Thumb arthritis sufferers: could a double injection be the key to less pain?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adults, ≥ 40 years * Pain located at the root of the thumb (near the wrist) and awakened by direct pressure and movement * Pain resistant to well-conducted medical treatment, with analgesics, NSAIDs, icing with pain (analog visual scale) ≥ 4 for more than 3 months * Radiological findings (kapandji face + profile incidence) typical of rhizarthrosis, stage II or III of Eaton and Litter, with at least 2 of the following 5 radiological elements observed on the trapeziometacarpal joint: * marginal osteophyte * pinching of the joint space * sclerosis of the subchondral space * subchondral kyst * absence of osteopenia * Patient with the ability to understand the protocol and signed informed consent * Patient receiving social security Exclusion Criteria: * Known allergy to any of the products (corticosteroids or hyaluronic acid) including its excipients (methyl parahydroxybenzoate, propyl parahydroxybenzoate, benzyl alcohol) * Change of analgesic treatment within 4 weeks before inclusion. * Patients with symptomatic bilateral rhizarthrosis * Scaphoid-trapezial arthrosis * Local or general infection * Severe coagulation disorders, ongoing anticoagulant therapy * severe and / or uncontrolled hypertension * Earlier local surgery * Associated inflammatory rheumatism * Tendinopathy of De Quervain, thumb to jump associated * Infiltrations earlier than 6 months * Diabetes imbalanced * Live vaccines * Severe water and / or sodium retention (hypernatremia), particularly in cases of heart failure, decompensated liver failure (edema and ascites failure) * Pregnant or lactating women * Immunocompromised or hemodialysis patients * Patients under guardianship, trusteeship, or deprived of liberty * Patients participating in another clinical research protocol involving a drug or medical device * Patients unable to follow the protocol, according to the judgment of the investigator