Considering that the high local concentration of antibiotic from bone cement is delivered intravenously through the self-transfusion process, systematic toxicity has never been evaluated. In addition, the effectiveness of self-transfusion with the routine concomitant use of other modern blood-salvage strategies, like tranexamic acid, should be also assessed. Therefore we performed a randomized study to assess: 1) the safety of self-transfusion in TKA by comparing the gentamicin concentrations resulting from the use or not of autologous blood transfusion. 2) the efficacy of self-transfusion in TKA, with the concomitant administration of tranexamic acid.

The serum concentration of aminoglycosides has been measured in two groups of 20 patients each, after TKA, according to the use of self-transfusion. Hemoglobin, renal function and calculated blood loss were compared at several time points between groups.

Inclusion Criteria:

• end-stage of knee osteoarthritis, who scheduled for unilateral primary TKA in our department

Exclusion Criteria:

• patients who had been treated with gentamicin within the past 10 days
• known allergies against the bone cement
• estimated glomerular filtration rate (eGFR) <30ml/minute
• previous nephrectomy and history of renal transplant
• contraindications against tranexamic acid