AB0791 ONE VERSUS TWO INJECTIONS OF INTRA-ARTICULAR HIGHLY CROSS-LINKED HYALURONAN YEARLY IN PATIENTS WITH KNEE OSTEOARTHRITIS: INSIGHTS FROM ROUTINE CLINICAL PRACTICE

Abstract

Background: Hyaluronic acid (HA) is a natural polysaccharide, which is an important structural component of synovial fluid and cartilage. There are different injectable forms of HA used for clinical application. Highly cross-linked/high-molecular-weight hyaluronans (HMWHA) provide additional stability and improve functionality [1], resulting in longer bioavailability in the knee joint and promoting viscoinduction [2]. A direct comparison between the two most common injection protocols of HMWHA in our routine practice is of great practical interest, since viscosupplementation is among the most commonly used treatment modalities for patients with knee osteoarthritis (KOA) in Bulgaria [3]. Objectives: Our aim was to compare the clinical effectiveness of two different regimens for injecting intra-articular HMWHA in KOA patients under ‘real-world’ conditions in routine clinical practice. Methods: This prospective, open-label, observational study included 50 patients with KOA who were followed for a period of 1 year. They were divided into two therapeutic arms according to their preselected treatment regimen: patients injected once with HMWHA (n = 25; group 1) at baseline and patients injected twice 6 months apart with HMWHA (n = 25; group 2). A 100-mm visual analogue scale (VAS) for pain, disease-specific (Western Ontario & McMaster Universities Osteoarthritis index [WOMAC]) and generic (health assessment questionnaire – disability index [HAQ-DI]) questionnaires were used to evaluate patients at baseline, three months, six months, and one year later. Standardized radiographs were obtained at baseline and after one year. The response to the treatment was determined using the OMERACT-OARSI set of responder criteria [4]. Results: A single injection of HMWHA resulted in a statistically significant improvement in pain even at 12 months (ΔVAS = 10.12 ± 14.5 mm, p 0.05). Physical function was statistically improved in both groups (p 0.05). In the end of the follow-up period HAQ-DI did only statistically improve among patients in group 2. Conclusion: If maximal symptomatic relief is our primary goal, it would be logical to choose a two-injection regimen. However, if we take into account the financial aspect, we may be satisfied with a single injection of highly cross-linked HA over a year.