Letter to the Editor: Intra-articular tranexamic acid wash during bilateral total knee arthroplasty.

Abstract

To the Editor: We read with interest the article by Zhu et al.1 The authors concluded that topical tranexamic acid (TXA) wash decreased the blood transfusion rate and length of hospital stay. Perioperative and total blood loss were mentioned, but the difference between the 2 was not elaborated. Perioperative includes the pre-, intraand post-operative periods. Only the haemoglobin balance method was described for calculation of blood loss. Generally the drop in haemoglobin level following bilateral total knee arthroplasty is 3 to 5 g/dl.2 However, the total drop in haemoglobin level in the TXA group ranged from 1.55 to 2.75 g/dl. As the minimum trigger for blood transfusion was a haemoglobin level of 9 g/dl, how did any patient receive a transfusion? What are the reasons for such a low haemoglobin drop in their series? When was the postoperative haemoglobin level measured? The haemoglobin level usually continues to drop for 2 to 4 days after surgery and then plateaues.3 The lowest value should be considered when calculating total blood loss. Please clarify the protocol for measurement of postoperative haemoglobin level. Drains were not used. Drains are thought to decrease haematoma collection, and in the TXA group, clamping of the drain for some time may have increased the contact time with TXA and may have increased its efficacy. Can the authors comment on this? In patients without a drain, was there any postoperative swelling, ecchymosis, or haematoma collection? Intra-articular TXA may be absorbed systemically. The authors used a combined dose of 3 g of TXA (1.5 g for each knee). The risk of systemic toxicity with such a high dose in the absence of a drain cannot be overlooked. Did the authors check the serum TXA level? Was there any advantage of topical use over intravenous use in bilateral cases? In our opinion, the intravenous route is preferred, particularly for bilateral cases, as a single low dose of 10 to 15 mg/kg may be effective for both knees. It avoids 10 minutes of waiting period/contact time, and decrease in surgical time itself may reduce blood loss. The authors mentioned only the functional criteria for discharge from hospital. Discharge of a patient depends on wound condition, oozing from wound, and fever. These may not have been controlled. The decision to discharge largely depends on the treating surgeon, and thus observer bias cannot be ruled out. The use of TXA is not the only cause of earlier discharge. Its effect on the length of hospital stay remains to be evaluated with further studies.