Chondroitin Sulphate Treatment Efficacy in Rhizarthrosis.

Inclusion Criteria: * both sex patients * age between 45 to 75 years * with mechanical pain at the trapezium-thumb metacarpal joint of more than 3 months duration * grade II or III Eaton \& Glickel rhizarthrosis radiological diagnose * pain at inclusion of \>= 40 mm at a visual analogue scale * without rehabilitation treatment or infiltration in the last 6 months * who accept to participate and sign informed consent Exclusion Criteria: * patients with rhizarthrosis resulted from rheumatic disease * patients with joint surgery or traumatic background * illiterate patients or unable to understand informed consent * patients with previous neuropsychopathology enough severe to unable participation at the study * patients with peripheral sensory impairment due to diabetes, peripheral neuropathy or central neurological sequelae of disease in the affected limb that can alter sensory perception * patients with coagulopathy * inflammation for other process at the joint at study * in treatment with non-steroidal anti-inflammatory drug in the last 7 days and/or corticosteroid in the last 30 days * allergy or hypersensibility at chondroitin sulfate or its excipients * pregnant or breastfeeding woman