Posted on March 19, 2010 to AOC Physician Articles
Dr. Clayton G. Lane
This football season, I saw a fair number of shoulder separations in my office. It was clear in talking to my patients, that many were not sure exactly what this injury is. Therefore, I think this explanation of the injury and prognosis may be helpful to my patients as well as anyone who has had a shoulder injury from a direct blow.
A shoulder separation is distinctly different than a shoulder dislocation. A shoulder dislocation usually occurs when the arm is hyperextended and the ball of the shoulder pops forward out of the cup, tearing ligaments and the labrum in the process. This is a dislocation of the glenohumeral joint. A shoulder separation, on the other hand, is a dislocation of the acromioclavicular joint or AC joint located on the point of the shoulder. The AC joint is the junction between the clavicle and the acromion which only moves 5-8˚ with full 180˚ motion of the glenohumeral joint. A shoulder separation occurs when one suffers a direct blow to the top of the shoulder. This type of injury can occur during a shoulder tackle in football or more classically in a running back who dives over a pile only to hit the ground directly on the point of the shoulder.
There are several ligaments in the AC joint, and the severity of the injury is determined by which ones are torn and which direction the clavicle dislocates. In low grade injuries, the ligaments are stretched such that there is still sufficient stability of the AC joint. These injuries heal very well with simple rest, compression, anti-inflammatories and progressive range of motion. In more severe injuries, the clavicle completely dislocates and may result in an obvious prominence or bump on the top of the shoulder where the clavicle “tents” the skin. These more severe injuries are more likely to need surgical stabilization. Fortunately, the surgical techniques in sports medicine have evolved such that this injury can usually be treated arthroscopically which is much less invasive than even 10 years ago.
Whether or not surgery is required, the prognosis is very good for isolated shoulder separations. Taken on the whole, an AC separation is a far less significant injury than a shoulder dislocation, therefore I think it’s important to distinguish the two. If this explanation doesn’t clarify the issue, or if you have questions about other orthopedic injuries, try checking my educational “Bonebreak” videos at www.alortho.com.