US-Approved Intra-Articular Hyaluronic Acid Injections are Safe and Effective in Patients with Knee Osteoarthritis: Systematic Review and Meta-Analysis of Randomized, Saline-Controlled Trials

We conducted a systematic review and meta-analysis of randomized saline-controlled trials to determine the safety and efficacy of US-approved intra-articular hyaluronic acid (IAHA) injections for symptomatic knee osteoarthritis. A total of 29 studies representing 4,866 unique subjects (IAHA: 2,673, saline: 2,193) were included. IAHA injection resulted in very large treatment effects between 4 and 26 weeks for knee pain and function compared to pre-injection values, with standardized mean difference (SMD) values ranging from 1.07-1.37 (all P < 0.001). Compared to saline controls, SMDs with IAHA ranged from 0.38-0.43 for knee pain and 0.32-0.34 for knee function (all P < 0.001). There were no statistically significant differences between IAHA and saline controls for any safety outcome, including serious adverse events (SAEs) (P = 0.12), treatment-related SAEs (P = 1.0), study withdrawal (P = 1.0), and AE-related study withdrawal (P = 0.46). We conclude that intra-articular injection of US-approved HA products is safe and efficacious in patients with symptomatic knee osteoarthritis.