AC separation usually results from a fall with a direct blow downward on the outer shoulder (snowboarders, football players).



  1. Type I & type II injuries: Sling immobilization, rest, ice, & analgesics. Early range of motion exercises are recommended at 7-14 days post injury.
  2. Type III Injury: Controversial, but the trend favors conservative management with sling immobilization rather than operative management.
  3. Type IV to Type VI injuries: Orthopedic Consult for surgery


Classification and Physical Findings in Acromioclavicular Joint Injuries:
Type Injury Radiograph Examination
I Sprained acromioclavicular ligaments Normal Tenderness over acromioclavicular joint
II Acromioclavicular ligaments ruptured; coracoclavicular ligaments sprained Slight widening of acromioclavicular joint; clavicle elevated 25%–50% above acromion; may be slight widening of the coracoclavicular interspace Tenderness and mild step-off deformity of acromioclavicular joint
III Acromioclavicular ligaments ruptured; coracoclavicular ligaments ruptured; deltoid and trapezius muscles detached Acromioclavicular joint dislocated 100%; coracoclavicular interspace widened 25%–100% Distal end of clavicle prominent; shoulder droops
IV Rupture of all supporting structures; clavicle displaced posteriorly in or through the trapezius May appear similar to type II and III; axillary radiograph required to visualize posterior dislocation Possible posterior displacement of clavicle
V Rupture of all supporting structures (more severe form of type III injury) Acromioclavicular joint dislocated; generally 200%–300% disparity of coracoclavicular interspace compared to normal shoulder More pain; gross deformity of clavicle
VI Acromioclavicular ligaments disrupted; coracoclavicular ligaments may be disrupted; deltoid and trapezius muscles disrupted Acromioclavicular joint dislocated; clavicle displaced inferiorly Severe swelling; multiple associated injuries