AC Joint Classifications

 

AC joint dislocation: Tossy Classification

Tossy et al, CORR, 28: 111-119, 1963

Grade 1: strain and contusions of AC joint; No deformity visible clinically or on x-ray

Grade 2: localised pain, swelling and deformity; X-rays show one-half separation of the AC joint, ie clavicle displaced cephalad by one-half the depth of the AC joint; Coraco-clavicular distance increased as compared to normal side; Partial tear of Coraco-clavicular ligaments

Grade 3: complete AC joint seperation more than one-half the depth of the AC joint; clavicle under skin; Coraco-clavicular distance significantly increased; complete tear of coraco-clavicular ligament

AC joint injury: Allman classification

Allman F L, JBJS (am) 49:774-784, 1967

Grade 1:

  • Sprain of AC joint capsule and AC ligament
  • No deformity
  • Xrays normal

Grade 2:

  • Rupture of AC capsule and ligaments
  • Mild deformity
  • Xrays show upward displacement of clavicle
  • Coraco-clavicular (C-C) ligaments normal

Grade 3:

  • Complete AC joint dislocation
  • Complete rupture of AC and C-C ligament

AC joint injury: Rockwood classification

In: Fractures in adults, edited by Rockwood, CA, 1341-1414, Lippincott-Raven, 1996

Type 1:

  • AC ligament sprain
  • AC joint intact, CC ligaments intact
  • Deltoid, Trapezius intact

Type 2:

  • AC Joint disruption
  • Slight vertical separation of ACJ
  • CC ligament sprain, CC distance wide
  • Deltoid, Trapezius intact

Type 3:

  • AC ligament disruption
  • AC joint dislocated
  • CC ligaments torn
  • CC distance 25 to 100 % > than normal side
  • Deltoid, Trapezius may be detached

Type 4:

  • AC ligament disruption
  • AC joint dislocated
  • Clavicle displaced posteriorly into Trapezius
  • CC ligaments completely torn
  • Deltoid, Trapezius detached from distal clavicle

Type 5:

  • AC ligament disruption
  • AC joint dislocated
  • CC ligaments completely torn
  • CC distance 100 to 300 % > than normal side
  • Deltoid, Trapezius detached from distal half clavicle

Type 6:

  • AC ligament disruption
  • AC joint dislocated
  • CC ligaments completely torn
  • Clavicle in subcoracoid position
  • Deltoid, Trapezius detached from distal half clavicle