Pseudarthrosis of the acromion--a differential diagnosis in anterolateral shoulder pain.

A case of longstanding posttraumatic anterolateral shoulder pain in a 25-year-old woman is presented. It was primarily unsuccessfully handled as impingement syndrome but turned out to be caused by pseudarthrosis of the acromion. The abnormality was not apparent on plain X-ray film. The suspicion was raised after scintigraphy, which showed increased density in the acromion. The diagnosis was made by computerized tomography and confirmed and treated successfully surgically.