Blood Loss after Total Knee Arthroplasty. A Comparison between an Intra-Medullary, Extra-Medullary and Computer Assisted Techniques

Background: Blood loss after Total Knee Arthroplasty (TKA) is a known side effect which can lead to the administration of blood transfusions. Different alignment techniques exist. These can be, intra-medullary (IM) device both in the femur and the tibia, extra-medullary (EM) of the tibia with femoral intramedular alighnment and computer assisted (CA) technique which is all extramedullary. Extramedullary alignment is said to cause less blood loss.

Purpose: To compare the three alignment techniques with regard to post-operative blood loss.

Methods: Medical files of patients after TKA were reviewed retrospectively and were divided according to alignment technique. In the IM group both intra-medullary femur and tibia technique was used. In the EM group an intra-medullary femur and extra-medullary tibia was used. In the CA group an all extra-medullary technique was utilized using a navigated surgery technique. All patients underwent TKA at Hadassah university medical center by an arthroplasty specialist. A cemented technique was used with a nexgen implants. A tourniquet was used in all patients and a drain was placed for 24 h after surgery. Low molocular heparin was used for thrombo-prophylaxis in all patients. Hemoglobin levels were compared from preoperative to one day postoperative. Number of blood units received was compared between groups.

Results: We reviewed 188 TKA surgeries. 77 in the IM group, 75 in the EM and 36 in the CA groups. On average in the IM group 1 blood unit was given per patient, this was significantly different compere to EM and CA groups with 0.55 (p=0.003) and 0.56 (p=0.03) blood units.

Conclusion: Increased blood loss may be associated with breaching of the tibial medullary canal. Use of extramedullary femoral alignment along with tibial extramedullary alignment has no additive effect.