RESUMO
BACKGROUND: Unnecessary costs and complications can be reduced by minimizing blood loss and allogeneic blood transfusion in cases of total knee arthroplasty (TKA). This study evaluated the effectiveness of bone wax in reducing blood loss and transfusion rates after TKA. METHODS: A total of 674 consecutive TKAs performed for degenerative osteoarthritis were retrospectively reviewed. Propensity score-matching and inverse probability of treatment weighting analyses were performed for demographics, comorbidities, use of medications, preoperative laboratory findings and radiologic prosthetic coverage of osteotomy surface. In the bone wax group, bone wax (2.5 g) was applied to the uncovered bone section around the prostheses along with the topical administration of tranexamic acid, whereas hemostasis was achieved in the control group with the topical administration of tranexamic acid. Intergroup comparisons of estimated blood loss, decreases in hemoglobin (Hb) levels, and transfusion rates were performed. RESULTS: The mean estimated blood loss and volume of postoperative drainage were reduced in the bone wax group. The maximum decreases in Hb levels on postoperative days 1, 3, 5, and 7 were 1.8 ± 0.7 ml, 2.5 ± 0.8 ml, 2.7 ± 0.8 ml, and 2.8 ± 0.8 ml in the bone wax group and 2.1 ± 1.0 ml, 3.0 ± 1.2 ml, 3.1 ± 1.1 ml, and 3.2 ± 1.1 ml in the control group, respectively. The postoperative transfusion rates decreased markedly from 8.8% to 2.0% when bone wax was used. CONCLUSIONS: The use of bone wax significantly reduced blood loss, decreased Hb levels, and the risk of transfusion. LEVEL OF EVIDENCE: Level III, Therapeutic studies.