Shoulder dislocation means the head of the humerus (the ball) is completely displaced out of the glenoid (the socket). Shoulder subluxation means a ‘partial dislocation’ where the ball only slips out partially out of the joint and slips back into position again.
Why does the shoulder dislocate?
The shoulder is one of the most mobile and least stable of all joints in the body. This makes it the most vulnerable for dislocations or subluxations. The shoulder tends to dislocate repeatedly after the first dislocation. Patients with a tendency for recurrent (repeated) dislocation are said to have an unstable shoulder.
How does the shoulder dislocate?
A shoulder may dislocate after an injury like a fall on an outstretched hand or a direct blow to the shoulder (traumatic dislocation), or without a significant injury (atraumatic dislocation) in loose jointed patients. In patients like throwing athletes, the repetitive action of forceful throwing causes the anterior capsule to stretch out and eventually dislocates or subluxates (microtraumatic dislocation).
Why recurrent shoulder dislocation is a concern / who is at risk?
A person under 21 years of age who has incurred a shoulder dislocation has a 70-90% chance of dislocating the shoulder again during his lifetime. The older a person is when first experiencing a dislocation, the less it will happen again. But every time an older individual dislocates a shoulder, there is a chance of tearing the rotator cuff.
Recurring shoulder dislocation is painful, costly and carries other risks. For every dislocation that takes place, more damage occurs, potentially leading to arthritic issues, and increasing these problems in older arthritic individuals. Continual damage could easily lead to a rotator cuff issue that requires a full surgical repair, or a total shoulder replacement. Thus, it’s becoming more common for younger persons to undergo arthroscopic surgery sooner, rather than more intensive surgery later.
What we can do about recurrent dislocation?
For those who have experienced a shoulder dislocation, surgery is decided on case-by-case basis. Patients and their families are presented with the applicable statistics surrounding the likelihood of a reoccurrence. The treatment options for repeated shoulder dislocations depend on the functional demands of the patient and the level of disability suffered by the patient due to these episodes of instability:
- Conservative (non-surgical) treatment Every patient with shoulder instability may not require surgery. Patients with a sedentary life-style or not involved in strenuous activities / active sports may be able to manage without surgery. However, there is a risk of dislocation or symptomatic instability if the shoulder is placed in a vulnerable position.
- Surgery Most young patients and those involved with any type of active sport are likely to need surgery to stabilise their unstable shoulder. The commonly used surgical options are:
- Arthroscopic Bankart repair (Key-hole surgery) • This is performed through three small holes (portals). The repair involves re-attaching the detached capsulo-labral complex to the glenoid using suture anchors. It is also possible to do a capsular shift (tightening of the lax capsule) at the same time. The technique is minimally invasive, which lessens morbidity of surgery and hospital stay. Arthroscopic capsular shift In some cases ehis is more common in young females. Strengthening of the surrounding muscles may improve it, but should this fail an operation may become necessary. For the cases of ligamentous laxity with instability, the ligaments are tightened using the arthroscopic technique with more emphasis on tightening and reducing the laxity of the ligaments.
- Bony operations • The Latarjet procedure (for bony lesions) If there is bone loss from the edge of the socket, or a large Hill-Sachs lesion (groove in the head of the humerus) the problem becomes more mechanical and the Latarjet procedure needs to be done. The coracoid, a bony outgrowth next to the joint is released and screwed on to the bony defect to fill it. The sling effect of the transferred tendon attached to the coracoid also plays a major role in achieving stability. Overall it will take around 2-3 months after surgery for any patient to return to pre-operation status as far routine day-to-day activities are concerned. (Around 3-4 months for a recreational athlete to return to sports, even longer for professional athletes).
by Dr. Lee Woo Guan