Corticosteroid injections are used to reduce pain and inflammation for various shoulder pathologies. Corticosteroid flare reaction is a well-described phenomenon that, despite being self-limited, causes significant pain and dysfunction. A flare reaction is defined for the purposes the study to be an increase of two or more points on a visual analog scale reported by the subject. Currently, there is a paucity of literature to drive the decision-making process between different corticosteroid medications. This study will compare the incidences of steroid flare reaction and three-month efficacy following methylprednisolone acetate (MPA) and triamcinolone acetonide (TA) corticosteroid injections into the glenohumeral joint or subacromial space.~Physicians administering a steroid injection in the shoulder will utilize MPA until 200 subjects have agreed to participate in this treatment arm. Enrollment will then be offered to 200 subjects utilizing TA for the shoulder injection. Subjects receive treatment for their shoulder pain regardless of willingness to participate in the follow up reported pain scores. There are no costs to subjects for study participation.
Compare FLARE reactions (increase in VAS by two or more points) in the first 48 hours following a shoulder injection.