Soft tissue fluid retention is a common problem after arthroscopy, with as much as 2% of patients having complications develop. A fenestrated outflow cannula has been introduced to reduce interstitial swelling. We tested the ability of this outflow cannula design to reduce fluid weight gain. We enrolled 28 patients undergoing shoulder arthroscopy and randomized them into two groups using fenestrated outflow versus conventional cannulae. The conventional group had greater weight gain as a function of the procedure duration than the fenestrated outflow group (slope = 0.542 +/- 1.160 kg/hour versus 0.0144 +/- 0.932 kg/hour). The conventional group also had greater weight gain as a function of fluid volume than the fenestrated outflow group (slope = 0.022 +/- 0.038 kg/L versus 0.002 +/- 0.341 kg/L). Compared with conventional nonoutflow cannulae, fenestrated outflow cannulae with negative pressure reduced weight gain associated with longer arthroscopic surgeries and increased arthroscopic fluid volume.
Level of evidence: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.