This document describes the different grades of acromioclavicular dislocation, ranging from Grade 1 strain with partial ligament tearing and soft tissue swelling to Grade 6 with inferior dislocation of the clavicle. Grade 2 involves ligament disruption and elevation of the clavicle less than 100% while Grade 3 is a superior dislocation over 100% with complete ligament disruption. Grade 4 is a posterior dislocation and Grade 5 penetrates the deltotrapezial fascia.

1. Acromioclavicular Dislocation
Grade 1 (strain)
= Stretching and
partial tearing of
acromioclavicular
ligament fibers
- Soft-tissue
swelling
- Stable AC joint
without joint
widening

2. Acromioclavicular Dislocation
Grade 2 (subluxation)
= Disruption of
acromioclavicular
ligament and strain
of
coracoclavicular
ligament
- Elevation of clavicle
of <100% of shaft
width (weight
bearing!)
- Widening of AC joint

3. Acromioclavicular Dislocation
Grade 3 (superior
dislocation)
= Disruption of
acromioclavicular
+ coracoclavicular
ligaments
- Widening of AC
joint
- Elevation of
clavicle > 100% of
shaft width

4. Acromioclavicular Dislocation
Grade 4 (posterior dislocation)
- Posterior position of clavicle
with respect to acromion

5. Acromioclavicular Dislocation
Grade 5 (fascial injury)
- Penetration of clavicle through
deltotrapezial fascia

6. Acromioclavicular Dislocation
Grade 6 (inferior dislocation)
- Inferior position of clavicle with
respect to acromion