Hidden blood loss following total knee arthroplasty: an analysis of influential factors

Abstract

Objective To study the characteristic and influential factor of the hidden blood loss after total knee arthroplasty (TKA) so as to provide a reference frame for clinical work. Methods There were 75 patients with osteoarthritis of the knee who were operated with unilateral primary TKA. The patients including 21 males and 54 females at a mean age of 68.7 years were retrospectively analyzed.The perioperative blood loss and the hidden blood loss following TKA were calculated by Gross formula. It was analyzed that if the perioperative blood loss and the hidden blood loss following TKA were affected by gender, haemostasis during operation with deflating tourniquet and reinfusion of the drained blood. Results The preoperative blood loss was (1551.3 ± 369.6) ml and the hidden blood loss was (792.3 ±228.6) ml. The hidden blood loss of male was significantly higher than that of female (P ＜ 0.05). The hidden blood loss was reduced by haemostasis during operation with deflating tourniquet (P ＜ 0.05) but was not affected by postoperative shed blood reinfusion. Conclusions The lowest value of Hct is a representative parameter for calculation of the hidden blood loss. There is no significant difference between male and female about the relative hidden blood loss. Haemostasis during operation with deflating tourniquet can reduce teh hidden blood loss but not affect the total perioperative blood loss. Reinfusion of the drained blood can reduce the transfusion rate but does not affect the total preoperative blood loss and the hidden blood loss. Key words: Arthroplasty,replacement,knee; Postoperative hemorrhage