The Diagnosis and Treatment of Acute Dislocation of the Acromioclavicular Joint

Abstract

echanical trauma of the acromioclavicular (AC) joint can result in the rupture of the ligament complex extending between the acromion, the clavicle and the coracoid process. Corresponding to the magnitude of the force to the shoulder, the severity of the injury is classified into various grades. Higher-grade injuries with complete rupture of the coracoclavicular ligaments may result in permanent impairment of shoulder function. In addition, the marked bulging of the lateral clavicle compared to the unaffected side occasionally gives rise to esthetic concerns.For decades, the correct diagnosis and management of acute injuries to the AC joint have remained the subject of controversy among orthopedic surgeons and trauma surgeons. Using arthroscopically assisted surgical techniques, today the injury can be treated less invasively.This article presents the current aspects of the diagnosis and treatment of acute instability of the AC joint based on a selective search of the literature. Particular attention was given to high level of evidence studies, to the extent these were available. EpidemiologyAcute dislocation of the AC joint typically occurs in young, athletic adults and is one of the most common injuries of the shoulder girdle (4-12%) (1). Its absolute incidence is approximately 3-4/100 000 population (2). The native stabilizers of the AC joint are frequently damaged during high-risk/high-energy contact sports, such as ice hockey, rugby or handball (3). In alpine skiing, approximately 20% (77/393) of all injuries to the shoulder girdle affect the AC joint (4). Mechanism of injuryIn case of a direct blow to the shoulder girdle, the forces act directly on the AC joint and the acromioclavicular and coracoclavicular (CC) ligaments. By contrast, in case of a fall on an extended arm, the force acts indirectly on the AC joint. Here, the humeral head presses against the acromion; thus, the mechanism is an axial compression. Clinical diagnosis and physical examinationDuring the clinical examination for acute AC joint injury, patients typically present holding their arm adducted to relieve the pain. In addition, there is painful limitation of mobility of the affected shoulder SummaryBackground: 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...

Clavicle Elevation or Shoulder Girdle Depression in Acromioclavicular Joint Dislocation: A Radiological Investigation

“…10 Nevertheless, this explanatory model cannot explain the observed dropping of the shoulder girdle. This phenomenon can most likely be explained by a loss of the bony connection between the scapula and the thorax, analogous to the observations made by Martetschlä ger et al 6 While the scapula can still be sufficiently stabilized in Rockwood III injuries, this seems to be no longer possible in Rockwood V injuries with additional rupture of the deltotrapezial fascia, which leads to a depression of the shoulder girdle. However, by analyzing weightbearing views in Rockwood V AC joint dislocations, an elevation of the clavicle without side-comparative dropping of the shoulder girdle seems to be primarily responsible for the vertical dislocation.…”

“…8 Direct or indirect mechanical trauma to the AC joint can result in ligament rupture with a subsequent instability. 6 Especially in higher-grade AC joint dislocations, persistent impairment of shoulder function can occur. 5 The classification of injury severity and therapy recommendations is essentially based on the degree of vertical and horizontal displacement.…”

“…In contrast, some authors describe a "pseudo-elevation" of the clavicle in which the clavicle retains its position but depression of the shoulder girdle occurs owing to the loss of the bony bridge to the thorax. 6 Increased CC distance is caused by elevation of the distal clavicle, depression of the shoulder girdle, or both. The direction of dislocation is not currently taken into account, nor is it included in current classification systems, which are based on only the increased CC distance.…”

Verletzungen des Akromioklavikulargelenks

“…Als klassischer Unfallmechanismus für die Verletzung des Bandapparats des AC-Gelenks gilt ein Direktsturz auf die Schulter bei adduziertem Arm, bei dem die Kräfte unmittelbar auf das Schultereckgelenk und den akromioklavikulären sowie korakoklavikulären Bandapparat einwirken [13,22]. Die direkte Krafteinwirkung drückt dabei das Akromion nach medial und kaudal unter die Klavikula.…”

“…Ziel der operativen Versorgung ist die anatomische Rekonstruktion und Wiederherstellung der Stabilität des AC-Gelenks in vertikaler sowie horizontaler Ebene. In der Literatur werden verschiedene operative Methoden zur ACG-Stabilisierung beschrieben, als Standardverfahren werden sowohl die arthroskopisch assistierte Bandrekonstruktion als auch die offene Hakenplattenversorgung gesehen [22]. Bei der arthroskopisch assistierten ACG-Stabilisierung werden moderne Double-button-Systeme transklavikulär-transkorakoidal eingebracht, um die korakoklavikulären Bänder zu rekonstruieren und somit die vertikale Stabilität wiederherzustellen [7,22].…”