Background: Epidural patient-controlled analgesia (PCA) achieves better pain relief compared to parenteral regimens in patients undergoing total knee replacement arthroplasty (TKRA). Previous studies have reported inconsistent results regarding the effect of epidural PCA on bleeding during the postoperative period following TKRA. We aimed to compare the effect of epidural and intravenous PCA on postoperative bleeding in patients undergoing unilateral TKRA.
Methods: In total, 2,600 patients who underwent TKRA were assigned to an intravenous PCA (n = 2,339) or epidural PCA (n = 128) group. We performed multivariate logistic regression analysis to determine the propensity score. After 1:1 propensity score-matching, the final analysis was performed in 212 patients. We compared the postoperative blood loss from the operation site between the groups. We also used conditional logistic regression to assess the associations between epidural PCA and red cell transfusion of >3 units, presented as odds ratio (OR) and 95% confidence intervals (CIs).
Results: The mean postoperative blood loss was greater in the epidural PCA group than in the intravenous PCA group (900.9 +/- 369.1 ml vs. 737.8 +/- 410.1 ml; P = 0.007). The incidence of packed red blood cell administration (>3 units) was significantly higher in the epidural PCA group than in the intravenous PCA group (30.2% vs. 16.0%; OR, 2.5; 95% CI, 1.201–5.205; P = 0.014).
Conclusions: Epidural PCA is strongly related to postoperative bleeding after unilateral TKRA, as compared to intravenous PCA. Furthermore, the incidence of transfusion of more than 3 units is strongly associated with postoperative epidural PCA.

Effect of epidural patient-controlled analgesia on the postoperative bleeding after unilateral total knee arthroplasty: a propensity score analysis