[Influence of tourniquet ischemia on perioperative blood loss after total knee arthroplasty].

The purpose of this study was to evaluate the effect of tourniquet use with constant pressure until wound closure on perioperative blood loss in total knee arthroplasty (TKA). Sufficient patients were included in the study to produce statistically relevant conclusions. In this retrospective case control study 547 patients who were treated with TKA because of osteoarthritis of the knee joint were included and of these 262 patients were operated with the use of a tourniquet (300 mmHg) and 285 without. The perioperative blood loss was calculated using patient height, body weight and preoperative and postoperative hematocrit values. The patient collectives were comparable in mean age, gender distribution and ASA classification. In the group with an operation using a tourniquet, 24 patients (9.2%) received erythrocyte transfusions compared to 36 patients (12.6%) in the group without tourniquet use (not significant). The average perioperative blood loss without tourniquet use was 1.5±0.6 l (range -0.2 to 4.3 l). In contrast patients treated with the use of a tourniquet lost on average only 1.2±0.5 l (range -0.2 to 3.4 l) (p<0.001). The use of a tourniquet reduces the perioperative blood loss in TKA if it is kept tight during the operation.