What is shoulder instability?
Shoulder instability is a problem that occurs when the structures that surround the shoulder joint do not work to keep the ball tightly within its socket. If the joint is too loose, it may slide partially out of place, a condition called shoulder subluxation. If the joint comes completely out of place, this is called a shoulder dislocation. Patients with shoulder instability often complain of an uncomfortable sensation that their shoulder may be about to shift out of place–this is what physicians call “apprehension.”
Shoulder instability tends to occur in three groups of people:
- Prior Shoulder Dislocators
Patients who have sustained a prior shoulder dislocation often develop chronic instability. In these patients, the ligaments that support the shoulder are torn when the dislocation occurs. If these ligaments heal too loosely, then the shoulder will be prone to repeat dislocation and episodes of instability. When younger patients (less than about 35 years old) sustain a traumatic dislocation, shoulder instability will follow in about 80% of patients.
- Young Athletes
Athletes who compete in sports that involve overhead activities may have a loose shoulder or multidirectional instability (MDI). These athletes, such as volleyball players, swimmers, and baseball pitchers, stretch out the shoulder capsule and ligaments, and may develop chronic shoulder instability. While they may not completely dislocate the joint, the apprehension, or feeling of being about to dislocate, may prevent their ability to play these sports.
- “Double-Jointed” Patients
Patients with some connective tissue disorders may have loose shoulder joints. In patients who have a condition that causes joint laxity, or double-jointedness, their joints may be too loose throughout their body. This can lead to shoulder instability and even dislocations.
Shoulder Instability Treatment
Treatment of shoulder instability depends on which condition is causing the shoulder to come out of joint. Most patients with multi-directional instability will be successfully treated with a focused physical therapy program to strengthen the muscles that help to hold the shoulder in position. In some patients with MDI, when prolonged therapy has been unsuccessful, there are surgical options to tighten the shoulder capsule to help reduce the amount of mobility of the joint.
Patients who have sustained a traumatic dislocation of the shoulder have usually torn one of the structures that holds the shoulder in proper position. In younger patients (under age 30), the shoulder labrum is usually torn, called a Bankart tear. In these situations, the labrum is usually surgically repaired, called a Bankart repair.
Patients over the age of 30 have a higher chance of tearing their rotator cuff, rather than the Bankart tear, when they dislocate their shoulder. In these situations, therapy may be considered for treatment of the rotator cuff tear, or rotator cuff surgery.