Horizontal Instability of the Acromioclavicular Joint: A Systematic Review

Abstract

Background: Injuries to the acromioclavicular (AC) joint are common and should be suspected in patients who have shoulder pain in the region of the acromion and clavicle. Injuries to the AC ligament can cause horizontal instability and are often neglected or underdiagnosed, which can lead to poor patient outcomes. Purpose: To perform a systematic review of the literature on the diagnosis and treatment of horizontal instability of the AC joint. Study Design: Systematic review. Methods: The authors performed a systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and EMBASE were searched for studies that investigated diagnosis, treatment, and failure of operative management of acute and chronic AC separations. Studies that did not specifically evaluate AC joint injuries, were not written in English, or were specific only to vertical instability of the AC joint were excluded. Results: Overall, 23 articles met the inclusion criteria and were therefore included in this systematic review. Diagnosing horizontal AC instability is difficult using plain radiographs; dynamic views were shown in some cases to better detect horizontal instability than with static views. More than 60 procedures for treating AC joint injuries have been published, but many focus on vertical rather than horizontal instability. Modifications to current surgical procedures to incorporate reconstruction of the horizontal component showed improved patient outcomes. Such modifications included additional AC joint suture cord cerclage, combined AC and coracoclavicular ligament reconstruction, and the Twin Tail TightRope triple button technique. Failure after surgical stabilization of AC joint separation has been reported to occur in 15% to 80% of cases. Conclusion: No consensus is available regarding the best practices for diagnosis, evaluation, and treatment of acute or chronic horizontal instability of the AC joint. Moreover, horizontal instability injuries are often neglected or poorly understood, making diagnosis difficult, which may lead to high complication rates and failure after surgical stabilization.

Restoring Horizontal Stability of the Acromioclavicular Joint: Open Acromioclavicular Ligament Reconstruction and Repair With Semitendinosus Allograft

“…There is currently no consensus for the best surgical procedure to treat horizontal instability of the AC joint, and many of the described procedures for AC joint reconstruction focus on treating vertical instability rather than horizontal instability. 12 , 14 The authors present a surgical technique for AC ligament reconstruction with a semitendinosus allograft with primary repair of the AC joint capsule for a type II AC joint separation with horizontal instability. The main advantage of our technique is the restoration of horizontal stability of the AC joint.…”

<p>Optimal Management of Acromioclavicular Dislocation: Current Perspectives</p>

“…In the authors' opinion, future research regarding AC joint dislocations will need to focus on evaluation, diagnosis and treatment of acute and chronic horizontal instability considering there is no consensus to date. 103 Various techniques have been described to address both the AC capsule and ligaments, using different fixation techniques as well as biological augmentation. 90,91,101 In a biomechanical study, Dyrna et al demonstrated that all investigated techniques of AC augmentation significantly improved the stability against translational and rotational loading, however, all tested suture constructs were unable to restore the properties of the native AC capsule and ligaments.…”

Minimum 10-Year Outcomes After Revision Anatomic Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Instability

“…Failure was defined as loss of reduction, leading to chronic scapular or glenohumeral joint dysfunction or pain, upper limb impairment, persistent vertical or horizontal instability of the AC joint, hardware failure, and fractures. 1,28,30,[46][47][48] After the diagnosis of recurrent instability, all patients underwent nonoperative treatment for a minimum of 1 month, which included physical therapy. Exclusion criteria included vulnerable populations (eg, inmates).…”