AC Joint Classifications
1. AC joint dislocation: Tossy Classification
2. AC joint injury: Allman classification
3. AC joint injury: Rockwood classification
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 ligaments
TopAC 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
