Dislocated Shoulder Injury

A dislocated shoulder is a common shoulder injury in contact sports such as cricket,football,basketball and martial arts.in our country it is also frequently seen after road traffic accident (RTA).A dislocated shoulder is characterised by severe shoulder pain and hospital treatment is required to restore normal shoulder anatomy.The shoulder is a ball-and-socket joint that has a large range of movement but not a lot of stability, which makes the shoulder joint prone to dislocation. The shoulder is particularly unstable when it is rotated outwards and the arm cocked back or 'abducted'. Any additional force in this position will cause the head of the Humerus (arm) bone to come out of the joint in a forward direction. This is referred to as an anterior dislocation.

             

The shoulder joint is enclosed by a fibrous capsule which is strengthened by ligaments that provide a reinforced thickening of the capsule. The joint also has a labrum - a fibrocartilage lip that increases the stability of the joint. In the case of a dislocation due to trauma (such as a fall or collision), the joint capsule and ligaments are usually torn, and the labrum may also be damaged.


What is a dislocated shoulder?

The arm is normally held in the shoulder socket by the soft tissue capsule which fits over the joint like a socket.It is also held together and stabilised by fibrous ligaments that lie within the capsule, by the muscles and tendons that rotate the arm.
          

Instability is usually defined as a clinical syndrome which occurs when a shoulder is loose enough to produce symptoms. It can refer to either outright dislocation where the upper arm bone comes out of the socket or to a more subtle slipping of the humeral head within the socket, a condition known as subluxation.

What causes the shoulder to dislocate?
Shoulders can dislocate when a strong force, such as a traumatic injury, abnormally stretches the ligaments and tendons, causing the ball-shaped end of the humerus to pop out of its socket. A minority of people have shoulders that can sublux or even dislocate spontaneously. However, almost 95% of shoulder dislocations result from either a forceful collision or from a sudden wrenching movement as may occur during sport, from falling onto an outstretched arm, and from motor vehicle collision. In my case, I fell from a bicycle onto my arm after a slight bump from a passing car that came too close.

How does it feel to have a dislocated shoulder?

Unless you have already experienced dislocation, you instinctively know that something is wrong with your shoulder but are not sure what has actually happened to it. I immediately knew I couldn't move my right arm and wanted to support it in front of me. I thought that I might have a broken bone but could see not see any evidence of that. For me, the pain was relatively mild as long as I held my arm still. Some people apparently have much more pain than I experienced during the period when their shoulder is still out-of-joint. Bruising, swelling, weakness, tingling,numbness and/or loss of sensation typically occur.
Dislocated Shoulder Signs & Symptoms
The most obvious symptom is shoulder pain. A person with a dislocated shoulder will be unable to move the affected shoulder and will hold the arm protectively against the chest. The normal rounded appearance of the shoulder will be replaced by a more squared-off edge because the head of the Humerus bone drops downwards. If a dislocation is suspected, an x-ray should be taken to confirm the damage.
Common dislocated shoulder symptoms:
• The most obvious symptom is shoulder pain.
• Loss of shoulder movement.
• Holding the arm protectively against the chest.
• The normal rounded appearance of the shoulder will be replaced by a more squared-off edge.

Dislocated Shoulder Treatment
What you can do?
Consult a sports injury expert
Apply ice packs/cold therapy to relieve pain & reduce bleeding
Wear a shoulder support for reassurance

It is important that a shoulder dislocation is seen quickly by a doctor who can put the joint back in place. This is because the position of the Humerus in a dislocated shoulder joint can cause damage to the Axillary nerve. This can lead to a loss of sensation and muscle strength in the affected arm. Pain relieving medication prescribed by a doctor can help to relieve the shoulder pain.
Ice packs can be applied to the injured shoulder for 20 minutes every two hours (never apply ice directly to the skin). The ice packs relieve pain and reduce bleeding in the damaged tissue.
Once the shoulder has been put back in place it is immobilised using a sling. The sling is kept on for about 2 to 3 weeks, during which time it is important that the elbow, wrist and fingers are kept moving to prevent them stiffening up.
Active rehabilitation is started as soon as possible but overhead arm movement and sporting activity should be avoided for at least 6 weeks. Gentle range of movement exercises under the supervision of a Physiotherapist can be started once the sling is removed. Strengthening exercises for the Rotator Cuff muscles should be started as soon as they can be done without pain..
Because of the damage to the structures surrounding the shoulder, there is a high chance of recurrent dislocation. Surgery on an unstable shoulder is usually required after four dislocations.

