3D MR Versus 3D CT for Glenohumeral Arthritis

Inclusion Criteria: * Patients suffering from glenohumeral OA; * Radiographic evidence of severe glenoid erosion; * Indication for TSA based on clinical exam; * Patient is willing to participate by complying with pre-operative visit requirements; * Patient is willing and able to review and sign a study informed consent form. Exclusion Criteria: * Prior arthroplasty at the affected shoulder; * Patients with inflammatory arthritis; * Patients with post-capsulorrhaphy arthritis; * Patients with post-traumatic arthritis; * Patients with rotator cuff tear arthropathy; * Patients exhibiting a lack of physical or mental ability to perform or comply with the study procedures; * Patients who are pregnant; * Patients with implanted medical devices that are contraindicated to exposure up to a 3.0-tesla magnetic field.