Acromio-clavicular Dislocation

• Distal clavicle dislocated relative to the acromion secondary to ligamentous injury.

Findings

1. Best diagnostic clue: Widening of the AC joint with variable displacement of the distal clavicle.
2. Increased AC distance (normal: 3-6 mm) � increased coracoclavicular (CC) distance (normal: 10-13 mm).

Complications

Acromioclavicular osteoarthritis

Staging, Grading or Classification Criteria

- (see here also)
Type I:   AC ligaments sprained but functionally intact; CC ligaments spared; normal radiograph.
Type II:   AC ligaments completely disrupted; CC ligaments sprained but functionally intact.
Type III:   AC and CC ligaments completely disrupted with mild to moderate superior displacement of clavicle.
Type IV:   Similar to type III, complete AC and CC disruption with posterior displacement of clavicle into trapezius muscle.
Type V:   Similar to type III, complete AC and CC disruption with severe superior displacement of clavicle into subcutaneous soft tissue.

Type VI: AC ligament disruption � CC ligament disruption with inferior displacement of clavicle into a subacromial or subcoracoid location.

Treatment

Conservative - Ice, analgesics and shoulder rest in sling (1-4 weeks) Heavy lifting/sports restriction (6-12 weeks)

Surgical - Repair of the AC and CC ligaments; distal clavicle excision; dynamic muscle transfers