[Timing of tourniquet release in total knee arthroplasty doesn't affect on transfusion needs]

To determine whether the removal of the ischaemia tourniquet to perform haemostasis during knee replacement surgery, reduces bleeding, the need for transfusions, the incidence of complications, the incidence of further surgery, and the hospital stay.

A non-randomised, prospective, descriptive and observational study was conducted on patients subjected to primary knee replacement with only one anaesthetist and 2 surgical teams. The same surgical technique and prosthesis model was used, with 2 schemes for ischaemia removal and drainage management. The patients were divided into 2 groups. In group i, the ischaemia tourniquet was released during the operation, before wound closure, and leaving the drainages without a vacuum. In group ii the tourniquet was released when the limb was bandaged and the drainages were connected to a vacuum. The parameters recorded were; bleeding during surgery, bleeding due to the drainages, monitoring the haemoglobin and haematocrit, incidence of complications and further surgery, transfusion needs, and hospital stay.

The study included 100 patients. The mean bleeding during surgery was 230,0mL in group i and 2,0mL in group ii (P<.05). The bleeding due to the drainages in group i was 531,2mL and 601,6mL in Group ii (P>.05). The total bleeding was 754,3mL in group i and 621,6mL in group ii. There were statistically significant differences in both cases (P<.05). The transfusion incidence in both groups was 16,7%. There were no significant differences between either group as regards medical complications or further surgery. A longer hospital stay was observed in group ii.

In this study, the need for transfusions in knee replacement surgery is not influenced by the time of releasing the ischaemia tourniquet. There is also no relationship between the incidence in postoperative complications and further surgery and the time of removing the tourniquet. The preoperative haemoglobin was the only predictive factor of transfusion in our study.