Do intra-articular therapies work and who will benefit most?

The main intra-articular (IA) treatments used in osteoarthritis are corticosteroids and hyaluronan injections. Data concerning their short- and long-term efficacy and their potential side-effects are reviewed here. IA corticosteroids are effective for reducing short-term pain and appear to have no long-term deleterious effects on the cartilage; they may be more efficacious in patients with joint effusion and/or symptom flares. IA hyaluronan have a modest but long-lived symptomatic effect on pain and functional outcome in knee osteoarthritis; the level of evidence is poor concerning their efficacy in other joints. The differences in efficacy related to the molecular weight of the hyaluronan are a subject of debate. There is a risk of acute painful reactions, which seem more frequent with higher-molecular-weight hyaluronan. Some data--mainly from animal studies--suggest a possible long-term chondroprotective effect of hyaluronan. This treatment seems more efficacious in non-radiologically severe osteoarthritis with no or mild effusion.