In a proportion of patients the Bankart Bankart's lesion does not heal completely causing the joint to be unstable and vulnerable to further dislocation with lesser injury (trivial trauma) trivial or no injury. It is now well known has been shown that the younger the patient at the time of first dislocation (age less than 25 years), higher is the chance of a re-dislocation. The chance of shoulder re-dislocating after the first dislocation can be as high as 70-90% in a young patient (below 25 yrs of age). With each dislocation the capsule in the front gets stretched and thinned out making further dislocations to happen occur with relative ease.
On the other hand, in In patients with an inherent laxity of the joint capsule, the joint is capacious (lax) and is easily dislocated with trivial injury or during activities like throwing or wearing a shirt.
How do you diagnose shoulder instability?
Shoulder instability is diagnosed on the basis of patient's symptoms and physical examination. Shoulder instability could present with history of repeated episodes frank dislocations or as episodes of subluxations (partial dislocations) causing pain or discomfort.
A patient with recurrent dislocating tendency may have suffered a dislocation after an injury, following which repeated dislocations occur with relative ease (without any significant injury).present with a history of more than one episode of dislocation (usually a few) occurring following an episode of "first dislocation" occurring after a significant injury with subsequent dislocations occurring "with ease". Most of these patients are able to reduce (put back the dislocated shoulder) on their own or with some assistance.
Patients with repeated episodes of subluxations will present Some patients may present with pain or discomfort while moving the shoulder without an obvious dislocation. This is due to the shoulder being subluxed (partially dislocated) instead of a complete dislocation. This usually occurs in the throwing position (abduction and external rotation of the arm) in athletes or while doing activities of daily living like putting on a shirt or lifting a heavy object. Physical examination will reveal an otherwise normal shoulder. The only positive finding is the 'apprehension test'. In this test the arm is put in the vulnerable position of abduction and external position. This will cause pain or discomfort and the patient becomes apprehensive that the shoulder will re-dislocate.
In patients with ligament laxity, episodes of dislocation or subluxation will occur without any significant injury. Further, since they have generalized ligament laxity, they may present with symptoms in both shoulders (bilateral dislocations or subluxations). Also these patients may exhibit evidence of laxity (loose-jointed) in the form of repeated patellar (knee cap) dislocations or hyper-extended knees. These patients will also have a positive 'apprehension test' on examination.
Are there any tests which help in diagnosis a patient with shoulder instability?
There are certain tests which may be performed to gain further information and plan out the treatment.
- Plain X-rays: These are helpful only in patients with a frank dislocation where it demonstrates the presence of a dislocated head. In cases with recurrent dislocation certain special views will demonstrate the Hill-Sach's lesion (indentation at the back of the head). Otherwise X-rays are not of much value.
- MRI / MR Arthrography: This will clearly demonstrate the Bankart lesion (which is diagnostic of a recurrent dislocation) as well as the Hill-Sach lesion. In patients with ligament laxity, arthrography reveals a very capacious joint with a lax capsule.
- CT / CT arthrography: This is very useful in demonstrating any bone loss in the glenoid socket. The amount of bone loss in the glenoid will dictate the type of surgical procedure to be performed.
Treatment of shoulder dislocation and instability (Bold print)
What is treatment of a 'First-time dislocation' of the shoulder?
When a shoulder dislocates it must be promptly relocated by closed reduction (manipulating the shoulder without the need for open surgery). This may require a general anaesthetic or some form of sedation. Once the shoulder is relocated, the arm is immobilized by the side of the chest using a shoulder immobilizer type of sling for a period of 3-6 weeks. In very young patients (below the age of 25 years) and high demand athletes, there may be a case need for surgery (Bankart repair) immediately after the first dislocation to prevent the chance of further dislocations as the incidence of recurrent dislocation in these patients is very high.
What is treatment of recurrent dislocation or instability of the shoulder?
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) treatmentEvery patient with shoulder instability may not require surgery. Those patients who have a sedentary life-style and those who are not involved in strenuous activities or active sports may be able to manage without surgery as long as they are able to restrict activities which are likely to cause a dislocation or subluxation. However, there is an ever present risk of dislocation or symptomatic instability occurring at any point in time 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 STABILIZE THEIR UNSTABLE SHOULDER. THE COMMONLY USED SURGICAL OPTIONS ARE:
Arthroscopic Bankart repair (Key-hole surgery)
This is performed through 3 small holes (called portals). The Bankart 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 advantage of the arthroscopic technique is its minimally invasive nature which minimizes morbidity of surgery and hospital stay. Further it allows excellent visualization of the entire shoulder joint and is very useful in detecting and treating other causes of dislocation like an ALPSA lesion as well as associated pathology like a SLAP lesion.