Chronic Shoulder Dislocations at Higher Risk of Re-dislocating After Surgery

United Arab Emirates, Abu Dhabi - 10 January 2016: Shoulder dislocations, which account for around half of all joint dislocations. Chronic shoulder dislocations are at risk of re-dislocating even after surgery, according to a recent study.

Shoulder dislocations are traumatic and painful injuries, which occur when the head of the humerus bone pops out of the shoulder joint socket (glenoid). They are rarely posterior where the head of the upper arm bone or humerus dislocates out of the back of the joint and more commonly anterior where it pops out forwards.

In most cases, the top of the upper arm bone is forced forwards when the arm is held out to the side and turned outwards. This is known as an anterior shoulder dislocation and happens in around 95 per cent of all injuries. Posterior dislocations, meanwhile, account for around 3 per cent of shoulder dislocations and can occur during epileptic seizures or when falling onto an outstretched hand.

Dr Ali Suwaidi, Consultant - Orthopedic Surgeon with fellowship training in shoulder surgery at Burjeel Hospital Abu Dhabi, explains: “You might get a dislocated shoulder by falling on it, being hit in the shoulder, or by trying to break a fall with your hand. If you think you have dislocated your shoulder and it doesn’t pop back into place of its own accord, it is necessary to consult an orthopedic specialist who is trained in diagnosing and treating such conditions.”

A recent study by the Journal of Orthopedic Surgery and Research found that, following surgery, re-dislocation occurred in nine out of 102 shoulders (8.8 per cent), of which seven sustained re-injuries within the first year. Of the remaining 93 shoulders without re-dislocation, eight had re-injury under the same conditions within the first year.

Dr Suwaidi adds: “Most shoulder dislocations cause tears to the glenoid labrum, which is a ring of cartilage that acts as a cup in which the humerus bone rests. There is likely to be damage to the surrounding bone , ligaments, tendons and nerves. The cup may fracture with the dislocation along with labrum attachment”.

“The shoulder is one of the most mobile joints in the body and it is capable of moving and twisting in many directions. The glenoid cavity is small in relation to the head of the humerus. Muscles, ligaments, and the bony anatomy of the shoulder all work together to maintain shoulder stability and prevent dislocation.

“Dislocation can occur when any of these structures are injured or altered in any way. Unfortunately the shoulder’s mobility can be a weakness and the risks of damaging the same area again following surgery mean that it is especially important that sufficient shoulder rehabilitation is done.”

Treatment for a dislocated shoulder depends on the severity of the injury. Usually a method called closed reduction is used to get the shoulder bone back in place. This treatment method involves performing a series of arm and shoulder maneuvers until the bones are properly aligned.

Some shoulder dislocations require surgery if it is a recurring condition and there are weak ligaments.

Studies showed that Age of dislocation is important where 20 years and younger have almost 100% risk of redislocations .

“The main goal of surgery is to repair the labrum and ligaments in order to provide stability to the shoulder,” explains Dr Suwaidi.

“Restoring normal motion and function and preventing recurrent dislocations are important outcomes of surgical intervention.”

There are many different ways to repair a chronically unstable shoulder following a first dislocation or after many recurrent shoulder dislocations. The direction of instability (anterior, posterior, inferior, or some combination) is taken into consideration when choosing the best reconstructive technique. The  type and number of episodes dislocation in addition to cup bone damage are major determining factors in how the surgeon approaches the repair.

One of the most common procedures is the Bankart operation. During the Bankart reconstruction procedure, the labrum and capsule are reattached to the anterior margin of the glenoid cavity.
Shoulder reconstruction surgery may be done with an open incision method or with the aid of an arthroscope. Current studies shows equal results with both methods but less damage to surrounding muscles , better cosmesis and quicker rehabilitation has been reported with Arthroscopic techniques.

Incisions of 1 cm  are usually still required with arthroscopic technique, but the surgery doesn't require the surgeon to open the joint. An arthroscope is used to view the inside of the shoulder joint as the surgeon performs the work.