Intra-articular Botulinum Toxin Type A Versus Corticosteroids: a Clinical Trial in Osteoarthritis of Knees

Introduction: Osteoarthritis of the knee is a very common disease. However there are few treatment options for these patients. Botulinum toxin type A is an option for chronic pain. If the investigators prove effectiveness of its use for intra-articular analgesia, Botulinum toxin type A can be useful for treat these patients.

Objective: Compare the effectiveness of the use of intra-articular corticosteroid versus Botulinum toxin type A in the treatment of patients with knee osteoarthritis.

Methods: A prospective controlled randomized double blind studied with three groups (n = 35 each group) of patients with symptomatic osteoarthritis of the knees receive intra-articular medication in a single moment will be undertaken. The three groups will be: Botulinum toxin type A Group: patients who receive 100 units of botulinum toxin; hexacetonide of triamcinolone Group: patients who receive 40mg of triamcinolone hexacetonide, and saline group: patients who receive 2ml of normal saline. Patients will be assessed by evaluators " blind " in 4 times during 12 weeks of follow-up with clinical assessment instruments (pain, quality of life questionnaire as short form 36 questionnaire) , functional ( WOMAC questionnaire) , and ultrasound (quantitative and semi quantitative measure of synovial hypertrophy and semi quantitative Power Doppler ) .The following statistical tests will be used : Student's t test, Mann - Whitney , chi- square test and ANOVA for repeated measures . Will be considered as statistical significance the difference of 5 %.