Acromioclavicular (AC) joint separation is a common shoulder injury. When the injury is graded as type III or higher in the Rockwood classification, surgical treatment can be proposed. However, an increasing number of practitioners are shifting back to conservative treatment as it is associated with fewer complications and seemingly close functional outcomes. The aim of our study was to evaluate the functional recovery of operated and non-operated patients with grade III or higher AC joint injuries. Secondarily, the reliability and relevance of the Rockwood classification was evaluated within and between raters.

We did a retrospective two-center study of 38 patients treated between 2014 and 2020. The clinical evaluation involved various functional outcome scores (Constant, QuickDASH, ASES, UCLA, SSV, STT) and a pain assessment (VAS). Return to sports and to work was also documented. The radiological evaluation consisted of Zanca AP and lateral axillary views immediately after the injury and at each radiographic follow-up visit until the final visit. An intra- and inter-rater analysis was also done for the Rockwood classification.

There was no significant difference in the functional scores (Constant score surgery group=91, nonoperative group=83; p=0.09) or the pain on VAS at the final assessment. Return to work and to sports was significantly faster in patients treated non-operatively. No complication was found in the non-operated patients, while nine of the operated patients suffered a complication. The inter-rater reliability of the Rockwood classification was found to be poor (kappa=0.08) to fair (kappa=0.35), while the intra-rater reliability was moderate (kappa=0.6) to good (kappa=0.63).

No matter which treatment is used, the functional outcomes and patient satisfaction level a minimum of 1 year after the injury appear to be identical. Thus, surgery should be only for patients whose AC joint is painful 7 days after the injury (VAS>7) and whose function has not improved. For young and athletic patients or for patients who simply want to regain nearly normal function, it is important to remember that the time to return to work and sports is longer with surgical management and to take into consideration the potential postoperative complications. While none of the patients who received the non-operative treatment required a secondary stabilizing surgery, this is a possible recourse.

III.