Hyaluronic acid vs corticosteroids in symptomatic knee osteoarthritis: a mini-review of the literature.

Introduction: Although intra-articular injections of hyaluronic acid (HA) are common non-operative measures used in clinical practice in the management of symptomatic osteoarthritis, there is a great controversy on their efficacy and safety compared to corticosteroids (CSs).

Efficacy: Conflicting results have been reported in clinical trials and meta-analysis due to methodological differences in study design, along with collection, analysis, and interpretation of data. Even if some studies reported small or no differences of HA compared with CSs (or inferred that HA is not more effective than saline as a placebo), in general CSs have shown to be superior in the short term (especially on pain control), while better results have been reported with HA at subsequent evaluations, but with only a moderate effect after 26 weeks.

Safety: Mild or moderate adverse events have generally been reported after HA injections, the most common being injection site pain. HA is generally considered safe compared to CSs or saline. Furthermore, HA has shown to be safe also after a previous course of injections.

Conclusions: Conflicting results have been reported on the efficacy and safety of HA. Guidelines are controversial and in most of the cases "uncertain" recommendations are provided due to inconclusive evidence in literature. However, HA does not seem to have significantly higher side effects when compared to saline or CSs injections, and provides better medium-term control of symptoms in patients with mild to moderate knee osteoarthritis.