The shoulder is one of the body’s most mobile joints. It can move in many directions and that flexibility makes it prone to dislocation. Like the hip, it’s a ball and socket joint, so the ball-like end of the upper arm bone fits into the cup-like socket of the shoulder blade. Think of a golf ball sitting delicately on a tee — an apt analogy, says Mass General Brigham Sports Medicine physical therapist Stephanie Boudreau.
“Anatomically, the shoulder is a very vulnerable joint because the socket is shallow,” says Boudreau. Muscles are primary stabilizers of the shoulder joint. However, the muscles more commonly strengthened in the gym environment — biceps, triceps; and pectorals — are not the most important for shoulder stability.
The goal, says Boudreau, is to develop the smaller, accessory muscles whose cumulative job is to stabilize the shoulder. These include the rotator cuff — the muscles and tendons that keep the ball in its socket — and the periscapular muscles that surround the shoulder blade.
What is Shoulder Instability?
Shoulder instability is a general term used to describe when the ball of the shoulder joint partially or completely comes out of the socket. Often, the dislocation happens along with a tear to the labrum, a fibrous tissue attached to the rim of the shoulder socket. Labral tears can also occur without a dislocation. Pitchers, swimmers and other athletes who do repetitive overhead movements are more prone to this type of injury.
Risk Factors for Dislocation
People who dislocate their shoulders tend to fall into two categories. The first are those who experience trauma to the shoulder through a mishap on or off the athletic field. They may have dislocated their shoulder by crashing into a wall during an ice hockey game or falling on the soccer field with an outstretched arm, for example. Mass General Brigham Sports Medicine physical therapist Laura Mattes treats many athletes that are included in this category. Other sports where shoulder dislocations can easily occur include field hockey, lacrosse and gymnastics.
The second group of patients who often are seen in physical therapists’ offices may be predisposed to dislocating their shoulders because they have a connective tissue disorder or they were born with a structural variation. One example is having a shoulder socket that is extremely shallow. These patients may be referred to as “volitional dislocators.” These patients, who tend to be young, have very loose joints that dislocate more frequently and easily.
Shoulder Injury Treatment
After you dislocate a shoulder, if it does not spontaneously relocate/reduce it is recommended to seek medical attention in an emergency room, urgent care setting or a doctor’s office. Often a dislocated shoulder can be treated with physical therapy (PT). Typically, a physical exam and X-rays will be needed to rule out shoulder damage that may ultimately require surgical intervention.
When appropriate, PT enters the picture. Boudreau and Mattes first work with patients to improve their range of motion and then progress to a program which includes strengthening the stabilizing muscles mentioned earlier.
Attaining shoulder stability requires a full-body approach according to Mattes. “We work on core strengthening and teaching patients how this multifactorial approach supports their successful shoulder rehabilitation.” Physical therapists also educate patients about proper positioning of the shoulders, overall body posture, shoulder instability exercises and other ways to prevent dislocation from recurring. A course of PT typically lasts anywhere from 8 to 16 weeks, depending on the case.
What’s important to remember, say Boudreau and Mattes, is that a shoulder dislocation does not mean an athlete has to give up their sport. “We make sure our athletes know they can usually still participate in their chosen sport and PT can help achieve this,” says Boudreau.