Abstract
To the editor,
I have read the recent article by Song et al. 1 with great enthusiasm, which dwells with a clinically relevant subject that has been churning the scientific discourse for last few years. I extend my heartfelt appreciation to the authors for their research which sought to evaluate blood loss transition after total knee arthroplasty (TKA) with topical administration of tranexamic acid (TXA); they have found that topical TXA was effective in reducing blood loss and hemoglobin drop up to 48 h after TKAs, and paradoxical blood loss tended to occur in TXA group 48 h after operation. Their research undoubtedly puts emphasis to keep constant vigil for hemodynamic monitoring even after 48 h of operation. However, there are few comments I would like to state which seem pertinent regarding this study.
First, it is well known that surgical trauma and tourniquet use activate local fibrinolysis; by virtue of antifibrinolytic effect, TXA has been a part of surgeon’s armamentarium to achieve satisfactory postoperative blood conservation. However, what has not yet been established is how long this fibrinolytic activity persists after operation. One laboratory study, albeit, demonstrated that local fibrinolytic activity peaks 6 h after operation and can last up to 24 h 2 ; based on this premise, Lei et al. 3 in their recent study contended favorable blood conservation with multiple IV doses of TXA. Song et al. in this study have speculated that paradoxical blood loss 48 h after TKAs could be explained by delayed fibrinolysis. 1 Against this backdrop, I believe, what could have made the denouement of their study more edifying is the postoperative analysis of fibrinolytic parameters, such as fibrin degradation product, and D-dimer level.
Second, it was established in this study that blood conservation efficacy of topical TXA abated 48 h after TKAs; nevertheless, it will be intriguing to see whether it bears any clinical significance, since transfusion requirements did not show any statistical difference between the groups. 1 Likewise, drainage volume on postoperative day 1 (PO1) (after 24 h of operation) was greater in TXA group; albeit it achieved statistical significance, however, I am afraid the differences seem small and might not be clinically relevant. These concerns were buttressed by the facts that there was no incidence of complications like wound discharge, discharge from drain removal site, bleeding, or hematoma. 1 Indeed, it remains to be seen how this paradoxical blood loss affects early functional recovery and rehabilitation after TKAs—evaluation of which with subjective knee function score or objective clinical examination would have added more credibility to the present research. Therefore, the pertinent questions naturally arise: Do surgeons need to be circumspect until more evidences are available at our disposal? Does the paradoxical blood loss have any tangible effect on patient’s perception and well-being?
Last but not least, it is not clear how did the authors allocate patients to study groups—was any randomization done? Measurement bias could potentially dent the veracity of the study, which could arise from the practice of drain clamping in TXA group contrary to non-TXA group—in fact, ambiguities also persist whether observer/data analyst were blinded to the group allocation and intervention. Was there any patient with bleeding diatheses in the groups? And finally, it remains to be seen whether TKAs operated without tourniquet are also fraught with the paradoxical blood loss phenomenon.
The present study by Song et al. 1 would undoubtedly fuel more high-quality randomized trials with large sample size to unravel the pharmacokinetic complexities of TXA and its clinical significance.
