title: Is there a need for routine post-operative hemoglobin level estimation in total knee arthroplasty with tranexamic acid use?
abstract: BACKGROUND
  Total knee arthroplasty (TKA) can result in significant blood loss, leading to a need for blood transfusion. The major indication of transfusion is post-operative hemoglobin (Hb) levels in association with symptomatic anemia. The aim of this study was to determine the possibility of eliminating routine post-operative Hb tests in patients undergoing TKA with intra-articular tranexamic acid (TXA) use based on the predictability of pre-operative factors.
  
  
  METHODS
  We conducted a retrospective analysis of 487 patients who underwent TKA with intra-articular TXA use. Statistical analysis was done to predict the transfusion risk based on multiple pre-operative parameters.
  
  
  RESULTS
  Post-operative blood transfusions were required in 2.5% of all patients. Pre-operative-Hb was the only significant predictor of post-operative transfusion (p<0.0001). Age, sex, weight, height and body mass index (BMI) were not related to post-operative transfusion risk. Transfusions were needed in 4.2% of patients with pre-operative Hb levels <14 g/dl. No patient with a pre-operative Hb >14 g/dl required a transfusion (p<0.0001).
  
  
  CONCLUSIONS
  Pre-operative Hb is a strong predictor of post-operative blood transfusion risk. Patients who receive TXA in TKA, with a pre-operative Hb >14 g/dl do not require routine post-operative Hb evaluation.
  
  
  METHODS
  IV.
authors.affiliation: Sydney Knee Specialists, NSW, Australia.
authors.forename: Navendu
authors.initials: N
authors.lastname: Goyal
authors.affiliation: Canterbury Hospital, NSW, Australia.
authors.forename: Ritik
authors.initials: R
authors.lastname: Kaul
authors.affiliation: Ingham Institute for Applied Medical Research, South Western Sydney Clinical School, UNSW, Australia.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Harris
authors.affiliation: St George Private Hospital, Sydney, NSW, Australia.
authors.forename: Darren B
authors.initials: DB
authors.lastname: Chen
authors.affiliation: St George Private Hospital, Sydney, NSW, Australia. Electronic address: samuelmacdessi@sydneyknee.com.au.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: MacDessi
mesh_terms: D000368:Aged; D000933:Antifibrinolytic Agents / Q000627:therapeutic use; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001804:Blood Transfusion, Autologous / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007270:Injections, Intra-Articular; D008297:Male; D019106:Postoperative Hemorrhage / Q000097:blood / Q000517:prevention & control*; D012189:Retrospective Studies; D014148:Tranexamic Acid / Q000627:therapeutic use*
chemical_list: D000933:Antifibrinolytic Agents; D006454:Hemoglobins; D014148:Tranexamic Acid
keywords: Blood transfusion; Pre-operative hemoglobin; Predictors of transfusion; Total knee arthroplasty; Tranexamic acid