Long term safety, efficacy, and patient acceptability of hyaluronic acid injection in patients with painful osteoarthritis of the knee.

The increasing prevalence of painful knee osteoarthritis has created an additional demand for pharmacologic management to prevent or delay surgical management. Viscosupplementation, via intraarticular injection of hyaluronic acid (HA), aims to restore the favorable milieu present in the nonarthritic joint. The safety profile of intraarticular HA injections for painful knee osteoarthritis is well established, with the most common adverse effect being a self-limited reaction at the injection site. Although acceptance of the early literature has been limited by publication bias and poor study quality, more recent and rigorous meta-analysis suggests that intraarticular HA injection is superior to placebo injection for pain relief and matches, if not surpasses, the effect size of other nonoperative treatments, such as nonsteroidal anti-inflammatory medication. Intraarticular HA injection is effective in providing temporary pain relief in patients with painful knee osteoarthritis. Future investigations should focus on optimizing the composition and administration of HA agents to provide prolonged relief of painful osteoarthritis in the knee and other joints.