Rockwood classification of acromioclavicular joint injury

The Rockwood classification (1998) is the most common classification system in use for acromioclavicular joint injuries 3. This well known 6-type system is a modification of the earlier 3-class classification system described by Allman (1967) 2 and Tossy (1963).

It takes into account not only the acromioclavicular joint itself but also the coracoclavicular ligament, the deltoid and trapezius muscles, and the direction of dislocation of the clavicle with respect to the acromion. Essentially types IV, V, and VI are variants of type III 6

  • type I: clavicle not elevated with respect to the acromion
  • type II: clavicle elevated but not above the superior border of the acromion
    • AC ligament: ruptured
    • CC ligament: sprain
    • joint capsule: ruptured
    • deltoid muscle: minimally detached
    • trapezius muscle: minimally detached
  • type III: clavicle elevated above the superior border of the acromion but coracoclavicular distance is less than twice normal (i.e. <25 mm)
    • AC ligament: ruptured
    • CC ligament: ruptured
    • joint capsule: ruptured
    • deltoid muscle: detached
    • trapezius muscle: detached
  • type IV: clavicle displaced posteriorly into trapezius
    • AC ligament: ruptured
    • CC ligament: ruptured
    • joint capsule: ruptured
    • deltoid muscle: detached
    • trapezius muscle: detached
  • type V: clavicle is markedly elevated and coracoclavicular distance is more than double normal (i.e. >25 mm)
    • AC ligament: ruptured
    • CC ligament: ruptured
    • joint capsule: ruptured
    • deltoid muscle: detached
    • trapezius muscle: detached
  • type VI: clavicle inferiorly displaced behind coracobrachialis and biceps tendons, which is rare
    • AC ligament: ruptured
    • CC ligament: ruptured
    • joint capsule: ruptured
    • deltoid muscle: detached
    • trapezius muscle: detached

See also

Fractures
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Article information

rID: 845
Synonyms or Alternate Spellings:
  • Acromioclavicular joint injury classification
  • Modified Allman and Tossy grading system of acromioclavicular joint injuries
  • Rockwood classification
  • Acromioclavicular injury classification

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Cases and figures

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    Figure 1: illustration - Rockwood types 1 - 6
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    Figure 2: annotated radiographs
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    Case 1: normal acromioclavicular joint
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    Case 2: type I
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    Case 3: type II
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    Case 4: type III
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    Case 6: type III
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    Case 7: type III
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     Case 8: type V (MRI)
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    Case 9: type V
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