[Post-operative retransfusion and intra-operative autotransfusion systems in total knee arthroplasty. A comparison of their efficacy].

PURPOSE OF THE STUDY The aim of the study was to compare the effect of post-operative retransfusion with that of intra-operative autotransfusion in non-anaemic patients undergoing total knee arthroplasty (TKA). MATERIAL AND METHODS Between February 2004 and June 2006, a total of 129 patients free of anaemia who underwent elective primary unilateral cemented TKA for primary arthritis received blood retransfusion by means of the post-operative retransfusion system. Intra-operative transfusion was not administered. Patients with coagulation disorders, thrombocytopaenia or other haematological diseases were not included. The results were compared with those of the group of 142 patients undergoing the same surgery, but with use of the intra-operative autotransfusion system, in the period from February 2009 to December 2010. The following patient data were reviewed: patient's age at the time of surgery; value of haemoglobin before and two days after surgery; allergic and febrile reactions associated with retransfusion, renal failure after retransfusion, number of postoperative allogeneic transfusions, early TKA infection and thrombo-embolic complications. RESULTS Of the 129 patients with post-operative retransfusion, 25 received one or more allogeneic blood transfusions due to the haemoglobin level below 90g/l and symptoms of anaemia. The average haemoglobin level was 136 g/l (range, 111 to 159 g/l) one day before surgery and 107 g/l (range, 81 to 143 g/l) on the 2nd post-operative day. A single allogeneic blood transfusion was administered to 12 patients and two were necessary in 13 patients. The average blood volume returned to the patient through the post-operative retransfusion system was 725.3 ml (range, 250 to 1 300 ml). Of the 142 patients with intra-operative autotransfusion, 11 patients required blood transfusion in the post-operative period, with seven receiving one and four receiving two transfusions. The average haemoglobin level was 135 g/l (range, 110 to 161 g/l ) one day before surgery and 107 g/l (range, 85 to 130 g/l ) two days after it. The average volume of erythrocyte mass returned to the patient through the intra-operative autotransfusion system was 330.7 ml (range, 0 to 850 ml). No allergic, pyretic or other reaction or complication was recorded in either group. No early TKA infection occurred. DISCUSSION No reports comparing the efficacies of post-operative retransfusion and intra-operative auto-transfusion systems in patients undergoing total knee replacement have been found in the literature. Therefore, the only possible comparison can be made with the studies that involve patients receiving blood recuperation and control groups with no blood recuperation. In our study, 19.3% of the patients with post-operative retransfusion required allogeneic blood transfusion while this was necessary in only 7.7% of the patients with intra-operative autotransfusion. This difference was caused by a better efficiency of the intra-operative autotransfusion system which can treat up to 2 litres of harvested blood per hour and return it to the patient in the form of erythrocyte mass, while the post-operative retransfusion system can salvage only 1500 ml of blood. CONCLUSIONS The use of either of these systems has proved to be a simple and safe method of reducing the need of allogeneic blood transfusion in the TKA procedure. While the post-operative retransfusion system facilitates the return of drained blood only, the more efficient "cell-saver" technology collects blood shed during both intra- and post-operative periods and allows for erythrocyte mass retransfusion during and after surgery. Since the administration of allogeneic blood was required in less than 10% of the patients receiving intra-operative autotransfusion, this system was adopted as a more efficient method in routine TKA procedures.