Comparison between 4-hour clamping drainage and nonclamping drainage after total knee arthroplasty

A prospective randomized trial of postoperative drainage-clamping practice was performed in 89 knees undergoing total knee arthroplasty. In group 1 (43 knees), drainage was clamped for the first 4 postoperative hours. In group 2 (46 knees), drainage was not clamped. The average bloody drainage was significantly less in group 1 than group 2 (514.85 ± 378.0 vs 843.4 ± 366.4 mL). The decrease of hemoglobin and hematocrit after surgery was also significantly less in group 1. Group differences between postoperative range of motion and narcotics requirements, length of stay, immediate wound problems, and deep vein thrombosis were nonsignificant. These results suggested that clamping the drainage in the first 4 postoperative hours reduces postoperative blood loss without causing excess morbidity after total knee arthroplasty.