Duration of symptom relief after intra-articular injection of hyaluronic acid combined with sorbitol (anti-ox-vs) in symptomatic hip osteoarthritis.

The intra-articular administration of hyaluronic acid (HA) in hip osteoarthritis (OA) has been recently increased following the use of ultrasound guidance to perform an accurate delivery of the injected product. Viscosupplementation in hip OA seems to show similar results to those obtained by viscosupplementation in knee OA. However, an unmet need is the duration of symptomatic relief, therefore several new products are proposed to prolong and increase symptomatic effects. Among these, an innovative viscosupplement has been produced from high a concentration of HA combined with a high concentration of sorbitol as a free radical scavenger. The aim of this study is to evaluate the mid-term pain-relief effect of an ultrasound-guided injection of SynolisV-A (ANTI-OX-VS) in patients suffering from symptomatic hip osteoarthritis. Lequesne index, Health Assessment Questionnaire (HAQ), pain reduction, Global Patient Assessment (GPA), Global Medical Assessment (GMA) and reduction in monthly analgesic consumption were assessed during the 12-month follow-up after the injection. A total of 20 patients were enrolled in the study and received one IA US-guided injection of two syringes of ANTI-OX-VS into the target hip. Eleven drop-out patients were registered, of whom 2 were for loss of efficacy at 6 months, 1 for loss of efficacy at 9 months and 8 patients for severe comorbilities. Mean scores of all clinical parameters evaluated at each control visit were significantly different when compared with baseline mean value. No systemic adverse events were observed. Even though the sample size of this study is limited, the results suggest a durable good efficacy of a 4-ml single injection of ANTI-OX-VS in hip OA, at least for the patients who completed the study. A larger number of patients and an RCT are needed to confirm these data, investigating also the predictive factors of clinical response to ANTI-OX-VS.