What is acromioclavicular joint dislocation?

What is acromioclavicular joint dislocation?

Acromioclavicular joint dislocation refers to a type of shoulder trauma in which the acromioclavicular ligament is damaged, resulting in dislocation of the clavicle. It is a dislocation of the acromioclavicular joint caused by an external force applied to the acromion end, which causes the scapula to move forwards or downwards (or backwards). Below, we will learn about the types and treatments of acromioclavicular joint dislocation.

Acromioclavicular joint dislocations (or separations, injuries) are more common in people who are involved in sports and physical work. An acromioclavicular joint dislocation is a separation of the clavicle from the scapula, and a common feature of this injury is a fall in which the highest point of the shoulder hits the ground or a direct impact of the highest point of the shoulder. Acromioclavicular joint dislocations often occur in football players and cyclists or motorcyclists after a fall.

Types of acromioclavicular joint dislocation  

II°(grade): the acromioclavicular joint is mildly displaced and the acromioclavicular ligament may be stretched or partially torn; this is the most common type of acromioclavicular joint injury.

II° (grade): partial dislocation of the acromioclavicular joint, displacement may not be apparent on examination. Complete tear of the acromioclavicular ligament, no rupture of the rostral clavicular ligament

III° (grade): complete separation of the acromioclavicular joint with complete tear of the acromioclavicular ligament, rostroclavicular ligament and acromioclavicular capsule. As there is no ligament to support or pull, the shoulder joint is sagging due to the weight of the upper arm, the clavicle therefore appears prominent and upturned, and a prominence can be seen in the shoulder.  

The severity of acromioclavicular joint dislocation can also be classified into six types, with types I-III being the most common and types IV-VI being rare. Because of severe damage to the ligaments that support the acromioclavicular region, all type III-VI injuries require surgical treatment.  

How is acromioclavicular dislocation treated?

For patients with acromioclavicular joint dislocation, the appropriate treatment is chosen according to the condition. For patients with mild disease, conservative treatment is feasible. Specifically, for type I acromioclavicular joint dislocation, rest and suspension with a triangular towel for 1 to 2 weeks is sufficient; for type II dislocation, a back strap can be used for immobilisation. Conservative treatment such as shoulder and elbow strap fixation and braking; patients with more serious condition, i.e. patients with type III injury, because their joint capsule and acromioclavicular ligament and rostral clavicular ligament have been ruptured, making the acromioclavicular joint completely unstable need to consider surgical treatment.

Surgical treatment can be divided into four categories: (1) internal fixation of the acromioclavicular joint; (5) rostral lock fixation with ligament reconstruction; (3) resection of the distal clavicle; and (4) power muscle transposition.