Shoulder instability refers to a range of disorders. Instability can occur when soft tissues like ligaments, capsule, and tendons are damaged around the shoulder joint. The result may be a partial dislocation. This means the head of the humerus (upper arm bone) comes out of the socket but can go back in by itself. This is called a subluxation.

The other end of the spectrum occurs when the shoulder completely dislocates and must be put back in or reduced under anesthesia. Most shoulder instabilities are caused by trauma. If the damaged tissue doesn't heal properly, the shoulder can dislocate many more times.

The treatment for chronic shoulder instability is usually surgery to repair the damage. This operation is done as an outpatient. The doctor puts a tiny lighted telescope and small instruments into the shoulder joint. Small anchors with suture attached are inserted right into the socket of the shoulder. The torn ligaments are reattached to the socket. Complete healing takes about four to six months.