Dislocated Shoulder Prevention
Once there has been a dislocation of the shoulder, the joint will have a degree of instability and will be more likely to dislocate again, or become subluxed (where it moves slightly but not fully out of joint). This is because the ligaments, capsule and labrum are damaged and cannot restrain the humeral head and prevent dislocation. In order to prevent dislocation, the Rotator Cuff muscles that surround the humeral head should be strengthened.
The Rotator Cuff muscles (Subscapularis, Supraspinatus, Infraspinatus and Teres minor) are small muscles situated around the shoulder joint. Although they have individual actions, their main role is to work together to stabilise the humeral head (ball) in the shoulder socket. Exercises using a resistance band can be very effective at strengthening the Rotator Cuff and maintaining shoulder stability.

Clinical Evaluation of Unstable Shoulders
The diagnosis is largely based on the history. The main points that the physician will ask you are:
1. What symptoms do you have and how long have you had them?
2. What forces were involved in the original injury (if there was one)? What was the direction and the magnitude of the forces involved, and where did they have contact with your body? For example, were you hit at high speed front-on by a car, did your shoulder impact with the steering wheel, or did you fall onto your outstretched arm while walking, running, skating, or cycling?
3. How long was your shoulder out of place before it was put back into place?
4. Did you shoulder go back into place by itself or was it put back into place by someone?
5. Did you have numbness or tingling in your arm after you were injured?
6. Did the injury occur at work?
7. What body positions or activities cause or exacerbate pain and other symptoms?
8. Is this a recurrence of symptoms or of a previous injury? If so, were the forces involved similar or was less force required to produce similar symptoms?
9. Has your shoulder problem affected your daily living skills, sporting performance, training, etc.?
10. How many other times have you had shoulder injury?

Clinical Tests for Shoulder Instability

A physical examination aids the physician in determining the precise cause of the symptoms. It is important to realise that if a shoulder is sore or uncomfortable when moved then the physician may not be able to fully examine it, making the diagnosis more difficult.
There are two basic types of tests for shoulder instability. (1) Laxity examinations aim to determine how loose the ligaments are that stabilise the shoulder. These tests are usually painless. (2) Provocative examinations provoke symptoms in the shoulder by stressing it in ways which let the physician know that the shoulder being tested is damaged.


                                  



Laxity Tests
Load and Shift Test: This test is used to determine how loose the shoulder ligaments are. There are several variations of this test in use. One of the most common one involves having the patient lie flat on the back so that the centre of the shoulder blade is on the edge of the bed (Fig. 5a). The physician holds the arm out at 90o from the side to see how much movement there is in the shoulder joint in the anterior direction (towards the front of the body) and the posterior direction (towards the back). The distance the arm can be moved in this position can be scored for a rough indication of the shoulder's stability or instability

Grade 0:	Little/no movement
Grade 1:	Shift to edge of glenoid
Grade 2:	hift over edge of glenoid, spontaneously relocates
Grade 3:	Shift over edge of glenoid doesn't spontaneously relocate

 
1 Sulcus Sign
2 Provocative Tests
3 Apprehension test
4 Relocation test

Non-surgical Management of the Unstable Shoulder
Usually, the doctor or general practitioner will recommend resting your injured shoulder and applying ice packs 3-4 times daily. A sling may or may not be recommended because experimental trials have shown that there is no difference in re-dislocation rates between patients allowed normal movement and others whose arm was immobilised in a sling or some other device for 3-4 weeks.
Your doctor may suggest some gentle exercises to gradually increase the shoulder's range of motion. These start with passive movements where the arm is moved by another person, progressing to active-assisted, and then to active movements made by the patient alone. Rehabilitation is best if based on the principle of progressive resistance and avoidance of aggravating factors.
After the pain and swelling are under control, the doctor may give you a program to strengthen your shoulder. The reported success rates of shoulder strengthening protocols for the management of multidirectional instability are better than those reported for unidirectional instability.





