Intra-articular tranexamic acid as an adjunct to intravenous tranexamic acid for simultaneous bilateral total knee arthroplasty: a randomized double-blind, placebo-controlled trial.

BACKGROUND: Intra-articular tranexamic acid (TXA) as an adjunct to intravenous TXA was reported to decrease perioperative blood loss during unilateral total knee arthroplasty (TKA). However, there have been no randomized controlled trials comparing intravenous versus combined intravenous and intra-articular TXA administration in patients undergoing simultaneous bilateral TKA. METHODS: We randomly assigned 77 patients with 154 involved knees undergoing simultaneous bilateral TKA to the intravenous TXA group (intra-articular placebo for each knee) or combined TXA group (1000 mg of intra-articular TXA for each knee) with 1:1 treatment allocation. In both groups, 1000 mg of TXA was given intravenously twice, just before surgery and 6 h after the initial administration. Other perioperative medications, surgical procedures, and blood management strategies were the same for all patients. The primary outcome was perioperative blood loss calculated from blood volume and change in hemoglobin from preoperative to postoperative day 3. RESULTS: Intention-to-treat analysis showed no statistically significant differences in perioperative blood loss until postoperative day 3 (1067 ± 403 mL in the intravenous TXA group vs. 997 ± 345 mL in the combined TXA group [95% CI, - 240 to 100 mL], P = 0.42). No patients required allogenic blood transfusion. The incidence of thrombotic events did not differ between groups (12% in the intravenous TXA group vs. 9% in the combined TXA group; P = 0.73). CONCLUSIONS: The addition of intra-articular TXA did not reduce perioperative blood loss in patients undergoing simultaneous bilateral TKA compared with placebo. TRIAL REGISTRATION: University Hospital Medical Information Network UMIN000026137 . Registered 14 February 2017.

A study on the relationship between subjective unpleasantness and body surface vibrations induced by high-level low-frequency pure tones.

Human body surface vibrations induced by high-level low-frequency pure tones were measured at the chest and the abdomen. At the same time, the subject rated the unpleasantness that he had just perceived during the exposure to low-frequency noise stimulus. Examining the relationship between the measured vibration and the rating score of the unpleasantness revealed that the unpleasantness was in close correlation with the vibration acceleration level (VAL) of the vibration measured. Taking previous results into account, this finding suggests that noise-induced vibrations primarily induce vibratory sensations and through the vibratory sensation or together with some other factors, secondarily contribute to the unpleasantness. The present results suggest that in evaluating high-level low-frequency noise, the effect of vibration should be taken into account.