What is Shoulder Instability?
The shoulder joint is made up of two joint surfaces which are held
together by capsular ligaments and some surrounding musculature. The
shoulder joint itself is not a "ball and socket" joint but
is made up of a large articular ball on one side and a shallow "dish"
on the other. The ball portion of the joint is formed by the upper arm
bone called the humerus and the dish is formed by the outer portion
of the scapula or shoulder blade called the glenoid. These two surfaces
fit smoothly against one another within an outer rim of a "cushioning
cartilage" structure called the labrum at the attachment of the
capsular ligaments to the glenoid. Because of the limited contact surface
between these structures, any loss of the normal integrity of the capsular
ligaments will result in tendency of the joint to slip out of its normal
alignment into an abnormal, incongruent position creating an unstable
Small degrees of damage to the capsule can result from recurrent injuries
to the capsular ligaments or their attachments to either side of the
joint, and may lead to smaller degrees of instability (subluxation).
With larger degrees of capsular ligamentous damage, the joint may become
more unstable resulting in complete dissociation of the two joint surfaces
Signs and Symptoms of Shoulder Instability?
A shoulder which is unstable may subluxate in different provocative
positions, or during certain provocative activities may be associated
with sudden pain, a sense of arm deadness or a perception of the shoulder.slipping
out and back into "joint".
A complete dislocation is associated with severe pain, inability to
"relocate" the joint, and usually requires the aid of a knowledgeable
person to restore the shoulder to its proper alignment. The joint may
dislocate anteriorly (towards the front), inferiorly (downward), or
posteriorly (towards the back).
How is Shoulder Instability Diagnosed?
The diagnosis of shoulder instability is made by the examining physician
after taking a thorough diagnostic history and doing a careful physical
examination. Certain maneuvers the examining physician puts the arm
through may reproduce some of the symptoms of subluxation, presenting
the patient with an uncomfortable feeling that the joint is about to
"slip out". This careful examination differentiates instability
from other sources of shoulder pain. Further details of the degree of
instability may be enhanced through a variety of x-rays and imaging
Common Treatments for Shoulder Instability?
When shoulder instability is diagnosed and there has not been a frank
dislocation, a vigorous rehabilitation program is designed to strengthen
some of the supportive musculature while limiting positioning of the
arm into provocative positions. When the shoulder is exceptionally painful,
a period of rest may be indicated combined with some anti-inflammatory
medication. The rehabilitation program is advanced as the patient makes
progress and the joint demonstrates improved dynamic stability over
time. A first time shoulder dislocation is frequently treated with rest
and immobilization over a period of time followed by progressive rehabilitation,
based on the severity of the injury. When recurrent dislocations occur
or an unstable shoulder fails to respond to conservative management,
surgery may be indicated. A number of surgical techniques exist which
may be employed, depending on the extent and location of the problem
causing the instability. These range from arthroscopic stabilization
techniques to open reconstruction of the joint capsule. Your surgeon
will advise you of the procedure most appropriate for you.
Following surgery, a period of rest and rehabilitation follows over
a period of time designed to return the individual to function, work