Classifications of acromioclavicular dislocation serve to facilitate communication between specialists and allow the derivation of medical therapy measures, which are summarized in recommended guidelines for the individual specialties. There are two common classifications for acromioclavicular joint injuries, both of which are used in everyday clinical practice The basis for the classification in both is the X-ray image.
Tossy classification of acromioclavicular joint dislocation
- Tossy I: Strain of the capsular ligament apparatus without visible displacement of the clavicle end towards the acromion.
- Tossy II: Partial rupture of the capsular ligament apparatus with displacement of the clavicle end towards the acromion by less than one shaft width of the clavicle.
- Tossy III: Complete rupture of the capsular ligament apparatus with displacement of the clavicle end towards the acromion by more than one shaft width of the clavicle.
Rockwood Classification
The Rockwood classification is more accurate than the Tossy classification and includes rare forms of dislocation. It can be used to describe all dislocations of the acromioclavicular joint.
- Rockwood I: Strain of the capsule/tape apparatus. No acromioclavicular instability (corresponds to Tossy I).
- Rockwood II: Partial rupture of the capsule/ligament apparatus (rupture of the acromioclavicular ligaments) with partial dislocation of the acromioclavicular joint (corresponds to Tossy II).
- Rockwood III: Rupture of the entire capsule/ligament apparatus (rupture of the acromioclavicular ligaments and the coraclavicular ligaments) with complete dislocation of the acromioclavicular joint in the vertical plane towards the head, so-called acromioclavicular dislocation (corresponds to Tossy III).
- Rockwood IV: The lateral collarbone end dislocates in the horizontal plane. It may become entangled in the trapezius muscle.
- Rockwood V: Extreme collarbone elevation with extensive separation of the muscle attachments at the lateral clavicle end.
- Rockwood VI: Dislocation of the lateral collarbone end under the coracoid at the foot.
