[Effectiveness of postoperative autologous blood transfusion after knee replacement surgery and influence of preoperative hemoglobin level].

OBJECTIVE: To evaluate the effectiveness of postoperative autologous blood transfusion on reducing the need for allogenic transfusion during recovery from total knee arthroplasty until hospital discharge, and to determine whether effectiveness is related to preoperative hemoglobin level.

MATERIAL AND METHODS: Retrospective study of patients undergoing surgery at Hospital Jerez de la Frontera, Spain, in 2003, assessing the association between postoperative autologous blood transfusion, preoperative hemoglobin, and allogenic transfusion requirements.

RESULTS: A total of 107 patients were studied. Eighty-three received autologous blood transfusions after surgery and 15 (14.02%) required allogenic transfusion. The rate of allogenic transfusion was higher in association with hemoglobin levels exceeding 13 g x dL(-1) (P=0.003) and it was lower in patients who received autologous blood transfusions (P=0.046). In patients who received autologous transfusion, preoperative hemoglobin level and risk of allogenic transfusion were unrelated. When autologous transfusion was not given, allogenic transfusion risk was higher when hemoglobin concentration was less than 13 g x dL(-1) (P=0.0008). Autologous transfusion had a significant effect when hemoglobin level was less than 13 g x dL(-1) (P=0.002) but did not affect the rate of transfusion when hemoglobin was 13 g x dL(-1) or more.

CONCLUSIONS: Autologous blood transfusion is effective for reducing the need for allogenic transfusion after knee replacement surgery, particulary when a patient's hemoglobin level is less than 13 g x dL(-1).