Hip pain is reported by 19.2% of people 65 years of age or older. The optimal treatment requires a combination of nonpharmacologic and pharmacologic modalities. Intra-articular hyaluronic acid (HA) injections are widely used and are recommended in existing guidelines for patients with knee osteoarthritis (OA), with less evidence available concerning arthritis of the hip. This study evaluated the efficacy and safety of intra-articular injections of a single dose of high molecular weight HA for patients with hip OA.

Subjects were 207 patients with hip OA, with an average age of 67 years. The patients received a single injection of 2.5% high molecular weight (2800 kDa) HA, with the injections performed under fluoroscopic guidance. All participants were evaluated before injections and at three, six and 12 months, using the modified brief pain inventory (BPI), the Harris Hip Score (HHS) and a visual analog scale (VAS) of pain.

Pain, as measured by the BPI severity score, improved significantly between baseline and the three follow-up visits (P<0.001). Changes in pain between baseline and the first follow-up were significant for worst pain (P＝0.037) and mean pain (P＝0.043). Changes in worst pain remained stable from three to 12 months, although changes in average pain, slightest pain and pain during the visit were significantly improved at all intervals. Scores on the HHS and VAS improved from baseline to three months (P<0.001 and P<0.001), remaining stable thereafter.

This uncontrolled study of patients with hip osteoarthritis suggests that a single dose of high molecular weight hyaluronic acid can improve pain by three months, with results continuing for one year.