Acromioclavicular joint dislocation

Acromioclavicular (AC) joint dislocation occurs due to rupture of the acromioclavicular and coracoclavicular ligaments. It is also known as a “separated shoulder”. It occurs due to direct trauma to the shoulder, like rugby or ice hockey. They’re classified according to Rockwood or Tossy. The “piano key” sign may be present. Stress view on x-ray may be required. Treatment is conservative for type I – II and surgical for III – VI.

Classification

AC dislocations are classified according to the Rockwood or Tossy classification.

Clinical features

AC dislocation presents with pain over the AC joint. In case of type III AC dislocation, the lateral cavity can be depressed manually, called the “piano key” sign.

Diagnosis and evaluation

Stress views (x-ray while weights are attached to the wrists) may be required to differentiate type I and II AC dislocations.

Treatment

AC dislocation is treated conservatively or operatively depending on the type:

• Type I – conservative
• Type II – conservative or operative
• Type III – mostly operative
• Type IV – VI – operative

Operative treatment involves ORIF with K-wire, tension band, or a plate.