AC Joint Separation

Discussion

• tears of AC & CC ligaments (from fall on tip of shoulder) allows upper limb to drop away from clavicle, producing separation of AC joint;

differential diagnosis

• distal clavicular physeal separation
  • childhood equivalent of AC separation;
• atraumatic AC joint laxity (from ligamentous laxity)

Classification

Rockwood Classification

• type I
  • sprain of joint with out a complete tear of either ligament
• type II
  • tear of AC ligaments w/ coracoclavicular ligaments intact;
  • will not show marked elevation of lateral end of clavicle;
• type III
  • in this injury both AC & CC ligaments are torn;
  • > 5 mm elevation of AC joint w/o weights is consistent w/ severe type II or a type III injury;
  • need to distinguish this from type III clavicular fracture
• type IV
  • distal clavicle impaled posteriorly into trapezial fascia;
• type V

 

 

 

 

Basamania Classification

• essentially relies on whether the distal clavicle is stable or unstable;
• w/ more than 50-75 % displacement on static films or more than 100% displacement on a cross arm AP, there will be disruption of not only the AC ligaments but also the CC ligaments;
• clinically, an unstable AC separation will cause significant prominence of the distal end of the clavicle when the arm is distracted in adduction;

 

 

 

 

Radiograph

• Cross Body Adduction View
  • (from C.J. Basamania MD personal communication, 1997);

 

 

 

 

case example

 

 

 

 

• 20-year-old who fell on tip of right shoulder, but did not show radiographic signs of AC joint injury in the ER;
• one month later the patient continued to have pain, and radiographs demonstrated greater than 100 percent displacement of AC joint on both AP and Cross Body AP (Cross Adduction View);

Operative Treatment

• Distal Clavicle Excision
• Modified Weaver Dunn Procedure

References

• Surgical treatment of acute type-V acromioclavicular injuries in athletes.
• Four-year outcome of operative treatment of acute acromioclavicular dislocation.
• Acromioclavicular joint injuries.
• A classification of acute acromioclavicular dislocation: a clinical, radiological and anatomical study.
• Late reconstruction of the ligaments following acromioclavicular separation.
• Acute, complete acromioclavicular separation.
• Conservative treatment of grade III acromioclavicular dislocations.
• Percutaneous cannulated screw coracoclavicular fixation for acute acromioclavicular dislocations.
• Complete acromioclavicular separations. A comparison of operative methods.
• Dislocation of the acromioclavicular joint. An end-result study.
• Conservative or surgical treatment of acromioclavicular dislocation. A prospective, controlled, randomized study.
• Year Book: Four-Year Outcome of Operative Treatment of Acute Acromioclavicular Dislocation.
• Acute dislocation of the acromioclavicular joint. Traumatic anatomy and the importance of deltoid and trapezius.
• Repair of complete acromioclavicular separations using the acromioclavicular-hook plate.
• Surgical treatment of acute type-V acromioclavicular injuries in athletes.
• Comprehensive functional analysis of shoulders following complete acromioclavicular separation.
• Conservative or surgical treatment of acromioclavicular dislocation. A prospective, controlled, randomized study.
• Surgical treatment of acute type-V acromioclavicular injuries in athletes.
• Radiological evaluation of the acromioclavicular joint.
• Biomechanical study of the ligamentous system of the acromioclavicular joint.