6. Non-surgical Management of the Unstable Shoulder

Usually, the doctor or general practitioner will recommend resting your injured shoulder and applying ice packs 3-4 times daily. A sling may or may not be recommended because experimental trials have shown that there is no difference in re-dislocation rates between patients allowed normal movement and others whose arm was immobilised in a sling or some other device for 3-4 weeks.
Your doctor may suggest some gentle exercises to gradually increase the shoulder's range of motion. These start with passive movements where the arm is moved by another person, progressing to active-assisted, and then to active movements made by the patient alone. Rehabilitation is best if based on the principle of progressive resistance and avoidance of aggravating factors.
After the pain and swelling are under control, the doctor may give you a program to strengthen your shoulder. The reported success rates of shoulder strengthening protocols for the management of multidirectional instability are better than those reported for unidirectional instability.
For recurrent unidirectional instability, non-surgical management based on exercise programs has generally had a poor success rate. Only 12 of 74 people (16%) with recurrent unidirectional shoulder instability had good or excellent results from an exercise program.
Younger patients, who have had surgical treatment following a single episode of anterior shoulder instability, have had much better functional results following an exercise program than others who did not have surgery. In adolescents with unstable shoulders, non-surgical management is insufficient to produce good results. In one study, up to 94% of 10-20 year olds relying on non-surgical management for their unstable shoulder re-dislocated. In another study, virtually all the adolescent patients, having an average age of 13 years, re-dislocated.

7. Physiotherapy for the Unstable Shoulder

Rehabilitation of the unstable shoulder, be it with non-operative or post-operative management, should aim to optimise the performance of the shoulder muscles. When the arm is held out 90o at the side with the palm facing upwards, this is a position where the shoulder is at extreme risk of dislocation if a large force is applied to it (Fig. 7a). The aim for rehabilitation would be to strengthen the muscles which normally help to prevent inadvertent dislocation.
To achieve this, the physiotherapist must consider all parts of the shoulder; in particular, its muscles and tendons, ligaments, and neuromuscular control.
1. Muscles. The rotator muscles of the shoulder, i.e. the rotator cuff, must work together to keep the shoulder still while moving the arm. Weakness affecting the balance of these muscles needs to be identified and corrected from the outset of rehabilitation. This is achieved by various resistance exercises using a "Theraband" (a tough elastic band).
Instability often occurs when the muscles responsible for stability tire. Hence, it is not only important to strengthen these muscles but also to improve endurance (the ability to maintain a contraction over a long period of time).
Two muscles at the back of the shoulder, the trapezius and serratus anterior muscles, are involved in positioning the scapula correctly. Exercises which help to strengthen these muscles are push-ups and rowing. However, all muscles around the scapula should be assessed to ensure their optimal function.
2. Tendon and ligament tension [4]: Tendons (the fibrous tissue which joins muscle to bone) of the rotator cuff muscles blend with the capsule (the tough sack which surrounds the humerus and the glenohumeral joint) at their point of insertion. Upon contraction, the tendons help tighten the slackened capsule together with its built-in ligaments. This tensioning of the capsule helps hold the humeral head in the socket.
Normalising the range of motion, particularly when the capsule is loose, is an important aspect of rehabilitation. In situations of asymmetrical capsular tightness, the humeral head moves excessively in the opposite direction to the tightness. In the athlete who uses his/her arm overhead, posterior capsular tightness is not an uncommon finding. Capsular length can be restored to some extent by specific stretching and mobilising of the joint capsule. Where restoration of capsular length is crucial for preventing/rehabilitating anterior shoulder instability, surgery may be warranted.
3. Neuromuscular control [5]: This is achieved by exercising the unstable shoulder in positions which maximally challenge the shoulder muscles. Messages relating to joint position awareness (proprioception) are fed back to the brain via receptors contained in the capsule and ligaments of the shoulder. When these receptors detect a situation of potential tissue damage, the brain sends a signal to the muscles to contract and thus reposition the joint to decrease the mechanical stress on the surrounding areas.
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To ensure shoulder stability, all parts of the shoulder complex need to be considered. In order to provide a stable platform under the humeral head, the scapula and humerus need to move together and the orientation of the shoulder cavity needs to adjust in response to changes in arm position.
In conclusion, shoulder stability for functional activity is dependent upon a balanced interaction between the shoulder muscles, tendons, ligaments, and nerves. Rehabilitation for the unstable shoulder should focus on more than just a "loose" joint. It should be individualised according to assessment findings and tailored in accordance with the activity demands of the patient.


