Acromioclavicular Joint Injury

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Rockwood Classification

• Type I: Sprain of the AC ligament. Normal radiograph
• Type II: AC ligament tear, coracoclavicular ligaments sprained. Radiograph demonstrates AC joint widening (normal AC joint distance is 1 to 3mm). Stress views show identical coracoclavicular distance compared to uninvolved side
•  Type III: AC and coracoclavicular ligament torn. Radiograph demonstrates loss of AC joint relationship and increased coracoclavicular distance in stress view (25% to 100% greater than the normal side.).
• Type IV: Type III with distal clavicle displaced posteriorly into or through the trapezius
• Type V: Type III with the distal clavicle grossly displaced superiorly.
• Type VI: AC dislocated with the clavicle displaced inferior to the acromion or the coracoid.