Viscosupplementation for the treatment of osteoarthritis of the knee

Background Osteoarthritis (OA) is the most prevalent chronic joint disorder worldwide and is associated with significant pain and disability. Objectives To assess the effects of viscosupplementation in the treatment of OA of the knee. The products were hyaluronan and hylan derivatives (Adant, Arthrum H, Artz (Artzal, Supartz), BioHy (Arthrease, Euflexxa, Nuflexxa), Durolane, Fermathron, Go‐On, Hyalgan, Hylan G‐F 20 (Synvisc Hylan G‐F 20), Hyruan, NRD‐101 (Suvenyl), Orthovisc, Ostenil, Replasyn, SLM‐10, Suplasyn, Synject and Zeel compositum). Search methods MEDLINE (up to January (week 1) 2006 for update), EMBASE, PREMEDLINE, Current Contents up to July 2003, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched. Specialised journals and reference lists of identified randomised controlled trials (RCTs) and pertinent review articles up to December 2005 were handsearched. Selection criteria RCTs of viscosupplementation for the treatment of people with a diagnosis of OA of the knee were eligible. Single and double‐blinded studies, placebo‐based and comparative studies were eligible. At least one of the four OMERACT III core set outcome measures had to be reported (Bellamy 1997). Data collection and analysis Each trial was assessed independently by two reviewers for its methodological quality using a validated tool. All data were extracted by one reviewer and verified by a second reviewer . Continuous outcome measures were analysed as weighted mean differences (WMD) with 95% confidence intervals (CI). However, where different scales were used to measure the same outcome, standardized mean differences (SMD) were used. Dichotomous outcomes were analyzed by relative risk (RR). Main results Seventy‐six trials with a median quality score of 3 (range 1 to 5) were identified. Follow‐up periods varied between day of last injection and eighteen months. Forty trials included comparisons of hyaluronan/hylan and placebo (saline or arthrocentesis), ten trials included comparisons of intra‐articular (IA) corticosteroids, six trials included comparisons of nonsteroidal anti‐inflammatory drugs (NSAIDs), three trials included comparisons of physical therapy, two trials included comparisons of exercise, two trials included comparisons of arthroscopy, two trials included comparisons of conventional treatment, and fifteen trials included comparisons of other hyaluronans/hylan. The pooled analyses of the effects of viscosupplements against 'placebo' control