Table 1 Rockwood classification system for AC joint injuries
Rockwood classification | Type I | Type II | Type III | Type IV | Type V | Type VI |
|---|---|---|---|---|---|---|
AC ligaments | sprained | disrupted | disrupted | disrupted | disrupted | disrupted |
CC ligaments | intact | sprained | disrupted | disrupted | disrupted | disrupted |
Deltoid and trapezius muscle | intact | intact | detached from clavicle | detached from clavicle | detached from clavicle | detached from clavicle |
Dislocation of the clavicle | none | AC joint widening, CC subluxation | AC joint dislocation, CC interspace 25–100% greater than compared to uninjured side | CC interspace may appear widened, clavicle horizontal unstable with posterior (sub-) luxation | AC joint dislocation, CC interspace more than 100% greater than compared to uninjured side | AC joint dislocation, clavicle displaced inferior to the coracoid |