Effect of hyaluronic acid in symptomatic hip osteoarthritis: a multicenter, randomized, placebo-controlled trial

To evaluate the efficacy and tolerability of a single intraarticular (IA) injection of hyaluronic acid (HA) for the treatment of hip osteoarthritis (OA).

A multicenter, randomized, parallel-group, placebo-controlled trial was conducted over 3 months. Patients (older than 30 years) with symptomatic hip OA (pain score of >40 mm on a visual analog scale [VAS]) and a Kellgren/Lawrence grade of 2 or 3 were randomly assigned to receive 1 fluoroscopically guided IA injection of HA (2.5 ml) or placebo (2.5 ml). Patients were followed up for 3 months. The main outcome measure was pain score on a VAS (100 mm) at month 3 compared with baseline. Secondary outcome measures were the proportion of responders defined by Osteoarthritis Research Society International criteria; Western Ontario and McMaster Universities Osteoarthritis Index subscores for pain, stiffness, and disability; and patient and physician global assessment. Randomization was computer generated. HA and placebo preparations were placed in numbered identical containers, and syringes were covered with masking tape. Physicians assessing outcomes were blinded with regard to group assignment.

Eighty-five patients were randomized to the HA group (n = 42) or placebo group (n = 43). Baseline characteristics were similar between the 2 groups. At 3 months, the decrease in pain score did not differ between the HA and placebo groups in the intent-to-treat analysis (mean +/- SD decrease 7.8 +/- 24.9 mm with HA versus 9.1 +/- 27.4 mm with placebo; P = 0.98). The responder rates were 33.3% and 32.6% in the HA and placebo groups, respectively (P = 0.94). Other secondary end points did not differ between the groups, nor did use of rescue medication or frequency of adverse events.

Our findings indicate that a single IA injection of HA is no more effective than placebo in treating the symptoms of hip OA.