The Case

A 17 year old dirt bike riding Evel Knievel wannabe presents to the ED with right shoulder pain. He had crashed his bike earlier in the day. On exam he has normal strength and sensation in his hand and forearm, and is able to passively abduct his shoulder. There is no prior history of shoulder injuries. You do what you normally do and obtain XRays, which show the following.


The Diagnosis

This young man has a separation of the acromioclavicular joint – AKA the AC joint.  The most common mechanisms of injury are falls onto the shoulder directly, then the good old FOOSH (fall on outstretched hand). AC injuries can be suspected on exam if there is asymmetry at the location of the joint. In addition, point tenderness at the joint and pain on cross-arm adduction (bring the arm across the body) are both suggestive but not diagnostic. For that you’re going to need X-Rays. vefore we talk about films I thought that it’d be helpful to review the joint itself. As you can see there are 4 ligaments that connect the clavicle to the scapula.

Wikipedia's AC joint picture

Wikipedia’s AC joint picture

Especially in fit patients, their overall muscle tone make make the inherent asymmetry caused by a tear of just one of these ligaments less obvious on conventional shoulder films. That is why you should get weighted films if you suspect an AC injury and your original X-Rays are inconclusive. generally patients are asked to hold 10kg weights in each hand with the arms resting at their sides. The image below is an example of this. Weighted films can be especially helpful in identifying Type III vs Type I-II injures, which brings us to the classification section of this post.


As you can see in the image below there are six types, beginning with a partial tear to the superior acromioclaviclar ligament all the way down to the nastiness depicted in the Type VI injury (ouch).



Let’s take a look at the different types and how they impact management.


Type I

This can be also referred to as just a sprain. Management is conservative and includes rest, antiinflammatories and a sling for comfort. return to play should be guided by symptoms alone.

Type II

A Type II AC separation involves a complete tear to the acromioclavicular ligament, and a partial tear of the coracoclavicular ligaments. This is when you’ll start to see a noticeable “bump” on exam. Patients will be in a lot more pain and have some decreased motion. Most patients with this type of injury still do well with a sling and conservative management.

Type III

Both the acromioclavicular and coracoclavicular ligaments are torn and the result is a very noticeable deformity at the lateral clavicle. If this isn’t addressed the bump is permanent. This is where the management becomes controversial and is best left to the Orthopedists.

A type III separation courtesy of Wikipedia

Type IV

The coracoclavicular ligament is avulsed from the clavicle like in a type III while the distal part of the clavicle becomes displaced posteriorly into or through the trapezius. Skin tenting may occur. The sternoclavicluar joint may also be involved. As one could imaging, surgery is the management de rigeur.

Type V

This is an even worse variation on type III, with the trapezial and deltoid fascia becoming forecfully stripped off of the acromion and clavicle. There is a much more exaggereated vertical displacement of the clavicle from the scapula. Surgery is necessary.

Type VI

It doesn’t get any worse than this. A type VI represents a Type III (Both the acromioclavicular and coracoclavicular ligaments are torn) plus inferior dislocation of the distal end of the clavicle below the coracoid. These are generally seen in severe trauma (think motorcycle crash or MVC) and should prompt investigation for other thoracic and intraabdominal injuries. Many patients will have paresthesias that will only resolve after the clavicle is relocated. Call Ortho and ask nicely for help.

And finally, since most of what we will be doing in the Pediatric Emergency Department I thought I’d summarize conservative management here – which is appropriate for Type I, II and most IIIs.

  • Ice, rest and sling for 3 weeks
  • Rehab with early range of motion exercises
  • Goals: Regain functional motion by 6 weeks and return to normal by 12 weeks
  • Refer to Orthopedics for any Type III and above