Hyaluronic Acid in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta-Analysis with Emphasis on the Efficacy of Different Products

Colen S et al. – In the future it will be important to determine the exact mechanism of action of placebo as this may give us an idea of how to treat osteoarthritis more efficiently. Due to the limitations of this review (follow–up of just 3 months and large heterogeneity of the included studies), it is also important to compare the different hyaluronic acid (HA) products to determine which product(s), or which molecular weight range, concentration, or volume of HA is the best option to treat osteoarthritis. The authors' recommendation is to start large (multicenter) randomized controlled trials (RCTs) to give us more evidence about the efficacy of the different HA products.

Methods

• A systematic review of randomized controlled trials (RCTs) was conducted using databases including MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Clinical Trial Register and EMBASE.
• Seventy–four RCTs were included in this systematic review.

Results

• HA improves pain by approximately 40–50% compared with baseline levels.
• However, when compared with saline the difference in efficacy is not that large.
• Due to a large ‘placebo effect’ of saline (approximately 30% pain reduction, persisting for at least 3 months) the authors determined a weighted mean difference between the efficacy of HA and saline of just 10.20 using the visual analog scale for pain.
• It is debatable whether this difference reaches the minimum clinically important difference.

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