One-year follow-up showing effects of single intra-articular injection of hyaluronic acid (1,500-2,000 kDa) in symptomatic knee osteoarthritis.

Clinical evidence on knee osteoarthritis suggests that intra-articular administration of hyaluronic acid may be useful in the management of patients with persistent pain. This study assesses the duration of effectiveness of a single intra-articular hyaluronic acid injection in a large population of patients with knee osteoarthritis. This retrospective post-marketing cohort study collected data from the ANTIAGE Registry (http://www.antiagefbf.it/registro), selecting patients of age ≥ 40 years, with symptomatic knee osteoarthritis (Kellgren-Lawrence grade I-III) of ≥ 12 months duration, and ≥12 months of follow-up. Patients had received a single intra-articular injection of high molecular weight hyaluronic acid (1,500-2,000 kDa) at baseline. WOMAC Osteoarthritis Index total scores measured using the LK 3.1 scale and 10 cm VAS pain scores were evaluated before IA Injection and at 6, 9, 10, 11 and 12 months. Blood cell counts, uricemia, erythrocyte sedimentation rates and levels of C-reactive protein were measured at baseline and 12 months. Time from initial treatment to second injection up to 12 months was recorded to assess event-free survival. Included patients (n=187) were 53.5% female and had a mean (±SD) age at baseline of 62 (±16.6) years and mean (±SD) body mass index of 26.2 (±2.5) kg/m2. Mean (±SD) WOMAC index total score and VAS pain scores were 60.9 (±7.1) and 5.9 cm (±1.8), respectively. There were statistically significant reductions compared to baseline in mean WOMAC index total score and VAS pain score at all time points (p less than0.01 at 6 and 9 months; p less than 0.05 at 10, 11 and 12 months for both parameters). These results support the clinical effectiveness and safety of hyaluronic acid for up to 12 months for pain relief and function improvement in patients with knee osteoarthritis, confirming previous data on intra-articular administration of hyaluronic acid as chronic therapy in the management of knee osteoarthritis.