We randomised 24 patients before they had a cemented hemiarthroplasty for hip fracture to receive either thorough or minimal saline lavage of the femoral canal. We then determined the effect in each group on the thromboembolic and cardiopulmonary responses to the pressurised insertion of cement, using transoesophageal echocardiography to show the echogenic embolic response. We found a statistically significant reduction in both the duration of the response and the number of large emboli in patients who had had thorough lavage as compared with the control group with minimal lavage. There was also less disturbance of pulmonary function, as assessed by the change in end-tidal CO2 levels and oxygen saturation, in patients who had thorough lavage. Three patients had a significant fall in blood pressure during cement insertion; all had only minimal lavage. We consider that thorough lavage should be an essential part of the preparation of the proximal femur before cement insertion.