The shoulder, the most movable joint in your body, allows you to move your arm in multiple directions.  When your upper arm bone, as a result of a sudden traumatic direct injury or repeated overuse, is forced out of your shoulder socket, it results in shoulder dislocation.

After several dislocations your shoulder becomes weak and you develop a condition called chronic shoulder instability, in which your arm bone becomes prone to popping out of your shoulder socket under littlest pressure.

Anatomy

The upper arm bone (humerus), the shoulder blade (scapula) and the collarbone (clavicle) make up your shoulder.

Shoulder works with the ball and socket movement that is given to it by your upper arm bone fixed into the shallow socket (glenoid) of the shoulder.  The ligament system also called the shoulder capsule helps to balance the upper arm bone into the glenoid centrally. A network of tendons and muscles, further, provides stability to your shoulder.

Explanation

When your shoulder gets dislocated frequently, it results in chronic shoulder instability. This happens because your tendons, ligaments or muscles become weak in holding your arm firmly inside the shoulder socket.  Any work or sports-related strain on your shoulder can cause a dislocation in two ways i.e.-

Partial dislocation- also known as subluxation, it occurs when the humeral head comes partially out of the glenoid.

Complete dislocation- When the humeral head comes completely out of the glenoid, it is known as complete dislocation.   

Causes

The main causes that bring about chronic shoulder instability are-

Shoulder Dislocations

Complete or partial repetitive dislocations of the shoulder may make your shoulder weak. This eventually makes the upper arm bone just hang in the glenoid and come out with minimal pressure and slowly develop a condition called chronic shoulder instability.

Stressful Activities

Work activities that involve repeated use of your shoulder and arm or sports like badminton, swimming, tennis and etc. where overhead movements are relatively high can cause shoulder dislocations. Gradually the ligament system in the shoulder becomes weak and loose. This may result in the shoulder becoming unstable.

Multidirectional Dislocation

Some people have naturally loose ligaments throughout their bodies or are double-jointed. When their shoulder is prone to dislocation because of this, the ball of their upper arm bone may come out of their shoulder socket from any direction including front, back, or bottom of their shoulder. This can result in multidirectional instability.

Symptoms

The most common symptoms that you may experience with chronic shoulder instability are-

• Persistent pain
• Frequent shoulder dislocations
• Shoulder seemingly loose and unstable than normal

Diagnosis

The diagnosis of chronic shoulder instability is carried out in two parts i.e. doctor’s examination and imaging tests.

Doctor’s examination- After considering your symptoms, your doctor will go into your medical history. He will physically examine your shoulder to test whether there is any instability in it. He may also look for loose ligaments. One of the specific tasks your doctor may ask you to do is to try and have you touch your thumb to the underside of your forearm.

Imaging tests- Besides the physical assessment, your doctor may ask you to undergo a few diagnostic tests that include:

X-ray- Even though they do not show any soft tissues inside the shoulder, x-rays help your doctor to see if there are any bone injuries in your shoulder.

 MRI- Magnetic Resonance Imaging helps the doctor to determine a tear in your ligaments or tendons.

Treatment

Treatment for your chronic shoulder instability depends on how grave your condition is. Your doctor may initiate your treatment with nonsurgical techniques and if your pain and instability do not reduce, they may recommend surgical intervention.

Non-Surgical Treatment Techniques 

Your doctor will begin your treatment with nonsurgical techniques and wait for a specific time period to assess their effect. The treatment techniques may include-

NSAIDs- Your doctor may give you some non-steroidal anti-inflammatory medicines to reduce your pain and swelling.

Therapy- Your shoulder becomes weak with chronic instability. Your doctor may advise some strengthening exercises for your shoulder.

Routine Changes- There may be some activities in your daily routine that are harmful to the condition. You will be asked to modify your chores or activities so that your shoulder can stay rested.

Surgical Treatment Techniques

If you do not get any relief after nonsurgical treatment, there is a possibility that the ligaments holding your shoulder joint may have sustained a tear or become stretched (Bankart lesion).

In such a case, your surgeon may decide to treat your ligaments surgically with-

Arthroscopy- Your surgeon may repair the damaged soft tissues within your shoulder joint, if they are mild, with an invasive and painless technique called arthroscopy.

Open Surgery- When the tear in the ligament is more severe, it may have to be treated with a lengthier procedure called open surgery.