We’ve just come back from the emergency room where our son had his dislocated shoulder put back in the socket. The ER staff told us just to watch him for a few weeks to make sure it doesn’t dislocate again. What would cause it to dislocate a second time?

Many people dislocate the shoulder one time and seem to recover just fine. But there are others who end up with a chronically dislocating joint. There are a variety of factors that may contribute to this.

Some people are born with greater laxity or looseness of their soft tissues and joints. If they don’t build up the muscles around the joint, they may be at a slightly greater risk of dislocation than someone with more tightly woven soft tissue fibers.

Certain movements may lead to a second dislocation. For example, if the shoulder dislocated anteriorly (forward), then hyperextension combined with abduction and external rotation can pop it out again. This would be the position volleyball or tennis players use to serve the ball.

If the labrum was torn during the first injury, the risk of redislocation goes up. The labrum is the dense fibrocartilage ring that is firmly attached to the shoulder socket.

The labrum provides depth and stability to the joint. Without an intact labrum, the head of the humerus (upper arm bone) can slip out of the socket. Changes in other soft tissues around the shoulder can also contribute to multiple dislocations. And the more times the shoulder dislocates, the greater the damage to the bone, capsule, and ligaments.