A prospective randomised controlled trial of hyaluronic acid in patients with symptomatic ankle osteoarthritis

R. Refaie, M. Chong, A. Murty, M. Reed

Introduction: Symptomatic treatment of ankle osteoarthritis (OA) with corticosteroid injections is well established. Hyaluronic acid is also reported as an effective symptomatic treatment for ankle OA but these two treatments have not been compared directly.

Methods: A prospective randomised controlled trial in patients with symptomatic ankle osteoarthritis. Twenty patients per group were required based on a significance level of 0.05, and a drop out rate of 5%. Patients were blindly allocated to the treatment or control group. Injections were carried out by the clinician in the outpatient department. Treatment group received Ostenil 20mg and control group received Depomedrone 40mg (both as single injections). The treatment arm was allocated by computer generated block randomization to match treatment allocation with grade of arthritis. The primary outcome measure was the change in Visual Analogue Scale (VAS) pain score at 6 months. Secondary outcome was the change in AOFAS score at 6 months. Research ethics committee approval was obtained.

Results: A total of 42 patients were recruited of which 38 completed the study. Male recruits predominated (79%; 33 recruits). More than 70% had radiographic OA of grade 3 or more. Both groups demonstrated statistically significant improvements in VAS at weeks 3, 6, and 3 months over baseline, but the Ostenil group faired better at 6 months follow-up. (difference in VAS scores of 3.5 Ostenil VAS - 4; Steroid VAS - 7.5; Mann Whitney test (p< =0.05). There was no statistical difference in AOFAS scores between both groups at baseline and follow-up (p = 0.48, Mann Whitney test). No complications noted. 30% of patients have had their surgical procedures delayed for 6 month post injection.

Conclusion: The Ostenil group revealed similar clinical efficacy to steroid group, however the benefits provided by Ostenil lasted longer. Ostenil provided sufficient mid-term pain-relief whilst patient awaits further definitive intervention.