Objectives: To review the scientific evidence on the efficacy, effectiveness, and safety of intra-articular injections of Hylan G-F 20 for the treatment of knee osteoarthritis.

Methods: Systematic review of experimental and observational studies performed in humans up to December 1999. Qualitative and quantitative (meta-analytic) techniques were used for data synthesis.

Results: A single course of intra-articular Hylan G{-}F 20 provides a statistically significant and clinically relevant short-term decrease of the painful symptomatology of knee osteoarthritis and improves joint function. It also seems to delay the need for knee replacement, if results observed in noncontrolled studies are confirmed. Hylan G-F 20 has a comparable efficacy to that of oral NSAID, and a smaller risk of gastrointestinal adverse effects. It seems to be well tolerated and safe, but the short follow-up in most studies limits any extrapolation of the effectiveness and safety over the longer term. There is also scarce evidence on the effect of multiple courses of Hylan G-F 20, and the scientific rigor of both experimental and nonexperimental studies reviewed is somewhat limited.

Conclusions: Whereas there is good quality scientific evidence showing that Hylan G-F 20 is a safe and well-tolerated therapy providing a short-term decrease of the pain symptoms while improving joint function, the delay of the need for knee replacement as well as the durability of the effect over the longer term have only been demonstrated in noncontrolled clinical series. The available evidence is not sufficient to reach firm conclusions on the effect of multiple courses of intra-articular injections of Hylan G-F 20 on health outcomes.