Shoulder Separation Rehabilitation

Acromioclavicular Joint Injury

• Shoulder Separation Rehabilitation

Acromioclavicular Joint Injury

Rehabilitation Rationale

Anatomy

The acromioclavicular (AC) joint is a diarthrodial joint with a fibrocartilaginous intra-articular disc. Two significant ligamentous structures are associated with the joint: the AC ligaments, which provide horizontal stability (Fig. 3 – 74), and the coracoclavicular ligaments, which are the main supensory ligament of the upper extremity, providing vertical stability to the joint.

Recent studies show that only 5 to 8 degrees of motion of the AC joint is possible in any plane.
The most common mechanism of injury of the AC joint is a direct force from a fall on the point of the shoulder (Fig. 3–75).
Rockwood (1990) classifies AC joint injuries into six types (Fig. 3–76).

• Type I
  • Mild sprain of the AC ligament.
  • No disruption of AC or coracoclavicular ligaments.
• Type II
  • Disruption of AC joint.
  • AC joint wider because of disruption (<4 mm or 40% difference).
  • Sprained but intact coracoclavicular ligaments with coracoclavicular space essentially the same as the normal shoulder on radiographs.
  • Downward force (weight) may disrupt AC ligament, but not the coracoacromial ligament.
• Type III
  • Coracoclavicular and AC ligaments disrupted.
  • Shoulder complex displaced inferiorly.
  • Coracoclavicular interspace 25 to 100% greater than in normal shoulder, or 4 mm distance (especially with weights applied).

• Type IV
  • Clavicle is displaced posteriorly through fibers of trapezius.
  • AC ligament and coracoclavicular ligaments disrupted.
  • Deltoid and trapezius muscles detached from distal clavicle.

• Type V
  • Vertical separation of clavicle is greatly separated from scapula over a type III injury (100 to 300% more than normal shoulder).

• Type VI
  • Clavicle is dislocated inferiorly under the coracoid process.

Types I and II injuries are treated conservatively, as are type III injuries in nonactive, nonlaboring patients. Most types IV, V and VI injuries require open reduction and internal fixation, as do type III injuries in more active individuals.

Tagged as: Acromioclavicular Joint, shoulder injury, shoulder separation