Prospective Randomized Controlled Clinical Trial Comparing Hyperosmolar Saline to Standard Isotonic Irrigation Fluid for Arthroscopic Knee Surgery: Initial Clinical Outcomes.

Abstract

Numerous in vitro studies suggest higher osmolarity irrigation fluids potentiate a chondroprotective environment, and a recent clinical study using hyperosmolar saline for shoulder arthroscopy reported potential clinical advantages. This prospective randomized double-blind controlled clinical trial was designed to assess initial clinical outcomes associated with use of a hyperosmolar irrigation solution in patients undergoing arthroscopic knee surgery. With institutional review board approval and informed consent, patients scheduled for arthroscopic knee surgery were randomized to surgery with either isotonic lactated Ringer's (273 mOsm/L) or hyperosmolar saline (593 mOsm/L) irrigation solution. Outcomes included perioperative blood pressure, knee girth, visual analogue scale (VAS) pain scores, and narcotic pain medication consumption. Forty-six patients underwent arthroscopic knee surgery with isotonic (n = 23) or hyperosmolar (n = 23) irrigation fluids. There were 11 males and 12 females (mean age = 44.0 years) in the isotonic cohort and 8 males and 15 females (mean age = 40.2 years) in the hyperosmolar cohort. There were no significant differences with respect to surgical duration (pump time) or amount of irrigation fluid used between the two cohorts. There were no significant differences with respect to change in knee girth, blood pressure, or VAS pain scores. However, patients treated with hyperosmolar saline consumed less narcotic medication on postoperative day 3 (4.0 ± 7.6 vs. 15.5 ± 17.4 mg, p = 0.01). The results of this randomized clinical trial suggest that a hyperosmolar irrigation solution is safe and relatively inexpensive for use in patients undergoing arthroscopic knee surgery and contributes to a reduction in initial postoperative narcotic pain medication consumption. A hyperosmolar saline irrigation fluid was not associated with any detrimental effects on the execution of the surgical procedure, postoperative pain, or periarticular fluid extravasation. Taken together with previous basic science, translational, and clinical studies, hyperosmolar saline irrigation fluid is promising alternative to traditional isotonic irrigation fluids for knee arthroscopy. This study is a prospective trial and reflects level of evidence I.