[The influence of the drain suction in knee arthroplasty].

Problem: In a prospective randomised clinical study, we investigated the impact of drain-suction on the post-operative blood loss and on both clinical and laboratory parameters after knee replacement operations.

Patients And Method: In this study, 116 patients with unilateral implantation of knee replacements were evaluated. The patients' average age was 71.2 years. The operation was carried out mostly without tourniquet application. All patients received two wound drains, 57 with and 59 without suction. The postoperative blood loss as well as clinical and laboratory parameters were assessed.

Results: The average peri-operative blood loss amounted to 338 ml. The post-operative blood loss in the group without drain suction was 436 ml and 528 ml in the group with suction. No significant differences could be found concerning the hemoglobin values pre-operatively and on the first and seventh post-operative day, the drainage quantity 12, 24, 36, and 48 hours post-operatively, the wound healing and the CRP. Six patients in the group without and five patients in the group with drain-suction had to receive blood transfusions.

Discussion: The application of suction on the drainage system had no significant impact on the post-operative blood loss and the postoperative course. In nine out of ten cases no homologous blood was needed.