Release of metals from osteosynthesis implants as a method for identification : post-autopsy histopathological and ultrastructural forensic study

Metal structures-especially of stainless steel, titanium and their alloys (biomaterials)-are widely used in orthopaedic practice and the subject of constant study in bioengineering and preventive medicine. This study presents the first experience of forensic research into the presence of permanent tissue variations around metal implants in various bone structures for the purpose of identification, with particular reference to skeletal remains or severely decomposed corpses in the absence of other identifying elements. The evaluation was conducted on 12 corpses who had undergone osteosynthesis intra-vitam, whose implants were still in place or had been removed, in comparison with five controls who had never undergone osteosynthesis. Bone fragments taken during autopsy were subjected to histopathological and scanning electron microscope-energy dispersive electroscopy examination in order to reveal and characterise any metal particles originating from osteosynthesis. The study enabled the discovery of intra-bone metal particles in tissues treated by osteosynthesis even in bone areas where the implants had been removed and even where there were no longer any radiological signs of their application. These results are therefore of considerable forensic importance, especially in the area of identification, providing a valid means of recognition beyond that of the well-established use of in situ metal implants.