Bone wax reduces blood loss in unicompartmental knee arthroplasty for osteoarthritis

Background: Unicompartmental knee arthroplasty (UKA) offer less trauma, faster recovery in the treatment of osteoarthritis of knee. Bone oozing in UKA may result in hematoma and complications after operation. Methods: : Visible blood loss and total blood loss were evaluated. Hb level of the patient postoperation was recorded. Circumference of knee was measured after operation.Visual analog scale (VAS) score were used and severe pain rate was caculated. Other complication such as wound healing, hemoarthrosis, infection, deep vein thrombosis (DVT), and transfusion were recorded. Results: : Bone wax group had less total blood loss(215.55.3±50.6 ml in group A, 236.74±48.5ml in group B; P = 0.023) The mean circumference of knee increased 2.73cm(range 1.5-4.1cm) in group B and 1.65cm (range 1.2-3.4cm)in group A at 3 days postoperation and the difference was significant(p<0.001). The rate of severe pain occured was significantly lower in group A than in group B (8.6%vs 22.4% p=0.040). Patients in bone wax group were more satisfied with UKA (89.7% in groupA, 74.1% in group B p=0.030). There was no infection occurred and blood transfusion was not performed in any patient. 2 patients in group A and 7 patients in group B underwent knee cavity aspiration due to hemoarthrosis.There was 1patient experienced delayed wound healingin both groups and 1 DVT in group B. Conclusion: Use of bone wax can reduce blood loss in UKA, and it do not increase the rate complications at short-term follow-up. More degradable bone waxes with good biocompatibility should be further investigated.