Mechanism of injury and morphology of the greater tuberosity fracture.

Only a few publications discuss the mechanism of injury and morphology of the greater tuberosity fracture. Often, it is described as an avulsion fracture of the rotator cuff. The exact pathobiomechanics is uncertain. We performed a retrospective study and evaluated the mechanism of injury, fracture morphology, and displacement in 103 patients over a 16-year period. Fifty-nine patients sustained a greater tuberosity fracture as part of a traumatic shoulder dislocation. In 44 cases, an isolated greater tuberosity fracture was diagnosed. Of the patients, 47.6% reported a direct mechanism of injury and 32% reported an indirect mechanism of injury. There was one abduction-external rotation injury thought to be the cause of the greater tuberosity fracture. Of the patients, 20.4% were unable to reconstruct the mechanism of injury. Radiologic evaluation revealed an inferior displacement of the fracture on the anteroposterior view in 25% of cases. Our data contradict the theory that this fracture is the result of a bony avulsion of the rotator cuff. Potential mechanisms of injury are discussed. We conclude that there has to be a specific mechanism of injury for greater tuberosity fractures. Further investigations would be beneficial.