A CLASSIFICATION OF ACUTE ACROMIOCLAVICULAR DISLOCATION - A CLINICAL,RADIOLOGICAL AND ANATOMICAL STUDY

Forty-eight patients with acute acromioclavicular dislocation were ass essed clinically and radiologically before random allocation to non-op erative management (28) or open reduction and coracoclavicular screw f ixation (20) and followed for a minimum of 4 years. In 6 patients, lat e salvage surgery was required, the results of which were inferior to early operative intervention. Early surgery also gave better results t han non-operative treatment in severe disruptions which could be ident ified in the acute stage. Three types of acromioclavicular dislocation which have predictable clinical outcomes could be distinguished on ra diographs. When treated non-operatively, type A dislocations (19 per c ent) may develop painful subluxation, type B (68 per cent) remain disl ocated but retain sufficient muscle attachment to avoid fatigue on act ivity, and type C (per cent) leave a weak and unsightly shoulder. In t ype C dislocations, the clavicle is displaced 2 cm or more from the ac romion on plain anteroposterior radiographs and the attached origin of the anterior deltoid is avulsed. Type C dislocations may benefit from early operative reconstruction.