Hyaluronic acid in the treatment of osteoarthritis of the knee joint: interim results of a comparative clinical study

The efficacy and safety of hyaluronic acid (HA) were investigated in comparison with glycosaminoglycan polysulphate (GAGPS) in a rondomised, masked observer, multicentre clinical study in patients with osteoarthritis of the knee. Patients underwent a five week treatment cycle, and received a total of either 5 intra-articular injections of 20 mg/2 ml HA or 10 intra-articular injections of 50 mg/ml GAGPS. An explorative interim analysis was carried out on data from 53 patients enrolled in the study. Efficacy parameters assessed were: - Knee joint function according to the Larson scale - Pain intensity on a Visual Analogue Scale (VAS) according to Huskisson - Pain intensity on an ordinal rating scale - Maximum duration of walking and global impression for efficacy. For the assessment of safety and tolerance, the global judgement of tolerance and adverse events were considered. Twenty seven patients were treated with HA and 26 with GAGPS. At the end of treatment, the mean of the scores for knee joint function had improved by 15.4% in the HA group and 7.8% in the GAGPS group compared with the baseline values (statistically significant differences between the groups, p = 0.048, Mann-Whitney-Wilcoxon test). Pain intensity on weight bearing, assessed using the VAS, showed a mean decrease of 57.5% in the HA group and 29.3% in the GAGPS group (p = 0.004, Student-t-test). A marked reduction in pain intensity could already be observed after three injections of HA. The mean of maximum walking distance increased by 50% (60.0 minutes) in the HA group and by 16.7% (15.0 minutes) in the GAGPS group. At the end of the treatment cycle, the investigator rated 55.5% of the HA patients and 30.8% of the GAGPS patients as being free from complaints or markedly improved