Osteoarthritis of the knee

Paul Creamer and Marc Hochberg’s seminar on osteoarthritis (Aug 16, p 503)

provides a comprehensive overview, including treatment strategies and options. They suggest that intra-articular hyaluronic acid is more efficacious than a single injection of intra-articular steroid in patients with knee osteoarthritis. As far as we can see, the only comparative studies have compared intra-articular 6-methyl prednisolone acetate (6-MPA), a short-acting corticosteroid with a half life of only 7 days, with intra-articular hyaluronic acid, rather than the more commonly used preparation of triamcinolone hexacetonide, which has a half life of 26–60 days.

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Although hyaluronic acid and 6-MPA seem to be equally efficacious in the short-term, a significant difference in favour of hyaluronic acid was reached only 39 days after the end of the treatment course.

The use of viscosupplementation with hyaluronic acid was first suggested in the 1960s, and since then the findings of trials have supported its use. The main limitations of these studies are that most are short-term and few are prospective, placebo-controlled trials.

Hyaluronic acid may prove to be an effective and innocuous form of therapy, but its use has not as yet been universally accepted and should not be seen as standard or routine treatment.