Nonanimal Hyaluronic Acid for the Treatment of Ankle Osteoarthritis: AProspective, Single-Arm Cohort Study.

Ankle osteoarthritis (OA) can cause disabling symptoms, and some patients prefer to be treated with minimally invasive procedures. Nonanimal hyaluronic acid (NASHA) is a cross-linked hyaluronic acid product that has a prolonged intra-articular residence time. The authors report the first study of NASHA for the treatment of ankle OA. Thirty-seven patients with Kellgren-Lawrence grade II or III ankle OA received an intra-articular injection of NASHA (1 mL). Outcomes included visual analogue scale (VAS) scores for pain and disability. At baseline, the mean VAS pain score was 50.1 ± 14.5mm. During the 26-week follow-up period, the least squares (LS) mean change from baseline in the ankle OA VAS pain score was -20.5mm (95% confidence interval [CI] -25.5 to -15.6 mm), an LS mean percentage reduction of 40.0% (95% CI 30.2% to 49.9%). The LS mean change from baseline in the VAS disability score during 26 weeks was -19.2mm (95% CI -24.8 to -13.6 mm), a percentage reduction of 34% (95% CI 22.3% to 45.7%). Five participants experienced a total of 7 adverse events considered to be related to study treatment (injection site pain, n = 3; injection site joint pain, n = 3; plantar fasciitis, n = 1). This study shows promise for viscosupplementation with NASHA in the treatment of ankle OA. A single injection was associated with clinically meaningful reductions in pain and disability during a 26-week period and, in general, was well tolerated.