Prevalence of Blood Transfusion and Factors Influencing Blood Loss Following Primary Total Knee Replacement Surgery.

Introduction: Total knee replacement (TKR) is a highly effective treatment for end-stage knee osteoarthritis and has been proven to have excellent results in relieving pain as well as improving mobility of the patient. Although becoming more increasingly performed, it is still associated with considerable perioperative blood loss requiring allogenic blood transfusion. Allogenic blood transfusion (ABT) can be lifesaving in certain clinical situations but also comes with their own risks and side effects. The reported incidence of ABT and blood loss following TKR surgery varies widely in the literature. The objectives of this study were to look at the prevalence of ABT, factors leading to transfusion as well as increase in blood loss.

Material and methods: A cross-sectional retrospective study was conducted involving 296 adult patients who underwent elective primary unilateral TKR surgery from January 2015 until December 2019 at Hospital Melaka. Medical records of these patients were reviewed, and relevant data were extracted for final analysis. Incidence of ABT, demographic data, use of antiplatelet/anticoagulant, tourniquet time, types of general anaesthesia, and pre- and post-operative haemoglobin count were recorded. These factors were analysed to look at the association with ABT as well as increase in blood loss.

Results: Prevalence of ABT following primary unilateral TKR surgery were found to be 4.39% (95% confidence interval 2.04, 6.74). Pre-operative haemoglobin value was found to be the only significant variable associated with blood transfusion [P<0.001; Odds ratio (OR) = 0.35; 95% Confidence interval (CI) 0.22, 0.54]. Meanwhile, prolonged tourniquet time of >120 minutes was the only significant variable towards an increase in blood loss. Participants with tourniquet time >120 minutes has 2.67 times the odds to have blood loss >2 g/dL compared to participants with tourniquet time of less or equal to 120 minutes (95% CI=1.54, 4.64).

Conclusion: The prevalence of ABT following primary unilateral TKR was lower in our centre compared to other reported studies. Pre-operative optimisation of anaemic patients with haematinics will help surgeons reduce the need for ABT.