A foreign body reaction to biodegradable fixation materials for internal fixation of a variety of fractures and osteotomies has been described since nineteen eighty five. Polyglycolide and other biodegradable poly-alpha-hydroxyacids such as polylactide (PLA) or polydioxanone (PDS) causes a non-specific inflammatory reaction with invasion of macrophages, multinucleated foreign body giant cells and neutrophilic polymorphonuclear leucocytes. The wood and needle fish were reported to cause foreign body reaction by several authors. But there is no report about aseptic synovitis caused by intraarticular stainless steel foreign body. So we report a case of aseptic synovitis reaction to stainless steel treated successfully by arthroscopic surgery and discuss the possible reasons for this inflammatory reaction.