AC Dislocation

Aka: AC Dislocation, Acromioclavicular Dislocation, AC Separation, Acromioclavicular Separation, Acromioclavicular Ligament Sprain

1. General
   1. Acromioclavicular joint dislocation or "Separation"
2. Mechanism
   1. Fall on an outstretched hand
   2. Direct trauma
      1. Top of Shoulder or
      2. Acromion with Shoulder adducted
3. Grading: AC joint dislocation (Rockwood Classification)
   1. Incomplete dislocation (Types I to II)
      1. Type I: Simple AC joint Contusion or strain
      2. Type II: AC joint ligament rupture
   2. Complete dislocation (Types III to V)
      1. Type III: Rupture of coracoclavicular ligaments
      2. Type IV: Joint posteriorly displaced (uncommon)
      3. Type V: Overlying muscle penetrated (uncommon)
      4. Type VI: Clavicle displaced behind biceps (rare)
4. Symptoms
   1. Tenderness and swelling over AC joint
   2. Pain on lifting arm
5. Signs
   1. Outer clavicle elevated
      1. Deformity if Grade III or higher
   2. Provocative Maneuvers eliciting pain
      1. Downward traction on arm
      2. Shoulder Crossover Maneuver
6. Differential Diagnosis
   1. Rotator Cuff Tear
7. Complications
   1. Clavicle Fracture (lateral third)
   2. Coracoid process Fracture
8. Radiology: Clavicle XRays
   1. Differentiate incomplete from complete AC Dislocation
   2. Weighted views are no longer indicated
      1. Diagnosis is clinical and XRay may be diagnostic with step-off seen
      2. Old protocol used XRay taken with 10 kg weights hanging from each arm
         1. Measured coracoid process to clavicle distance
         2. Discrepancy between sides suggested AC Dislocation
9. Management
   1. Symptomatic relief
      1. Immobilize with sling for 3 days based on pain
      2. See RICE-M
      3. Analgesics as needed
         1. Clavicle tip often prominent, but usually painless
   2. Active range of motion of strengthening
      1. Begin as soon as possible
      2. See Shoulder Range of Motion Exercises
      3. See Shoulder Strengthening Exercises
   3. Surgery Indications
      1. Type 4 to 6 AC Dislocation
      2. Type 3 AC Dislocation if physically active
10. Management: Taping Technique (consider in Wilderness)
    1. Realignment
       1. Examiner 1 pushes down on clavicle
       2. Examiner 2 pushes up on upper arm from elbow
    2. Taping technique
       1. Start Tape from just medial and superior to nipple
          1. Extend tape over Shoulder and onto mid Scapula
          2. Repeat with overlapping strips moving laterally
       2. Secure above taping with tape over ends
       3. Start tape perpendicularly to above
          1. Run over top of Shoulder from medial to lateral
11. References
    1. Wirth in Greene (2001) Musculoskeletal Care, p.115-7