Objective: Hyaluronic acid (HA) and corticosteroids are both widely used for intra-articular treatment of knee osteoarthritis (OA). We examined the effect of both drugs in intra-articular treatment for hip OA.
Methods: One hundred and one patients with hip OA were included in a prospective double blind study, using a randomized controlled trial with a three-armed parallel-group design. Three ultrasound-guided, intra-articular injections were given at 14 days interval. The primary outcome measure was 'pain on walking', registered on a visual analogue scale (VAS). Evaluation was performed at baseline and after 14, 28 and 90 days. The study adhered to the Consolidated Standards of Reporting Trials. All analyses were based on intention-to-treat analyses, and used 'mixed-procedures' with the baseline-observation as covariate.
Results: There were no significant interactions with respect to Treatment x Time for any of the analyzed outcome measures. There was a significant treatment effect for 'pain on walking' (P=0.044) due to a significant improvement following corticosteroid compared to saline with an effect-size of 0.6 (95% confidence interval: 0.1-1.1, P=0.021). By contrast, HA compared to saline had an effect size of 0.4 (-0.1 to 0.9; P=0.13). The peak-effect was obtained after 2 weeks. There was no difference between the treatment groups at endpoint. No significant side effects of the injections were observed.
Conclusions: Patients treated with corticosteroids experienced significant improvement during the 3 months of intervention, with an effect size indicating a moderate clinical effect. Although a similar significant result following treatment with HA could not be shown, the effect size indicated a small clinical improvement. A higher number of patients in future HA studies would serve to clarify this point.