Title : Non-selective day 1 Hemoglobin (Hb) monitoring post elective primary knee arthroplasty: Clinical value or outdated practice
Abstract:
Background: Knee arthroplasty is one of the most commonly performed elective surgeries in the UK. Routine Day-1 postoperative hemoglobin (Hb) monitoring is standard practice, but its value is increasingly questioned. Improvements in perioperative care, surgical technique, and adjunct use have significantly reduced blood loss and transfusion rates.
Objectives: To evaluate the need for universal routine Day-1 Hb monitoring following elective primary knee arthroplasty by assessing Hb drop, rate of severe anaemia and rate of transfusion requirements, and clinical outcomes.
Methods: We conducted a retrospective audit of 452 consecutive total and unicondylar primary knee arthroplasties performed by a single surgeon between March 2013 and February 2020. Standardized surgical techniques were employed, including anteromedial approach, universal tranexamic acid and adrenaline administration, avoidance of surgical drains, controlled blood pressure management, and electrocautery hemostasis. A restrictive transfusion protocol was followed (transfusion for symptomatic anemia or Hb <70 g/L). Primary outcomes were mean Hb drop, incidence of severe anemia (Hb <80 g/L), and transfusion rates.
Results: Mean preoperative Hb was 137.2±14.2 g/L, decreasing to 113.8±14.1 g/L on Day-1 (mean drop 23.3±9.0 g/L). Only 6 patients (1.3%) had Day-1 Hb levels below 80 g/L, and 12 patients (2.4%) required postoperative transfusion. No patients required return to theatre for hemorrhage control, and no transfusion-related complications occurred.
Conclusions: With modern blood conservation techniques, universal Day-1 Hb monitoring offers minimal clinical value in elective primary knee arthroplasty. We recommend selective Hb testing for patients with low preoperative Hb levels, relevant comorbidities, or clinical symptoms of anemia, rather than routine testing for all patients. This approach maintains patient safety while reducing unnecessary interventions, healthcare costs, and environmental impact.
