Rockwood classification of acromioclavicular joint injury

Acromioclavicular joint injuries are classified most commonly using the 6-grade system described by Rockwood (1998) 3. This is a modification of the earlier 3-grade classification system described by Allman (1967) 2 and Tossy (1963) and at the time of writing (June 2016) remains the most recent system for acromioclavicular joint injury assessment.

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 grades IV, V and VI are variants of grade 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 mucle: 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

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Article Information

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

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    Figure 1: illustration - Rockwood types 1 - 6
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    Figure 2: Rockwood classification of acromioclavicular joint injury - annotated radiographs
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    Case 1: normal acromioclavicular joint
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    Case 2: grade I
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    Case 3: grade II
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    Case 4: grade III
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    Acromioclavicular...
    Case 5: grade III
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    Case 6: grade III
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    Case 7: grade III
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     Case 8: grade V (MRI)
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    Case 9: grade V
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