The purpose of this study is to assess the efficacy and safety of glucosamine and chondroitin sulfate association in the treatment of patients with osteoarthrosis of the knee.

To assess the efficacy and safety of the association of glucosamine sulphate 500 mg/chondroitin sulphate 400 mg (Eurofarma) in the treatment of osteoarthritis, compared to Cosamin DS® (Nutramax) in same presentation and pharmaceutical form.

Some eligibility criteria:

Osteoarthritis of the knee confirmed by radiological examination; Visual analogue scale (VAS) > 40 mm; Clinical diagnosis of pain and functional limitation

Inclusion Criteria:

• Subjects have to read and sign the approved the Informed Consent form prior to any participation in the study.
• Male or female Subjects, aged upper to 40 years.
• Osteoarthritis of the knee confirmed by radiological examination.
• Visual analogue scale (VAS) > 40 mm.
• Kellgren and Lawrence grade 1 to 3.
• Clinical diagnosis of pain and functional limitation.

Exclusion Criteria:

• History of significant trauma or surgery in the affected joint.
• Pregnant women, lactating or not using appropriate contraceptive method.
• History or presence of active rheumatic disease that may be responsible for secondary osteoarthritis.
• Severe inflammation of the joint confirmed by physical examination (excluding also erythrocyte sedimentation <40mm/h and rheumatoid factor <1:40).
• Body mass index > 30.
• Hematologic abnormalities, liver, renal or metabolic functions which undermine the serious participation of the patient (at investigator's criteria).
• Systemic administration and/or intra-articular corticosteroids in the last 3 months.
• Have made use of glucosamine and/or chondroitin.
• Lequesne index of > 12.
• Arthroplasty in the affected joint.
• Use of narcotic analgesics.
• Any condition that, in the opinion of the investigator, renders the patient unable to participate in the study.