Rheologic changes in the synovial fluid of patients with gonarthritis induced by intraarticular infiltration of hyaluronic acid.

The aim of the present study was to evaluate possible changes in synovial fluid viscosity in gonarthritic patients treated with intraarticular infiltration of hyaluronic acid. Thirty patients with radiologically proven (Stage III Kellgren) serious gonarthrosis, local pain and functional limitation were enrolled. All patients had reported at least 4-5 episodes of hydrarthrosis during the previous 12 months. Therefore, two different phases of their illness could be observed: a relatively silent phase of hydrarthrosis and a symptomatic phase. According to the protocol, one sample of synovial fluid was collected for evaluation of baseline viscosity (pretreatment); immediately afterwards, intraarticular administration of high molecular weight sodium hyaluronate (one 20 mg vial/week for 3 weeks) was initiated. During the entire treatment period and for 3 weeks following the end of treatment, intraarticular synovial fluid samples (one sample per week for 3 treatment weeks followed by a further 3 weeks as control) were collected to perform rheologic assessment and viscosimetric analysis. The results of this preliminary study show that exogenous administration of high molecular weight sodium hyaluronate induced normalization of hyaluronic acid viscosity values in patients with high and low baseline hyaluronic acid viscosity values.