By Dr. Eric W. Edmonds
A shoulder separation is distinct from a shoulder dislocation. Each involves a different joint. There are three joints that make up the shoulder girdle, and they all involve the shoulder blade.
A shoulder dislocation is defined by a disruption of the arm bone from the shoulder blade; whereas, a shoulder separation is an injury to the joint formed by the collarbone (clavicle) and the shoulder blade. The upper front tip of the shoulder blade is called the acromion, and therefore a shoulder separation, also known as an AC separation, involves the acromioclavicular joint.
An AC separation is almost always the result of a sudden, traumatic blow to the shoulder from the side. The two most common causes include a direct force with tackling (often seen in football, rugby or hockey), or a fall directly onto the shoulder (seen after falling off a bicycle or horse). The athlete is usually quite aware of the injury immediately, with pain centered on the AC joint (front upper aspect of the shoulder) and subsequent swelling and even bruising.
The diagnosis of shoulder separation is done with a physician, or other trained medical provider, by correlating the injury, physical examination and often an X-ray. An X-ray can be important to distinguish an AC separation from a clavicle fracture. It is much more common for children to fracture a bone, compared to teenagers that are at greater risk to separate a joint. Occasionally, if the diagnosis is unclear, an X-ray with and without holding a weight in your hand on the affected arm may demonstrate an increased space in the AC joint.
As with all joint dislocations or separations, soft tissue structures such as ligaments must get injured in the process. This ligament injury allows for the separation to occur. In the case of the AC separation, the injured ligaments allow the shoulder blade to fall down with gravity which then gives the appearance of a “raised” collarbone. This creates a bump on the top front of the shoulder. The amount of ligament injury is directly related to the degree of separation in the joint, and AC separations are graded on the amount and direction of separation.
In turn, the treatment for AC separations is dependent on the grade of injury. Both grade I and II injuries can be considered sprains and are therefore treated in a sling for comfort with return to sports after a couple of weeks depending on symptoms.
A grade III AC separation is a more significant injury with an obvious deformity, but treatment is controversial. Many surgeons feel that treatment should involve activity modification and physical therapy; whereas, other surgeons feel that surgery to reconstruct the torn ligaments gives more predictable outcomes. If successful, nonsurgical treatment can allow return to sports after six weeks; in contrast, surgical treatment should not permit contact sport for four to six months.
Most athletes have good success in returning to sports after treatment for these injuries, even if there is residual pain or a slight deformity or bump at the shoulder. Appropriate rehabilitation to restore motion and strength are paramount to giving the injured shoulder time to heal.
To prevent these injuries, it is important to teach kids appropriate technique for tackling and hitting in contact sports. There are also specific methods that can be utilized on a bike to help prevent injury.
You should contact your doctor if your child’s shoulder has pain not improving after two weeks of rest, or if the pain is associated with a fever.
Dr. Eric W. Edmonds is a pediatric and adolescent orthopedic sports medicine specialist at Rady Children’s Hospital-San Diego and an assistant professor of orthopedics at UC San Diego. He can be reached at sports@rchsd.org.