Methods	In 2003, patients ≥18 years of age who were scheduled for a primary or revision total hip replacement or total knee replacement at the Leiden University Medical Centre were included in this randomised controlled trial. All patients were of American Society of Anaesthesiologists (ASA) 2 or 3 category. A randomisation list was generated by a statistical software package. Sealed envelopes were made which contained the randomisation group. Pre-operatively, the patient was allocated to one of the groups by opening a sealed envelope
Participants	70 patients undergoing a primary or revision total hip replacement or total knee replacement were randomised to one of three groups: Group 1 (Autotransfusion group I): n=23; M//F=9//14; mean (sd) age = 66 (15.6) years Group 2 (Autotransfusion group II): n=24; M//F=10//14; mean (sd) age = 58 (17. 2) years Group 3 (Control group): n=22; M//F=7//15; mean (sd) age = 58 (14.3) years NB: Of the 70 patients included in the study, one patient was not operated, leaving 69 evaluable patients
Interventions	Group 1: Autotransfusion group (I) had their drainage processed by the DONOR system. The re-infusion system uses continuous suction at a vacuum pressure of 120mmHg and just prior to re-infusion a double-shielded 40um filter (Pall Lipiguard VS filter) entrapping lipids larger than 10um and 2 log of leukocytes. Group 2: Autotransfusion group (II) had their drainage processed by the Bellovac A.B.T. system. The re-infusion system uses intermittent suction pressure by a manually expandable bag at a maximum pressure of 90mmHg and three filters, a 200um filter, a secondary 80um filter and prior to re-infusion a third 40um filter. Group 3: Control group received standard closed suction wound drainage.
Outcomes	Outcomes reported: number of patients transfused allogeneic blood, amount of allogeneic blood transfused, volume of blood re-transfused from the cell saver, blood loss, hospital length of stay, adverse events
Notes	Transfusion threshold: during the study, a restrictive transfusion trigger according to the Dutch guidelines was used (CBO consensus guidelines, 2004)
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Method used to generate allocation sequences was adequate.
Allocation concealment (selection bias)	High risk	Method used to conceal treatment allocation was inadequate.
Blinding (performance bias and detection bias) All outcomes	High risk