The Diagnosis and Treatment of Acute Dislocation of the Acromioclavicular Joint

Abstract

Background: The acromioclavicular joint (ACJ) is one of the more common sites of shoulder girdle injury, accounting for 4-12% of all such injuries, with an incidence of 3-4 cases per 100 000 persons per year in the general population. Current topics of debate include the proper standard diagnostic evaluation, the indications for surgery, and the best operative method.

Methods: This review is based on publications retrieved by a selective literature search.

Results: Mechanical trauma of the ACG can tear the ligamentous apparatus that holds the acromion, clavicle, and coracoid process together. Different interventions are indicated depending on the nature of the injury. In recent years, the horizontal component of the instability has received more attention, in addition to its vertical component. Persistent instability can lead to chronic, painful limitation of shoulder function, particularly with respect to working above the head. Surgical stabilization is therefore recommended for high-grade instability of Rockwood types IV and V. Modern reconstruction techniques enable selective vertical and horizontal treatment of the instability and have been found superior to traditional methods, particularly in young athletes. Arthroscopic techniques are advantageous because they are less invasive, do not require removal of implanted material, and afford the opportunity to diagnose any accompanying lesions definitively and to treat them if necessary. Surgery for acute injuries should be performed within three weeks of the trauma. For chronic injuries, additional tendon augmentation is now considered standard treatment.

Conclusion: High-grade ACJ instability is a complex and significant injury of the shoulder girdle that can cause persistent pain and functional impairment. The state of the evidence regarding its optimal treatment is weak. Large-scale, prospective, randomized comparative studies are needed in order to define a clear standard of treatment.

Figure 1

Rockwood classification of acute AC joint injury—with reprint permission from [e7] (Reprinted by courtesy of Springer Nature).

Figure 2

Bilateral weight-bearing radiographs: “Water bearer radiographs“ to assess the vertical stability of the acromioclavicular joint

Figure 3

Bilateral weight-bearing Alexander view radiographs to assess the horizontal stability of the acromioclavicular joint

eFigure 1

Postoperative radiograph of a temporary hook plate retention

eFigure 2

Postoperative radiograph of an arthroscopic stabilization using the pulley implant technique