Viscosupplementation with intra-articular hyaluronic acid for treatment of osteoarthritis in the elderly

Osteoarthritis (OA) is very disabling condition in the elderly. The current therapeutic approaches (analgesics, NSAIDs, COX-2 inhibitors, steroids) do not delay the OA progression or reverse joint damage. Moreover, they may cause relevant systemic side effects. Hyaluronic acid (HA) is a physiologic component of the synovial fluid and is reduced in OA joints. Therefore, intra-articular injection of HA, due to its viscoelastic properties and protective effect on articular cartilage and soft tissue surfaces of joints, can restore the normal articular homoeostasis. These effects are evident when HA is properly administered into the articular space; therefore, the use of "image-guided" infiltration techniques is mandatory. Viscosupplementation (VS), with different HA preparations (Low and High molecular weight), can be considered when the patient has not found pain relief from other therapies or is intolerant to analgesics or NSAIDs. A 3-5 doses regimen is usually recommended with 1 week interval between each injection. Several studies have shown the efficacy of HA for the treatment of knee OA, with positive effects on pain, articular function (Western Ontario and Mc Master Universities Osteoarthritis Index [WOMAC], Lequesne Index [LI], Range of Motion [ROM]), subjective global assessment and reduction in NSAIDs consumption. In general, the benefit is evident within 3 months and persists in the following 6-12 months. Encouraging but inconclusive results have also been observed for the treatment of shoulder, carpo-metacarpal, hip and ankle OA. However there is the need of better designed studies to prove the effectiveness of these medications, in order to rule out a placebo effect. The therapy is well tolerated with absence of systemic side effects and only with limited local discomfort.