The concentration of methylmethacrylate monomer (MMA) in the blood stream after implantation of the components of 15 total hip prostheses using bone cement was determined in the pulmonary artery, the radial artery, and the superior vena cava after cement application, and correlated with the observed drop in blood pressure and the increase in the pulmonary arterial pressure. In all samples MMA was found. The values ranged from 0.02 micrograms/ml to 59 micrograms/ml. The mean maximum value after implantation of the stem was measured to be 7.8 micrograms/ml in the pulmonary artery, 4.6 micrograms/ml in the radial artery, and 1.75 micrograms/ml in the superior vena cava. After implantation of the cup the values were clearly lower. The simultaneously recorded blood pressure decreased slightly during the first 3 min and then returned to previous values. The pulmonary arterial mean pressure increased from 18 to 20 mmHg during the first 10 min. Although in some patients a drop in blood pressure started at the same time as MMA reached maximum values, high concentrations did not result in a greater effect on the circulatory parameters. Statistical analysis by the Spearman test revealed no correlation between MMA concentrations and the decrease in blood pressure or the increase in the pulmonary arterial pressure.

In this study the degree and the time interval of the release of toxic methylmethacrylic monomers in neighboring bone tissue has been investigated after implantation of self couring acrylic cements. It has been shown that the majority of unpolymerized monomers is diminuated by a biologically uneffective later polymerization; thus only a minor part of methylmethacrylic monomers undergoes diffusion. The processes occur mainly during the first 24 hrs after implantation and are below the laboratory detection after 2 weeks. Cement additives such as X-ray contrast materials (BaSO4 or ZrO2) do not influence these reactions. Among the cements investigated herein (CMW-bone cement, Surgical simplex, Palacos) pronounced differences in the release of residual monomers during the first week have clearly been demonstrated.

Titelbild (Peper): Das Foto zeigt ein Kupferblech, das in der Bunsenbrennerflamme zur Rotglut erhitzt wird. Nach dem Abkfhlen ist das Kupfer mit einer schwarzen Schicht bedeckt. C. Zenner, H. Scheuermann und M. Ropohl haben im Rahmen einer Interventionsstudie Hypothesen sowie Experimentplanungen hinsichtlich des von Hadfield beschriebenen Kupfer‐Problems erhoben und analysiert (S. 370 ff.).

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