In non-operative treatment, pain reduction and improved function are the primary goals. It is important to distinguish between systemic and local therapeutic options. In the systemic treatment, palliation of pain can be achieved by simple analgetics, non- steroidal anti-inflammatory drugs and opioids. Local therapy can selectively treat the symptomatic joint. Intraarticular application of different drugs by injection can be performed. Glucocorticoids are the most commonly used intraarticular agents, which reduce pain and improve function and well being. In recent years, the intraarticular use of different hyaluronan (HA) products became more widely accepted. Hyaluronan is a physiological component of the synovial fluid and cartilage matrix. It is responsible for the viscoelastic properties of the synovial fluid. In osteoarthrotic joints, the molecular weight and the concentration of endogenous HA are decreased compared with healthy joints. This implies a reduction of the viscoelasticity of the synovial fluid. In order to restore this viscoelasticity, augment the flow of the synovial fluid, normalise the synthesis and inhibit the degradation of endogenous hyaluronan, an application of exogenous HA can be performed. The therapeutic effects and the safety of intraarticular application of HA in the treatment of OA in the knee have been demonstrated in several clinical trials. Until now there are only three studies that objectively analysed few aspects of the functional outcome after treatment with HA.