Drain clamping in knee arthroplasty, a randomized controlled trial

The purpose of this study was to determine whether repeated clamping of a suction drainage system will result in less external blood loss, blood transfusion and no increase in complications compared to a routine continuous suction drainage system. This was a randomized prospective study on patients undergoing total knee arthroplasty.

Group A patients' drains were left clamped for all but 5 min (or 100 mL drainage) every 2 h for the first 6 h, then at 12-h and 24-h periods, when the drains were removed. Group B patients had continuous suction drainage. The amount of external blood loss, transfusion requirements and complications were compared between the two groups. The study group comprised 66 patients.

The mean external blood loss in the clamped drain group was 296.67 mL (standard deviation 160.28 mL) with a mean drain in situ time of 32 h, significantly less (P < 0.05) than the continuous drain group that had a mean external blood loss of 796 mL (standard deviation 250.34 mL) with a mean drain in situ time of 34 h. There was no difference in the requirements for transfusion between the two groups.

We conclude that clamping drains intermittently in hybrid total knee arthroplasty results in significantly less external blood loss with no change in morbidity or mortality. This study was a level 1 therapeutic study (i.e. with level of evidence randomized control trial with a significant difference).