Closed suction drainage after knee arthroplasty. A prospective study of the effectiveness of the operation and of bacterial contamination.

A prospective investigation was designed to determine the volume and the evolution of bleeding after closure of the surgical wound following knee arthroplasty, as well as the incidence of infection and bacterial contamination in relation with the time that the suction drain was left in place. The drain was removed either 12, 24 or 48 hours after the operation. The presence of any signs of clinical infection was recorded. The tip of the drain, 1 cm of its subcutaneous portion and a sample from the collecting bottle were studied for bacterial contamination. In the 12-hr group, no microorganisms were isolated in cultures either from the tip, the subcutaneous portion or the bottle of the drain. In the 24-hr group, 87% of the total postoperative bleeding was collected during the first 12 hours. In two cases, the samples obtained from the tip and the subcutaneous portion of the drain were positive for Staphylococcus epidermidis. In the 48-hr group, 91% and 97% of the total bleeding volume was collected during the first 12 and 24 hours, respectively. In two cases, St. epidermidis was isolated in cultures from the subcutaneous portion of the drain. The clinical evaluation of wound healing was comparable in all three groups.