3 The best results of VS using low weight HA are observed with a dosage that ranges between three and five weekly applications, each with 2 to 2.5 ml of HA. 7 , 8 High molecular Crizotinib ROS1 weight HA demonstrated efficacy with just one 6 ml application. 11 The single application is certainly more comfortable, especially considering the profile of patients with OA, who are generally elderly and often have impaired mobility. The aim of this study is to compare two different dosages of an intermediate molecular weight HA (Osteonil? -TRB Pharma), evaluating whether the single application of 6ml of this HA has the same efficacy as the classical regime of three weekly applications of 2 ml.

MATERIAL AND METHOD This study was conducted in the Department of Orthopedics and Traumatology of the Institute of Orthopedics and Traumatology of Hospital das Cl��nicas da Faculdade de Medicina da Universidade de S?o Paulo (DOT-IOT-HCFMUSP), according to the guidelines of CONSORT (Consolidated Standards of Reporting Trials), and approved by the Commission of Ethics for Analysis of Research Projects (CAPPesq) under no. 0199/11. It is registered on the website clinicaltrials.org under no. NCT01824485. This prospective randomized clinical trial featured an evaluation of 108 patients diagnosed with OA of the knee(s), who were already in treatment in the metabolic disease group of IOT-HCFMUSP. Our habitual treatment consists of education through lessons, typed handouts, audiovisual material and guidance with orthopedists, nutritionist, psychologist, occupational therapist, physiotherapist, physical education teacher and social worker.

All the patients, except for those with contraindications, make use of on-demand analgesics (paracetamol and codeine). According to knee alignment the use of insoles is also recommended. None of the patients makes routine use of non-hormonal anti-inflammatory agents, and their use was discouraged throughout the study, including in the seven-day period before the procedure. Inclusion criteria: ? Fulfill the diagnostic criteria for osteoarthritis of the American College of Rheumatology; 12 ? Understand, agree to and sign the informed consent form; ? Absence of history of previous fracture in the knee to be studied; ? Absence of history of previous surgery on the knee to be studied; ? Absence of history of allergy to any of the substances used; ? Not have performed any infiltration in the studied knee in the last 6 months; ? Be in treatment in the group for at least six months; ? Not have made use of non-hormonal anti-inflammatory agents in the last seven days.

Exclusion criteria: ? Submit to surgery on the studied knee during the follow-up period; ? Require further infiltration in the studied knee during the follow-up period – severe reaction to the procedure; ? Development of active Cilengitide infection in the studied joint during the study; ? Use non-hormonal anti-inflammatory agents at any time.