Review
SynthèseO steoarthritis affects about 10% of the population over 55 years of age. Of those, one-quarter are severely disabled.1 The condition is characterized by degeneration of the articular cartilage and subsequent subchondral bone changes. The underlying mechanisms remain unknown, but the glycosaminoglycan-proteoglycan matrix may play a major role. 2 Hyaluronic acid, a glycosaminoglycan, is widely used for the treatment of osteoarthritis of the knee. A survey of 2 general practices in the United Kingdom showed that about 15% of patients with osteoarthritis received intraarticular treatment with glucosamine sulfates. 3 The costs of such treatment are significant. At present, 1 syringe of hyaluronic acid costs at least Can$130 (US$110). The treatment of knee osteoarthritis is covered by the US Medicare program but not by provincial formularies in Canada. In Austria (which has 8 million inhabitants) more than 10 million euros (approximately US$12 million or Can$15 million) is spent by social insurance programs annually for hyaluronic acid preparations (excluding the cost of application).Hyaluronic acid has beneficial effects in vitro. 4 Because of its viscoelastic quality, it may replace synovial fluid. Furthermore, it may reduce the perception of pain. Beneficial molecular and cellular effects have also been reported.
2,4Hyaluronic acid is frequently applied by intra-articular injection, but the evidence concerning its clinical relevance is conflicting. The European League against Rheumatism (EULAR) recommends the intra-articular application of hyaluronic acid as "category 2" evidence (at least 1 controlled study without randomization). 5 The American College of Rheumatology recommends intra-articular hyaluron therapy for patients with no response to nonpharmacologic therapy and simple analgesics. 6 In contrast, other specialists have concluded that "hyaluronate sodium is not efficacious" in the treatment of osteoarthritis. 7 The first state-of-the-art systematic review and meta-analysis was published recently, 8 and its authors concluded "that intra-articular hyaluronic acid, at best, has a small effect."We performed a systematic review and meta-analysis of Abstract Background: Osteoarthritis of the knee affects up to 10% of the elderly population. The condition is frequently treated by intra-articular injection of hyaluronic acid. We performed a systematic review and meta-analysis of randomized controlled trials to assess the effectiveness of this treatment.
Methods: We searched MEDLINE, EMBASE, CINAHL, BIOSISand the Cochrane Controlled Trial Register from inception until April 2004 using a combination of search terms for knee osteoarthritis and hyaluronic acid and a filter for randomized controlled trials. We extracted data on pain at rest, pain during or immediately after movement, joint function and adverse events. Results: Twenty-two trials that reported usable quantitative information on any of the predefined end points were identified and included in the systematic review. Even though pain at res...