Articular Hyaluronan Viscosupplementation

Intra-articular hyaluronan (lA-HA) injections are widely used to treat osteoarthritis (OA). This procedure is often referred to as viscosupplementation (22) because it involves the replacement of pathologic synovial fluid with viscoelastic hyaluro-nan-based solutions or gels. In the United States, lA-HA is specifically labeled as an intra-articular analgesic and is indicated to treat pain associated with knee OA when conservative measures and simple analgesics fail (e.g., acetaminophen). In other parts of the world, lA-HA is also approved for treatment of joints other than the knee and in some countries for arthritic conditions other than OA. The molecular basis for this application of hyaluronan, and the history of its development, has been recently reviewed (23). In this chapter, we will update the clinical evidence and describe the different types of hyaluronan formulations available in the United States. 

Five lA-HA products are currently available in the United States (35-39). All of them are also available worldwide (see Table 1). Two of these products (Supartz and Hyalgan ) have an average molecular weight (avg MW) of 0.6-1.0 million. Two other products (Orthovisc , Euflexxa ) have higher avg MW (1-3.6 million) and the fifth product (Synvisc ) has an even higher avg MW (6 million) and contains both fluid and gel components. Synvisc is made of two modified hyaluronans 

Trade names Hyaluronan concentration (%] Hyaluronan 1 source Average MW Treatment schedule on label 

Supartz (Smith Nephew) 1 Avian 0.6-1 million 3-5 weekly injections 

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Viscosupplementation is a clinical procedure that is being used increasingly in the treatment of osteoarthritis. This technique uses a substance known as hyaluronan to restore the lubricating properties of synovial fluid in osteoarthritic joints.6,41 Hyaluronan is a polysaccharide that can be injected into an arthritic joint to help restore the normal viscosity of the synovial fluid.6 This treatment helps reduce joint stresses, thus limiting the progression of articular destruction seen in osteoarthritis.106 Viscosupplementation has therefore been shown to reduce pain and improve function in osteoarthritis.1,95... 

With knee osteoarthritis (OA) patients increasing to a staggering 19 million in 2010, treatment by viscosupplementation has become popular. Visco-supplementation refers to the concept of synovial fluid replacement with intra-articular injections of hyaluronan mainly for the relief of pain associated with OA [47,48]. Intra-articular injections of hyaluronan ameliorate pain and function, generally for up to 3 months with no serious adverse events. In the... 

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