The clinical and experimental use of hyaluronic acid in the therapy of gonarthrosis: A review.

Aim: The aim of this survey is to review the clinical and experimental back ground for the use of hyaluronan (HA) in the therapy of gonarthrosis. Mater ials and methods: Clinical and experimental studies were analysed following a medline literature-research. To determine the clinical efficiency of KA only randomised and controlled studies were taken into account. As a result of this analysis the current knowledge for the clinical and experimental u se of HA is portrayed. Results: Numerous controlled, randomised studies sho wed beneficial effects for pain relief and joint function after i.art. inje ction with HA. Placebo, NSAIDs and steroids were used as control medication s. The effect of HA was significantly better compared to placebo, and simil ar or superior in comparison to other verums (NSAIDs, steroids). After comp letion of HA-therapy a long lasting effect compared to steroids was shown. Review of the literature reveals side-effect rates for HA-therapy similar t o those for placebos. In various experimental studies a clear working mecha nism could not be identified, especially reasons for the long lasting effec ts are still unknown. However, some studies showed an anti-inflammatory eff ect in inflamed joints and in stimulated culture-conditions. A stimulating effect of the HA-production by synoviocytes after administration of HA was shown. Further studies will have to demonstrate the cellular effects in vit ro and in animal models in detail. Conclusion: HA is therefore classified a s a "symptom slow acting drug for osteoarthritis" because a "structure-modi fying (chondroprotective) effect" has not been proven yet.