100 patients who underwent uncomplicated total knee arthroplasty (TKA) were randomized to assess the efficacy of bleeding control for a clamping protocol compared to a non-clamping protocol. Patients received either non-clamping (where a vacuum drain was run continuously during the first postoperative day) or 3-hour interval clamping (where the vacuum was stopped twice for 3 hours each time). Results during the first 48 hours indicated that the drainage blood volume in the interval clamping group was significantly lower than the non-clamping group and that the mean hemoglobin fall at 12 hours was less in interval clamping group.