Management of glenohumeral synovitis secondary to influenza vaccination

Glenohumeral synovitis is a rare complication of vaccination that can lead to shoulder dysfunction and prolonged pain. We report a case of florid glenohumeral synovitis after routine influenza vaccination, which we consider to have occurred because of the unintentional injection of antigenic material into synovial tissues, resulting in an immune-mediated inflammatory reaction. We provide a review of the literature for this condition and describe an invasive management approach, providing, for the first time, an arthroscopic evaluation and histopathological analysis.