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Hylan G-F20 for arthritis


Clinical bottom line

Hylan G-F 20 in limited studies appears to be more effective than placebo, and perhaps as effective as NSAIDs for reducing pain in knee osteoarthritis.


M Espallargues, JM Pons. Efficacy and safety of viscosupplementation with Hylan G-F 20 for the treatment of knee osteoarthritis. International Journal of Technology Assessment in Health Care 2003 19: 41-56.


Primary data from studies on Hylan G-F 20 were supplied by the UK manufacturer, supplemented by literature searches in five electronic databases, including the Cochrane Library. Dates of the last searches appeared to be in 1999. Experimental and observational studies were accepted, where there was treatment of knee osteoarthritis with Hylan G-F 20.


There were fourteen identified studies, seven of which were randomised trials, and of which four were full publications and three abstracts. Four of the other seven reports were abstracts.

Four of the randomised studies compared Hylan G-F 20 with placebo. All were described as double blind. Three were of at least 12 weeks duration, and mean VAS pain scores at the end of treatment are shown in Figure 1. Two studies apparently also reported the number of patients with pain scores of 20 mm or below at the end of treatment, with NNTs in individual studies of 1.3 (90% of patients with Hylan G-F 20 with low pain scores) and 3.8 (39% with low pain scores).

Figure 1: VAS pain scores at the end of treatment (12 week studies)

Two randomised trials comparing Hylan G-F 20 with oral NSAIDs showed little difference, but with a tendency for lower scores at the end of treatment with Hylan G-F 20 than with NSAID.

Adverse events

It was stated that adverse events, including anaphylactoid reactions, occur in 0-3% of injections, but with no indication of the balance between local mild reactions and more serious ones. Case series of patients where injections were used long-term suggested higher rates of mild adverse events.


This is a comprehensive review, though with information on only 190 patients in longer term comparisons with placebo in randomised trials. Of course, placebo in this context is not necessarily doing nothing, as arthrocentesis itself may involve removing the joint effusion, and both sham injections and saline injections were used as placebo. The reality, though, is that there is insufficient high-quality research upon which to build definite conclusions.