Surgery for the Unstable Shoulder

                          
In general, shoulder surgery can be done in two fundamentally different ways: using closed surgical techniques (arthroscopy or "keyhole" surgery) or using open surgical techniques. Arthroscopy is a microsurgical technique whereby the surgeon can use an endoscope to look through a small hole into a joint. The endoscope is an instrument, the size of a pen, which essentially consists of a tube containing a light and/or a miniature video camera, which transmits an image of the joint interior to the examiner's eye via a television monitor.

 
Traumatic Unidirectional Instability

Bankart Lesion Repair

Shoulder instability resulting from trauma usually involves a Bankart lesion; i.e., detachment of the anterior part of the labrum from the rim of the glenohumeral cavity (as shown on Fig. 8b). The most recent and successful surgical procedure for unidirectional shoulder instability is an arthroscopic variation of open Bankart repair. In the arthroscopic procedure, the detached part of the labrum and the associated ligaments are reattached to bone along the rim of the glenohumeral cavity through a small "keyhole" incision. This is done with little disruption to the other shoulder structures; e.g., without the need to detach and reattach the overlying subscapularis muscle. Because it is less invasive than open surgery, the arthroscopic procedure tends to preserve the range of movement for external rotation, and to reduce the risk of osteoarthritis. However, 7%-17% of shoulders redislocate if they are repaired using arthroscopic anterior shoulder stabilisation whereas only 5% of unstable shoulders redislocate if repaired using open surgical procedures

          


Arthroscopic techniques for reattaching the labrum to the glenohumeral cavity may use:

1. sutures
2. suture anchors or
3. biodegradable tacks

By way of comparison, an open Bankart repair consists of detaching and later reattaching the humeral insertion of the subscapularis tendon, and also reattaching the labrum to the anterior glenoid cavity with sutures through the bone or with suture anchors. With the open technique, the shoulder loses on the average 12o of external rotation following anterior stabilisation, probably because the subscapularis tendon is shortened after the detachment/reattachment process.

SLAP Lesion Repair

SLAP stands for "Superior Labrum Anterior Posterior". SLAP lesions occur less frequently than Bankart lesions. In SLAP lesions, the labrum detaches from its usual location along the top margin of the shoulder cavity. This detachment is associated with clicking sounds, locking of the shoulder, and/or a feeling that the shoulder is "not right" but it is rarely associated with frank shoulder instability. Best diagnosed by arthroscopy, the labrum can be reattached using an arthroscopically delivered biodegradable tac or suture anchor.
Rotator Interval Closure
Normally there is a small gap between the subscapularis and supraspinatus muscles. In a preliminary study of patients with subluxation, some success was achieved in stabilising the shoulder by closing this gap.

Multidirectional Instability Repair

Anterior Capsular Shift: The most commonly performed and the most successfully reported surgical procedure for tightening the capsule is the anterior capsular shift. This can be used for patients with a large amount of anterior instability but it is particularly useful for patients with multidirectional shoulder instability. For this, slack in the capsule is reduced by making a "T-shaped" cut through the capsule, overlapping the anterior and inferior margins of the cut, and then stitching the overlapped part of the capsule (Fig. 8f).
Capsular Shrinkage: Several studies have shown that heat applied to a loose capsule can cause local shrinkage and, therefore, tightening of the capsule. Heating an area of the shoulder capsule to 65-71o resulted in a shortening of capsule collagen fibres and a 15-40% reduction in capsule size [6]. Arthroscopic devices have been designed to deliver heat to the shoulder capsule so the loose capsule can be shrunk through a small incision. This procedure is still being developed and improved.