Aim: To determine the factors affecting the blood loss and blood transfusion in primary total knee arthroplasty (TKA)

Patients and methods: A prospective study involving 59 patients, who underwent primary total knee arthroplasty were included. A standardized protocol was used. Patients demographic details, intraoperative blood loss, post operative blood loss, pre-operative and post-operative hemoglobin values on day 1,2,7,14 were recorded.

Results: Average(+/− SD) intraoperative and post operative blood loss were 220(+/−115.6) ml and 443.6 (+/−160.9)ml respectively. Male patients had post-operative blood loss more than female (p= 0.001, students t- test). Patients with rheumatoidarthritic knees and osteoarthritic knees did not show any statistical difference in intraoperative or postoperative blood loss. Tourniquet time and surgical time showed a positive correlation with intraoperative blood loss. Body mass index did not show any correlation with intraoperative or postoperative blood loss. Incidence of blood transfusion was more in patients with rheumatoid knees as the pre operative haemoglobin value was lower in these patients. There was no statistical difference in the incidence of blood transfusion in male and female patients. There was 66% incidence of blood transfusion in patient with pre-operative hemoglobin less then 10.5 gm% . The over all blood loss and blood transfusion incidence were lower in our series when compared to many other series reported in the literature.

Discussion and conclusion: Gender has a role in blood loss in TKA, but diagnosis (OA or RA) has no role. Increase in tourniquet time and surgical time increase the intraoperative and hence the total blood loss. Blood loss and blood transfusion can be reduced to a lower level by following a standardized protocol. Blood transfusion depends on pre-operative hemoglobin rather than intraoperative blood loss. The post operative transfusion trigger can be brought to 8.5 gm% in a haemodynamically stable patient.