Acromioclavicular dislocation associated with scapular fractures - pathoanatomy of the injury.

Introduction: No detailed study dealing with an injury to the AC joint in combination with scapular fractures has been published to date. The aim of this study is to describe pathoanatomy of these injuries.

Methods: In a series of 519 scapular fractures in adult patients from the period of 20022020 we identified a total of 20 (3.9%) cases associated with AC dislocation. The group comprised 17 men and 3 women with the mean age of 49 years (range, 2178). Radiographs of the shoulder joint followed by CT examination, including 3D reconstructions, were performed in all patients. This documentation allowed assessment of the scapular fracture pattern and type of injury to the AC joint.

Results: AC dislocation was associated with a simple scapular fracture in 15 cases (7 fractures of the coracoid base, 4 fractures of the acromion or the lateral spine, 2 fractures of the scapular body, 1 fracture of the superior and 1 fracture of the inferior glenoid). In 5 cases AC dislocation accompanied multiple or complex scapular fractures (once a combination of a coracoid fracture and a fracture of the lateral scapular spine, once a combination of a fracture of the superior glenoid and of the acromion, 2 cases of a complex intraarticular fracture and 1 case of scapulothoracic dissociation).

Conclusion: AC dislocation is relatively infrequent injury accompanying scapular fractures. It is most commonly associated with fractures of coracoid, acromion/lateral spine or superior glenoid. No case of AC dislocation was recorded in a fracture of the scapular neck.