Injuries to the Acromio-clavicular joint (ACJ)

Background

• Injuries may involve the ACJ to be subluxed (clavicle preserves some contact with the acromion as damage confined to acromioclavicular ligaments) or dislocated (clavicle loses contact with scapula with tearing of the conoid and trapezoid ligaments)

Classification

Rockwood

• Type 1 - AC joint capsule partially disrupted
• Type 2 - AC joint capsule and Coracoclavicular ligaments partially disrupted
• Type 3 - AC joint capsule and Coracoclavicular ligaments completely disrupted
• Type 4 - Type 3 + avulsion of Coracoclavicular ligament from clavicle, with the distal clavicle displaced posteriorly into or through the trapezius
• Type 5 - Type 3 but with exaggeration of the vertical displacement of the clavicle from the scapula- coracoclavicular interspace 100- 300% greater than the normal side
• Type 6 - Type 3 + inferior dislocation of lateral end of clavicle