Are intra-articular injections of Hylan G-F 20 efficacious in painful osteoarthritis of the knee? A systematic review & meta-analysis

Aim: To systematically review evidence and perform a meta-analysis of the efficacy of intra-articular (IA) injections of Hylan G-F 20 for the treatment of painful osteoarthritis (OA) of the knee. Methods: Systematic review of the Embase and PubMed databases up to July 2013 of randomised placebo-controlled trials studying the effect of Hylan G-F 20 in patients with painful knee OA, with a meta-analysis of trials reporting visual analogue scores (VAS) for weight-bearing pain in the knees of patients followed up for a minimum of 6 months. Results: Six placebo-controlled randomised trials were identified on systematic review of which two studies met criteria for inclusion in the meta-analysis. Meta-analysis demonstrated that at 6-month follow up, there was no significant difference between Hylan G-F 20 and control in terms of reduction in VAS for weight bearing pain. (Mean Difference -12.96 (95% CI: -35.48, 9.56). Z tests used to test for overall effect showed that the difference between the two groups was not significant (p = 0.26). Discussion: A significant placebo effect exists for patients receiving IA injections for the treatment of painful knee OA. The withdrawal of fluid from the affected knee prior to any injectable therapy may itself have additional benefits which in isolation have not been studied. This may form the basis of future research. The authors' acknowledge that although limited conclusions can be drawn from the results of this study, the meta-analysis presented has not been performed previously and will further contribute to the knowledge on this subject. Conclusion: Although Hylan G-F 20 may produce improvement in VAS scores for weight-bearing pain at 6-month follow up in OA knees treated with it, patients should be informed that this may be equivalent to that seen with control treatments.