Stainless steel particulate and human tissue responses

Biomaterial particulate properties, such as chemistry, size, shape, and number, are key factors in determining biological performance of implants. Debris has been shown to elicit inflammatory responses and possibly lead to osteolysis. One objective of this study is to provide a more in-depth understanding of human tissue responses to 316L stainless steel particulates. The histological interactions and overall metallic contents of tissues collected from cross-screw stabilized, explanted intramedullary rods were qualitatively analyzed via light microscopy. More metallic debris was detected at sites near locking screws, where metal-on-metal motion existed. However, no direct correlations were observed between debris amounts and inflammatory response scores. There was also no direct correlation observed between inflammatory response scores in tissues near locking screws when compared to tissues away from sites of mechanical motion and debris generation. The results of this study represent responses over a relatively short period of time, typically less than three years, as the IM nails were utilized as temporary fixation devices.