Background

It is unclear which form of anaesthesia is the most favourable in primary total hip replacement (THR) surgery. A recently published systematic review of modern anaesthesia techniques in primary THR surgery (Macfarlane 2009) was not able to show any convincing benefit of regional or general anaesthesia. One retrospective study that examined anaesthesia and leg length (Sathappan 2008), found an increased incidence of leg length difference > 5 mm in those patients who were operated with regional anaesthesia. Our department used a mini invasive approach in supine as standard procedure in THR. The type of anaesthesia that is chosen is up to the individual anaesthetist.

Primary total hip replacement (THR) surgery is a common procedure. Benchmarking studies in the last decade has shown that those patients have a substantial risk for blood transfusions. The orthopaedic department at Drammen Hospital had implemented a multimodal primary THR care pathway with a focus on minimising surgical trauma and negative trauma response. Neither blood salvage, autologuos blood predonation or erythropoietin has been used. We had reviewed 399 consecutive unselected cases with a mean age of 67 years (range 31–94). We performed a statistic analysis of pre- and postoperative haemoglobin level (g/l). A gender neutral 125 was used as cut point for anaemia. Preoperative haemoglobin level, mean 136 (SD 1.33), and postoperative haemoglobin, mean 113 (SD 1.41), showed an almost perfect Gaussian distribution. Eleven patients received 26 units of allogeneic blood in the first eight postoperative days. There had been a violation of transfusion policy in six of the eleven transfused patients. Mortality during the first 90 postoperative days was zero and 4 patients was readmitted due to cardiac disease during the first 90 postoperative days. All those readmitted due to cardiac disease had an haemoglobin level above 100 at discharge. By combining the Gaussian distribution of the postoperative haemoglobin level and a restrictive transfusion trigger (80 g/l), we calculated a two percent probability of transfusion. For the anaemic patients the calculated probability of transfusion were five percent. Applying a multimodal care pathway in primary THR almost abolish the need for blood transfusion without any preconditioning of anaemic patients. This study supports that an restrictive transfusion trigger are safe in an unselected total hip replacement patient population.