251 consecutive patients with knee arthrosis were randomized to one of three interventions: Four weekly injections of 2 ml isotonic saline (placebo), 2 ml sodium hyaluronate (hyaluronan) or 20 ml isotonic saline (excessive saline).

They all suffered from clinically and radiologically verified arthrosis of the knee with daily pain that did not respond to treatment with analgetics.

Results were evaluated at weeks 1,2,3,4,8,12,16 and 26. Biochemical markers for bone and cartilage degradation were measured in urine/blood.

Inclusion Criteria:

• Patients, men/women age > 60 years with clinical,
• Radiological and possible arthroscopical verified knee osteoarthritis.
• Knee pain on the day of examination scoring more than 20 mm on a visual analogue scale (VAS) at baseline.

Exclusion Criteria:

• Age below 60
• Unconsciousness
• Psychosis
• Demens
• Ingestion of drugs that may influence the results of the clinical examinations
• Inflammatory diseases of the joints
• Rheumatoid arthritis or other inflammatory arthritis as diagnosed by American College of Rheumatology criteria
• Contraindication to hyalgan treatment
• Previous intraarticular fracture of a knee joint
• Infection or skin disease located at the place of injection and invasive procedures done to the knee joint within previous two months inclusive intra-articular injections of steroids.
• Any other condition that might interfere with the efficacy assessment or completion of the trial.