Comparison of the Analgesic Effect of 2 Shoulder Infiltrations

Inclusion Criteria: * A clinical examination that confirms the radiological diagnosis of moderate to severe primary shoulder osteoarthritis, stage II and above, according to the Samilson-Prieto classification. * Patients aged between 20 and 90 years. * A patient with bilateral shoulder osteoarthritis will choose the side of the infiltration, only one side can be chosen to participate in the study. * The patient must have a clinical pain threshold of a minimum of 4/10 on the visual analogue scale. * The patient must have the cognitive ability to read and fill out the questionnaires. * The patient must be able to read and understand French or English Exclusion Criteria: * Presence of a transfixing rotator cuff tear assessed on MRI. * No previous shoulder reconstruction surgery. * Pregnant woman. * A patient who has received a cortisone infiltration within 6 months prior to the start of the study. * A patient who has received a platelet-rich plasma or a hyaluronic acid infiltration within 12 months prior to the start of the study. * Diagnosis of avascular necrosis. * Disease affecting the studied joint (systemic inflammatory disease, history of septic arthritis, osteonecrosis, etc.) * Suspicion or presence of active local infectious process. * Presence or suspicion of neoplasia or local metastasis. * Severe trauma to the shoulder ( ≤ 3 months) * Significant cognitive impairment or insufficient language proficiency to adequately answer the questionnaires. * Any other serious medical condition that does not allow participation in the study or may be a contraindication to cortisone injection.