Intra-articular hyaluronic acid for knee osteoarthritis
Clinical bottom line
There is no evidence from good quality trials that intra-articular hyaluronic acid id effective.
References
J Arrich et al. Intra-articular hyaluronic acid for the treatment of osteoarthritis of the knee: systematic review and meta-analysis. Canadian Medical Association Journal 2005 172: XXXXXXX.
Other systematic reviews of the same topic:
- M Pagnano, G Westrich. Successful nonoperative management of chronic osteoarthritis of the knee: safety and efficacy of retreatment with intra-articular hyaluronate, OsteoArthritis and cartilage 2005 13: 751-761.
- CT Wang et al. Therapeutic effects of hyaluronic acid on osteoarthritis of the knee. A meta-analysis of randomized controlled trials. Journal of Bone and Joint Surgery 2004 86-A: 538-545.
- M Espallargues, JM Pons. Efficacy and safety of viscosupplementation with Hylan G_F 20 for the treatment of knee osteoarthritis: a systematic review. International Journal of Technology Assessment in Health Care 2003: 19: 41-56.
Background
Several previous systematic reviews have failed to demonstrate any major benefits from this treatment (see here and here), partlt because of low quality and partly because of the insecurity of low numbers. New reviews are therefore to be welcomed.
Main review
There is no doubt that the best review is that of Arrich and co-workers. It is the only one to adequately examine methodological isues.
It sought randomised trials published up to April 2004. It examined a number of predefined clinical outcomes (pain at rest, on movement, joint function), at various times. It looked at results obtained in terms of the methodological quality of the trials.
Results
No trial that was randomised, double blind, and with an intention to treat analysis could demonstrate any benefit. Benefit was shown in trials that were open, or which were of per-protocol analysis.
Comment
It may not be beyond the bounds of belief that a small number of patients could benefit with long term use of injections of hyaluronic acid into their knee joints. The review of Pagnano & Westrich examines the evidence from studies of continued log term use, and concludes that there is benefit. However, of the six studies, only one is randomised, and all are small, some just a few patients. As things stand, this does not look like a reasonable therapy.