Rockwood classification of acromioclavicular joint injury

Last revised by Dr Bálint Botz ◉ on 16 Mar 2021

Citation, DOI & article data

Citation:

Gaillard, F., Botz, B. Rockwood classification of acromioclavicular joint injury. Reference article, Radiopaedia.org. (accessed on 17 Aug 2022) https://doi.org/10.53347/rID-845

DOI:

https://doi.org/10.53347/rID-845

Permalink:

https://radiopaedia.org/articles/845

rID:

845

Article created:

02 May 2008 by Assoc Prof Frank Gaillard ◉ ◈

Revisions:

70 times by 21 users - see full revision history

System:

Musculoskeletal

Section:

Classifications

Tag:

shoulder

Synonyms:

Rockwood classification of AC joint injury
Acromioclavicular joint injury classification
Rockwood classification
Acromioclavicular injury classification

The Rockwood classification (1998) is the most common (c.2020) classification system in use for acromioclavicular joint injuries ^3,8.

The Rockwood classification takes into account not only the acromioclavicular joint itself but also the coracoclavicular ligament, the deltoid, and trapezius muscles, whilst considering 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
- AC ligament: mild sprain
- CC ligament: intact
- joint capsule: intact
- deltoid muscle: intact
- trapezius muscle: intact
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 the 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 posterior into the 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) - bilateral weight-bearing projections are able to distinguish type V injuries
- 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