The increasing number of primary hip arthroplasties leads to a corresponding increase in revision hip arthroplasty. In Germany approximately 15.000 cemented total hip arthroplasties are revised annually. In these cases cement removal remains a critical point in this procedure. Ultrasonic instruments have shown to facilitate the removal of bone cement considerably. But during the use of these divices large ammounts of fumes are emitted. For occupational safety reasons, we analized the fumes emitted from the ultrasonic instrument while removing PMMA bone under standardized in vitro conditions using GC-FID-analysis and GC-masspectrometry. The analysis revealed PMMA concentrations of 5 ml/m3 (ppm9 corresponding to 10% of the MAK-value (maximum working concentration). For occupational safety matters the PMMA fumes emitted are considered safe.