The shoulder joint may dislocate after a heavy fall, for example in contact sports. Most often the head of the humerus dislocates to the front of the shoulder. Repositioning the joint usually requires strong pain medication or even general anesthesia. However, sometimes the joint may reposition itself. A violent dislocation commonly damages the fibrous ring surrounding the joint cup. The fibrous ring is called the labrum. Tough ligaments, which hold the ball of the joint in place, are attached onto the labrum. When the system is damaged, the stability of the joint fails. The shoulder joint is painful, feels loose, and it may easily dislocate again. A deep dorsal wedge, called a Hill-Sachs lesion, may also form in the joint ball. It may complicate the treatment of shoulder instability.
In first-time cases, the treatment may be conservative. The affected arm should be held in a sling, usually for two weeks in hopes that the structures will heal in place. In the best case scenario, the injured fibrous ring heals back into place and the shoulder remains stable. However, in many cases, the shoulder does not heal without help. With regard to first-time dislocations, the probability of a new dislocation is high. In modern practice, the injured shoulder is examined with an MRI. If there is significant damage in the supporting structures and the shoulder is unstable, operative treatment is recommended.