This work aims at studying the operative complications of the stabilisation of total hip arthroplasties with the help of 11 hemodynamic studies, 19 functional records of the epinephrines and 25 surveys of the impact of the stabilisation on arterial blood gas. 1) Within the few minutes following the implantation of bone cement one may remark: -- a drop in the average arterial pressure, -- greater lowering of the stroke index after a femoral implantation than after a cotyloïdal implantation, -- a constant and massive rise of pulmonary resistances which appears mainly after a femoral stabilisation. 2) The hemodynamic disturbances are accompanied by neither a significant rise nor a significant fall of the plasmatic and urinary levels of the epinephrines. 3) There appears with the insertion a massive hypoxemia which can be prevented by the inhalation of pure oxygen.