Many authours classify the first 21 days after an AC joint injury as the acute injury phase, with symptoms persisting for more than three weeks being classified as chronic. If surgical treatment is performed acutely, some surgeons prefer AC joint stabilization without additional graft augmentation and, in such instances, rely on the healing of the original coracoclavicular (CC) and AC ligaments. While the use of an additional allo- or autograft augmentation is done by some for acute injuries graft use is clearly recommended for surgical stabilization performed more than three weeks after the injury (chronic AC joint injuries). Addressing both the CC and AC ligaments may be important to restore horizontal as well as vertical AC joint stability, independent of the duration between injury and surgical treatment.
The prevalence of concomitant glenohumeral pathologies (CGP) associated with surgically treated AC joint injuries has been described to lie somewhere between 15 and 43%, and several authors have emphasized glenohumeral arthroscopy prior to AC joint stabilization. Most studies with evaluation of CGP have focused on acute AC joint injuries, and some evidence suggests that concomitant lesions may be more common in higher grade injuries. Arrigoni found a significantly higher rate of CGP for older versus younger patients with the cutoff age arbitrarily set at 45 years. Furthermore, the authors observed more CGP in patients with chronic injuries (41%) compared to patients with acute injuries (23%) but this difference was not statistically significant. Despite these previous observations, the probability of missing a CGP if AC joint stabilization surgery is performed without glenohumeral arthroscopy remains unclear for individual patients.