The probability of allogeneic blood transfusion and its influencing factors in patients undergoing total knee arthroplasty: A retrospective cohort study.

Context: Total knee arthroplasty (TKA) is associated with blood loss and allogeneic blood transfusion (ABT).

Aims: The present study aimed to determine the predicting factors for ABT in patients undergoing TKA.

Setting and design: This was a retrospective cohort study, performed from 2003 to 2021 in Kashani hospital (a tertiary referral center) in Isfahan, Iran.

Subjects and methods: Patients who underwent TKA during the period of the study were included in the study. Demographic data including age, sex, marital status, and place of living were extracted. Surgery-related factors, including the day of admission and surgery, indication for surgery, and the American Society of Anesthesiologists score, were recorded. Data about ABT during and after surgery, hemoglobin (Hb), creatinine (Cr), platelet (Plt) level before the surgery and past medical history including comorbidities and drug history were also evaluated.

Statistical analysis used: Independent sample t-test and Chi-square were used for the comparison between study groups and logistic regression model on an as-needed basis.

Results: During the study period, 889 patients underwent TKA and were included. Three hundred and seven (34.53%) patients received ABT. In the univariate analysis, factors including asthma, anemia, antihypertensive drug consumption, preoperative Hb and Plt, and Cr had a significant relation with transfusion. Among these factors, preoperative Hb and Plt level had a significant association with transfusion in the logistic regression analysis.

Conclusion: We deduce that preoperative Hb and Plt can predict the probability of transfusion in patients undergoing TKA. We suggest routine blood preservation before the surgery in hospitals with a high rate of transfusion.