The aim of this survey is to review the clinical and experimental background for the use of hyaluronan (HA) in the therapy of gonarthrosis.
Clinical and experimental studies were analysed following a medline literature-research. To determine the clinical efficiency of HA only randomised and controlled studies were taken into account. As a result of this analysis the current knowledge for the clinical and experimental use of HA is portrayed.
Numerous controlled, randomised studies showed beneficial effects for pain relief and joint function after i.art.injection with HA. Placebo, NSAIDs and steroids were used as control medications. The effect of HA was significantly better compared to placebo, and similar or superior in comparison to other verums (NSAIDs, steroids). After completion of HA-therapy a long lasting effect compared to steroids was shown. Review of the literature reveals side-effect rates for HA-therapy similar to those for placebos. In various experimental studies a clear working mechanism could not be identified, especially reasons for the long lasting effects are still unknown. However, some studies showed an anti-inflammatory effect 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 vitro and in animal models in detail.
HA is therefore classified as a "symptom slow acting drug for osteoarthritis" because a "structure-modifying (chondroprotective) effect" has not been proven yet.