Evaluating the use of intra-articular injections as a treatment for painful hip osteoarthritis: a randomized, double-blind, multicenter, parallel-group study comparing a single 6-mL injection of hylan G-F 20 with saline

Abstract

Objective: Hip osteoarthritis (OA) is difficult to treat. Steroid injections reduce pain with short duration. With widespread adoption of office-based, image-guided injections, hyaluronic acid is a potentially relevant therapy. In the largest clinical trial to-date, we compared safety/efficacy of a single, 6-mL image-guided injection of hylan G-F 20 to saline in painful hip OA.

Method: 357 patients were enrolled in a multicenter, double-blind, randomized saline placebo- controlled trial. Subjects were ≥35 years of age, with painful (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]-A1:5.0-8.0; numeric rating scale [NRS]: 0-10) mild-to-moderate hip OA (Kellgren-Lawrence grade II/III) and minimal contralateral hip pain (WOMAC-A1 < 4). Outcome measures included "pain on walking" (WOMAC-A1 and -A), Patient Global Self-Assessment (PTGA), WOMAC-A1 responder rate (+≥2 points on NRS), and adverse events (AEs) over 26 weeks.

Results: 357 patients (hylan G-F 20 single:182; saline:175) were enrolled. Both groups demonstrated significant pain improvement from baseline over 26 weeks (P < 0.0001); saline-induced pain reduction was a remarkable 35%. WOMAC-A and PTGA scores also significantly improved (P < 0.0001). No statistically significant difference was observed between groups in WOMAC-A1 scores (hylan G-F 20 single:-2.19 ± 0.16; saline:-2.26 ± 0.17) or WOMAC-A1 responders (41-52%). Treatment-related AE rates at target hip were similar (hylan G-F 20 single:23 patients [12.8%]; saline:12 [7.0%]). Posthoc analysis found, despite protocol requirements, many patients had psychological (31%) or potential neuropathic pain (27.5%) conditions.

Conclusion: A single 6-mL hylan G-F 20 injection or saline for painful hip OA resulted in similar, statistically significant/clinically relevant pain and function improvements up to 6 months following injection; no differences between hylan G-F 20 and saline placebo were observed.

Keywords: Hip osteoarthritis; Hylan G-F 20; Intra-articular injections; Osteoarthritis; Synvisc-one.