What is shoulder instability?
Shoulder instability is the inability of the shoulder joint to stay in place during normal use of the shoulder. In the x-ray image on the left,
the ball and socket are completely separated in a shoulder dislocation.
Although dislocation of the shoulder is the ultimate example of instability, there are many other types of instability.
Subluxation is a term used to describe a partial dislocation. When the humeral head slides part of the way out of joint, it is a subluxation.
In a normal shoulder, the forces across the joints are centered.
In an unstable joint, the forces are off center and can cause premature wear of the joint, leading to arthritis.
Some patients have ligaments and joint capsules throughout their bodies that are more flexible than others.
These patients are frequently perceived as being ‘double-jointed’. When this extra motion takes place in the shoulder and causes problems,
it is likely that subluxation of the shoulder has occurred. Frequently, a simple activity such as throwing a ball or serving in tennis
can cause pain in these patients. The pain on extreme motion can be an indicator of subtle instability.
Traumatic dislocation of the shoulder is a different type of shoulder problem than hyperlaxity (being double-jointed).
Initial shoulder dislocations are usually due to a violent force applied to the shoulder forcing it out of joint. When this occurs,
the restraining ligaments that support the joint are torn. Sometimes, small fractures and rotator cuff tears can occur as well.
For example: Collisions during football are a common cause of shoulder dislocations. When the shoulder is dislocated, the humeral head (ball)
is forced out of the glenoid (socket) causing damage to ligaments (see illustration on right).
How is an unstable shoulder diagnosed?
When the ligaments that prevent dislocation in a normal shoulder are torn during a dislocation, the majority of the time they do not heal
in the right position. This can lead to involuntary dislocation of the shoulder. Patients can dislocate in their sleep, while working, or
during simple activities such as combing hair, frequently requiring a visit to the emergency room to reduce the dislocation.
When the ligaments are not torn, but stretched as in a subluxing shoulder, the diagnosis can be difficult. Many patients who have a subluxing
shoulder do not know what is occurring in their shoulder when it is painful. A careful history and physical examination is the key to
diagnosis of subtle instability. Sometimes, an MRI or arthrogram (an x-ray test involving dye injection into the shoulder) can be
useful to demonstrate the torn ligaments.
The most common group of patients in Dr. Routman's practice with adhesive capsulitis are perimenopausal females with usually left (non-dominant)
shoulder pain. Diabetics and patients with thyroid disorders are also prone to this condition. Idiopathic Adhesive Capsulitis occurs in
patients with no obvious reason to get the disorder.
How is shoulder instability treated?
Treatment for shoulder instability is based on many factors. The activity level of the patient, the anatomic changes associated with the
specific type of instability, and the frequency of the symptoms are crucial parts of the criteria for non-surgical vs. surgical treatment.
The treatment for instability is highly individualized. Strengthening of the muscles surrounding the rotator cuff and the shoulder
girdle itself through physical therapy is a crucial part of treatment for shoulder instability.
However, should non-surgical treatment fail to improve the patient’s
symptoms operative intervention may be indicated. Operative treatment of shoulder instability is directed at the specific anatomic
alterations that occur when the shoulder is unstable. Bone and soft tissue alterations are addressed either via an arthroscopic or
traditional open procedures when instability is treated surgically.
Take a step toward recovery
If you are experiencing shoulder instability issues, make an appointment to consult with one o our experienced surgeon at the Palm Beach Shoulder Service
within Atlantis Orthopaedics. We will point you in the right direction and get you on your way to recovery.