Purpose: To monitor the changes in nitric oxide levels and synovium thickness index in synovial fluid following intra-articular injection of sodium hyaluronate. Methods: One hundred patients diagnosed with osteoarthritis of the knee from April 2014 to January 2015 in The Third Hospital of Jinan, Jinan, Shandong, China were selected and categorized into three phases; namely, mild, moderate and severe. Patients received a 20 mL sodium hyaluronate injection into the articular cavity of the knee once per week for 15 weeks, with continuous observation. The Visual Analogue Scale (VAS) and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores were recorded after five weeks. A total of 56 patients (78 knees) remaining in serious condition after 5 weeks were divided into mild, moderate, and severe groups and treated with sodium hyaluronate once a week. Internationally reorganized VAS and WOMAC scores were adopted as clinical observation indices to indicate the curative effect of sodium hyaluronate among the 56 patients after 15 weeks of treatment. The conditions of the patients in the two phases were compared. Results: After 5 weeks of treatment, treatment effective rate in the mild, moderate and severe groups was 72.92, 66.10 and 28.57 %, respectively, with an overall effective rate of 78 %. After 15 weeks of treatment, treatment effective rate in mild, moderate, and severe groups was 96.77, 95.45 and 66.67 %, respectively, with an overall effective rate of 67.95 %. Conclusions: Clinically curative effect of sodium hyaluronate is significant for mild and moderate phase patients after intra-articular injection of sodium hyaluronate, while the effect is insignificant in severe patients. Thus, sodium hyaluronate can effectively improve nitric oxide levels in synovial fluid, reduce synovium thickness, enhances articular cavity lubrication and effectively alleviates disease severity.
