It is helpful to know the basics of shoulder anatomy in order to understand how these injuries occur. The shoulder complex is made up of three bones: the scapula (shoulder blade), clavicle (collar bone), and humerus (arm bone). The actual shoulder joint is where the scapula and humerus meet and is surrounded by various ligaments, which hold the bones together and limit excessive movement. Overlying this are the muscles, specifically the rotator cuff muscles that surround the joint and stabilize the humerus into the shoulder socket during active use of the arm.
When the shoulder dislocates, the ligaments in the front of the shoulder tear, causing pain and at least some loss of function in the affected arm. Although the ligaments may heal, the result is a shoulder that has even more laxity and instability than prior to the injury. Many athletes and active individuals will experience multiple occurrences of dislocation after the first event due to the increasingly unstable shoulder. Successive dislocations, because of the increased amount of instability in the joint, often take significantly less force to occur. Whereas the first dislocation is usually the result of a traumatic force upon the shoulder, subsequent dislocations could result from ordinary, athletic or heavy use of the arm.
Athletes may experience 2nd and 3rd dislocations with the act of throwing a ball or quickly raising the arm for a jump shot. Another common condition that may exist with shoulder dislocation is a SLAP tear, which is a tear to a structure in the shoulder known as the glenoid labrum. The labrum is a cartilage rim, similar to an O-ring, which covers the outside edge of the shoulder socket. This acts to deepen the socket and give the shoulder some extra stability. But under the extreme force of a shoulder dislocation, the labrum can be torn from the bone, creating a painful injury with reduced motion and strength of the arm.
Labral tears often produce a clicking or popping with shoulder motion, along with apprehension in the overhead ranges. Because these cartilaginous structures do not have a great blood supply, they often do not heal on their own and may require surgical intervention to re-attach the labrum to the bone.
There are many treatment options available for these types of shoulder injuries. Some are non-surgical such as physical therapy, while more extensive injuries may require surgical repair. Be sure to contact an orthopedic specialist that offers both surgical and non-surgical options.