literally dissolve in the body.
Current biodegradable screws are made of polylactic acid, but those leave holes once they degrade. IFAM researchers developed a moldable composite made of polylactic acid and hydroxylapatite, a ceramic that is the main constituent of bone material.
IFAM engineers rely on conventional injection-molding methods, but they developed a granulate from the biomaterials with a net shape that results in a robust screw. The prototype's properties are very similar to a real bone's, with compressive strength of more than 130 newtons per square millimeter (a real bone withstands 130 to 180).
I had a couple of these put into my knee several years ago. If I remember correctly, the doctor said mine was made out of cadaver bone.
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