Background:The management of the postoperative period after knee arthroscopic surgery may be challenging because surgical trauma deeply alters the joint microenvironment, causing the release of several catabolic molecules and proinflammatory factors that might slow down functional recovery. The possibility of using hyaluronic acid (HA) to promote postoperative pain relief and expedite functional improvement seems attractive, considering its biological properties.Purpose:The aim of the present double-blind randomized controlled trial was to evaluate the effects, in terms of pain control and functional recovery, provided by a single HA injection performed at the end of arthroscopic meniscectomy.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:A total of 90 patients, 18 to 55 years old, were included according to the following criteria: (1) chronic, symptomatic meniscal tears requiring partial resection; (2) a healthy contralateral knee; (3) no previous surgery on the index knee; and (4) no other concurrent articular lesions requiring surgical treatment (eg, cartilage or ligament injuries). Patients were randomized into 2 treatment groups: one underwent meniscectomy alone, whereas the other also received an injection of 3 mL HA at the end of the procedure. All patients were evaluated at baseline and then at 15, 30, 60, and 180 days using the following tools: International Knee Documentation Committee (IKDC) subjective, Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) for pain, VAS for general health status, and Tegner scores. The transpatellar circumference and active and passive ranges of motion were also recorded during the follow-up evaluations.Results:No major adverse events were reported using HA postoperatively. A statistically significant increase in all the clinical scores was reported in both treatment groups, but no significant intergroup difference was documented at any follow-up evaluation. No difference was observed also in the objective measurements. The mean time to return to full sports activity was not different between groups, and a comparable satisfaction rate was recorded in both treatment groups.Conclusion:Early postoperative viscosupplementation did not provide significant clinical benefits after arthroscopic meniscectomy. Despite the lack of major adverse events, the administration of a single HA injection at the end of the surgical procedure is not a successful strategy to provide either faster functional recovery or symptomatic improvement after meniscectomy.Trial Registration:ClinicalTrials.gov identifier: NCT02629380.